-/* AC3 Audio Decoder.
+/*
+ * AC-3 Audio Decoder
+ * This code is developed as part of Google Summer of Code 2006 Program.
*
* Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com).
+ * Copyright (c) 2007 Justin Ruggles
*
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
+ * Portions of this code are derived from liba52
+ * http://liba52.sourceforge.net
+ * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
+ * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
- * This library is distributed in the hope that it will be useful,
+ * FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
+ * General Public License for more details.
*
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
+ * You should have received a copy of the GNU General Public
+ * License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <stddef.h>
#include <math.h>
-#include <inttypes.h>
#include <string.h>
-#define ALT_BITSTREAM_READER
-
-#include "ac3tab.h"
-#include "ac3.h"
-#include "ac3_decoder.h"
#include "avcodec.h"
+#include "ac3_parser.h"
#include "bitstream.h"
#include "dsputil.h"
-#include "avutil.h"
-#include "common.h"
+#include "random.h"
-#define MAX_CHANNELS 6
-#define BLOCK_SIZE 256
-#define AUDIO_BLOCKS 6
+/**
+ * Table of bin locations for rematrixing bands
+ * reference: Section 7.5.2 Rematrixing : Frequency Band Definitions
+ */
+static const uint8_t rematrix_band_tab[5] = { 13, 25, 37, 61, 253 };
-/* Synchronization information. */
-typedef struct {
- uint16_t sync_word; //synchronization word = always 0x0b77
- uint16_t crc1; //crc for the first 5/8 of the frame
- uint8_t fscod; //sampling rate code
- uint8_t frmsizecod; //frame size code
-
- /* Derived Attributes */
- int sampling_rate; //sampling rate - 48, 44.1 or 32 kHz (value in Hz)
- int bit_rate; //nominal bit rate (value in kbps)
- int framesize; //frame size - 16 bit words
-} ac3_sync_info;
-
-/* flags for the BSI. */
-#define AC3_BSI_LFEON 0x00000001 //low frequency effects channel on
-#define AC3_BSI_COMPRE 0x00000002 //compression exists
-#define AC3_BSI_LANGCODE 0x00000004 //langcode exists
-#define AC3_BSI_AUDPRODIE 0x00000008 //audio production information exists
-#define AC3_BSI_COMPR2E 0x00000010 //compr2 exists
-#define AC3_BSI_LANGCOD2E 0x00000020 //langcod2 exists
-#define AC3_BSI_AUDPRODI2E 0x00000040 //audio production information 2 exists
-#define AC3_BSI_COPYRIGHTB 0x00000080 //copyright
-#define AC3_BSI_ORIGBS 0x00000100 //original bit stream
-#define AC3_BSI_TIMECOD1E 0x00000200 //timecod1 exists
-#define AC3_BSI_TIMECOD2E 0x00000400 //timecod2 exists
-#define AC3_BSI_ADDBSIE 0x00000800 //additional bit stream information exists
-
-/* Bit Stream Information. */
-typedef struct {
- uint32_t flags;
- uint8_t bsid; //bit stream identification
- uint8_t bsmod; //bit stream mode - type of service
- uint8_t acmod; //audio coding mode - which channels are in use
- uint8_t cmixlev; //center mix level
- uint8_t surmixlev; //surround mix level
- uint8_t dsurmod; //dynamic surround encoded
- uint8_t dialnorm; //dialog normalization
- uint8_t compr; //compression gain word
- uint8_t langcod; //language code
- uint8_t mixlevel; //mixing level
- uint8_t roomtyp; //room type
- uint8_t dialnorm2; //dialogue normalization for 1+1 mode
- uint8_t compr2; //compression gain word for 1+1 mode
- uint8_t langcod2; //language code for 1+1 mode
- uint8_t mixlevel2; //mixing level for 1+1 mode
- uint8_t roomtyp2; //room type for 1+1 mode
- uint16_t timecod1; //timecode 1
- uint16_t timecod2; //timecode 2
- uint8_t addbsil; //additional bit stream information length
-
- /* Dervied Attributes */
- int nfchans; //number of full bandwidth channels - derived from acmod
-} ac3_bsi;
-
-/* #defs relevant to Audio Block. */
-#define MAX_FBW_CHANNELS 5 //maximum full bandwidth channels
-#define NUM_LFE_GROUPS 3 //number of LFE Groups
-#define MAX_NUM_SEGS 8 //maximum number of segments per delta bit allocation
-#define NUM_LFE_MANTS 7 //number of lfe mantissas
-#define MAX_CPL_SUBNDS 18 //maximum number of coupling sub bands
-#define MAX_CPL_BNDS 18 //maximum number of coupling bands
-#define MAX_CPL_GRPS 253 //maximum number of coupling groups
-#define MAX_CHNL_GRPS 88 //maximum number of channel groups
-#define MAX_NUM_MANTISSAS 256 //maximum number of mantissas
-
-/* flags for the Audio Block. */
-#define AC3_AB_DYNRNGE 0x00000001 //dynamic range control exists
-#define AC3_AB_DYNRNG2E 0x00000002 //dynamic range control 2 exists
-#define AC3_AB_CPLSTRE 0x00000004 //coupling strategy exists
-#define AC3_AB_CPLINU 0x00000008 //coupling in use
-#define AC3_AB_PHSFLGINU 0x00000010 //phase flag in use
-#define AC3_AB_REMATSTR 0x00000020 //rematrixing required
-#define AC3_AB_LFEEXPSTR 0x00000100 //lfe exponent strategy
-#define AC3_AB_BAIE 0x00000200 //bit allocation information exists
-#define AC3_AB_SNROFFSTE 0x00000400 //SNR offset exists
-#define AC3_AB_CPLLEAKE 0x00000800 //coupling leak initialization exists
-#define AC3_AB_DELTBAIE 0x00001000 //delta bit allocation information exists
-#define AC3_AB_SKIPLE 0x00002000 //skip length exists
-
-/* Exponent strategies. */
-#define AC3_EXPSTR_D15 0x01
-#define AC3_EXPSTR_D25 0x02
-#define AC3_EXPSTR_D45 0x03
-#define AC3_EXPSTR_REUSE 0x00
-
-/* Bit allocation strategies */
-#define AC3_DBASTR_NEW 0x01
-#define AC3_DBASTR_NONE 0x02
-#define AC3_DBASTR_RESERVED 0x03
-#define AC3_DBASTR_REUSE 0x00
-
-/* Audio Block */
-typedef struct {
- uint32_t flags;
- uint8_t blksw; //block switch flags for channels in use
- uint8_t dithflag; //dithering flags for channels in use
- int8_t dynrng; //dynamic range word
- int8_t dynrng2; //dynamic range word for 1+1 mode
- uint8_t chincpl; //channel in coupling flags for channels in use
- uint8_t cplbegf; //coupling begin frequency code
- uint8_t cplendf; //coupling end frequency code
- uint32_t cplbndstrc; //coupling band structure
- uint8_t cplcoe; //coupling co-ordinates exists for the channel in use
- uint32_t phsflg; //phase flag per band
- uint8_t rematflg; //rematrixing flag
- uint8_t cplexpstr; //coupling exponent strategy
- uint8_t chexpstr[5]; //channel exponent strategy
- uint8_t lfeexpstr; //lfe exponent strategy
- uint8_t chbwcod[5]; //channel bandwdith code for channels in use
- uint8_t cplabsexp; //coupling absolute exponent
- uint8_t gainrng[5]; //gain range
- uint8_t sdcycod; //slow decay code
- uint8_t fdcycod; //fast decay code
- uint8_t sgaincod; //slow gain code
- uint8_t dbpbcod; //dB per bit code
- uint8_t floorcod; //masking floor code
- uint8_t csnroffst; //coarse SNR offset
- uint8_t cplfsnroffst; //coupling fine SNR offset
- uint8_t cplfgaincod; //coupling fast gain code
- uint8_t fsnroffst[5]; //fine SNR offset for channels in use
- uint8_t fgaincod[5]; //fast gain code for channels in use
- uint8_t lfefsnroffst; //lfe fine SNR offset
- uint8_t lfefgaincod; //lfe fast gain code
- uint8_t cplfleak; //coupling fast leak initialization value
- uint8_t cplsleak; //coupling slow leak initialization value
- uint8_t cpldeltbae; //coupling delta bit allocation exists
- uint8_t deltbae[5]; //delta bit allocation exists for channels in use
- uint8_t cpldeltnseg; //coupling delta bit allocation number of segments
- uint8_t cpldeltoffst[8]; //coupling delta offset
- uint8_t cpldeltlen[8]; //coupling delta len
- uint8_t cpldeltba[8]; //coupling delta bit allocation
- uint8_t deltnseg[5]; //delta bit allocation number of segments per channel
- uint8_t deltoffst[5][8]; //delta offset for channels in use
- uint8_t deltlen[5][8]; //delta len for channels in use
- uint8_t deltba[5][8]; //delta bit allocation
- uint16_t skipl; //skip length
-
- /* Derived Attributes */
- int ncplsubnd; //number of active coupling sub bands = 3 + cplendf - cplbegf
- int ncplbnd; //derived from ncplsubnd and cplbndstrc
- int ncplgrps; //derived from ncplsubnd, cplexpstr
- int nchgrps[5]; //derived from chexpstr, and cplbegf or chbwcod
- int ncplmant; //derived from ncplsubnd = 12 * ncplsubnd
-
- uint8_t cplstrtmant; //coupling start mantissa
- uint8_t cplendmant; //coupling end mantissa
- uint8_t endmant[5]; //channel end mantissas
-
- uint8_t dcplexps[256]; //decoded coupling exponents
- uint8_t dexps[5][256]; //decoded fbw channel exponents
- uint8_t dlfeexps[256]; //decoded lfe exponents
- uint8_t cplbap[256]; //coupling bit allocation parameters table
- uint8_t bap[5][256]; //fbw channels bit allocation parameters table
- uint8_t lfebap[256]; //lfe bit allocaiton parameters table
-
- DECLARE_ALIGNED_16(float, transform_coeffs[MAX_CHANNELS][BLOCK_SIZE]); //transform coefficients
- DECLARE_ALIGNED_16(float, output[MAX_CHANNELS][BLOCK_SIZE]); //output of the block
- DECLARE_ALIGNED_16(float, delay[MAX_CHANNELS][BLOCK_SIZE]); //delay (for overlap and add)
- DECLARE_ALIGNED_16(float, tmp_imdct[BLOCK_SIZE]); //temporary storage for ff_imdct_calc
- DECLARE_ALIGNED_16(float, tmp_output[BLOCK_SIZE * 2]); //output of ff_imdct_calc
- float cplco[5][18]; //coupling coordinates
- float chcoeffs[6]; //channel coefficients for downmix
-} ac3_audio_block;
-
-
-
-#define AC3_OUTPUT_UNMODIFIED 0x01
-#define AC3_OUTPUT_MONO 0x02
-#define AC3_OUTPUT_STEREO 0x04
-#define AC3_OUTPUT_DOLBY 0x08
-#define AC3_OUTPUT_LFEON 0x10
-
-#define AC3_INPUT_DUALMONO 0x00
-#define AC3_INPUT_MONO 0x01
-#define AC3_INPUT_STEREO 0x02
-#define AC3_INPUT_3F 0x03
-#define AC3_INPUT_2F_1R 0x04
-#define AC3_INPUT_3F_1R 0x05
-#define AC3_INPUT_2F_2R 0x06
-#define AC3_INPUT_3F_2R 0x07
-
-/* BEGIN Mersenne Twister Code. */
-#define N 624
-#define M 397
-#define MATRIX_A 0x9908b0df
-#define UPPER_MASK 0x80000000
-#define LOWER_MASK 0x7fffffff
+/**
+ * table for exponent to scale_factor mapping
+ * scale_factors[i] = 2 ^ -i
+ */
+static float scale_factors[25];
-typedef struct {
- uint32_t mt[N];
- int mti;
-} dither_state;
+/** table for grouping exponents */
+static uint8_t exp_ungroup_tab[128][3];
-static void dither_seed(dither_state *state, uint32_t seed)
-{
- if (seed == 0)
- seed = 0x1f2e3d4c;
- state->mt[0] = seed;
- for (state->mti = 1; state->mti < N; state->mti++)
- state->mt[state->mti] = ((69069 * state->mt[state->mti - 1]) + 1);
-}
+/** tables for ungrouping mantissas */
+static float b1_mantissas[32][3];
+static float b2_mantissas[128][3];
+static float b3_mantissas[8];
+static float b4_mantissas[128][2];
+static float b5_mantissas[16];
-static uint32_t dither_uint32(dither_state *state)
-{
- uint32_t y;
- static const uint32_t mag01[2] = { 0x00, MATRIX_A };
- int kk;
-
- if (state->mti >= N) {
- for (kk = 0; kk < N - M; kk++) {
- y = (state->mt[kk] & UPPER_MASK) | (state->mt[kk + 1] & LOWER_MASK);
- state->mt[kk] = state->mt[kk + M] ^ (y >> 1) ^ mag01[y & 0x01];
- }
- for (;kk < N - 1; kk++) {
- y = (state->mt[kk] & UPPER_MASK) | (state->mt[kk + 1] & LOWER_MASK);
- state->mt[kk] = state->mt[kk + (M - N)] ^ (y >> 1) ^ mag01[y & 0x01];
- }
- y = (state->mt[N - 1] & UPPER_MASK) | (state->mt[0] & LOWER_MASK);
- state->mt[N - 1] = state->mt[M - 1] ^ (y >> 1) ^ mag01[y & 0x01];
+/**
+ * Quantization table: levels for symmetric. bits for asymmetric.
+ * reference: Table 7.18 Mapping of bap to Quantizer
+ */
+static const uint8_t qntztab[16] = {
+ 0, 3, 5, 7, 11, 15,
+ 5, 6, 7, 8, 9, 10, 11, 12, 14, 16
+};
- state->mti = 0;
- }
+/** dynamic range table. converts codes to scale factors. */
+static float dynrng_tab[256];
+
+/** dialogue normalization table */
+static float dialnorm_tab[32];
+
+/** Adjustments in dB gain */
+#define LEVEL_MINUS_3DB 0.7071067811865476
+#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
+#define LEVEL_MINUS_6DB 0.5000000000000000
+#define LEVEL_MINUS_9DB 0.3535533905932738
+#define LEVEL_ZERO 0.0000000000000000
+#define LEVEL_ONE 1.0000000000000000
+
+static const float gain_levels[6] = {
+ LEVEL_ZERO,
+ LEVEL_ONE,
+ LEVEL_MINUS_3DB,
+ LEVEL_MINUS_4POINT5DB,
+ LEVEL_MINUS_6DB,
+ LEVEL_MINUS_9DB
+};
- y = state->mt[state->mti++];
- y ^= (y >> 11);
- y ^= ((y << 7) & 0x9d2c5680);
- y ^= ((y << 15) & 0xefc60000);
- y ^= (y >> 18);
+/**
+ * Table for center mix levels
+ * reference: Section 5.4.2.4 cmixlev
+ */
+static const uint8_t clevs[4] = { 2, 3, 4, 3 };
- return y;
-}
+/**
+ * Table for surround mix levels
+ * reference: Section 5.4.2.5 surmixlev
+ */
+static const uint8_t slevs[4] = { 2, 4, 0, 4 };
-static inline int16_t dither_int16(dither_state *state)
-{
- return ((dither_uint32(state) << 16) >> 16);
-}
+/**
+ * Table for default stereo downmixing coefficients
+ * reference: Section 7.8.2 Downmixing Into Two Channels
+ */
+static const uint8_t ac3_default_coeffs[8][5][2] = {
+ { { 1, 0 }, { 0, 1 }, },
+ { { 2, 2 }, },
+ { { 1, 0 }, { 0, 1 }, },
+ { { 1, 0 }, { 3, 3 }, { 0, 1 }, },
+ { { 1, 0 }, { 0, 1 }, { 4, 4 }, },
+ { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 5, 5 }, },
+ { { 1, 0 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
+ { { 1, 0 }, { 3, 3 }, { 0, 1 }, { 4, 0 }, { 0, 4 }, },
+};
-/* END Mersenne Twister */
+/* override ac3.h to include coupling channel */
+#undef AC3_MAX_CHANNELS
+#define AC3_MAX_CHANNELS 7
+#define CPL_CH 0
+
+#define AC3_OUTPUT_LFEON 8
-/* AC3 Context. */
typedef struct {
- ac3_sync_info sync_info;
- ac3_bsi bsi;
- ac3_audio_block audio_block;
- dither_state state;
- MDCTContext imdct_ctx_256;
- MDCTContext imdct_ctx_512;
- GetBitContext gb;
- int output;
+ int acmod; ///< audio coding mode
+ int dsurmod; ///< dolby surround mode
+ int blksw[AC3_MAX_CHANNELS]; ///< block switch flags
+ int dithflag[AC3_MAX_CHANNELS]; ///< dither flags
+ int dither_all; ///< true if all channels are dithered
+ int cplinu; ///< coupling in use
+ int chincpl[AC3_MAX_CHANNELS]; ///< channel in coupling
+ int phsflginu; ///< phase flags in use
+ int cplbndstrc[18]; ///< coupling band structure
+ int rematstr; ///< rematrixing strategy
+ int nrematbnd; ///< number of rematrixing bands
+ int rematflg[4]; ///< rematrixing flags
+ int expstr[AC3_MAX_CHANNELS]; ///< exponent strategies
+ int snroffst[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets
+ int fgain[AC3_MAX_CHANNELS]; ///< fast gain values (signal-to-mask ratio)
+ int deltbae[AC3_MAX_CHANNELS]; ///< delta bit allocation exists
+ int deltnseg[AC3_MAX_CHANNELS]; ///< number of delta segments
+ uint8_t deltoffst[AC3_MAX_CHANNELS][8]; ///< delta segment offsets
+ uint8_t deltlen[AC3_MAX_CHANNELS][8]; ///< delta segment lengths
+ uint8_t deltba[AC3_MAX_CHANNELS][8]; ///< delta values for each segment
+
+ int sampling_rate; ///< sample frequency, in Hz
+ int bit_rate; ///< stream bit rate, in bits-per-second
+ int frame_size; ///< current frame size, in bytes
+
+ int nchans; ///< number of total channels
+ int nfchans; ///< number of full-bandwidth channels
+ int lfeon; ///< lfe channel in use
+ int lfe_ch; ///< index of LFE channel
+ int output_mode; ///< output channel configuration
+ int out_channels; ///< number of output channels
+
+ float downmix_coeffs[AC3_MAX_CHANNELS][2]; ///< stereo downmix coefficients
+ float dialnorm[2]; ///< dialogue normalization
+ float dynrng[2]; ///< dynamic range
+ float cplco[AC3_MAX_CHANNELS][18]; ///< coupling coordinates
+ int ncplbnd; ///< number of coupling bands
+ int ncplsubnd; ///< number of coupling sub bands
+ int startmant[AC3_MAX_CHANNELS]; ///< start frequency bin
+ int endmant[AC3_MAX_CHANNELS]; ///< end frequency bin
+ AC3BitAllocParameters bit_alloc_params; ///< bit allocation parameters
+
+ int8_t dexps[AC3_MAX_CHANNELS][256]; ///< decoded exponents
+ uint8_t bap[AC3_MAX_CHANNELS][256]; ///< bit allocation pointers
+ int16_t psd[AC3_MAX_CHANNELS][256]; ///< scaled exponents
+ int16_t bndpsd[AC3_MAX_CHANNELS][50]; ///< interpolated exponents
+ int16_t mask[AC3_MAX_CHANNELS][50]; ///< masking curve values
+
+ DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); ///< transform coefficients
+
+ /* For IMDCT. */
+ MDCTContext imdct_512; ///< for 512 sample IMDCT
+ MDCTContext imdct_256; ///< for 256 sample IMDCT
+ DSPContext dsp; ///< for optimization
+ float add_bias; ///< offset for float_to_int16 conversion
+ float mul_bias; ///< scaling for float_to_int16 conversion
+
+ DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS-1][256]); ///< output after imdct transform and windowing
+ DECLARE_ALIGNED_16(short, int_output[AC3_MAX_CHANNELS-1][256]); ///< final 16-bit integer output
+ DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS-1][256]); ///< delay - added to the next block
+ DECLARE_ALIGNED_16(float, tmp_imdct[256]); ///< temporary storage for imdct transform
+ DECLARE_ALIGNED_16(float, tmp_output[512]); ///< temporary storage for output before windowing
+ DECLARE_ALIGNED_16(float, window[256]); ///< window coefficients
+
+ /* Miscellaneous. */
+ GetBitContext gb; ///< bitstream reader
+ AVRandomState dith_state; ///< for dither generation
+ AVCodecContext *avctx; ///< parent context
} AC3DecodeContext;
-static void ac3_common_init1(void)
+/**
+ * Generate a Kaiser-Bessel Derived Window.
+ */
+static void ac3_window_init(float *window)
{
- int i, j, k, l, v;
- /* compute bndtab and masktab from bandsz */
- k = 0;
- l = 0;
- for(i=0;i<50;i++) {
- bndtab[i] = l;
- v = bndsz[i];
- for(j=0;j<v;j++) masktab[k++]=i;
- l += v;
- }
- masktab[253] = masktab[254] = masktab[255] = 0;
- bndtab[50] = 0;
+ int i, j;
+ double sum = 0.0, bessel, tmp;
+ double local_window[256];
+ double alpha2 = (5.0 * M_PI / 256.0) * (5.0 * M_PI / 256.0);
+
+ for (i = 0; i < 256; i++) {
+ tmp = i * (256 - i) * alpha2;
+ bessel = 1.0;
+ for (j = 100; j > 0; j--) /* default to 100 iterations */
+ bessel = bessel * tmp / (j * j) + 1;
+ sum += bessel;
+ local_window[i] = sum;
+ }
+
+ sum++;
+ for (i = 0; i < 256; i++)
+ window[i] = sqrt(local_window[i] / sum);
}
-
-static int ac3_decode_init(AVCodecContext *avctx)
+/**
+ * Symmetrical Dequantization
+ * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
+ * Tables 7.19 to 7.23
+ */
+static inline float
+symmetric_dequant(int code, int levels)
{
- AC3DecodeContext *ctx = avctx->priv_data;
- int i;
-
- ac3_common_init1();
-
- ff_mdct_init(&ctx->imdct_ctx_256, 8, 1);
- ff_mdct_init(&ctx->imdct_ctx_512, 9, 1);
- dither_seed(&ctx->state, 0);
- for (i = 0; i < MAX_CHANNELS; i++)
- memset(ctx->audio_block.delay[i], 0, sizeof(ctx->audio_block.delay[i]));
-
- return 0;
+ return (code - (levels >> 1)) * (2.0f / levels);
}
-static int ac3_synchronize(uint8_t *buf, int buf_size)
+/*
+ * Initialize tables at runtime.
+ */
+static void ac3_tables_init(void)
{
int i;
- for (i = 0; i < buf_size - 1; i++)
- if (buf[i] == 0x0b && buf[i + 1] == 0x77)
- return i;
+ /* generate grouped mantissa tables
+ reference: Section 7.3.5 Ungrouping of Mantissas */
+ for(i=0; i<32; i++) {
+ /* bap=1 mantissas */
+ b1_mantissas[i][0] = symmetric_dequant( i / 9 , 3);
+ b1_mantissas[i][1] = symmetric_dequant((i % 9) / 3, 3);
+ b1_mantissas[i][2] = symmetric_dequant((i % 9) % 3, 3);
+ }
+ for(i=0; i<128; i++) {
+ /* bap=2 mantissas */
+ b2_mantissas[i][0] = symmetric_dequant( i / 25 , 5);
+ b2_mantissas[i][1] = symmetric_dequant((i % 25) / 5, 5);
+ b2_mantissas[i][2] = symmetric_dequant((i % 25) % 5, 5);
+
+ /* bap=4 mantissas */
+ b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
+ b4_mantissas[i][1] = symmetric_dequant(i % 11, 11);
+ }
+ /* generate ungrouped mantissa tables
+ reference: Tables 7.21 and 7.23 */
+ for(i=0; i<7; i++) {
+ /* bap=3 mantissas */
+ b3_mantissas[i] = symmetric_dequant(i, 7);
+ }
+ for(i=0; i<15; i++) {
+ /* bap=5 mantissas */
+ b5_mantissas[i] = symmetric_dequant(i, 15);
+ }
+
+ /* generate dynamic range table
+ reference: Section 7.7.1 Dynamic Range Control */
+ for(i=0; i<256; i++) {
+ int v = (i >> 5) - ((i >> 7) << 3) - 5;
+ dynrng_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
+ }
- return -1;
+ /* generate dialogue normalization table
+ references: Section 5.4.2.8 dialnorm
+ Section 7.6 Dialogue Normalization */
+ for(i=1; i<32; i++) {
+ dialnorm_tab[i] = expf((i-31) * M_LN10 / 20.0f);
+ }
+ dialnorm_tab[0] = dialnorm_tab[31];
+
+ /* generate scale factors for exponents and asymmetrical dequantization
+ reference: Section 7.3.2 Expansion of Mantissas for Asymmetric Quantization */
+ for (i = 0; i < 25; i++)
+ scale_factors[i] = pow(2.0, -i);
+
+ /* generate exponent tables
+ reference: Section 7.1.3 Exponent Decoding */
+ for(i=0; i<128; i++) {
+ exp_ungroup_tab[i][0] = i / 25;
+ exp_ungroup_tab[i][1] = (i % 25) / 5;
+ exp_ungroup_tab[i][2] = (i % 25) % 5;
+ }
}
-//Returns -1 when 'fscod' is not valid;
-static int ac3_parse_sync_info(AC3DecodeContext *ctx)
-{
- ac3_sync_info *sync_info = &ctx->sync_info;
- ac3_bsi *bsi = &ctx->bsi;
- GetBitContext *gb = &ctx->gb;
- sync_info->sync_word = get_bits(gb, 16);
- sync_info->crc1 = get_bits(gb, 16);
- sync_info->fscod = get_bits(gb, 2);
- if (sync_info->fscod == 0x03)
- return 0;
- sync_info->frmsizecod = get_bits(gb, 6);
- if (sync_info->frmsizecod >= 38)
- return 0;
- sync_info->sampling_rate = ac3_freqs[sync_info->fscod];
- sync_info->bit_rate = ac3_bitratetab[sync_info->frmsizecod >> 1];
-
- /* we include it here in order to determine validity of ac3 frame */
- bsi->bsid = get_bits(gb, 5);
- if (bsi->bsid > 0x08)
- return 0;
- bsi->bsmod = get_bits(gb, 3);
-
- switch (sync_info->fscod) {
- case 0x00:
- sync_info->framesize = 4 * sync_info->bit_rate;
- return sync_info->framesize;
- case 0x01:
- sync_info->framesize = 2 * (320 * sync_info->bit_rate / 147 + (sync_info->frmsizecod & 1));
- return sync_info->framesize;
- case 0x02:
- sync_info->framesize = 6 * sync_info->bit_rate;
- return sync_info->framesize;
+/**
+ * AVCodec initialization
+ */
+static int ac3_decode_init(AVCodecContext *avctx)
+{
+ AC3DecodeContext *ctx = avctx->priv_data;
+ ctx->avctx = avctx;
+
+ ac3_common_init();
+ ac3_tables_init();
+ ff_mdct_init(&ctx->imdct_256, 8, 1);
+ ff_mdct_init(&ctx->imdct_512, 9, 1);
+ ac3_window_init(ctx->window);
+ dsputil_init(&ctx->dsp, avctx);
+ av_init_random(0, &ctx->dith_state);
+
+ /* set bias values for float to int16 conversion */
+ if(ctx->dsp.float_to_int16 == ff_float_to_int16_c) {
+ ctx->add_bias = 385.0f;
+ ctx->mul_bias = 1.0f;
+ } else {
+ ctx->add_bias = 0.0f;
+ ctx->mul_bias = 32767.0f;
}
- /* never reached */
return 0;
}
-//Returns -1 when
-static int ac3_parse_bsi(AC3DecodeContext *ctx)
+/**
+ * Parse the 'sync info' and 'bit stream info' from the AC-3 bitstream.
+ * GetBitContext within AC3DecodeContext must point to
+ * start of the synchronized ac3 bitstream.
+ */
+static int ac3_parse_header(AC3DecodeContext *ctx)
{
- ac3_bsi *bsi = &ctx->bsi;
- uint32_t *flags = &bsi->flags;
+ AC3HeaderInfo hdr;
GetBitContext *gb = &ctx->gb;
- int i;
-
- *flags = 0;
- bsi->cmixlev = 0;
- bsi->surmixlev = 0;
- bsi->dsurmod = 0;
- bsi->nfchans = 0;
- ctx->audio_block.cpldeltbae = AC3_DBASTR_NONE;
- ctx->audio_block.cpldeltnseg = 0;
- for (i = 0; i < 5; i++) {
- ctx->audio_block.deltbae[i] = AC3_DBASTR_NONE;
- ctx->audio_block.deltnseg[i] = 0;
+ float cmixlev, surmixlev;
+ int err, i;
+
+ err = ff_ac3_parse_header(gb->buffer, &hdr);
+ if(err)
+ return err;
+
+ /* get decoding parameters from header info */
+ ctx->bit_alloc_params.fscod = hdr.fscod;
+ ctx->acmod = hdr.acmod;
+ cmixlev = gain_levels[clevs[hdr.cmixlev]];
+ surmixlev = gain_levels[slevs[hdr.surmixlev]];
+ ctx->dsurmod = hdr.dsurmod;
+ ctx->lfeon = hdr.lfeon;
+ ctx->bit_alloc_params.halfratecod = hdr.halfratecod;
+ ctx->sampling_rate = hdr.sample_rate;
+ ctx->bit_rate = hdr.bit_rate;
+ ctx->nchans = hdr.channels;
+ ctx->nfchans = ctx->nchans - ctx->lfeon;
+ ctx->lfe_ch = ctx->nfchans + 1;
+ ctx->frame_size = hdr.frame_size;
+
+ /* set default output to all source channels */
+ ctx->out_channels = ctx->nchans;
+ ctx->output_mode = ctx->acmod;
+ if(ctx->lfeon)
+ ctx->output_mode |= AC3_OUTPUT_LFEON;
+
+ /* skip over portion of header which has already been read */
+ skip_bits(gb, 16); // skip the sync_word
+ skip_bits(gb, 16); // skip crc1
+ skip_bits(gb, 8); // skip fscod and frmsizecod
+ skip_bits(gb, 11); // skip bsid, bsmod, and acmod
+ if(ctx->acmod == AC3_ACMOD_STEREO) {
+ skip_bits(gb, 2); // skip dsurmod
+ } else {
+ if((ctx->acmod & 1) && ctx->acmod != AC3_ACMOD_MONO)
+ skip_bits(gb, 2); // skip cmixlev
+ if(ctx->acmod & 4)
+ skip_bits(gb, 2); // skip surmixlev
}
+ skip_bits1(gb); // skip lfeon
- bsi->acmod = get_bits(gb, 3);
- if (bsi->acmod & 0x01 && bsi->acmod != 0x01)
- bsi->cmixlev = get_bits(gb, 2);
- if (bsi->acmod & 0x04)
- bsi->surmixlev = get_bits(gb, 2);
- if (bsi->acmod == 0x02)
- bsi->dsurmod = get_bits(gb, 2);
- if (get_bits1(gb))
- *flags |= AC3_BSI_LFEON;
- bsi->dialnorm = get_bits(gb, 5);
- if (get_bits1(gb)) {
- *flags |= AC3_BSI_COMPRE;
- bsi->compr = get_bits(gb, 8);
- }
- if (get_bits1(gb)) {
- *flags |= AC3_BSI_LANGCODE;
- bsi->langcod = get_bits(gb, 8);
- }
- if (get_bits1(gb)) {
- *flags |= AC3_BSI_AUDPRODIE;
- bsi->mixlevel = get_bits(gb, 5);
- bsi->roomtyp = get_bits(gb, 2);
- }
- if (bsi->acmod == 0x00) {
- bsi->dialnorm2 = get_bits(gb, 5);
- if (get_bits1(gb)) {
- *flags |= AC3_BSI_COMPR2E;
- bsi->compr2 = get_bits(gb, 8);
- }
- if (get_bits1(gb)) {
- *flags |= AC3_BSI_LANGCOD2E;
- bsi->langcod2 = get_bits(gb, 8);
- }
- if (get_bits1(gb)) {
- *flags |= AC3_BSI_AUDPRODIE;
- bsi->mixlevel2 = get_bits(gb, 5);
- bsi->roomtyp2 = get_bits(gb, 2);
- }
- }
+ /* read the rest of the bsi. read twice for dual mono mode. */
+ i = !(ctx->acmod);
+ do {
+ ctx->dialnorm[i] = dialnorm_tab[get_bits(gb, 5)]; // dialogue normalization
+ if (get_bits1(gb))
+ skip_bits(gb, 8); //skip compression
+ if (get_bits1(gb))
+ skip_bits(gb, 8); //skip language code
+ if (get_bits1(gb))
+ skip_bits(gb, 7); //skip audio production information
+ } while (i--);
+
+ skip_bits(gb, 2); //skip copyright bit and original bitstream bit
+
+ /* skip the timecodes (or extra bitstream information for Alternate Syntax)
+ TODO: read & use the xbsi1 downmix levels */
if (get_bits1(gb))
- *flags |= AC3_BSI_COPYRIGHTB;
+ skip_bits(gb, 14); //skip timecode1 / xbsi1
if (get_bits1(gb))
- *flags |= AC3_BSI_ORIGBS;
- if (get_bits1(gb)) {
- *flags |= AC3_BSI_TIMECOD1E;
- bsi->timecod1 = get_bits(gb, 14);
- }
- if (get_bits1(gb)) {
- *flags |= AC3_BSI_TIMECOD2E;
- bsi->timecod2 = get_bits(gb, 14);
- }
+ skip_bits(gb, 14); //skip timecode2 / xbsi2
+
+ /* skip additional bitstream info */
if (get_bits1(gb)) {
- *flags |= AC3_BSI_ADDBSIE;
- bsi->addbsil = get_bits(gb, 6);
+ i = get_bits(gb, 6);
do {
skip_bits(gb, 8);
- } while(bsi->addbsil--);
+ } while(i--);
}
- bsi->nfchans = nfchans_tbl[bsi->acmod];
+ /* set stereo downmixing coefficients
+ reference: Section 7.8.2 Downmixing Into Two Channels */
+ for(i=0; i<ctx->nfchans; i++) {
+ ctx->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[ctx->acmod][i][0]];
+ ctx->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[ctx->acmod][i][1]];
+ }
+ if(ctx->acmod > 1 && ctx->acmod & 1) {
+ ctx->downmix_coeffs[1][0] = ctx->downmix_coeffs[1][1] = cmixlev;
+ }
+ if(ctx->acmod == AC3_ACMOD_2F1R || ctx->acmod == AC3_ACMOD_3F1R) {
+ int nf = ctx->acmod - 2;
+ ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf][1] = surmixlev * LEVEL_MINUS_3DB;
+ }
+ if(ctx->acmod == AC3_ACMOD_2F2R || ctx->acmod == AC3_ACMOD_3F2R) {
+ int nf = ctx->acmod - 4;
+ ctx->downmix_coeffs[nf][0] = ctx->downmix_coeffs[nf+1][1] = surmixlev;
+ }
return 0;
}
- /* Decodes the grouped exponents and stores them
- * in decoded exponents (dexps).
- * The code is derived from liba52.
- * Uses liba52 tables.
+/**
+ * Decode the grouped exponents according to exponent strategy.
+ * reference: Section 7.1.3 Exponent Decoding
*/
-static int decode_exponents(GetBitContext *gb, int expstr, int ngrps, uint8_t absexp, uint8_t *dexps)
+static void decode_exponents(GetBitContext *gb, int expstr, int ngrps,
+ uint8_t absexp, int8_t *dexps)
{
- int exps;
-
- while (ngrps--) {
- exps = get_bits(gb, 7);
-
- absexp += exp_1[exps];
- if (absexp > 24) {
- av_log(NULL, AV_LOG_ERROR, "Absolute Exponent > 24, ngrp = %d\n", ngrps);
- return -ngrps;
- }
- switch (expstr) {
- case AC3_EXPSTR_D45:
- *(dexps++) = absexp;
- *(dexps++) = absexp;
- case AC3_EXPSTR_D25:
- *(dexps++) = absexp;
- case AC3_EXPSTR_D15:
- *(dexps++) = absexp;
- }
-
- absexp += exp_2[exps];
- if (absexp > 24) {
- av_log(NULL, AV_LOG_ERROR, "Absolute Exponent > 24, ngrp = %d\n", ngrps);
- return -ngrps;
- }
- switch (expstr) {
- case AC3_EXPSTR_D45:
- *(dexps++) = absexp;
- *(dexps++) = absexp;
- case AC3_EXPSTR_D25:
- *(dexps++) = absexp;
- case AC3_EXPSTR_D15:
- *(dexps++) = absexp;
- }
-
- absexp += exp_3[exps];
- if (absexp > 24) {
- av_log(NULL, AV_LOG_ERROR, "Absolute Exponent > 24, ngrp = %d\n", ngrps);
- return -ngrps;
- }
- switch (expstr) {
- case AC3_EXPSTR_D45:
- *(dexps++) = absexp;
- *(dexps++) = absexp;
- case AC3_EXPSTR_D25:
- *(dexps++) = absexp;
- case AC3_EXPSTR_D15:
- *(dexps++) = absexp;
- }
+ int i, j, grp, grpsize;
+ int dexp[256];
+ int expacc, prevexp;
+
+ /* unpack groups */
+ grpsize = expstr + (expstr == EXP_D45);
+ for(grp=0,i=0; grp<ngrps; grp++) {
+ expacc = get_bits(gb, 7);
+ dexp[i++] = exp_ungroup_tab[expacc][0];
+ dexp[i++] = exp_ungroup_tab[expacc][1];
+ dexp[i++] = exp_ungroup_tab[expacc][2];
}
- return 0;
-}
-
-static inline int logadd(int a, int b)
-{
- int c = a - b;
- int address;
-
- address = FFMIN(ABS(c) >> 1, 255);
-
- if (c >= 0)
- return (a + latab[address]);
- else
- return (b + latab[address]);
-}
-
-static inline int calc_lowcomp(int a, int b0, int b1, int bin)
-{
- if (bin < 7) {
- if ((b0 + 256) == b1)
- a = 384;
- else if (b0 > b1)
- a = FFMAX(0, a - 64);
- }
- else if (bin < 20) {
- if ((b0 + 256) == b1)
- a = 320;
- else if (b0 > b1)
- a = FFMAX(0, a - 64);
+ /* convert to absolute exps and expand groups */
+ prevexp = absexp;
+ for(i=0; i<ngrps*3; i++) {
+ prevexp = av_clip(prevexp + dexp[i]-2, 0, 24);
+ for(j=0; j<grpsize; j++) {
+ dexps[(i*grpsize)+j] = prevexp;
+ }
}
- else
- a = FFMAX(0, a - 128);
-
- return a;
}
-/* do the bit allocation for chnl.
- * chnl = 0 to 4 - fbw channel
- * chnl = 5 coupling channel
- * chnl = 6 lfe channel
+/**
+ * Generate transform coefficients for each coupled channel in the coupling
+ * range using the coupling coefficients and coupling coordinates.
+ * reference: Section 7.4.3 Coupling Coordinate Format
*/
-static void do_bit_allocation1(AC3DecodeContext *ctx, int chnl)
+static void uncouple_channels(AC3DecodeContext *ctx)
{
- ac3_audio_block *ab = &ctx->audio_block;
- int sdecay, fdecay, sgain, dbknee, floor;
- int lowcomp = 0, fgain = 0, snroffset = 0, fastleak = 0, slowleak = 0;
- int psd[256], bndpsd[50], excite[50], mask[50], delta;
- int start = 0, end = 0, bin = 0, i = 0, j = 0, k = 0, lastbin = 0, bndstrt = 0;
- int bndend = 0, begin = 0, deltnseg = 0, band = 0, seg = 0, address = 0;
- int fscod = ctx->sync_info.fscod;
- uint8_t *exps, *deltoffst = 0, *deltlen = 0, *deltba = 0;
- uint8_t *baps;
- int do_delta = 0;
-
- /* initialization */
- sdecay = sdecaytab[ab->sdcycod];
- fdecay = fdecaytab[ab->fdcycod];
- sgain = sgaintab[ab->sgaincod];
- dbknee = dbkneetab[ab->dbpbcod];
- floor = floortab[ab->floorcod];
-
- if (chnl == 5) {
- start = ab->cplstrtmant;
- end = ab->cplendmant;
- fgain = fgaintab[ab->cplfgaincod];
- snroffset = (((ab->csnroffst - 15) << 4) + ab->cplfsnroffst) << 2;
- fastleak = (ab->cplfleak << 8) + 768;
- slowleak = (ab->cplsleak << 8) + 768;
- exps = ab->dcplexps;
- baps = ab->cplbap;
- if (ab->cpldeltbae == AC3_DBASTR_NEW || ab->cpldeltbae == AC3_DBASTR_REUSE) {
- do_delta = 1;
- deltnseg = ab->cpldeltnseg;
- deltoffst = ab->cpldeltoffst;
- deltlen = ab->cpldeltlen;
- deltba = ab->cpldeltba;
- }
- }
- else if (chnl == 6) {
- start = 0;
- end = 7;
- lowcomp = 0;
- fastleak = 0;
- slowleak = 0;
- fgain = fgaintab[ab->lfefgaincod];
- snroffset = (((ab->csnroffst - 15) << 4) + ab->lfefsnroffst) << 2;
- exps = ab->dlfeexps;
- baps = ab->lfebap;
- }
- else {
- start = 0;
- end = ab->endmant[chnl];
- lowcomp = 0;
- fastleak = 0;
- slowleak = 0;
- fgain = fgaintab[ab->fgaincod[chnl]];
- snroffset = (((ab->csnroffst - 15) << 4) + ab->fsnroffst[chnl]) << 2;
- exps = ab->dexps[chnl];
- baps = ab->bap[chnl];
- if (ab->deltbae[chnl] == AC3_DBASTR_NEW || ab->deltbae[chnl] == AC3_DBASTR_REUSE) {
- do_delta = 1;
- deltnseg = ab->deltnseg[chnl];
- deltoffst = ab->deltoffst[chnl];
- deltlen = ab->deltlen[chnl];
- deltba = ab->deltba[chnl];
- }
- }
-
- for (bin = start; bin < end; bin++) /* exponent mapping into psd */
- psd[bin] = (3072 - ((int)(exps[bin]) << 7));
+ int i, j, ch, bnd, subbnd;
- /* psd integration */
- j = start;
- k = masktab[start];
- do {
- lastbin = FFMIN(bndtab[k] + bndsz[k], end);
- bndpsd[k] = psd[j];
- j++;
- for (i = j; i < lastbin; i++) {
- bndpsd[k] = logadd(bndpsd[k], psd[j]);
- j++;
- }
- k++;
- } while (end > lastbin);
-
- /* compute the excite function */
- bndstrt = masktab[start];
- bndend = masktab[end - 1] + 1;
- if (bndstrt == 0) {
- lowcomp = calc_lowcomp(lowcomp, bndpsd[0], bndpsd[1], 0);
- excite[0] = bndpsd[0] - fgain - lowcomp;
- lowcomp = calc_lowcomp(lowcomp, bndpsd[1], bndpsd[2], 1);
- excite[1] = bndpsd[1] - fgain - lowcomp;
- begin = 7;
- for (bin = 2; bin < 7; bin++) {
- if (!(chnl == 6 && bin == 6))
- lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin + 1], bin);
- fastleak = bndpsd[bin] - fgain;
- slowleak = bndpsd[bin] - sgain;
- excite[bin] = fastleak - lowcomp;
- if (!(chnl == 6 && bin == 6))
- if (bndpsd[bin] <= bndpsd[bin + 1]) {
- begin = bin + 1;
- break;
+ subbnd = -1;
+ i = ctx->startmant[CPL_CH];
+ for(bnd=0; bnd<ctx->ncplbnd; bnd++) {
+ do {
+ subbnd++;
+ for(j=0; j<12; j++) {
+ for(ch=1; ch<=ctx->nfchans; ch++) {
+ if(ctx->chincpl[ch])
+ ctx->transform_coeffs[ch][i] = ctx->transform_coeffs[CPL_CH][i] * ctx->cplco[ch][bnd] * 8.0f;
}
- }
- for (bin = begin; bin < FFMIN(bndend, 22); bin++) {
- if (!(chnl == 6 && bin == 6))
- lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin + 1], bin);
- fastleak -= fdecay;
- fastleak = FFMAX(fastleak, bndpsd[bin] - fgain);
- slowleak -= sdecay;
- slowleak = FFMAX(slowleak, bndpsd[bin] - sgain);
- excite[bin] = FFMAX(fastleak - lowcomp, slowleak);
- }
- begin = 22;
- }
- else {
- begin = bndstrt;
- }
- for (bin = begin; bin < bndend; bin++) {
- fastleak -= fdecay;
- fastleak = FFMAX(fastleak, bndpsd[bin] - fgain);
- slowleak -= sdecay;
- slowleak = FFMAX(slowleak, bndpsd[bin] - sgain);
- excite[bin] = FFMAX(fastleak, slowleak);
- }
-
- /* compute the masking curve */
- for (bin = bndstrt; bin < bndend; bin++) {
- if (bndpsd[bin] < dbknee)
- excite[bin] += ((dbknee - bndpsd[bin]) >> 2);
- mask[bin] = FFMAX(excite[bin], hth[bin][fscod]);
- }
-
- /* apply the delta bit allocation */
- if (do_delta) {
- band = 0;
- for (seg = 0; seg < deltnseg + 1; seg++) {
- band += (int)(deltoffst[seg]);
- if ((int)(deltba[seg]) >= 4)
- delta = ((int)(deltba[seg]) - 3) << 7;
- else
- delta = ((int)(deltba[seg]) - 4) << 7;
- for (k = 0; k < (int)(deltlen[seg]); k++) {
- mask[band] += delta;
- band++;
+ i++;
}
- }
- }
-
- /*compute the bit allocation */
- i = start;
- j = masktab[start];
- do {
- lastbin = FFMIN(bndtab[j] + bndsz[j], end);
- mask[j] -= snroffset;
- mask[j] -= floor;
- if (mask[j] < 0)
- mask[j] = 0;
- mask[j] &= 0x1fe0;
- mask[j] += floor;
- for (k = i; k < lastbin; k++) {
- address = (psd[i] - mask[j]) >> 5;
- address = FFMIN(63, FFMAX(0, address));
- baps[i] = baptab[address];
- i++;
- }
- j++;
- } while (end > lastbin);
-}
-
-static void do_bit_allocation(AC3DecodeContext *ctx, int flags)
-{
- ac3_audio_block *ab = &ctx->audio_block;
- int i, snroffst = 0;
-
- if (!flags) /* bit allocation is not required */
- return;
-
- if (ab->flags & AC3_AB_SNROFFSTE) { /* check whether snroffsts are zero */
- snroffst += ab->csnroffst;
- if (ab->flags & ab->chincpl)
- snroffst += ab->cplfsnroffst;
- for (i = 0; i < ctx->bsi.nfchans; i++)
- snroffst += ab->fsnroffst[i];
- if (ctx->bsi.flags & AC3_BSI_LFEON)
- snroffst += ab->lfefsnroffst;
- if (!snroffst) {
- memset(ab->cplbap, 0, sizeof (ab->cplbap));
- for (i = 0; i < ctx->bsi.nfchans; i++)
- memset(ab->bap[i], 0, sizeof (ab->bap[i]));
- memset(ab->lfebap, 0, sizeof (ab->lfebap));
-
- return;
- }
+ } while(ctx->cplbndstrc[subbnd]);
}
-
- /* perform bit allocation */
- if (ab->chincpl && (flags & 64))
- do_bit_allocation1(ctx, 5);
- for (i = 0; i < ctx->bsi.nfchans; i++)
- if (flags & (1 << i))
- do_bit_allocation1(ctx, i);
- if ((ctx->bsi.flags & AC3_BSI_LFEON) && (flags & 32))
- do_bit_allocation1(ctx, 6);
}
-typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantization */
- uint8_t gcodesl3[3];
- uint8_t gcodesl5[3];
- uint8_t gcodesl11[3];
- int l3ptr;
- int l5ptr;
- int l11ptr;
+/**
+ * Grouped mantissas for 3-level 5-level and 11-level quantization
+ */
+typedef struct {
+ float b1_mant[3];
+ float b2_mant[3];
+ float b4_mant[2];
+ int b1ptr;
+ int b2ptr;
+ int b4ptr;
} mant_groups;
-#define TRANSFORM_COEFF(tc, m, e, f) (tc) = (m) * (f)[(e)]
-
-/* Get the transform coefficients for coupling channel and uncouple channels.
- * The coupling transform coefficients starts at the the cplstrtmant, which is
- * equal to endmant[ch] for fbw channels. Hence we can uncouple channels before
- * getting transform coefficients for the channel.
+/**
+ * Get the transform coefficients for a particular channel
+ * reference: Section 7.3 Quantization and Decoding of Mantissas
*/
-static int get_transform_coeffs_cpling(AC3DecodeContext *ctx, mant_groups *m)
+static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_groups *m)
{
- ac3_audio_block *ab = &ctx->audio_block;
GetBitContext *gb = &ctx->gb;
- int sbnd, bin, ch, index, gcode;
- float cplcos[5], cplcoeff;
- uint8_t *exps = ab->dcplexps;
- uint8_t *bap = ab->cplbap;
-
- for (sbnd = ab->cplbegf; sbnd < ab->cplendf + 3; sbnd++) {
- for (ch = 0; ch < ctx->bsi.nfchans; ch++)
- cplcos[ch] = ab->chcoeffs[ch] * ab->cplco[ch][sbnd];
- for (bin = 0; bin < 12; bin++) {
- index = sbnd * 12 + bin + 37;
- switch(bap[index]) {
- case 0:
- for (ch = 0; ch < ctx->bsi.nfchans; ctx++)
- if (((ab->chincpl) >> ch) & 1) {
- if (((ab->dithflag) >> ch) & 1) {
- TRANSFORM_COEFF(cplcoeff, dither_int16(&ctx->state), exps[index], scale_factors);
- ab->transform_coeffs[ch + 1][index] = cplcoeff * cplcos[ch];
- } else
- ab->transform_coeffs[ch + 1][index] = 0;
- }
- continue;
- case 1:
- if (m->l3ptr > 2) {
- gcode = get_bits(gb, 5);
- if (gcode > 26)
- return -1;
- m->gcodesl3[0] = gcode / 9;
- m->gcodesl3[1] = (gcode % 9) / 3;
- m->gcodesl3[2] = (gcode % 9) % 3;
- m->l3ptr = 0;
- }
- TRANSFORM_COEFF(cplcoeff, l3_q_tab[m->gcodesl3[m->l3ptr++]], exps[index], scale_factors);
- break;
-
- case 2:
- if (m->l5ptr > 2) {
- gcode = get_bits(gb, 7);
- if (gcode > 124)
- return -1;
- m->gcodesl5[0] = gcode / 25;
- m->gcodesl5[1] = (gcode % 25) / 5;
- m->gcodesl5[2] = (gcode % 25) % 5;
- m->l5ptr = 0;
- }
- TRANSFORM_COEFF(cplcoeff, l5_q_tab[m->gcodesl5[m->l5ptr++]], exps[index], scale_factors);
- break;
-
- case 3:
- gcode = get_bits(gb, 3);
- if (gcode > 6)
- return -1;
- TRANSFORM_COEFF(cplcoeff, l7_q_tab[gcode], exps[index], scale_factors);
- break;
-
- case 4:
- if (m->l11ptr > 1) {
- gcode = get_bits(gb, 7);
- if (gcode > 120)
- return -1;
- m->gcodesl11[0] = gcode / 11;
- m->gcodesl11[1] = gcode % 11;
- m->l11ptr = 0;
- }
- TRANSFORM_COEFF(cplcoeff, l11_q_tab[m->gcodesl11[m->l11ptr++]], exps[index], scale_factors);
- break;
-
- case 5:
- gcode = get_bits(gb, 4);
- if (gcode > 14)
- return -1;
- TRANSFORM_COEFF(cplcoeff, l15_q_tab[gcode], exps[index], scale_factors);
- break;
-
- default:
- TRANSFORM_COEFF(cplcoeff, get_bits(gb, qntztab[bap[index]]) << (16 - qntztab[bap[index]]),
- exps[index], scale_factors);
- }
- for (ch = 0; ch < ctx->bsi.nfchans; ch++)
- if (((ab->chincpl) >> ch) & 1)
- ab->transform_coeffs[ch][index] = cplcoeff * cplcos[ch];
- }
- }
+ int i, gcode, tbap, start, end;
+ uint8_t *exps;
+ uint8_t *bap;
+ float *coeffs;
- return 0;
-}
-
-/* Get the transform coefficients for particular channel */
-static int get_transform_coeffs_ch(uint8_t *exps, uint8_t *bap, float chcoeff,
- float *coeffs, int start, int end, int dith_flag, GetBitContext *gb,
- dither_state *state, mant_groups *m)
-{
- int i;
- int gcode;
- float factors[25];
-
- for (i = 0; i < 25; i++)
- factors[i] = scale_factors[i] * chcoeff;
+ exps = ctx->dexps[ch_index];
+ bap = ctx->bap[ch_index];
+ coeffs = ctx->transform_coeffs[ch_index];
+ start = ctx->startmant[ch_index];
+ end = ctx->endmant[ch_index];
for (i = start; i < end; i++) {
- switch (bap[i]) {
+ tbap = bap[i];
+ switch (tbap) {
case 0:
- if (!dith_flag) {
- coeffs[i] = 0;
- continue;
- }
- else {
- TRANSFORM_COEFF(coeffs[i], dither_int16(state), exps[i], factors);
- continue;
- }
+ coeffs[i] = ((av_random(&ctx->dith_state) & 0xFFFF) * LEVEL_MINUS_3DB) / 32768.0f;
+ break;
case 1:
- if (m->l3ptr > 2) {
+ if(m->b1ptr > 2) {
gcode = get_bits(gb, 5);
- if (gcode > 26)
- return -1;
- m->gcodesl3[0] = gcode / 9;
- m->gcodesl3[1] = (gcode % 9) / 3;
- m->gcodesl3[2] = (gcode % 9) % 3;
- m->l3ptr = 0;
+ m->b1_mant[0] = b1_mantissas[gcode][0];
+ m->b1_mant[1] = b1_mantissas[gcode][1];
+ m->b1_mant[2] = b1_mantissas[gcode][2];
+ m->b1ptr = 0;
}
- TRANSFORM_COEFF(coeffs[i], l3_q_tab[m->gcodesl3[m->l3ptr++]], exps[i], factors);
- continue;
+ coeffs[i] = m->b1_mant[m->b1ptr++];
+ break;
case 2:
- if (m->l5ptr > 2) {
+ if(m->b2ptr > 2) {
gcode = get_bits(gb, 7);
- if (gcode > 124)
- return -1;
- m->gcodesl5[0] = gcode / 25;
- m->gcodesl5[1] = (gcode % 25) / 5;
- m->gcodesl5[2] = (gcode % 25) % 5;
- m->l5ptr = 0;
+ m->b2_mant[0] = b2_mantissas[gcode][0];
+ m->b2_mant[1] = b2_mantissas[gcode][1];
+ m->b2_mant[2] = b2_mantissas[gcode][2];
+ m->b2ptr = 0;
}
- TRANSFORM_COEFF(coeffs[i], l5_q_tab[m->gcodesl5[m->l5ptr++]], exps[i], factors);
- continue;
+ coeffs[i] = m->b2_mant[m->b2ptr++];
+ break;
case 3:
- gcode = get_bits(gb, 3);
- if (gcode > 6)
- return -1;
- TRANSFORM_COEFF(coeffs[i], l7_q_tab[gcode], exps[i], factors);
- continue;
+ coeffs[i] = b3_mantissas[get_bits(gb, 3)];
+ break;
case 4:
- if (m->l11ptr > 1) {
+ if(m->b4ptr > 1) {
gcode = get_bits(gb, 7);
- if (gcode > 120)
- return -1;
- m->gcodesl11[0] = gcode / 11;
- m->gcodesl11[1] = gcode % 11;
- m->l11ptr = 0;
+ m->b4_mant[0] = b4_mantissas[gcode][0];
+ m->b4_mant[1] = b4_mantissas[gcode][1];
+ m->b4ptr = 0;
}
- TRANSFORM_COEFF(coeffs[i], l11_q_tab[m->gcodesl11[m->l11ptr++]], exps[i], factors);
- continue;
+ coeffs[i] = m->b4_mant[m->b4ptr++];
+ break;
case 5:
- gcode = get_bits(gb, 4);
- if (gcode > 14)
- return -1;
- TRANSFORM_COEFF(coeffs[i], l15_q_tab[gcode], exps[i], factors);
- continue;
+ coeffs[i] = b5_mantissas[get_bits(gb, 4)];
+ break;
default:
- TRANSFORM_COEFF(coeffs[i], get_bits(gb, qntztab[bap[i]]) << (16 - qntztab[bap[i]]), exps[i], factors);
- continue;
+ /* asymmetric dequantization */
+ coeffs[i] = get_sbits(gb, qntztab[tbap]) * scale_factors[qntztab[tbap]-1];
+ break;
}
+ coeffs[i] *= scale_factors[exps[i]];
}
return 0;
}
+/**
+ * Remove random dithering from coefficients with zero-bit mantissas
+ * reference: Section 7.3.4 Dither for Zero Bit Mantissas (bap=0)
+ */
+static void remove_dithering(AC3DecodeContext *ctx) {
+ int ch, i;
+ int end=0;
+ float *coeffs;
+ uint8_t *bap;
+
+ for(ch=1; ch<=ctx->nfchans; ch++) {
+ if(!ctx->dithflag[ch]) {
+ coeffs = ctx->transform_coeffs[ch];
+ bap = ctx->bap[ch];
+ if(ctx->chincpl[ch])
+ end = ctx->startmant[CPL_CH];
+ else
+ end = ctx->endmant[ch];
+ for(i=0; i<end; i++) {
+ if(bap[i] == 0)
+ coeffs[i] = 0.0f;
+ }
+ if(ctx->chincpl[ch]) {
+ bap = ctx->bap[CPL_CH];
+ for(; i<ctx->endmant[CPL_CH]; i++) {
+ if(bap[i] == 0)
+ coeffs[i] = 0.0f;
+ }
+ }
+ }
+ }
+}
+
+/**
+ * Get the transform coefficients.
+ */
static int get_transform_coeffs(AC3DecodeContext * ctx)
{
- int i, end;
- ac3_audio_block *ab = &ctx->audio_block;
+ int ch, end;
int got_cplchan = 0;
- int dithflag = 0;
mant_groups m;
- m.l3ptr = m.l5ptr = m.l11ptr = 3;
+ m.b1ptr = m.b2ptr = m.b4ptr = 3;
- for (i = 0; i < ctx->bsi.nfchans; i++) {
- dithflag = ab->dithflag & (1 << i);
- /* transform coefficients for individual channel */
- if (get_transform_coeffs_ch(ab->dexps[i], ab->bap[i], ab->chcoeffs[i], ab->transform_coeffs[i + 1],
- 0, ab->endmant[i], dithflag, &ctx->gb, &ctx->state, &m))
+ for (ch = 1; ch <= ctx->nchans; ch++) {
+ /* transform coefficients for full-bandwidth channel */
+ if (get_transform_coeffs_ch(ctx, ch, &m))
return -1;
- /* tranform coefficients for coupling channels */
- if (((ab->chincpl) >> i & 1)) {
+ /* tranform coefficients for coupling channel come right after the
+ coefficients for the first coupled channel*/
+ if (ctx->chincpl[ch]) {
if (!got_cplchan) {
- if (get_transform_coeffs_cpling(ctx, &m))
+ if (get_transform_coeffs_ch(ctx, CPL_CH, &m)) {
+ av_log(ctx->avctx, AV_LOG_ERROR, "error in decoupling channels\n");
return -1;
+ }
+ uncouple_channels(ctx);
got_cplchan = 1;
}
- end = ab->cplendmant;
- } else
- end = ab->endmant[i];
+ end = ctx->endmant[CPL_CH];
+ } else {
+ end = ctx->endmant[ch];
+ }
do
- ab->transform_coeffs[i + 1][end] = 0;
+ ctx->transform_coeffs[ch][end] = 0;
while(++end < 256);
}
- if (ctx->bsi.flags & AC3_BSI_LFEON) {
- if (get_transform_coeffs_ch(ab->dlfeexps, ab->lfebap, 1.0f, ab->transform_coeffs[0], 0, 7, 0, &ctx->gb, &ctx->state, &m))
- return -1;
- for (i = 7; i < 256; i++) {
- ab->transform_coeffs[0][i] = 0;
- }
- }
+
+ /* if any channel doesn't use dithering, zero appropriate coefficients */
+ if(!ctx->dither_all)
+ remove_dithering(ctx);
return 0;
}
-static void do_rematrixing1(AC3DecodeContext *ctx, int start, int end)
+/**
+ * Stereo rematrixing.
+ * reference: Section 7.5.4 Rematrixing : Decoding Technique
+ */
+static void do_rematrixing(AC3DecodeContext *ctx)
{
+ int bnd, i;
+ int end, bndend;
float tmp0, tmp1;
- while (start < end) {
- tmp0 = ctx->audio_block.transform_coeffs[1][start];
- tmp1 = ctx->audio_block.transform_coeffs[2][start];
- ctx->audio_block.transform_coeffs[1][start] = tmp0 + tmp1;
- ctx->audio_block.transform_coeffs[2][start] = tmp0 - tmp1;
- start++;
- }
-}
-
-static void do_rematrixing(AC3DecodeContext *ctx)
-{
- ac3_audio_block *ab = &ctx->audio_block;
- uint8_t bnd1 = 13, bnd2 = 25, bnd3 = 37, bnd4 = 61;
- uint8_t bndend;
-
- bndend = FFMIN(ab->endmant[0], ab->endmant[1]);
- if (ab->rematflg & 1)
- do_rematrixing1(ctx, bnd1, bnd2);
- if (ab->rematflg & 2)
- do_rematrixing1(ctx, bnd2, bnd3);
- if (ab->rematflg & 4) {
- if (ab->cplbegf > 0 && ab->cplbegf <= 2 && (ab->chincpl))
- do_rematrixing1(ctx, bnd3, bndend);
- else {
- do_rematrixing1(ctx, bnd3, bnd4);
- if (ab->rematflg & 8)
- do_rematrixing1(ctx, bnd4, bndend);
- }
- }
-}
+ end = FFMIN(ctx->endmant[1], ctx->endmant[2]);
-static void get_downmix_coeffs(AC3DecodeContext *ctx)
-{
- int from = ctx->bsi.acmod;
- int to = ctx->output;
- float clev = clevs[ctx->bsi.cmixlev];
- float slev = slevs[ctx->bsi.surmixlev];
- ac3_audio_block *ab = &ctx->audio_block;
-
- if (to == AC3_OUTPUT_UNMODIFIED)
- return;
-
- switch (from) {
- case AC3_INPUT_DUALMONO:
- switch (to) {
- case AC3_OUTPUT_MONO:
- case AC3_OUTPUT_STEREO: /* We Assume that sum of both mono channels is requested */
- ab->chcoeffs[0] *= LEVEL_MINUS_6DB;
- ab->chcoeffs[1] *= LEVEL_MINUS_6DB;
- break;
- }
- break;
- case AC3_INPUT_MONO:
- switch (to) {
- case AC3_OUTPUT_STEREO:
- ab->chcoeffs[0] *= LEVEL_MINUS_3DB;
- break;
- }
- break;
- case AC3_INPUT_STEREO:
- switch (to) {
- case AC3_OUTPUT_MONO:
- ab->chcoeffs[0] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[1] *= LEVEL_MINUS_3DB;
- break;
- }
- break;
- case AC3_INPUT_3F:
- switch (to) {
- case AC3_OUTPUT_MONO:
- ab->chcoeffs[0] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[2] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[1] *= clev * LEVEL_PLUS_3DB;
- break;
- case AC3_OUTPUT_STEREO:
- ab->chcoeffs[1] *= clev;
- break;
- }
- break;
- case AC3_INPUT_2F_1R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- ab->chcoeffs[0] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[1] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[2] *= slev * LEVEL_MINUS_3DB;
- break;
- case AC3_OUTPUT_STEREO:
- ab->chcoeffs[2] *= slev * LEVEL_MINUS_3DB;
- break;
- case AC3_OUTPUT_DOLBY:
- ab->chcoeffs[2] *= LEVEL_MINUS_3DB;
- break;
- }
- break;
- case AC3_INPUT_3F_1R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- ab->chcoeffs[0] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[2] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[1] *= clev * LEVEL_PLUS_3DB;
- ab->chcoeffs[3] *= slev * LEVEL_MINUS_3DB;
- break;
- case AC3_OUTPUT_STEREO:
- ab->chcoeffs[1] *= clev;
- ab->chcoeffs[3] *= slev * LEVEL_MINUS_3DB;
- break;
- case AC3_OUTPUT_DOLBY:
- ab->chcoeffs[1] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[3] *= LEVEL_MINUS_3DB;
- break;
+ for(bnd=0; bnd<ctx->nrematbnd; bnd++) {
+ if(ctx->rematflg[bnd]) {
+ bndend = FFMIN(end, rematrix_band_tab[bnd+1]);
+ for(i=rematrix_band_tab[bnd]; i<bndend; i++) {
+ tmp0 = ctx->transform_coeffs[1][i];
+ tmp1 = ctx->transform_coeffs[2][i];
+ ctx->transform_coeffs[1][i] = tmp0 + tmp1;
+ ctx->transform_coeffs[2][i] = tmp0 - tmp1;
}
- break;
- case AC3_INPUT_2F_2R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- ab->chcoeffs[0] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[1] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[2] *= slev * LEVEL_MINUS_3DB;
- ab->chcoeffs[3] *= slev * LEVEL_MINUS_3DB;
- break;
- case AC3_OUTPUT_STEREO:
- ab->chcoeffs[2] *= slev;
- ab->chcoeffs[3] *= slev;
- break;
- case AC3_OUTPUT_DOLBY:
- ab->chcoeffs[2] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[3] *= LEVEL_MINUS_3DB;
- break;
- }
- break;
- case AC3_INPUT_3F_2R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- ab->chcoeffs[0] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[2] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[1] *= clev * LEVEL_PLUS_3DB;
- ab->chcoeffs[3] *= slev * LEVEL_MINUS_3DB;
- ab->chcoeffs[4] *= slev * LEVEL_MINUS_3DB;
- break;
- case AC3_OUTPUT_STEREO:
- ab->chcoeffs[1] *= clev;
- ab->chcoeffs[3] *= slev;
- ab->chcoeffs[4] *= slev;
- break;
- case AC3_OUTPUT_DOLBY:
- ab->chcoeffs[1] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[3] *= LEVEL_MINUS_3DB;
- ab->chcoeffs[4] *= LEVEL_MINUS_3DB;
- break;
- }
- break;
- }
-}
-
-static inline void mix_dualmono_to_mono(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++)
- output[1][i] += output[2][i];
- memset(output[2], 0, sizeof(output[2]));
-}
-
-static inline void mix_dualmono_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float tmp;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++) {
- tmp = output[1][i] + output[2][i];
- output[1][i] = output[2][i] = tmp;
- }
-}
-
-static inline void upmix_mono_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++)
- output[2][i] = output[1][i];
-}
-
-static inline void mix_stereo_to_mono(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++)
- output[1][i] += output[2][i];
- memset(output[2], 0, sizeof(output[2]));
-}
-
-static inline void mix_3f_to_mono(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++)
- output[1][i] += (output[2][i] + output[3][i]);
- memset(output[2], 0, sizeof(output[2]));
- memset(output[3], 0, sizeof(output[3]));
-}
-
-static inline void mix_3f_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++) {
- output[1][i] += output[2][i];
- output[2][i] += output[3][i];
+ }
}
- memset(output[3], 0, sizeof(output[3]));
}
-static inline void mix_2f_1r_to_mono(AC3DecodeContext *ctx)
+/**
+ * Perform the 256-point IMDCT
+ */
+static void do_imdct_256(AC3DecodeContext *ctx, int chindex)
{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++)
- output[1][i] += (output[2][i] + output[3][i]);
- memset(output[2], 0, sizeof(output[2]));
- memset(output[3], 0, sizeof(output[3]));
-
-}
+ int i, k;
+ DECLARE_ALIGNED_16(float, x[128]);
+ FFTComplex z[2][64];
+ float *o_ptr = ctx->tmp_output;
+
+ for(i=0; i<2; i++) {
+ /* de-interleave coefficients */
+ for(k=0; k<128; k++) {
+ x[k] = ctx->transform_coeffs[chindex][2*k+i];
+ }
-static inline void mix_2f_1r_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
+ /* run standard IMDCT */
+ ctx->imdct_256.fft.imdct_calc(&ctx->imdct_256, o_ptr, x, ctx->tmp_imdct);
- for (i = 0; i < 256; i++) {
- output[1][i] += output[2][i];
- output[2][i] += output[3][i];
+ /* reverse the post-rotation & reordering from standard IMDCT */
+ for(k=0; k<32; k++) {
+ z[i][32+k].re = -o_ptr[128+2*k];
+ z[i][32+k].im = -o_ptr[2*k];
+ z[i][31-k].re = o_ptr[2*k+1];
+ z[i][31-k].im = o_ptr[128+2*k+1];
+ }
}
- memset(output[3], 0, sizeof(output[3]));
-}
-static inline void mix_2f_1r_to_dolby(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++) {
- output[1][i] -= output[3][i];
- output[2][i] += output[3][i];
+ /* apply AC-3 post-rotation & reordering */
+ for(k=0; k<64; k++) {
+ o_ptr[ 2*k ] = -z[0][ k].im;
+ o_ptr[ 2*k+1] = z[0][63-k].re;
+ o_ptr[128+2*k ] = -z[0][ k].re;
+ o_ptr[128+2*k+1] = z[0][63-k].im;
+ o_ptr[256+2*k ] = -z[1][ k].re;
+ o_ptr[256+2*k+1] = z[1][63-k].im;
+ o_ptr[384+2*k ] = z[1][ k].im;
+ o_ptr[384+2*k+1] = -z[1][63-k].re;
}
- memset(output[3], 0, sizeof(output[3]));
}
-static inline void mix_3f_1r_to_mono(AC3DecodeContext *ctx)
+/**
+ * Inverse MDCT Transform.
+ * Convert frequency domain coefficients to time-domain audio samples.
+ * reference: Section 7.9.4 Transformation Equations
+ */
+static inline void do_imdct(AC3DecodeContext *ctx)
{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++)
- output[1][i] = (output[2][i] + output[3][i] + output[4][i]);
- memset(output[2], 0, sizeof(output[2]));
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
-}
+ int ch;
+ int nchans;
-static inline void mix_3f_1r_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
+ /* Don't perform the IMDCT on the LFE channel unless it's used in the output */
+ nchans = ctx->nfchans;
+ if(ctx->output_mode & AC3_OUTPUT_LFEON)
+ nchans++;
- for (i = 0; i < 256; i++) {
- output[1][i] += (output[2][i] + output[4][i]);
- output[2][i] += (output[3][i] + output[4][i]);
- }
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
-}
-
-static inline void mix_3f_1r_to_dolby(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++) {
- output[1][i] += (output[2][i] - output[4][i]);
- output[2][i] += (output[3][i] + output[4][i]);
+ for (ch=1; ch<=nchans; ch++) {
+ if (ctx->blksw[ch]) {
+ do_imdct_256(ctx, ch);
+ } else {
+ ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output,
+ ctx->transform_coeffs[ch],
+ ctx->tmp_imdct);
+ }
+ /* For the first half of the block, apply the window, add the delay
+ from the previous block, and send to output */
+ ctx->dsp.vector_fmul_add_add(ctx->output[ch-1], ctx->tmp_output,
+ ctx->window, ctx->delay[ch-1], 0, 256, 1);
+ /* For the second half of the block, apply the window and store the
+ samples to delay, to be combined with the next block */
+ ctx->dsp.vector_fmul_reverse(ctx->delay[ch-1], ctx->tmp_output+256,
+ ctx->window, 256);
}
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
-}
-
-static inline void mix_2f_2r_to_mono(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++)
- output[1][i] = (output[2][i] + output[3][i] + output[4][i]);
- memset(output[2], 0, sizeof(output[2]));
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
}
-static inline void mix_2f_2r_to_stereo(AC3DecodeContext *ctx)
+/**
+ * Downmix the output to mono or stereo.
+ */
+static void ac3_downmix(float samples[AC3_MAX_CHANNELS][256], int nfchans,
+ int output_mode, float coef[AC3_MAX_CHANNELS][2])
{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++) {
- output[1][i] += output[3][i];
- output[2][i] += output[4][i];
+ int i, j;
+ float v0, v1, s0, s1;
+
+ for(i=0; i<256; i++) {
+ v0 = v1 = s0 = s1 = 0.0f;
+ for(j=0; j<nfchans; j++) {
+ v0 += samples[j][i] * coef[j][0];
+ v1 += samples[j][i] * coef[j][1];
+ s0 += coef[j][0];
+ s1 += coef[j][1];
+ }
+ v0 /= s0;
+ v1 /= s1;
+ if(output_mode == AC3_ACMOD_MONO) {
+ samples[0][i] = (v0 + v1) * LEVEL_MINUS_3DB;
+ } else if(output_mode == AC3_ACMOD_STEREO) {
+ samples[0][i] = v0;
+ samples[1][i] = v1;
+ }
}
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
}
-static inline void mix_2f_2r_to_dolby(AC3DecodeContext *ctx)
+/**
+ * Parse an audio block from AC-3 bitstream.
+ */
+static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
+ int nfchans = ctx->nfchans;
+ int acmod = ctx->acmod;
+ int i, bnd, seg, ch;
+ GetBitContext *gb = &ctx->gb;
+ uint8_t bit_alloc_stages[AC3_MAX_CHANNELS];
- for (i = 0; i < 256; i++) {
- output[1][i] -= output[3][i];
- output[2][i] += output[4][i];
- }
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
-}
+ memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
-static inline void mix_3f_2r_to_mono(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++)
- output[1][i] += (output[2][i] + output[3][i] + output[4][i] + output[5][i]);
- memset(output[2], 0, sizeof(output[2]));
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
- memset(output[5], 0, sizeof(output[5]));
-}
+ /* block switch flags */
+ for (ch = 1; ch <= nfchans; ch++)
+ ctx->blksw[ch] = get_bits1(gb);
-static inline void mix_3f_2r_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
-
- for (i = 0; i < 256; i++) {
- output[1][i] += (output[2][i] + output[4][i]);
- output[2][i] += (output[3][i] + output[5][i]);
+ /* dithering flags */
+ ctx->dither_all = 1;
+ for (ch = 1; ch <= nfchans; ch++) {
+ ctx->dithflag[ch] = get_bits1(gb);
+ if(!ctx->dithflag[ch])
+ ctx->dither_all = 0;
}
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
- memset(output[5], 0, sizeof(output[5]));
-}
-
-static inline void mix_3f_2r_to_dolby(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->audio_block.output;
- for (i = 0; i < 256; i++) {
- output[1][i] += (output[2][i] - output[4][i] - output[5][i]);
- output[2][i] += (output[3][i] + output[4][i] + output[5][i]);
- }
- memset(output[3], 0, sizeof(output[3]));
- memset(output[4], 0, sizeof(output[4]));
- memset(output[5], 0, sizeof(output[5]));
-}
+ /* dynamic range */
+ i = !(ctx->acmod);
+ do {
+ if(get_bits1(gb)) {
+ ctx->dynrng[i] = dynrng_tab[get_bits(gb, 8)];
+ } else if(blk == 0) {
+ ctx->dynrng[i] = 1.0f;
+ }
+ } while(i--);
-static void do_downmix(AC3DecodeContext *ctx)
-{
- int from = ctx->bsi.acmod;
- int to = ctx->output;
-
- switch (from) {
- case AC3_INPUT_DUALMONO:
- switch (to) {
- case AC3_OUTPUT_MONO:
- mix_dualmono_to_mono(ctx);
- break;
- case AC3_OUTPUT_STEREO: /* We assume that sum of both mono channels is requested */
- mix_dualmono_to_stereo(ctx);
- break;
- }
- break;
- case AC3_INPUT_MONO:
- switch (to) {
- case AC3_OUTPUT_STEREO:
- upmix_mono_to_stereo(ctx);
- break;
- }
- break;
- case AC3_INPUT_STEREO:
- switch (to) {
- case AC3_OUTPUT_MONO:
- mix_stereo_to_mono(ctx);
- break;
- }
- break;
- case AC3_INPUT_3F:
- switch (to) {
- case AC3_OUTPUT_MONO:
- mix_3f_to_mono(ctx);
- break;
- case AC3_OUTPUT_STEREO:
- mix_3f_to_stereo(ctx);
- break;
- }
- break;
- case AC3_INPUT_2F_1R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- mix_2f_1r_to_mono(ctx);
- break;
- case AC3_OUTPUT_STEREO:
- mix_2f_1r_to_stereo(ctx);
- break;
- case AC3_OUTPUT_DOLBY:
- mix_2f_1r_to_dolby(ctx);
- break;
- }
- break;
- case AC3_INPUT_3F_1R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- mix_3f_1r_to_mono(ctx);
- break;
- case AC3_OUTPUT_STEREO:
- mix_3f_1r_to_stereo(ctx);
- break;
- case AC3_OUTPUT_DOLBY:
- mix_3f_1r_to_dolby(ctx);
- break;
- }
- break;
- case AC3_INPUT_2F_2R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- mix_2f_2r_to_mono(ctx);
- break;
- case AC3_OUTPUT_STEREO:
- mix_2f_2r_to_stereo(ctx);
- break;
- case AC3_OUTPUT_DOLBY:
- mix_2f_2r_to_dolby(ctx);
- break;
+ /* coupling strategy */
+ if (get_bits1(gb)) {
+ memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
+ ctx->cplinu = get_bits1(gb);
+ if (ctx->cplinu) {
+ /* coupling in use */
+ int cplbegf, cplendf;
+
+ /* determine which channels are coupled */
+ for (ch = 1; ch <= nfchans; ch++)
+ ctx->chincpl[ch] = get_bits1(gb);
+
+ /* phase flags in use */
+ if (acmod == AC3_ACMOD_STEREO)
+ ctx->phsflginu = get_bits1(gb);
+
+ /* coupling frequency range and band structure */
+ cplbegf = get_bits(gb, 4);
+ cplendf = get_bits(gb, 4);
+ if (3 + cplendf - cplbegf < 0) {
+ av_log(ctx->avctx, AV_LOG_ERROR, "cplendf = %d < cplbegf = %d\n", cplendf, cplbegf);
+ return -1;
}
- break;
- case AC3_INPUT_3F_2R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- mix_3f_2r_to_mono(ctx);
- break;
- case AC3_OUTPUT_STEREO:
- mix_3f_2r_to_stereo(ctx);
- break;
- case AC3_OUTPUT_DOLBY:
- mix_3f_2r_to_dolby(ctx);
- break;
+ ctx->ncplbnd = ctx->ncplsubnd = 3 + cplendf - cplbegf;
+ ctx->startmant[CPL_CH] = cplbegf * 12 + 37;
+ ctx->endmant[CPL_CH] = cplendf * 12 + 73;
+ for (bnd = 0; bnd < ctx->ncplsubnd - 1; bnd++) {
+ if (get_bits1(gb)) {
+ ctx->cplbndstrc[bnd] = 1;
+ ctx->ncplbnd--;
+ }
}
- break;
- }
-}
-
-static void dump_floats(const char *name, int prec, const float *tab, int n)
-{
- int i;
-
- av_log(NULL, AV_LOG_INFO, "%s[%d]:\n", name, n);
- for(i=0;i<n;i++) {
- if ((i & 7) == 0)
- av_log(NULL, AV_LOG_INFO, "%4d: ", i);
- av_log(NULL, AV_LOG_INFO, " %8.*f", prec, tab[i]);
- if ((i & 7) == 7)
- av_log(NULL, AV_LOG_INFO, "\n");
- }
- if ((i & 7) != 0)
- av_log(NULL, AV_LOG_INFO, "\n");
-}
-
-/*static void window_and_de_interleave(float *output)
-{
- int n2, n4, n8;
- int k;
-
- n2 = 512 >> 1;
- n4 = 512 >> 2;
- n8 = 512 >> 3;
-
- for (k = 0; k < n8; k++) {
- output[2 * k] *= window[2 * k];
- output[n2 - 2 * k - 1] *= window[n2 - 2 * k - 1];
-
- output[2 * k + 1] *= window[2 * k + 1];
- output[n2 - 2 * k - 2] *= window[n2 - 2 * k - 2];
-
- output[n2 + 2 * k] *= window[n2 - 2 * k - 1];
- output[n - 2 * k - 1] *= window[n - 2 * k - 1];
-
- output[n2 + 2 * k + 1] *= window[n2 - 2 * k - 2];
- output[n - 2 * k - 2] *= window[n - 2 * k - 2];
- output[3 * n4 + 2 * k + 1] *= window[n4 - 2 * k - 2];
- }
-}*/
-
-static inline void overlap_and_add(float *tmp_output, float *delay, float *output)
-{
- int n;
-
- for (n = 0; n < BLOCK_SIZE; n++) {
- output[n] = 2 * (tmp_output[n] * window[n] + delay[n] * window[255 - n]);
- delay[n] = tmp_output[BLOCK_SIZE + n];
- }
-}
-
-
-static inline void do_imdct(AC3DecodeContext *ctx)
-{
- ac3_audio_block *ab = &ctx->audio_block;
- int i;
-
- if (ctx->output & AC3_OUTPUT_LFEON) {
- av_log(NULL, AV_LOG_INFO, "imdct lfe\n");
- ff_imdct_calc(&ctx->imdct_ctx_512, ab->tmp_output, ab->transform_coeffs[0], ab->tmp_imdct);
- //window_and_de_interleave(ab->tmp_output);
- overlap_and_add(ab->tmp_output, ab->delay[0], ab->output[0]);
- }
- for (i = 0; i < ctx->bsi.nfchans; i++) {
- if (!(((ab->blksw) >> i) & 1)) {
- av_log(NULL, AV_LOG_INFO, "imdct channel %d - block switching not enabled\n", i);
- ff_imdct_calc(&ctx->imdct_ctx_512, ab->tmp_output, ab->transform_coeffs[i + 1], ab->tmp_imdct);
- //window_and_de_interleave(ab->tmp_output);
- overlap_and_add(ab->tmp_output, ab->delay[i + 1], ab->output[i + 1]);
} else {
- av_log(NULL, AV_LOG_INFO, "imdct channel %d skipping - block switching enabled\n", i);
+ /* coupling not in use */
+ for (ch = 1; ch <= nfchans; ch++)
+ ctx->chincpl[ch] = 0;
}
}
-}
-
+ /* coupling coordinates */
+ if (ctx->cplinu) {
+ int cplcoe = 0;
-static int ac3_parse_audio_block(AC3DecodeContext * ctx, int index)
-{
- ac3_audio_block *ab = &ctx->audio_block;
- int nfchans = ctx->bsi.nfchans;
- int acmod = ctx->bsi.acmod;
- int i, bnd, rbnd, seg, grpsize;
- GetBitContext *gb = &ctx->gb;
- uint32_t *flags = &ab->flags;
- int bit_alloc_flags = 0;
- float drange, tmpco;
- uint8_t *dexps;
- int mstrcplco, cplcoexp, cplcomant, sbnd, cplbndstrc;
-
- *flags = 0;
- ab->blksw = 0;
- for (i = 0; i < 5; i++)
- ab->chcoeffs[i] = 1.0;
- for (i = 0; i < nfchans; i++) /*block switch flag */
- ab->blksw |= get_bits1(gb) << i;
- ab->dithflag = 0;
- for (i = 0; i < nfchans; i++) /* dithering flag */
- ab->dithflag |= get_bits1(gb) << i;
- if (get_bits1(gb)) { /* dynamic range */
- *flags |= AC3_AB_DYNRNGE;
- ab->dynrng = get_bits(gb, 8);
- drange = ((((ab->dynrng & 0x1f) | 0x20) << 13) * scale_factors[3 - (ab->dynrng >> 5)]);
- for (i = 0; i < nfchans; i++)
- ab->chcoeffs[i] *= drange;
- }
- if (acmod == 0x00) { /* dynamic range 1+1 mode */
- if (get_bits1(gb)) {
- *flags |= AC3_AB_DYNRNG2E;
- ab->dynrng2 = get_bits(gb, 8);
- drange = ((((ab->dynrng2 & 0x1f) | 0x20) << 13) * scale_factors[3 - (ab->dynrng2 >> 5)]);
- ab->chcoeffs[1] *= drange;
- }
- }
- get_downmix_coeffs(ctx);
- if (get_bits1(gb)) { /* coupling strategy */
- *flags |= AC3_AB_CPLSTRE;
- ab->cplbndstrc = 0;
- ab->chincpl = 0;
- if (get_bits1(gb)) { /* coupling in use */
- *flags |= AC3_AB_CPLINU;
- for (i = 0; i < nfchans; i++)
- ab->chincpl |= get_bits1(gb) << i;
- if (acmod == 0x02)
- if (get_bits1(gb)) /* phase flag in use */
- *flags |= AC3_AB_PHSFLGINU;
- ab->cplbegf = get_bits(gb, 4);
- ab->cplendf = get_bits(gb, 4);
- if (3 + ab->cplendf - ab->cplbegf < 0)
- return -1;
- ab->ncplbnd = ab->ncplsubnd = 3 + ab->cplendf - ab->cplbegf;
- ab->cplstrtmant = ab->cplbegf * 12 + 37;
- ab->cplendmant = ab->cplendf * 12 + 73;
- for (i = 0; i < ab->ncplsubnd - 1; i++) /* coupling band structure */
+ for (ch = 1; ch <= nfchans; ch++) {
+ if (ctx->chincpl[ch]) {
if (get_bits1(gb)) {
- ab->cplbndstrc |= 1 << i;
- ab->ncplbnd--;
- }
- }
- }
- if (ab->chincpl) {
- ab->cplcoe = 0;
- for (i = 0; i < nfchans; i++)
- if ((ab->chincpl) >> i & 1)
- if (get_bits1(gb)) { /* coupling co-ordinates */
- ab->cplcoe |= 1 << i;
+ int mstrcplco, cplcoexp, cplcomant;
+ cplcoe = 1;
mstrcplco = 3 * get_bits(gb, 2);
- sbnd = ab->cplbegf;
- cplbndstrc = ab->cplbndstrc;
- for (bnd = 0; bnd < ab->ncplbnd; bnd++) {
+ for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
cplcoexp = get_bits(gb, 4);
cplcomant = get_bits(gb, 4);
if (cplcoexp == 15)
- cplcomant <<= 14;
+ ctx->cplco[ch][bnd] = cplcomant / 16.0f;
else
- cplcomant = (cplcomant | 0x10) << 13;
- tmpco = ab->cplco[i][sbnd++] = cplcomant * scale_factors[cplcoexp + mstrcplco];
- while (cplbndstrc & 1) {
- ab->cplco[i][sbnd++] = tmpco;
- cplbndstrc >>= 1;
- }
- cplbndstrc >>= 1;
+ ctx->cplco[ch][bnd] = (cplcomant + 16.0f) / 32.0f;
+ ctx->cplco[ch][bnd] *= scale_factors[cplcoexp + mstrcplco];
}
}
- ab->phsflg = 0;
- if ((acmod == 0x02) && (*flags & AC3_AB_PHSFLGINU) && (ab->cplcoe & 1 || ab->cplcoe & (1 << 1))) {
- sbnd = ab->cplbegf;
- cplbndstrc = ab->cplbndstrc;
- for (bnd = 0; bnd < ab->ncplbnd; bnd++)
- if (get_bits1(gb)) {
- ab->phsflg |= 1 << bnd;
- ab->cplco[1][sbnd] = -ab->cplco[1][sbnd];
- sbnd++;
- while (cplbndstrc & 1) {
- ab->cplco[1][sbnd] = -ab->cplco[1][sbnd];
- sbnd++;
- cplbndstrc >>= 1;
- }
- cplbndstrc >>= 1;
- } else {
- sbnd++;
- while (cplbndstrc & 1) {
- sbnd++;
- cplbndstrc >>= 1;
- }
- cplbndstrc >>= 1;
- }
+ }
+ }
+ /* phase flags */
+ if (acmod == AC3_ACMOD_STEREO && ctx->phsflginu && cplcoe) {
+ for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
+ if (get_bits1(gb))
+ ctx->cplco[2][bnd] = -ctx->cplco[2][bnd];
+ }
}
}
- ab->rematflg = 0;
- if (acmod == 0x02) /* rematrixing */
- if (get_bits1(gb)) {
- *flags |= AC3_AB_REMATSTR;
- if (!(ab->chincpl) || ab->cplbegf > 2)
- for (rbnd = 0; rbnd < 4; rbnd++)
- ab->rematflg |= get_bits1(gb) << rbnd;
- if (ab->cplbegf > 0 && ab->cplbegf <= 2 && (ab->chincpl))
- for (rbnd = 0; rbnd < 3; rbnd++)
- ab->rematflg |= get_bits1(gb) << rbnd;
- if (ab->cplbegf == 0 && (ab->chincpl))
- for (rbnd = 0; rbnd < 2; rbnd++)
- ab->rematflg |= get_bits1(gb) << rbnd;
+
+ /* stereo rematrixing strategy and band structure */
+ if (acmod == AC3_ACMOD_STEREO) {
+ ctx->rematstr = get_bits1(gb);
+ if (ctx->rematstr) {
+ ctx->nrematbnd = 4;
+ if(ctx->cplinu && ctx->startmant[CPL_CH] <= 61)
+ ctx->nrematbnd -= 1 + (ctx->startmant[CPL_CH] == 37);
+ for(bnd=0; bnd<ctx->nrematbnd; bnd++)
+ ctx->rematflg[bnd] = get_bits1(gb);
}
- ab->cplexpstr = AC3_EXPSTR_REUSE;
- ab->lfeexpstr = AC3_EXPSTR_REUSE;
- if (ab->chincpl) /* coupling exponent strategy */
- ab->cplexpstr = get_bits(gb, 2);
- for (i = 0; i < nfchans; i++) /* channel exponent strategy */
- ab->chexpstr[i] = get_bits(gb, 2);
- if (ctx->bsi.flags & AC3_BSI_LFEON) /* lfe exponent strategy */
- ab->lfeexpstr = get_bits1(gb);
- for (i = 0; i < nfchans; i++) /* channel bandwidth code */
- if (ab->chexpstr[i] != AC3_EXPSTR_REUSE) {
- if (((ab->chincpl) >> i) & 1) {
- ab->endmant[i] = ab->cplstrtmant;
- }
+ }
+
+ /* exponent strategies for each channel */
+ ctx->expstr[CPL_CH] = EXP_REUSE;
+ ctx->expstr[ctx->lfe_ch] = EXP_REUSE;
+ for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) {
+ if(ch == ctx->lfe_ch)
+ ctx->expstr[ch] = get_bits(gb, 1);
+ else
+ ctx->expstr[ch] = get_bits(gb, 2);
+ if(ctx->expstr[ch] != EXP_REUSE)
+ bit_alloc_stages[ch] = 3;
+ }
+
+ /* channel bandwidth */
+ for (ch = 1; ch <= nfchans; ch++) {
+ ctx->startmant[ch] = 0;
+ if (ctx->expstr[ch] != EXP_REUSE) {
+ int prev = ctx->endmant[ch];
+ if (ctx->chincpl[ch])
+ ctx->endmant[ch] = ctx->startmant[CPL_CH];
else {
- ab->chbwcod[i] = get_bits(gb, 6);
- if (ab->chbwcod[i] > 60) {
- av_log(NULL, AV_LOG_ERROR, "chbwcod = %d > 60", ab->chbwcod[i]);
+ int chbwcod = get_bits(gb, 6);
+ if (chbwcod > 60) {
+ av_log(ctx->avctx, AV_LOG_ERROR, "chbwcod = %d > 60", chbwcod);
return -1;
}
- ab->endmant[i] = ab->chbwcod[i] * 3 + 73;
+ ctx->endmant[ch] = chbwcod * 3 + 73;
}
+ if(blk > 0 && ctx->endmant[ch] != prev)
+ memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
}
- if (ab->cplexpstr != AC3_EXPSTR_REUSE) {/* coupling exponents */
- bit_alloc_flags |= 64;
- ab->cplabsexp = get_bits(gb, 4) << 1;
- ab->ncplgrps = (ab->cplendmant - ab->cplstrtmant) / (3 << (ab->cplexpstr - 1));
- if (decode_exponents(gb, ab->cplexpstr, ab->ncplgrps, ab->cplabsexp, ab->dcplexps + ab->cplstrtmant)) {
- av_log(NULL, AV_LOG_ERROR, "error decoding coupling exponents\n");
- return -1;
+ }
+ ctx->startmant[ctx->lfe_ch] = 0;
+ ctx->endmant[ctx->lfe_ch] = 7;
+
+ /* decode exponents for each channel */
+ for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) {
+ if (ctx->expstr[ch] != EXP_REUSE) {
+ int grpsize, ngrps;
+ grpsize = 3 << (ctx->expstr[ch] - 1);
+ if(ch == CPL_CH)
+ ngrps = (ctx->endmant[ch] - ctx->startmant[ch]) / grpsize;
+ else if(ch == ctx->lfe_ch)
+ ngrps = 2;
+ else
+ ngrps = (ctx->endmant[ch] + grpsize - 4) / grpsize;
+ ctx->dexps[ch][0] = get_bits(gb, 4) << !ch;
+ decode_exponents(gb, ctx->expstr[ch], ngrps, ctx->dexps[ch][0],
+ &ctx->dexps[ch][ctx->startmant[ch]+!!ch]);
+ if(ch != CPL_CH && ch != ctx->lfe_ch)
+ skip_bits(gb, 2); /* skip gainrng */
}
}
- for (i = 0; i < nfchans; i++) /* fbw channel exponents */
- if (ab->chexpstr[i] != AC3_EXPSTR_REUSE) {
- bit_alloc_flags |= 1 << i;
- grpsize = 3 << (ab->chexpstr[i] - 1);
- ab->nchgrps[i] = (ab->endmant[i] + grpsize - 4) / grpsize;
- dexps = ab->dexps[i];
- dexps[0] = get_bits(gb, 4);
- if (decode_exponents(gb, ab->chexpstr[i], ab->nchgrps[i], dexps[0], dexps + 1)) {
- av_log(NULL, AV_LOG_ERROR, "error decoding channel %d exponents\n", i);
- return -1;
- }
- ab->gainrng[i] = get_bits(gb, 2);
+
+ /* bit allocation information */
+ if (get_bits1(gb)) {
+ ctx->bit_alloc_params.sdecay = ff_sdecaytab[get_bits(gb, 2)] >> ctx->bit_alloc_params.halfratecod;
+ ctx->bit_alloc_params.fdecay = ff_fdecaytab[get_bits(gb, 2)] >> ctx->bit_alloc_params.halfratecod;
+ ctx->bit_alloc_params.sgain = ff_sgaintab[get_bits(gb, 2)];
+ ctx->bit_alloc_params.dbknee = ff_dbkneetab[get_bits(gb, 2)];
+ ctx->bit_alloc_params.floor = ff_floortab[get_bits(gb, 3)];
+ for(ch=!ctx->cplinu; ch<=ctx->nchans; ch++) {
+ bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
}
- if (ab->lfeexpstr != AC3_EXPSTR_REUSE) { /* lfe exponents */
- bit_alloc_flags |= 32;
- ab->dlfeexps[0] = get_bits(gb, 4);
- if (decode_exponents(gb, ab->lfeexpstr, 2, ab->dlfeexps[0], ab->dlfeexps + 1)) {
- av_log(NULL, AV_LOG_ERROR, "error decoding lfe exponents\n");
- return -1;
+ }
+
+ /* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
+ if (get_bits1(gb)) {
+ int csnr;
+ csnr = (get_bits(gb, 6) - 15) << 4;
+ for (ch = !ctx->cplinu; ch <= ctx->nchans; ch++) { /* snr offset and fast gain */
+ ctx->snroffst[ch] = (csnr + get_bits(gb, 4)) << 2;
+ ctx->fgain[ch] = ff_fgaintab[get_bits(gb, 3)];
}
+ memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
}
- if (get_bits1(gb)) { /* bit allocation information */
- *flags |= AC3_AB_BAIE;
- bit_alloc_flags |= 127;
- ab->sdcycod = get_bits(gb, 2);
- ab->fdcycod = get_bits(gb, 2);
- ab->sgaincod = get_bits(gb, 2);
- ab->dbpbcod = get_bits(gb, 2);
- ab->floorcod = get_bits(gb, 3);
+ /* coupling leak information */
+ if (ctx->cplinu && get_bits1(gb)) {
+ ctx->bit_alloc_params.cplfleak = get_bits(gb, 3);
+ ctx->bit_alloc_params.cplsleak = get_bits(gb, 3);
+ bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
}
- if (get_bits1(gb)) { /* snroffset */
- *flags |= AC3_AB_SNROFFSTE;
- bit_alloc_flags |= 127;
- ab->csnroffst = get_bits(gb, 6);
- if (ab->chincpl) { /* couling fine snr offset and fast gain code */
- ab->cplfsnroffst = get_bits(gb, 4);
- ab->cplfgaincod = get_bits(gb, 3);
+
+ /* delta bit allocation information */
+ if (get_bits1(gb)) {
+ /* delta bit allocation exists (strategy) */
+ for (ch = !ctx->cplinu; ch <= nfchans; ch++) {
+ ctx->deltbae[ch] = get_bits(gb, 2);
+ if (ctx->deltbae[ch] == DBA_RESERVED) {
+ av_log(ctx->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
+ return -1;
+ }
+ bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
}
- for (i = 0; i < nfchans; i++) { /* channel fine snr offset and fast gain code */
- ab->fsnroffst[i] = get_bits(gb, 4);
- ab->fgaincod[i] = get_bits(gb, 3);
+ /* channel delta offset, len and bit allocation */
+ for (ch = !ctx->cplinu; ch <= nfchans; ch++) {
+ if (ctx->deltbae[ch] == DBA_NEW) {
+ ctx->deltnseg[ch] = get_bits(gb, 3);
+ for (seg = 0; seg <= ctx->deltnseg[ch]; seg++) {
+ ctx->deltoffst[ch][seg] = get_bits(gb, 5);
+ ctx->deltlen[ch][seg] = get_bits(gb, 4);
+ ctx->deltba[ch][seg] = get_bits(gb, 3);
+ }
+ }
}
- if (ctx->bsi.flags & AC3_BSI_LFEON) { /* lfe fine snr offset and fast gain code */
- ab->lfefsnroffst = get_bits(gb, 4);
- ab->lfefgaincod = get_bits(gb, 3);
+ } else if(blk == 0) {
+ for(ch=0; ch<=ctx->nchans; ch++) {
+ ctx->deltbae[ch] = DBA_NONE;
}
}
- if (ab->chincpl)
- if (get_bits1(gb)) { /* coupling leak information */
- bit_alloc_flags |= 64;
- *flags |= AC3_AB_CPLLEAKE;
- ab->cplfleak = get_bits(gb, 3);
- ab->cplsleak = get_bits(gb, 3);
+
+ /* Bit allocation */
+ for(ch=!ctx->cplinu; ch<=ctx->nchans; ch++) {
+ if(bit_alloc_stages[ch] > 2) {
+ /* Exponent mapping into PSD and PSD integration */
+ ff_ac3_bit_alloc_calc_psd(ctx->dexps[ch],
+ ctx->startmant[ch], ctx->endmant[ch],
+ ctx->psd[ch], ctx->bndpsd[ch]);
}
- ab->cpldeltbae = AC3_DBASTR_RESERVED;
- for (i = 0; i < nfchans; i++)
- ab->deltbae[i] = AC3_DBASTR_RESERVED;
- if (get_bits1(gb)) { /* delta bit allocation information */
- *flags |= AC3_AB_DELTBAIE;
- bit_alloc_flags |= 127;
- if (ab->chincpl) {
- ab->cpldeltbae = get_bits(gb, 2);
- if (ab->cpldeltbae == AC3_DBASTR_RESERVED) {
- av_log(NULL, AV_LOG_ERROR, "coupling delta bit allocation strategy reserved\n");
- return -1;
- }
+ if(bit_alloc_stages[ch] > 1) {
+ /* Compute excitation function, Compute masking curve, and
+ Apply delta bit allocation */
+ ff_ac3_bit_alloc_calc_mask(&ctx->bit_alloc_params, ctx->bndpsd[ch],
+ ctx->startmant[ch], ctx->endmant[ch],
+ ctx->fgain[ch], (ch == ctx->lfe_ch),
+ ctx->deltbae[ch], ctx->deltnseg[ch],
+ ctx->deltoffst[ch], ctx->deltlen[ch],
+ ctx->deltba[ch], ctx->mask[ch]);
}
- for (i = 0; i < nfchans; i++) {
- ab->deltbae[i] = get_bits(gb, 2);
- if (ab->deltbae[i] == AC3_DBASTR_RESERVED) {
- av_log(NULL, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
- return -1;
- }
+ if(bit_alloc_stages[ch] > 0) {
+ /* Compute bit allocation */
+ ff_ac3_bit_alloc_calc_bap(ctx->mask[ch], ctx->psd[ch],
+ ctx->startmant[ch], ctx->endmant[ch],
+ ctx->snroffst[ch],
+ ctx->bit_alloc_params.floor,
+ ctx->bap[ch]);
}
- if (ab->chincpl)
- if (ab->cpldeltbae == AC3_DBASTR_NEW) { /*coupling delta offset, len and bit allocation */
- ab->cpldeltnseg = get_bits(gb, 3);
- for (seg = 0; seg <= ab->cpldeltnseg; seg++) {
- ab->cpldeltoffst[seg] = get_bits(gb, 5);
- ab->cpldeltlen[seg] = get_bits(gb, 4);
- ab->cpldeltba[seg] = get_bits(gb, 3);
- }
- }
- for (i = 0; i < nfchans; i++)
- if (ab->deltbae[i] == AC3_DBASTR_NEW) {/*channel delta offset, len and bit allocation */
- ab->deltnseg[i] = get_bits(gb, 3);
- for (seg = 0; seg <= ab->deltnseg[i]; seg++) {
- ab->deltoffst[i][seg] = get_bits(gb, 5);
- ab->deltlen[i][seg] = get_bits(gb, 4);
- ab->deltba[i][seg] = get_bits(gb, 3);
- }
- }
}
- do_bit_allocation (ctx, bit_alloc_flags); /* perform the bit allocation */
- if (get_bits1(gb)) { /* unused dummy data */
- *flags |= AC3_AB_SKIPLE;
- ab->skipl = get_bits(gb, 9);
- while(ab->skipl--)
+ /* unused dummy data */
+ if (get_bits1(gb)) {
+ int skipl = get_bits(gb, 9);
+ while(skipl--)
skip_bits(gb, 8);
}
+
/* unpack the transform coefficients
- * * this also uncouples channels if coupling is in use.
- */
+ this also uncouples channels if coupling is in use. */
if (get_transform_coeffs(ctx)) {
- av_log(NULL, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
+ av_log(ctx->avctx, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
return -1;
}
- /*for (i = 0; i < nfchans; i++)
- dump_floats("channel transform coefficients", 10, ab->transform_coeffs[i + 1], BLOCK_SIZE);*/
/* recover coefficients if rematrixing is in use */
- if (*flags & AC3_AB_REMATSTR)
+ if(ctx->acmod == AC3_ACMOD_STEREO)
do_rematrixing(ctx);
- do_imdct(ctx);
- /*for(i = 0; i < nfchans; i++)
- dump_floats("channel output", 10, ab->output[i + 1], BLOCK_SIZE);*/
-
- do_downmix(ctx);
+ /* apply scaling to coefficients (headroom, dialnorm, dynrng) */
+ for(ch=1; ch<=ctx->nchans; ch++) {
+ float gain = 2.0f * ctx->mul_bias;
+ if(ctx->acmod == AC3_ACMOD_DUALMONO) {
+ gain *= ctx->dialnorm[ch-1] * ctx->dynrng[ch-1];
+ } else {
+ gain *= ctx->dialnorm[0] * ctx->dynrng[0];
+ }
+ for(i=0; i<ctx->endmant[ch]; i++) {
+ ctx->transform_coeffs[ch][i] *= gain;
+ }
+ }
- return 0;
-}
+ do_imdct(ctx);
-/* from FreeSWITCH Modular Media Switching Library */
-#define NORMFACT (float)0x8000
-#define MAXSAMPLE (float)0x7fff
+ /* downmix output if needed */
+ if(ctx->nchans != ctx->out_channels && !((ctx->output_mode & AC3_OUTPUT_LFEON) &&
+ ctx->nfchans == ctx->out_channels)) {
+ ac3_downmix(ctx->output, ctx->nfchans, ctx->output_mode,
+ ctx->downmix_coeffs);
+ }
+ /* convert float to 16-bit integer */
+ for(ch=0; ch<ctx->out_channels; ch++) {
+ for(i=0; i<256; i++) {
+ ctx->output[ch][i] += ctx->add_bias;
+ }
+ ctx->dsp.float_to_int16(ctx->int_output[ch], ctx->output[ch], 256);
+ }
-static inline int16_t convert(float f)
-{
- /*short s;
- f = f * NORMFACT;
- if (f >= 0)
- s = (short)(f + 0.5);
- else
- s = (short)(f - 0.5);
- if ((float)s > MAXSAMPLE)
- s = (float)MAXSAMPLE;
- if (s < (short) -MAXSAMPLE)
- s = (short) -MAXSAMPLE;
-
- return s;*/
- int a;
- a = lrintf(f * 32767.0);
- return ((int16_t)a);
+ return 0;
}
+/**
+ * Decode a single AC-3 frame.
+ */
static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
{
AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
- ac3_audio_block *ab = &ctx->audio_block;
- int frame_start;
int16_t *out_samples = (int16_t *)data;
- int i, j, k, value;
-
- //Synchronize the frame.
- frame_start = ac3_synchronize(buf, buf_size);
- if (frame_start == -1) {
- av_log(avctx, AV_LOG_ERROR, "frame is not synchronized\n");
- *data_size = 0;
- return buf_size;
- }
+ int i, blk, ch;
- //Initialize the GetBitContext with the start of valid AC3 Frame.
- init_get_bits(&(ctx->gb), buf + frame_start, (buf_size - frame_start) * 8);
+ /* initialize the GetBitContext with the start of valid AC-3 Frame */
+ init_get_bits(&ctx->gb, buf, buf_size * 8);
- //Parse the syncinfo.
- //If 'fscod' or 'bsid' is not valid the decoder shall mute as per the standard.
- if (!ac3_parse_sync_info(ctx)) {
+ /* parse the syncinfo */
+ if (ac3_parse_header(ctx)) {
av_log(avctx, AV_LOG_ERROR, "\n");
*data_size = 0;
return buf_size;
}
- //Check for the errors.
- /* if (ac3_error_check(ctx)) {
- *data_size = 0;
- return -1;
- } */
-
- //Parse the BSI.
- //If 'bsid' is not valid decoder shall not decode the audio as per the standard.
- ac3_parse_bsi(ctx);
+ avctx->sample_rate = ctx->sampling_rate;
+ avctx->bit_rate = ctx->bit_rate;
- avctx->sample_rate = ctx->sync_info.sampling_rate;
- avctx->bit_rate = ctx->sync_info.bit_rate;
+ /* channel config */
+ ctx->out_channels = ctx->nchans;
if (avctx->channels == 0) {
- ctx->output |= AC3_OUTPUT_UNMODIFIED;
- avctx->channels = ctx->bsi.nfchans;
- } else if ((ctx->bsi.nfchans + ((ctx->bsi.flags & AC3_BSI_LFEON) ? 1 : 0)) < avctx->channels) {
- av_log(avctx, AV_LOG_INFO, "ac3_decoder: AC3 Source Channels Are Less Then Specified %d: Output to %d Channels\n",
- avctx->channels, (ctx->bsi.nfchans + ((ctx->bsi.flags & AC3_BSI_LFEON) ? 1 : 0)));
- avctx->channels = ctx->bsi.nfchans;
- ctx->output |= AC3_OUTPUT_UNMODIFIED;
- } else if (avctx->channels == 1) {
- ctx->output |= AC3_OUTPUT_MONO;
- } else if (avctx->channels == 2) {
- if (ctx->bsi.dsurmod == 0x02)
- ctx->output |= AC3_OUTPUT_DOLBY;
- else
- ctx->output |= AC3_OUTPUT_STEREO;
+ avctx->channels = ctx->out_channels;
+ } else if(ctx->out_channels < avctx->channels) {
+ av_log(avctx, AV_LOG_ERROR, "Cannot upmix AC3 from %d to %d channels.\n",
+ ctx->out_channels, avctx->channels);
+ return -1;
}
- if (ctx->bsi.flags & AC3_BSI_LFEON) {
- avctx->channels++;
- ctx->output |= AC3_OUTPUT_LFEON;
+ if(avctx->channels == 2) {
+ ctx->output_mode = AC3_ACMOD_STEREO;
+ } else if(avctx->channels == 1) {
+ ctx->output_mode = AC3_ACMOD_MONO;
+ } else if(avctx->channels != ctx->out_channels) {
+ av_log(avctx, AV_LOG_ERROR, "Cannot downmix AC3 from %d to %d channels.\n",
+ ctx->out_channels, avctx->channels);
+ return -1;
}
+ ctx->out_channels = avctx->channels;
- av_log(avctx, AV_LOG_INFO, "channels = %d \t bit rate = %d \t sampling rate = %d \n", avctx->channels, avctx->bit_rate * 1000, avctx->sample_rate);
-
- //Parse the Audio Blocks.
- for (i = 0; i < AUDIO_BLOCKS; i++) {
- if (ac3_parse_audio_block(ctx, i)) {
+ /* parse the audio blocks */
+ for (blk = 0; blk < NB_BLOCKS; blk++) {
+ if (ac3_parse_audio_block(ctx, blk)) {
av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
*data_size = 0;
- return ctx->sync_info.framesize;
- }
- j = ((ctx->output & AC3_OUTPUT_LFEON) ? 0 : 1);
- for (;j < avctx->channels; j++) {
- for(k = 0; k < BLOCK_SIZE; k++) {
- value = convert(ab->output[j][k]);
- av_log(NULL, AV_LOG_INFO, "%d\t", value);
- *(out_samples++) = value;
- }
+ return ctx->frame_size;
}
+ for (i = 0; i < 256; i++)
+ for (ch = 0; ch < ctx->out_channels; ch++)
+ *(out_samples++) = ctx->int_output[ch][i];
}
- *data_size = AUDIO_BLOCKS * BLOCK_SIZE * avctx->channels * sizeof (int16_t);
- return ctx->sync_info.framesize;
+ *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t);
+ return ctx->frame_size;
}
-static int ac3_decode_end(AVCodecContext *ctx)
+/**
+ * Uninitialize the AC-3 decoder.
+ */
+static int ac3_decode_end(AVCodecContext *avctx)
{
+ AC3DecodeContext *ctx = (AC3DecodeContext *)avctx->priv_data;
+ ff_mdct_end(&ctx->imdct_512);
+ ff_mdct_end(&ctx->imdct_256);
+
return 0;
}
-AVCodec lgpl_ac3_decoder = {
- "ac3",
- CODEC_TYPE_AUDIO,
- CODEC_ID_AC3,
- sizeof (AC3DecodeContext),
- ac3_decode_init,
- NULL,
- ac3_decode_end,
- ac3_decode_frame,
+AVCodec ac3_decoder = {
+ .name = "ac3",
+ .type = CODEC_TYPE_AUDIO,
+ .id = CODEC_ID_AC3,
+ .priv_data_size = sizeof (AC3DecodeContext),
+ .init = ac3_decode_init,
+ .close = ac3_decode_end,
+ .decode = ac3_decode_frame,
};
-
projects / ffmpeg / blobdiff