/*
* AC-3 Audio Decoder
- * This code is developed as part of Google Summer of Code 2006 Program.
+ * This code was developed as part of Google Summer of Code 2006.
+ * E-AC-3 support was added as part of Google Summer of Code 2007.
*
* Copyright (c) 2006 Kartikey Mahendra BHATT (bhattkm at gmail dot com).
- * Copyright (c) 2007 Justin Ruggles
+ * Copyright (c) 2007-2008 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
+ * Copyright (c) 2007 Justin Ruggles <justin.ruggles@gmail.com>
*
* Portions of this code are derived from liba52
* http://liba52.sourceforge.net
#include <math.h>
#include <string.h>
-#include "avcodec.h"
+#include "libavutil/crc.h"
#include "ac3_parser.h"
-#include "bitstream.h"
-#include "crc.h"
-#include "dsputil.h"
-#include "random.h"
+#include "ac3dec.h"
+#include "ac3dec_data.h"
-/**
- * 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 };
+/** Large enough for maximum possible frame size when the specification limit is ignored */
+#define AC3_FRAME_BUFFER_SIZE 32768
/**
- * table for exponent to scale_factor mapping
- * scale_factors[i] = 2 ^ -i
+ * table for ungrouping 3 values in 7 bits.
+ * used for exponents and bap=2 mantissas
*/
-static float scale_factors[25];
-
-/** table for grouping exponents */
-static uint8_t exp_ungroup_tab[128][3];
+static uint8_t ungroup_3_in_7_bits_tab[128][3];
/** 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 int b1_mantissas[32][3];
+static int b2_mantissas[128][3];
+static int b3_mantissas[8];
+static int b4_mantissas[128][2];
+static int b5_mantissas[16];
/**
* Quantization table: levels for symmetric. bits for asymmetric.
static float dynamic_range_tab[256];
/** Adjustments in dB gain */
+#define LEVEL_PLUS_3DB 1.4142135623730950
+#define LEVEL_PLUS_1POINT5DB 1.1892071150027209
+#define LEVEL_MINUS_1POINT5DB 0.8408964152537145
#define LEVEL_MINUS_3DB 0.7071067811865476
#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
#define LEVEL_MINUS_6DB 0.5000000000000000
#define LEVEL_ZERO 0.0000000000000000
#define LEVEL_ONE 1.0000000000000000
-static const float gain_levels[6] = {
- LEVEL_ZERO,
+static const float gain_levels[9] = {
+ LEVEL_PLUS_3DB,
+ LEVEL_PLUS_1POINT5DB,
LEVEL_ONE,
+ LEVEL_MINUS_1POINT5DB,
LEVEL_MINUS_3DB,
LEVEL_MINUS_4POINT5DB,
LEVEL_MINUS_6DB,
+ LEVEL_ZERO,
LEVEL_MINUS_9DB
};
* Table for center mix levels
* reference: Section 5.4.2.4 cmixlev
*/
-static const uint8_t center_levels[4] = { 2, 3, 4, 3 };
+static const uint8_t center_levels[4] = { 4, 5, 6, 5 };
/**
* Table for surround mix levels
* reference: Section 5.4.2.5 surmixlev
*/
-static const uint8_t surround_levels[4] = { 2, 4, 0, 4 };
+static const uint8_t surround_levels[4] = { 4, 6, 7, 6 };
/**
* 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 }, },
+ { { 2, 7 }, { 7, 2 }, },
+ { { 4, 4 }, },
+ { { 2, 7 }, { 7, 2 }, },
+ { { 2, 7 }, { 5, 5 }, { 7, 2 }, },
+ { { 2, 7 }, { 7, 2 }, { 6, 6 }, },
+ { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 8, 8 }, },
+ { { 2, 7 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
+ { { 2, 7 }, { 5, 5 }, { 7, 2 }, { 6, 7 }, { 7, 6 }, },
};
-/* 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
-
-typedef struct {
- int channel_mode; ///< channel mode (acmod)
- int block_switch[AC3_MAX_CHANNELS]; ///< block switch flags
- int dither_flag[AC3_MAX_CHANNELS]; ///< dither flags
- int dither_all; ///< true if all channels are dithered
- int cpl_in_use; ///< coupling in use
- int channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling
- int phase_flags_in_use; ///< phase flags in use
- int cpl_band_struct[18]; ///< coupling band structure
- int rematrixing_strategy; ///< rematrixing strategy
- int num_rematrixing_bands; ///< number of rematrixing bands
- int rematrixing_flags[4]; ///< rematrixing flags
- int exp_strategy[AC3_MAX_CHANNELS]; ///< exponent strategies
- int snr_offset[AC3_MAX_CHANNELS]; ///< signal-to-noise ratio offsets
- int fast_gain[AC3_MAX_CHANNELS]; ///< fast gain values (signal-to-mask ratio)
- int dba_mode[AC3_MAX_CHANNELS]; ///< delta bit allocation mode
- int dba_nsegs[AC3_MAX_CHANNELS]; ///< number of delta segments
- uint8_t dba_offsets[AC3_MAX_CHANNELS][8]; ///< delta segment offsets
- uint8_t dba_lengths[AC3_MAX_CHANNELS][8]; ///< delta segment lengths
- uint8_t dba_values[AC3_MAX_CHANNELS][8]; ///< delta values for each segment
-
- int sample_rate; ///< sample frequency, in Hz
- int bit_rate; ///< stream bit rate, in bits-per-second
- int frame_size; ///< current frame size, in bytes
-
- int channels; ///< number of total channels
- int fbw_channels; ///< number of full-bandwidth channels
- int lfe_on; ///< 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 dynamic_range[2]; ///< dynamic range
- float cpl_coords[AC3_MAX_CHANNELS][18]; ///< coupling coordinates
- int num_cpl_bands; ///< number of coupling bands
- int num_cpl_subbands; ///< number of coupling sub bands
- int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin
- int end_freq[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 band_psd[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 gbc; ///< bitstream reader
- AVRandomState dith_state; ///< for dither generation
- AVCodecContext *avctx; ///< parent context
-} AC3DecodeContext;
-
-/**
- * Generate a Kaiser-Bessel Derived Window.
- */
-static void ac3_window_init(float *window)
-{
- 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);
-}
-
/**
* Symmetrical Dequantization
* reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
* Tables 7.19 to 7.23
*/
-static inline float
+static inline int
symmetric_dequant(int code, int levels)
{
- return (code - (levels >> 1)) * (2.0f / levels);
+ return ((code - (levels >> 1)) << 24) / levels;
}
/*
* Initialize tables at runtime.
*/
-static void ac3_tables_init(void)
+static av_cold void ac3_tables_init(void)
{
int i;
+ /* generate table for ungrouping 3 values in 7 bits
+ reference: Section 7.1.3 Exponent Decoding */
+ for(i=0; i<128; i++) {
+ ungroup_3_in_7_bits_tab[i][0] = i / 25;
+ ungroup_3_in_7_bits_tab[i][1] = (i % 25) / 5;
+ ungroup_3_in_7_bits_tab[i][2] = (i % 25) % 5;
+ }
+
/* 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);
+ b1_mantissas[i][0] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][0], 3);
+ b1_mantissas[i][1] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][1], 3);
+ b1_mantissas[i][2] = symmetric_dequant(ff_ac3_ungroup_3_in_5_bits_tab[i][2], 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);
+ b2_mantissas[i][0] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][0], 5);
+ b2_mantissas[i][1] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][1], 5);
+ b2_mantissas[i][2] = symmetric_dequant(ungroup_3_in_7_bits_tab[i][2], 5);
/* bap=4 mantissas */
b4_mantissas[i][0] = symmetric_dequant(i / 11, 11);
int v = (i >> 5) - ((i >> 7) << 3) - 5;
dynamic_range_tab[i] = powf(2.0f, v) * ((i & 0x1F) | 0x20);
}
-
- /* 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;
- }
}
/**
* AVCodec initialization
*/
-static int ac3_decode_init(AVCodecContext *avctx)
+static av_cold int ac3_decode_init(AVCodecContext *avctx)
{
AC3DecodeContext *s = avctx->priv_data;
s->avctx = avctx;
ac3_tables_init();
ff_mdct_init(&s->imdct_256, 8, 1);
ff_mdct_init(&s->imdct_512, 9, 1);
- ac3_window_init(s->window);
+ ff_kbd_window_init(s->window, 5.0, 256);
dsputil_init(&s->dsp, avctx);
- av_init_random(0, &s->dith_state);
+ av_lfg_init(&s->dith_state, 0);
/* set bias values for float to int16 conversion */
- if(s->dsp.float_to_int16 == ff_float_to_int16_c) {
+ if(s->dsp.float_to_int16_interleave == ff_float_to_int16_interleave_c) {
s->add_bias = 385.0f;
s->mul_bias = 1.0f;
} else {
s->mul_bias = 32767.0f;
}
+ /* allow downmixing to stereo or mono */
+ if (avctx->channels > 0 && avctx->request_channels > 0 &&
+ avctx->request_channels < avctx->channels &&
+ avctx->request_channels <= 2) {
+ avctx->channels = avctx->request_channels;
+ }
+ s->downmixed = 1;
+
+ /* allocate context input buffer */
+ if (avctx->error_resilience >= FF_ER_CAREFUL) {
+ s->input_buffer = av_mallocz(AC3_FRAME_BUFFER_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
+ if (!s->input_buffer)
+ return AVERROR_NOMEM;
+ }
+
+ avctx->sample_fmt = SAMPLE_FMT_S16;
return 0;
}
/**
* 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.
+ * the start of the synchronized AC-3 bitstream.
*/
static int ac3_parse_header(AC3DecodeContext *s)
{
- AC3HeaderInfo hdr;
GetBitContext *gbc = &s->gbc;
- float center_mix_level, surround_mix_level;
- int err, i;
-
- err = ff_ac3_parse_header(gbc->buffer, &hdr);
- if(err)
- return err;
-
- /* get decoding parameters from header info */
- s->bit_alloc_params.sr_code = hdr.sr_code;
- s->channel_mode = hdr.channel_mode;
- center_mix_level = gain_levels[center_levels[hdr.center_mix_level]];
- surround_mix_level = gain_levels[surround_levels[hdr.surround_mix_level]];
- s->lfe_on = hdr.lfe_on;
- s->bit_alloc_params.sr_shift = hdr.sr_shift;
- s->sample_rate = hdr.sample_rate;
- s->bit_rate = hdr.bit_rate;
- s->channels = hdr.channels;
- s->fbw_channels = s->channels - s->lfe_on;
- s->lfe_ch = s->fbw_channels + 1;
- s->frame_size = hdr.frame_size;
-
- /* set default output to all source channels */
- s->out_channels = s->channels;
- s->output_mode = s->channel_mode;
- if(s->lfe_on)
- s->output_mode |= AC3_OUTPUT_LFEON;
-
- /* skip over portion of header which has already been read */
- skip_bits(gbc, 16); // skip the sync_word
- skip_bits(gbc, 16); // skip crc1
- skip_bits(gbc, 8); // skip fscod and frmsizecod
- skip_bits(gbc, 11); // skip bsid, bsmod, and acmod
- if(s->channel_mode == AC3_CHMODE_STEREO) {
- skip_bits(gbc, 2); // skip dsurmod
- } else {
- if((s->channel_mode & 1) && s->channel_mode != AC3_CHMODE_MONO)
- skip_bits(gbc, 2); // skip cmixlev
- if(s->channel_mode & 4)
- skip_bits(gbc, 2); // skip surmixlev
- }
- skip_bits1(gbc); // skip lfeon
+ int i;
/* read the rest of the bsi. read twice for dual mono mode. */
i = !(s->channel_mode);
} while(i--);
}
- /* set stereo downmixing coefficients
- reference: Section 7.8.2 Downmixing Into Two Channels */
+ return 0;
+}
+
+/**
+ * Common function to parse AC-3 or E-AC-3 frame header
+ */
+static int parse_frame_header(AC3DecodeContext *s)
+{
+ AC3HeaderInfo hdr;
+ int err;
+
+ err = ff_ac3_parse_header(&s->gbc, &hdr);
+ if(err)
+ return err;
+
+ /* get decoding parameters from header info */
+ s->bit_alloc_params.sr_code = hdr.sr_code;
+ s->channel_mode = hdr.channel_mode;
+ s->lfe_on = hdr.lfe_on;
+ s->bit_alloc_params.sr_shift = hdr.sr_shift;
+ s->sample_rate = hdr.sample_rate;
+ s->bit_rate = hdr.bit_rate;
+ s->channels = hdr.channels;
+ s->fbw_channels = s->channels - s->lfe_on;
+ s->lfe_ch = s->fbw_channels + 1;
+ s->frame_size = hdr.frame_size;
+ s->center_mix_level = hdr.center_mix_level;
+ s->surround_mix_level = hdr.surround_mix_level;
+ s->num_blocks = hdr.num_blocks;
+ s->frame_type = hdr.frame_type;
+ s->substreamid = hdr.substreamid;
+
+ if(s->lfe_on) {
+ s->start_freq[s->lfe_ch] = 0;
+ s->end_freq[s->lfe_ch] = 7;
+ s->num_exp_groups[s->lfe_ch] = 2;
+ s->channel_in_cpl[s->lfe_ch] = 0;
+ }
+
+ if (hdr.bitstream_id <= 10) {
+ s->eac3 = 0;
+ s->snr_offset_strategy = 2;
+ s->block_switch_syntax = 1;
+ s->dither_flag_syntax = 1;
+ s->bit_allocation_syntax = 1;
+ s->fast_gain_syntax = 0;
+ s->first_cpl_leak = 0;
+ s->dba_syntax = 1;
+ s->skip_syntax = 1;
+ memset(s->channel_uses_aht, 0, sizeof(s->channel_uses_aht));
+ return ac3_parse_header(s);
+ } else {
+ /*s->eac3 = 1;
+ return ff_eac3_parse_header(s);*/
+ return AC3_PARSE_ERROR_BSID;
+ }
+}
+
+/**
+ * Set stereo downmixing coefficients based on frame header info.
+ * reference: Section 7.8.2 Downmixing Into Two Channels
+ */
+static void set_downmix_coeffs(AC3DecodeContext *s)
+{
+ int i;
+ float cmix = gain_levels[center_levels[s->center_mix_level]];
+ float smix = gain_levels[surround_levels[s->surround_mix_level]];
+ float norm0, norm1;
+
for(i=0; i<s->fbw_channels; i++) {
s->downmix_coeffs[i][0] = gain_levels[ac3_default_coeffs[s->channel_mode][i][0]];
s->downmix_coeffs[i][1] = gain_levels[ac3_default_coeffs[s->channel_mode][i][1]];
}
if(s->channel_mode > 1 && s->channel_mode & 1) {
- s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = center_mix_level;
+ s->downmix_coeffs[1][0] = s->downmix_coeffs[1][1] = cmix;
}
if(s->channel_mode == AC3_CHMODE_2F1R || s->channel_mode == AC3_CHMODE_3F1R) {
int nf = s->channel_mode - 2;
- s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = surround_mix_level * LEVEL_MINUS_3DB;
+ s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf][1] = smix * LEVEL_MINUS_3DB;
}
if(s->channel_mode == AC3_CHMODE_2F2R || s->channel_mode == AC3_CHMODE_3F2R) {
int nf = s->channel_mode - 4;
- s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf+1][1] = surround_mix_level;
+ s->downmix_coeffs[nf][0] = s->downmix_coeffs[nf+1][1] = smix;
}
- return 0;
+ /* renormalize */
+ norm0 = norm1 = 0.0;
+ for(i=0; i<s->fbw_channels; i++) {
+ norm0 += s->downmix_coeffs[i][0];
+ norm1 += s->downmix_coeffs[i][1];
+ }
+ norm0 = 1.0f / norm0;
+ norm1 = 1.0f / norm1;
+ for(i=0; i<s->fbw_channels; i++) {
+ s->downmix_coeffs[i][0] *= norm0;
+ s->downmix_coeffs[i][1] *= norm1;
+ }
+
+ if(s->output_mode == AC3_CHMODE_MONO) {
+ for(i=0; i<s->fbw_channels; i++)
+ s->downmix_coeffs[i][0] = (s->downmix_coeffs[i][0] + s->downmix_coeffs[i][1]) * LEVEL_MINUS_3DB;
+ }
}
/**
group_size = exp_strategy + (exp_strategy == EXP_D45);
for(grp=0,i=0; grp<ngrps; grp++) {
expacc = get_bits(gbc, 7);
- dexp[i++] = exp_ungroup_tab[expacc][0];
- dexp[i++] = exp_ungroup_tab[expacc][1];
- dexp[i++] = exp_ungroup_tab[expacc][2];
+ dexp[i++] = ungroup_3_in_7_bits_tab[expacc][0];
+ dexp[i++] = ungroup_3_in_7_bits_tab[expacc][1];
+ dexp[i++] = ungroup_3_in_7_bits_tab[expacc][2];
}
/* convert to absolute exps and expand groups */
* range using the coupling coefficients and coupling coordinates.
* reference: Section 7.4.3 Coupling Coordinate Format
*/
-static void uncouple_channels(AC3DecodeContext *s)
+static void calc_transform_coeffs_cpl(AC3DecodeContext *s)
{
int i, j, ch, bnd, subbnd;
subbnd++;
for(j=0; j<12; j++) {
for(ch=1; ch<=s->fbw_channels; ch++) {
- if(s->channel_in_cpl[ch])
- s->transform_coeffs[ch][i] = s->transform_coeffs[CPL_CH][i] * s->cpl_coords[ch][bnd] * 8.0f;
+ if(s->channel_in_cpl[ch]) {
+ s->fixed_coeffs[ch][i] = ((int64_t)s->fixed_coeffs[CPL_CH][i] * (int64_t)s->cpl_coords[ch][bnd]) >> 23;
+ if (ch == 2 && s->phase_flags[bnd])
+ s->fixed_coeffs[ch][i] = -s->fixed_coeffs[ch][i];
+ }
}
i++;
}
* 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 b1_mant[3];
+ int b2_mant[3];
+ int b4_mant[2];
int b1ptr;
int b2ptr;
int b4ptr;
* Get the transform coefficients for a particular channel
* reference: Section 7.3 Quantization and Decoding of Mantissas
*/
-static int get_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
+static void ac3_decode_transform_coeffs_ch(AC3DecodeContext *s, int ch_index, mant_groups *m)
{
GetBitContext *gbc = &s->gbc;
int i, gcode, tbap, start, end;
uint8_t *exps;
uint8_t *bap;
- float *coeffs;
+ int *coeffs;
exps = s->dexps[ch_index];
bap = s->bap[ch_index];
- coeffs = s->transform_coeffs[ch_index];
+ coeffs = s->fixed_coeffs[ch_index];
start = s->start_freq[ch_index];
end = s->end_freq[ch_index];
tbap = bap[i];
switch (tbap) {
case 0:
- coeffs[i] = ((av_random(&s->dith_state) & 0xFFFF) / 65535.0f) - 0.5f;
+ coeffs[i] = (av_lfg_get(&s->dith_state) & 0x7FFFFF) - 0x400000;
break;
case 1:
coeffs[i] = b5_mantissas[get_bits(gbc, 4)];
break;
- default:
+ default: {
/* asymmetric dequantization */
- coeffs[i] = get_sbits(gbc, quantization_tab[tbap]) * scale_factors[quantization_tab[tbap]-1];
+ int qlevel = quantization_tab[tbap];
+ coeffs[i] = get_sbits(gbc, qlevel) << (24 - qlevel);
break;
+ }
}
- coeffs[i] *= scale_factors[exps[i]];
+ coeffs[i] >>= exps[i];
}
-
- return 0;
}
/**
static void remove_dithering(AC3DecodeContext *s) {
int ch, i;
int end=0;
- float *coeffs;
+ int *coeffs;
uint8_t *bap;
for(ch=1; ch<=s->fbw_channels; ch++) {
if(!s->dither_flag[ch]) {
- coeffs = s->transform_coeffs[ch];
+ coeffs = s->fixed_coeffs[ch];
bap = s->bap[ch];
if(s->channel_in_cpl[ch])
end = s->start_freq[CPL_CH];
end = s->end_freq[ch];
for(i=0; i<end; i++) {
if(!bap[i])
- coeffs[i] = 0.0f;
+ coeffs[i] = 0;
}
if(s->channel_in_cpl[ch]) {
bap = s->bap[CPL_CH];
for(; i<s->end_freq[CPL_CH]; i++) {
if(!bap[i])
- coeffs[i] = 0.0f;
+ coeffs[i] = 0;
}
}
}
}
}
+static void decode_transform_coeffs_ch(AC3DecodeContext *s, int blk, int ch,
+ mant_groups *m)
+{
+ if (!s->channel_uses_aht[ch]) {
+ ac3_decode_transform_coeffs_ch(s, ch, m);
+ } else {
+ /* if AHT is used, mantissas for all blocks are encoded in the first
+ block of the frame. */
+ int bin;
+ /*
+ if (!blk)
+ ff_eac3_decode_transform_coeffs_aht_ch(s, ch);
+ */
+ for (bin = s->start_freq[ch]; bin < s->end_freq[ch]; bin++) {
+ s->fixed_coeffs[ch][bin] = s->pre_mantissa[ch][bin][blk] >> s->dexps[ch][bin];
+ }
+ }
+}
+
/**
* Get the transform coefficients.
*/
-static int get_transform_coeffs(AC3DecodeContext *s)
+static void decode_transform_coeffs(AC3DecodeContext *s, int blk)
{
int ch, end;
int got_cplchan = 0;
for (ch = 1; ch <= s->channels; ch++) {
/* transform coefficients for full-bandwidth channel */
- if (get_transform_coeffs_ch(s, ch, &m))
- return -1;
+ decode_transform_coeffs_ch(s, blk, ch, &m);
/* tranform coefficients for coupling channel come right after the
coefficients for the first coupled channel*/
if (s->channel_in_cpl[ch]) {
if (!got_cplchan) {
- if (get_transform_coeffs_ch(s, CPL_CH, &m)) {
- av_log(s->avctx, AV_LOG_ERROR, "error in decoupling channels\n");
- return -1;
- }
- uncouple_channels(s);
+ decode_transform_coeffs_ch(s, blk, CPL_CH, &m);
+ calc_transform_coeffs_cpl(s);
got_cplchan = 1;
}
end = s->end_freq[CPL_CH];
end = s->end_freq[ch];
}
do
- s->transform_coeffs[ch][end] = 0;
+ s->fixed_coeffs[ch][end] = 0;
while(++end < 256);
}
/* if any channel doesn't use dithering, zero appropriate coefficients */
if(!s->dither_all)
remove_dithering(s);
-
- return 0;
}
/**
{
int bnd, i;
int end, bndend;
- float tmp0, tmp1;
+ int tmp0, tmp1;
end = FFMIN(s->end_freq[1], s->end_freq[2]);
for(bnd=0; bnd<s->num_rematrixing_bands; bnd++) {
if(s->rematrixing_flags[bnd]) {
- bndend = FFMIN(end, rematrix_band_tab[bnd+1]);
- for(i=rematrix_band_tab[bnd]; i<bndend; i++) {
- tmp0 = s->transform_coeffs[1][i];
- tmp1 = s->transform_coeffs[2][i];
- s->transform_coeffs[1][i] = tmp0 + tmp1;
- s->transform_coeffs[2][i] = tmp0 - tmp1;
+ bndend = FFMIN(end, ff_ac3_rematrix_band_tab[bnd+1]);
+ for(i=ff_ac3_rematrix_band_tab[bnd]; i<bndend; i++) {
+ tmp0 = s->fixed_coeffs[1][i];
+ tmp1 = s->fixed_coeffs[2][i];
+ s->fixed_coeffs[1][i] = tmp0 + tmp1;
+ s->fixed_coeffs[2][i] = tmp0 - tmp1;
}
}
}
}
-/**
- * Perform the 256-point IMDCT
- */
-static void do_imdct_256(AC3DecodeContext *s, int chindex)
-{
- int i, k;
- DECLARE_ALIGNED_16(float, x[128]);
- FFTComplex z[2][64];
- float *o_ptr = s->tmp_output;
-
- for(i=0; i<2; i++) {
- /* de-interleave coefficients */
- for(k=0; k<128; k++) {
- x[k] = s->transform_coeffs[chindex][2*k+i];
- }
-
- /* run standard IMDCT */
- s->imdct_256.fft.imdct_calc(&s->imdct_256, o_ptr, x, s->tmp_imdct);
-
- /* 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];
- }
- }
-
- /* 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;
- }
-}
-
/**
* 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 *s)
+static inline void do_imdct(AC3DecodeContext *s, int channels)
{
int ch;
- int channels;
-
- /* Don't perform the IMDCT on the LFE channel unless it's used in the output */
- channels = s->fbw_channels;
- if(s->output_mode & AC3_OUTPUT_LFEON)
- channels++;
+ float add_bias = s->add_bias;
+ if(s->out_channels==1 && channels>1)
+ add_bias *= LEVEL_MINUS_3DB; // compensate for the gain in downmix
for (ch=1; ch<=channels; ch++) {
if (s->block_switch[ch]) {
- do_imdct_256(s, ch);
+ int i;
+ float *x = s->tmp_output+128;
+ for(i=0; i<128; i++)
+ x[i] = s->transform_coeffs[ch][2*i];
+ ff_imdct_half(&s->imdct_256, s->tmp_output, x);
+ s->dsp.vector_fmul_window(s->output[ch-1], s->delay[ch-1], s->tmp_output, s->window, add_bias, 128);
+ for(i=0; i<128; i++)
+ x[i] = s->transform_coeffs[ch][2*i+1];
+ ff_imdct_half(&s->imdct_256, s->delay[ch-1], x);
} else {
- s->imdct_512.fft.imdct_calc(&s->imdct_512, s->tmp_output,
- s->transform_coeffs[ch], s->tmp_imdct);
+ ff_imdct_half(&s->imdct_512, s->tmp_output, s->transform_coeffs[ch]);
+ s->dsp.vector_fmul_window(s->output[ch-1], s->delay[ch-1], s->tmp_output, s->window, add_bias, 128);
+ memcpy(s->delay[ch-1], s->tmp_output+128, 128*sizeof(float));
}
- /* For the first half of the block, apply the window, add the delay
- from the previous block, and send to output */
- s->dsp.vector_fmul_add_add(s->output[ch-1], s->tmp_output,
- s->window, s->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 */
- s->dsp.vector_fmul_reverse(s->delay[ch-1], s->tmp_output+256,
- s->window, 256);
}
}
/**
* Downmix the output to mono or stereo.
*/
-static void ac3_downmix(AC3DecodeContext *s)
+void ff_ac3_downmix_c(float (*samples)[256], float (*matrix)[2], int out_ch, int in_ch, int len)
{
int i, j;
- float v0, v1, s0, s1;
-
- for(i=0; i<256; i++) {
- v0 = v1 = s0 = s1 = 0.0f;
- for(j=0; j<s->fbw_channels; j++) {
- v0 += s->output[j][i] * s->downmix_coeffs[j][0];
- v1 += s->output[j][i] * s->downmix_coeffs[j][1];
- s0 += s->downmix_coeffs[j][0];
- s1 += s->downmix_coeffs[j][1];
+ float v0, v1;
+ if(out_ch == 2) {
+ for(i=0; i<len; i++) {
+ v0 = v1 = 0.0f;
+ for(j=0; j<in_ch; j++) {
+ v0 += samples[j][i] * matrix[j][0];
+ v1 += samples[j][i] * matrix[j][1];
+ }
+ samples[0][i] = v0;
+ samples[1][i] = v1;
}
- v0 /= s0;
- v1 /= s1;
- if(s->output_mode == AC3_CHMODE_MONO) {
- s->output[0][i] = (v0 + v1) * LEVEL_MINUS_3DB;
- } else if(s->output_mode == AC3_CHMODE_STEREO) {
- s->output[0][i] = v0;
- s->output[1][i] = v1;
+ } else if(out_ch == 1) {
+ for(i=0; i<len; i++) {
+ v0 = 0.0f;
+ for(j=0; j<in_ch; j++)
+ v0 += samples[j][i] * matrix[j][0];
+ samples[0][i] = v0;
}
}
}
/**
- * Parse an audio block from AC-3 bitstream.
+ * Upmix delay samples from stereo to original channel layout.
*/
-static int ac3_parse_audio_block(AC3DecodeContext *s, int blk)
+static void ac3_upmix_delay(AC3DecodeContext *s)
+{
+ int channel_data_size = sizeof(s->delay[0]);
+ switch(s->channel_mode) {
+ case AC3_CHMODE_DUALMONO:
+ case AC3_CHMODE_STEREO:
+ /* upmix mono to stereo */
+ memcpy(s->delay[1], s->delay[0], channel_data_size);
+ break;
+ case AC3_CHMODE_2F2R:
+ memset(s->delay[3], 0, channel_data_size);
+ case AC3_CHMODE_2F1R:
+ memset(s->delay[2], 0, channel_data_size);
+ break;
+ case AC3_CHMODE_3F2R:
+ memset(s->delay[4], 0, channel_data_size);
+ case AC3_CHMODE_3F1R:
+ memset(s->delay[3], 0, channel_data_size);
+ case AC3_CHMODE_3F:
+ memcpy(s->delay[2], s->delay[1], channel_data_size);
+ memset(s->delay[1], 0, channel_data_size);
+ break;
+ }
+}
+
+/**
+ * Decode a single audio block from the AC-3 bitstream.
+ */
+static int decode_audio_block(AC3DecodeContext *s, int blk)
{
int fbw_channels = s->fbw_channels;
int channel_mode = s->channel_mode;
int i, bnd, seg, ch;
+ int different_transforms;
+ int downmix_output;
+ int cpl_in_use;
GetBitContext *gbc = &s->gbc;
uint8_t bit_alloc_stages[AC3_MAX_CHANNELS];
memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
/* block switch flags */
- for (ch = 1; ch <= fbw_channels; ch++)
- s->block_switch[ch] = get_bits1(gbc);
+ different_transforms = 0;
+ if (s->block_switch_syntax) {
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ s->block_switch[ch] = get_bits1(gbc);
+ if(ch > 1 && s->block_switch[ch] != s->block_switch[1])
+ different_transforms = 1;
+ }
+ }
/* dithering flags */
- s->dither_all = 1;
- for (ch = 1; ch <= fbw_channels; ch++) {
- s->dither_flag[ch] = get_bits1(gbc);
- if(!s->dither_flag[ch])
- s->dither_all = 0;
+ if (s->dither_flag_syntax) {
+ s->dither_all = 1;
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ s->dither_flag[ch] = get_bits1(gbc);
+ if(!s->dither_flag[ch])
+ s->dither_all = 0;
+ }
}
/* dynamic range */
}
} while(i--);
+ /* spectral extension strategy */
+ if (s->eac3 && (!blk || get_bits1(gbc))) {
+ if (get_bits1(gbc)) {
+ av_log_missing_feature(s->avctx, "Spectral extension", 1);
+ return -1;
+ }
+ /* TODO: parse spectral extension strategy info */
+ }
+
+ /* TODO: spectral extension coordinates */
+
/* coupling strategy */
if (get_bits1(gbc)) {
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
- s->cpl_in_use = get_bits1(gbc);
- if (s->cpl_in_use) {
+ if (!s->eac3)
+ s->cpl_in_use[blk] = get_bits1(gbc);
+ if (s->cpl_in_use[blk]) {
/* coupling in use */
int cpl_begin_freq, cpl_end_freq;
+ if (channel_mode < AC3_CHMODE_STEREO) {
+ av_log(s->avctx, AV_LOG_ERROR, "coupling not allowed in mono or dual-mono\n");
+ return -1;
+ }
+
+ /* check for enhanced coupling */
+ if (s->eac3 && get_bits1(gbc)) {
+ /* TODO: parse enhanced coupling strategy info */
+ av_log_missing_feature(s->avctx, "Enhanced coupling", 1);
+ return -1;
+ }
+
/* determine which channels are coupled */
- for (ch = 1; ch <= fbw_channels; ch++)
- s->channel_in_cpl[ch] = get_bits1(gbc);
+ if (s->eac3 && s->channel_mode == AC3_CHMODE_STEREO) {
+ s->channel_in_cpl[1] = 1;
+ s->channel_in_cpl[2] = 1;
+ } else {
+ for (ch = 1; ch <= fbw_channels; ch++)
+ s->channel_in_cpl[ch] = get_bits1(gbc);
+ }
/* phase flags in use */
if (channel_mode == AC3_CHMODE_STEREO)
s->phase_flags_in_use = get_bits1(gbc);
- /* coupling frequency range and band structure */
+ /* coupling frequency range */
+ /* TODO: modify coupling end freq if spectral extension is used */
cpl_begin_freq = get_bits(gbc, 4);
cpl_end_freq = get_bits(gbc, 4);
if (3 + cpl_end_freq - cpl_begin_freq < 0) {
s->num_cpl_bands = s->num_cpl_subbands = 3 + cpl_end_freq - cpl_begin_freq;
s->start_freq[CPL_CH] = cpl_begin_freq * 12 + 37;
s->end_freq[CPL_CH] = cpl_end_freq * 12 + 73;
- for (bnd = 0; bnd < s->num_cpl_subbands - 1; bnd++) {
- if (get_bits1(gbc)) {
- s->cpl_band_struct[bnd] = 1;
- s->num_cpl_bands--;
+
+ /* coupling band structure */
+ if (!s->eac3 || get_bits1(gbc)) {
+ for (bnd = 0; bnd < s->num_cpl_subbands - 1; bnd++) {
+ s->cpl_band_struct[bnd] = get_bits1(gbc);
}
+ } else if (!blk) {
+ }
+ s->cpl_band_struct[s->num_cpl_subbands-1] = 0;
+
+ /* calculate number of coupling bands based on band structure */
+ for (bnd = 0; bnd < s->num_cpl_subbands-1; bnd++) {
+ s->num_cpl_bands -= s->cpl_band_struct[bnd];
}
} else {
/* coupling not in use */
- for (ch = 1; ch <= fbw_channels; ch++)
+ for (ch = 1; ch <= fbw_channels; ch++) {
s->channel_in_cpl[ch] = 0;
+ s->first_cpl_coords[ch] = 1;
+ }
+ s->first_cpl_leak = s->eac3;
+ s->phase_flags_in_use = 0;
+ }
+ } else if (!s->eac3) {
+ if(!blk) {
+ av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must be present in block 0\n");
+ return -1;
+ } else {
+ s->cpl_in_use[blk] = s->cpl_in_use[blk-1];
}
}
+ cpl_in_use = s->cpl_in_use[blk];
/* coupling coordinates */
- if (s->cpl_in_use) {
+ if (cpl_in_use) {
int cpl_coords_exist = 0;
for (ch = 1; ch <= fbw_channels; ch++) {
cpl_coord_exp = get_bits(gbc, 4);
cpl_coord_mant = get_bits(gbc, 4);
if (cpl_coord_exp == 15)
- s->cpl_coords[ch][bnd] = cpl_coord_mant / 16.0f;
+ s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
else
- s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16.0f) / 32.0f;
- s->cpl_coords[ch][bnd] *= scale_factors[cpl_coord_exp + master_cpl_coord];
+ s->cpl_coords[ch][bnd] = (cpl_coord_mant + 16) << 21;
+ s->cpl_coords[ch][bnd] >>= (cpl_coord_exp + master_cpl_coord);
}
+ } else if (!blk) {
+ av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must be present in block 0\n");
+ return -1;
}
}
}
/* phase flags */
- if (channel_mode == AC3_CHMODE_STEREO && s->phase_flags_in_use && cpl_coords_exist) {
+ if (channel_mode == AC3_CHMODE_STEREO && cpl_coords_exist) {
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
- if (get_bits1(gbc))
- s->cpl_coords[2][bnd] = -s->cpl_coords[2][bnd];
+ s->phase_flags[bnd] = s->phase_flags_in_use? get_bits1(gbc) : 0;
}
}
}
/* stereo rematrixing strategy and band structure */
if (channel_mode == AC3_CHMODE_STEREO) {
- s->rematrixing_strategy = get_bits1(gbc);
- if (s->rematrixing_strategy) {
+ if ((s->eac3 && !blk) || get_bits1(gbc)) {
s->num_rematrixing_bands = 4;
- if(s->cpl_in_use && s->start_freq[CPL_CH] <= 61)
+ if(cpl_in_use && s->start_freq[CPL_CH] <= 61)
s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
for(bnd=0; bnd<s->num_rematrixing_bands; bnd++)
s->rematrixing_flags[bnd] = get_bits1(gbc);
+ } else if (!blk) {
+ av_log(s->avctx, AV_LOG_ERROR, "new rematrixing strategy must be present in block 0\n");
+ return -1;
}
}
/* exponent strategies for each channel */
- s->exp_strategy[CPL_CH] = EXP_REUSE;
- s->exp_strategy[s->lfe_ch] = EXP_REUSE;
- for (ch = !s->cpl_in_use; ch <= s->channels; ch++) {
- if(ch == s->lfe_ch)
- s->exp_strategy[ch] = get_bits(gbc, 1);
- else
- s->exp_strategy[ch] = get_bits(gbc, 2);
- if(s->exp_strategy[ch] != EXP_REUSE)
+ s->exp_strategy[blk][CPL_CH] = EXP_REUSE;
+ s->exp_strategy[blk][s->lfe_ch] = EXP_REUSE;
+ for (ch = !cpl_in_use; ch <= s->channels; ch++) {
+ s->exp_strategy[blk][ch] = get_bits(gbc, 2 - (ch == s->lfe_ch));
+ if(s->exp_strategy[blk][ch] != EXP_REUSE)
bit_alloc_stages[ch] = 3;
}
/* channel bandwidth */
for (ch = 1; ch <= fbw_channels; ch++) {
s->start_freq[ch] = 0;
- if (s->exp_strategy[ch] != EXP_REUSE) {
+ if (s->exp_strategy[blk][ch] != EXP_REUSE) {
+ int group_size;
int prev = s->end_freq[ch];
if (s->channel_in_cpl[ch])
s->end_freq[ch] = s->start_freq[CPL_CH];
}
s->end_freq[ch] = bandwidth_code * 3 + 73;
}
+ group_size = 3 << (s->exp_strategy[blk][ch] - 1);
+ s->num_exp_groups[ch] = (s->end_freq[ch]+group_size-4) / group_size;
if(blk > 0 && s->end_freq[ch] != prev)
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
}
}
- s->start_freq[s->lfe_ch] = 0;
- s->end_freq[s->lfe_ch] = 7;
+ if (cpl_in_use && s->exp_strategy[blk][CPL_CH] != EXP_REUSE) {
+ s->num_exp_groups[CPL_CH] = (s->end_freq[CPL_CH] - s->start_freq[CPL_CH]) /
+ (3 << (s->exp_strategy[blk][CPL_CH] - 1));
+ }
/* decode exponents for each channel */
- for (ch = !s->cpl_in_use; ch <= s->channels; ch++) {
- if (s->exp_strategy[ch] != EXP_REUSE) {
- int group_size, num_groups;
- group_size = 3 << (s->exp_strategy[ch] - 1);
- if(ch == CPL_CH)
- num_groups = (s->end_freq[ch] - s->start_freq[ch]) / group_size;
- else if(ch == s->lfe_ch)
- num_groups = 2;
- else
- num_groups = (s->end_freq[ch] + group_size - 4) / group_size;
+ for (ch = !cpl_in_use; ch <= s->channels; ch++) {
+ if (s->exp_strategy[blk][ch] != EXP_REUSE) {
s->dexps[ch][0] = get_bits(gbc, 4) << !ch;
- decode_exponents(gbc, s->exp_strategy[ch], num_groups, s->dexps[ch][0],
+ decode_exponents(gbc, s->exp_strategy[blk][ch],
+ s->num_exp_groups[ch], s->dexps[ch][0],
&s->dexps[ch][s->start_freq[ch]+!!ch]);
if(ch != CPL_CH && ch != s->lfe_ch)
skip_bits(gbc, 2); /* skip gainrng */
}
/* bit allocation information */
- if (get_bits1(gbc)) {
- s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
- s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
- s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
- s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
- s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
- for(ch=!s->cpl_in_use; ch<=s->channels; ch++) {
- bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
+ if (s->bit_allocation_syntax) {
+ if (get_bits1(gbc)) {
+ s->bit_alloc_params.slow_decay = ff_ac3_slow_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
+ s->bit_alloc_params.fast_decay = ff_ac3_fast_decay_tab[get_bits(gbc, 2)] >> s->bit_alloc_params.sr_shift;
+ s->bit_alloc_params.slow_gain = ff_ac3_slow_gain_tab[get_bits(gbc, 2)];
+ s->bit_alloc_params.db_per_bit = ff_ac3_db_per_bit_tab[get_bits(gbc, 2)];
+ s->bit_alloc_params.floor = ff_ac3_floor_tab[get_bits(gbc, 3)];
+ for(ch=!cpl_in_use; ch<=s->channels; ch++)
+ bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
+ } else if (!blk) {
+ av_log(s->avctx, AV_LOG_ERROR, "new bit allocation info must be present in block 0\n");
+ return -1;
}
}
if (get_bits1(gbc)) {
int csnr;
csnr = (get_bits(gbc, 6) - 15) << 4;
- for (ch = !s->cpl_in_use; ch <= s->channels; ch++) { /* snr offset and fast gain */
+ for (ch = !cpl_in_use; ch <= s->channels; ch++) { /* snr offset and fast gain */
s->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2;
s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
}
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
+ } else if (!blk) {
+ av_log(s->avctx, AV_LOG_ERROR, "new snr offsets must be present in block 0\n");
+ return -1;
+ }
+
+ /* fast gain (E-AC-3 only) */
+ if (s->fast_gain_syntax && get_bits1(gbc)) {
+ for (ch = !cpl_in_use; ch <= s->channels; ch++) {
+ int prev = s->fast_gain[ch];
+ s->fast_gain[ch] = ff_ac3_fast_gain_tab[get_bits(gbc, 3)];
+ /* run last 2 bit allocation stages if fast gain changes */
+ if(blk && prev != s->fast_gain[ch])
+ bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
+ }
+ } else if (s->eac3 && !blk) {
+ for (ch = !cpl_in_use; ch <= s->channels; ch++)
+ s->fast_gain[ch] = ff_ac3_fast_gain_tab[4];
+ }
+
+ /* E-AC-3 to AC-3 converter SNR offset */
+ if (s->frame_type == EAC3_FRAME_TYPE_INDEPENDENT && get_bits1(gbc)) {
+ skip_bits(gbc, 10); // skip converter snr offset
}
/* coupling leak information */
- if (s->cpl_in_use && get_bits1(gbc)) {
- s->bit_alloc_params.cpl_fast_leak = get_bits(gbc, 3);
- s->bit_alloc_params.cpl_slow_leak = get_bits(gbc, 3);
- bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
+ if (cpl_in_use) {
+ if (get_bits1(gbc)) {
+ s->bit_alloc_params.cpl_fast_leak = get_bits(gbc, 3);
+ s->bit_alloc_params.cpl_slow_leak = get_bits(gbc, 3);
+ bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
+ } else if (!blk) {
+ av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must be present in block 0\n");
+ return -1;
+ }
}
/* delta bit allocation information */
- if (get_bits1(gbc)) {
+ if (s->dba_syntax && get_bits1(gbc)) {
/* delta bit allocation exists (strategy) */
- for (ch = !s->cpl_in_use; ch <= fbw_channels; ch++) {
+ for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
s->dba_mode[ch] = get_bits(gbc, 2);
if (s->dba_mode[ch] == DBA_RESERVED) {
av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
}
/* channel delta offset, len and bit allocation */
- for (ch = !s->cpl_in_use; ch <= fbw_channels; ch++) {
+ for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
if (s->dba_mode[ch] == DBA_NEW) {
s->dba_nsegs[ch] = get_bits(gbc, 3);
for (seg = 0; seg <= s->dba_nsegs[ch]; seg++) {
s->dba_lengths[ch][seg] = get_bits(gbc, 4);
s->dba_values[ch][seg] = get_bits(gbc, 3);
}
+ /* run last 2 bit allocation stages if new dba values */
+ bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
}
}
} else if(blk == 0) {
}
/* Bit allocation */
- for(ch=!s->cpl_in_use; ch<=s->channels; ch++) {
+ for(ch=!cpl_in_use; ch<=s->channels; ch++) {
if(bit_alloc_stages[ch] > 2) {
/* Exponent mapping into PSD and PSD integration */
ff_ac3_bit_alloc_calc_psd(s->dexps[ch],
}
if(bit_alloc_stages[ch] > 0) {
/* Compute bit allocation */
+ const uint8_t *bap_tab = s->channel_uses_aht[ch] ?
+ ff_eac3_hebap_tab : ff_ac3_bap_tab;
ff_ac3_bit_alloc_calc_bap(s->mask[ch], s->psd[ch],
s->start_freq[ch], s->end_freq[ch],
s->snr_offset[ch],
s->bit_alloc_params.floor,
- s->bap[ch]);
+ bap_tab, s->bap[ch]);
}
}
/* unused dummy data */
- if (get_bits1(gbc)) {
+ if (s->skip_syntax && get_bits1(gbc)) {
int skipl = get_bits(gbc, 9);
while(skipl--)
skip_bits(gbc, 8);
/* unpack the transform coefficients
this also uncouples channels if coupling is in use. */
- if (get_transform_coeffs(s)) {
- av_log(s->avctx, AV_LOG_ERROR, "Error in routine get_transform_coeffs\n");
- return -1;
- }
+ decode_transform_coeffs(s, blk);
+
+ /* TODO: generate enhanced coupling coordinates and uncouple */
+
+ /* TODO: apply spectral extension */
/* recover coefficients if rematrixing is in use */
if(s->channel_mode == AC3_CHMODE_STEREO)
/* apply scaling to coefficients (headroom, dynrng) */
for(ch=1; ch<=s->channels; ch++) {
- float gain = 2.0f * s->mul_bias;
+ float gain = s->mul_bias / 4194304.0f;
if(s->channel_mode == AC3_CHMODE_DUALMONO) {
gain *= s->dynamic_range[ch-1];
} else {
gain *= s->dynamic_range[0];
}
- for(i=0; i<s->end_freq[ch]; i++) {
- s->transform_coeffs[ch][i] *= gain;
- }
+ s->dsp.int32_to_float_fmul_scalar(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
}
- do_imdct(s);
+ /* downmix and MDCT. order depends on whether block switching is used for
+ any channel in this block. this is because coefficients for the long
+ and short transforms cannot be mixed. */
+ downmix_output = s->channels != s->out_channels &&
+ !((s->output_mode & AC3_OUTPUT_LFEON) &&
+ s->fbw_channels == s->out_channels);
+ if(different_transforms) {
+ /* the delay samples have already been downmixed, so we upmix the delay
+ samples in order to reconstruct all channels before downmixing. */
+ if(s->downmixed) {
+ s->downmixed = 0;
+ ac3_upmix_delay(s);
+ }
- /* downmix output if needed */
- if(s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
- s->fbw_channels == s->out_channels)) {
- ac3_downmix(s);
- }
+ do_imdct(s, s->channels);
- /* convert float to 16-bit integer */
- for(ch=0; ch<s->out_channels; ch++) {
- for(i=0; i<256; i++) {
- s->output[ch][i] += s->add_bias;
+ if(downmix_output) {
+ s->dsp.ac3_downmix(s->output, s->downmix_coeffs, s->out_channels, s->fbw_channels, 256);
}
- s->dsp.float_to_int16(s->int_output[ch], s->output[ch], 256);
+ } else {
+ if(downmix_output) {
+ s->dsp.ac3_downmix(s->transform_coeffs+1, s->downmix_coeffs, s->out_channels, s->fbw_channels, 256);
+ }
+
+ if(downmix_output && !s->downmixed) {
+ s->downmixed = 1;
+ s->dsp.ac3_downmix(s->delay, s->downmix_coeffs, s->out_channels, s->fbw_channels, 128);
+ }
+
+ do_imdct(s, s->out_channels);
}
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)
+static int ac3_decode_frame(AVCodecContext * avctx, void *data, int *data_size,
+ const uint8_t *buf, int buf_size)
{
AC3DecodeContext *s = avctx->priv_data;
int16_t *out_samples = (int16_t *)data;
- int i, blk, ch, err;
+ int blk, ch, err;
/* initialize the GetBitContext with the start of valid AC-3 Frame */
- init_get_bits(&s->gbc, buf, buf_size * 8);
+ if (s->input_buffer) {
+ /* copy input buffer to decoder context to avoid reading past the end
+ of the buffer, which can be caused by a damaged input stream. */
+ memcpy(s->input_buffer, buf, FFMIN(buf_size, AC3_FRAME_BUFFER_SIZE));
+ init_get_bits(&s->gbc, s->input_buffer, buf_size * 8);
+ } else {
+ init_get_bits(&s->gbc, buf, buf_size * 8);
+ }
/* parse the syncinfo */
- err = ac3_parse_header(s);
- if(err) {
+ *data_size = 0;
+ err = parse_frame_header(s);
+
+ /* check that reported frame size fits in input buffer */
+ if(s->frame_size > buf_size) {
+ av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
+ err = AC3_PARSE_ERROR_FRAME_SIZE;
+ }
+
+ /* check for crc mismatch */
+ if(err != AC3_PARSE_ERROR_FRAME_SIZE && avctx->error_resilience >= FF_ER_CAREFUL) {
+ if(av_crc(av_crc_get_table(AV_CRC_16_ANSI), 0, &buf[2], s->frame_size-2)) {
+ av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
+ err = AC3_PARSE_ERROR_CRC;
+ }
+ }
+
+ if(err && err != AC3_PARSE_ERROR_CRC) {
switch(err) {
case AC3_PARSE_ERROR_SYNC:
av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
- break;
+ return -1;
case AC3_PARSE_ERROR_BSID:
av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
break;
case AC3_PARSE_ERROR_FRAME_SIZE:
av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
break;
+ case AC3_PARSE_ERROR_FRAME_TYPE:
+ /* skip frame if CRC is ok. otherwise use error concealment. */
+ /* TODO: add support for substreams and dependent frames */
+ if(s->frame_type == EAC3_FRAME_TYPE_DEPENDENT || s->substreamid) {
+ av_log(avctx, AV_LOG_ERROR, "unsupported frame type : skipping frame\n");
+ return s->frame_size;
+ } else {
+ av_log(avctx, AV_LOG_ERROR, "invalid frame type\n");
+ }
+ break;
default:
av_log(avctx, AV_LOG_ERROR, "invalid header\n");
break;
}
- return -1;
}
- /* check that reported frame size fits in input buffer */
- if(s->frame_size > buf_size) {
- av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
- return -1;
- }
+ /* if frame is ok, set audio parameters */
+ if (!err) {
+ avctx->sample_rate = s->sample_rate;
+ avctx->bit_rate = s->bit_rate;
+
+ /* channel config */
+ s->out_channels = s->channels;
+ s->output_mode = s->channel_mode;
+ if(s->lfe_on)
+ s->output_mode |= AC3_OUTPUT_LFEON;
+ if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&
+ avctx->request_channels < s->channels) {
+ s->out_channels = avctx->request_channels;
+ s->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
+ }
+ avctx->channels = s->out_channels;
- /* check for crc mismatch */
- if(avctx->error_resilience > 0) {
- if(av_crc(av_crc8005, 0, &buf[2], s->frame_size-2)) {
- av_log(avctx, AV_LOG_ERROR, "frame CRC mismatch\n");
- return -1;
+ /* set downmixing coefficients if needed */
+ if(s->channels != s->out_channels && !((s->output_mode & AC3_OUTPUT_LFEON) &&
+ s->fbw_channels == s->out_channels)) {
+ set_downmix_coeffs(s);
}
- /* TODO: error concealment */
+ } else if (!s->out_channels) {
+ s->out_channels = avctx->channels;
+ if(s->out_channels < s->channels)
+ s->output_mode = s->out_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
}
- avctx->sample_rate = s->sample_rate;
- avctx->bit_rate = s->bit_rate;
-
- /* channel config */
- s->out_channels = s->channels;
- if (avctx->request_channels > 0 && avctx->request_channels <= 2 &&
- avctx->request_channels < s->channels) {
- s->out_channels = avctx->request_channels;
- s->output_mode = avctx->request_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
- }
- avctx->channels = s->out_channels;
-
- /* parse the audio blocks */
- for (blk = 0; blk < NB_BLOCKS; blk++) {
- if (ac3_parse_audio_block(s, blk)) {
- av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
- *data_size = 0;
- return s->frame_size;
+ /* decode the audio blocks */
+ for (blk = 0; blk < s->num_blocks; blk++) {
+ const float *output[s->out_channels];
+ if (!err && decode_audio_block(s, blk)) {
+ av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n");
}
- for (i = 0; i < 256; i++)
- for (ch = 0; ch < s->out_channels; ch++)
- *(out_samples++) = s->int_output[ch][i];
+ for (ch = 0; ch < s->out_channels; ch++)
+ output[ch] = s->output[ch];
+ s->dsp.float_to_int16_interleave(out_samples, output, 256, s->out_channels);
+ out_samples += 256 * s->out_channels;
}
- *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t);
+ *data_size = s->num_blocks * 256 * avctx->channels * sizeof (int16_t);
return s->frame_size;
}
/**
* Uninitialize the AC-3 decoder.
*/
-static int ac3_decode_end(AVCodecContext *avctx)
+static av_cold int ac3_decode_end(AVCodecContext *avctx)
{
AC3DecodeContext *s = avctx->priv_data;
ff_mdct_end(&s->imdct_512);
ff_mdct_end(&s->imdct_256);
+ av_freep(&s->input_buffer);
+
return 0;
}
.init = ac3_decode_init,
.close = ac3_decode_end,
.decode = ac3_decode_frame,
+ .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52 (AC-3, E-AC-3)"),
};
projects / ffmpeg / blobdiff