#include <string.h>
#include "avcodec.h"
-#include "ac3.h"
-#include "ac3tab.h"
+#include "ac3_parser.h"
#include "bitstream.h"
#include "dsputil.h"
#include "random.h"
-static const int nfchans_tbl[8] = { 2, 1, 2, 3, 3, 4, 4, 5 };
+/**
+ * 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 };
-/* table for exponent to scale_factor mapping
- * scale_factor[i] = 2 ^ -(i + 15)
+/**
+ * table for exponent to scale_factor mapping
+ * scale_factors[i] = 2 ^ -i
*/
static float scale_factors[25];
/** table for grouping exponents */
-static uint8_t exp_ungroup_tbl[128][3];
+static uint8_t exp_ungroup_tab[128][3];
-static int16_t l3_quantizers_1[32];
-static int16_t l3_quantizers_2[32];
-static int16_t l3_quantizers_3[32];
-static int16_t l5_quantizers_1[128];
-static int16_t l5_quantizers_2[128];
-static int16_t l5_quantizers_3[128];
+/** 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 int16_t l7_quantizers[7];
-
-static int16_t l11_quantizers_1[128];
-static int16_t l11_quantizers_2[128];
+/**
+ * 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
+};
-static int16_t l15_quantizers[15];
+/** dynamic range table. converts codes to scale factors. */
+static float dynrng_tab[256];
-static const uint8_t qntztab[16] = { 0, 5, 7, 3, 7, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16 };
+/** dialogue normalization table */
+static float dialnorm_tab[32];
-/* Adjustmens in dB gain */
+/** Adjustments in dB gain */
#define LEVEL_MINUS_3DB 0.7071067811865476
#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
#define LEVEL_MINUS_6DB 0.5000000000000000
-#define LEVEL_PLUS_3DB 1.4142135623730951
-#define LEVEL_PLUS_6DB 2.0000000000000000
+#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
+};
+
+/**
+ * Table for center mix levels
+ * reference: Section 5.4.2.4 cmixlev
+ */
+static const uint8_t clevs[4] = { 2, 3, 4, 3 };
-static const float clevs[4] = { LEVEL_MINUS_3DB, LEVEL_MINUS_4POINT5DB,
- LEVEL_MINUS_6DB, LEVEL_MINUS_4POINT5DB };
+/**
+ * Table for surround mix levels
+ * reference: Section 5.4.2.5 surmixlev
+ */
+static const uint8_t slevs[4] = { 2, 4, 0, 4 };
-static const float slevs[4] = { LEVEL_MINUS_3DB, LEVEL_MINUS_6DB, LEVEL_ZERO, LEVEL_MINUS_6DB };
+/**
+ * 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 }, },
+};
-#define BLOCK_SIZE 256
+/* override ac3.h to include coupling channel */
+#undef AC3_MAX_CHANNELS
+#define AC3_MAX_CHANNELS 7
+#define CPL_CH 0
-/* Output and input configurations. */
-#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_OUTPUT_LFEON 8
typedef struct {
- uint16_t crc1;
- uint8_t fscod;
-
- uint8_t acmod;
- uint8_t cmixlev;
- uint8_t surmixlev;
- uint8_t dsurmod;
-
- uint8_t blksw;
- uint8_t dithflag;
- uint8_t cplinu;
- uint8_t chincpl;
- uint8_t phsflginu;
- uint8_t cplbegf;
- uint8_t cplendf;
- uint8_t cplcoe;
- uint32_t cplbndstrc;
- uint8_t rematstr;
- uint8_t rematflg;
- uint8_t cplexpstr;
- uint8_t lfeexpstr;
- uint8_t chexpstr[5];
- uint8_t sdcycod;
- uint8_t fdcycod;
- uint8_t sgaincod;
- uint8_t dbpbcod;
- uint8_t floorcod;
- uint8_t csnroffst;
- uint8_t cplfsnroffst;
- uint8_t cplfgaincod;
- uint8_t fsnroffst[5];
- uint8_t fgaincod[5];
- uint8_t lfefsnroffst;
- uint8_t lfefgaincod;
- uint8_t cplfleak;
- uint8_t cplsleak;
- uint8_t cpldeltbae;
- uint8_t deltbae[5];
- uint8_t cpldeltnseg;
- uint8_t cpldeltoffst[8];
- uint8_t cpldeltlen[8];
- uint8_t cpldeltba[8];
- uint8_t deltnseg[5];
- uint8_t deltoffst[5][8];
- uint8_t deltlen[5][8];
- uint8_t deltba[5][8];
-
- /* Derived Attributes. */
- int sampling_rate;
- int bit_rate;
- int frame_size;
-
- int nfchans; //number of channels
- int lfeon; //lfe channel in use
-
- float dynrng; //dynamic range gain
- float dynrng2; //dynamic range gain for 1+1 mode
- float chcoeffs[6]; //normalized channel coefficients
- float cplco[5][18]; //coupling coordinates
- int ncplbnd; //number of coupling bands
- int ncplsubnd; //number of coupling sub bands
- int cplstrtmant; //coupling start mantissa
- int cplendmant; //coupling end mantissa
- int endmant[5]; //channel end mantissas
+ 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
- uint8_t dcplexps[256]; //decoded coupling exponents
- uint8_t dexps[5][256]; //decoded fbw channel exponents
- uint8_t dlfeexps[256]; //decoded lfe channel exponents
- uint8_t cplbap[256]; //coupling bit allocation pointers
- uint8_t bap[5][256]; //fbw channel bit allocation pointers
- uint8_t lfebap[256]; //lfe channel bit allocation pointers
-
- int blkoutput; //output configuration for block
+ 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][BLOCK_SIZE]); //transform coefficients
+ DECLARE_ALIGNED_16(float, transform_coeffs[AC3_MAX_CHANNELS][256]); ///< transform coefficients
/* For IMDCT. */
- MDCTContext imdct_512; //for 512 sample imdct transform
- MDCTContext imdct_256; //for 256 sample imdct transform
- DSPContext dsp; //for optimization
-
- DECLARE_ALIGNED_16(float, output[AC3_MAX_CHANNELS][BLOCK_SIZE]); //output after imdct transform and windowing
- DECLARE_ALIGNED_16(float, delay[AC3_MAX_CHANNELS][BLOCK_SIZE]); //delay - added to the next block
- DECLARE_ALIGNED_16(float, tmp_imdct[BLOCK_SIZE]); //temporary storage for imdct transform
- DECLARE_ALIGNED_16(float, tmp_output[BLOCK_SIZE * 2]); //temporary storage for output before windowing
- DECLARE_ALIGNED_16(float, window[BLOCK_SIZE]); //window coefficients
+ 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;
- AVRandomState dith_state; //for dither generation
+ GetBitContext gb; ///< bitstream reader
+ AVRandomState dith_state; ///< for dither generation
+ AVCodecContext *avctx; ///< parent context
} AC3DecodeContext;
-/*********** BEGIN INIT HELPER FUNCTIONS ***********/
/**
* Generate a Kaiser-Bessel Derived Window.
*/
for (i = 0; i < 256; i++) {
tmp = i * (256 - i) * alpha2;
bessel = 1.0;
- for (j = 100; j > 0; j--) /* defaul to 100 iterations */
+ for (j = 100; j > 0; j--) /* default to 100 iterations */
bessel = bessel * tmp / (j * j) + 1;
sum += bessel;
local_window[i] = sum;
window[i] = sqrt(local_window[i] / sum);
}
-/*
- * Generate quantizer tables.
+/**
+ * Symmetrical Dequantization
+ * reference: Section 7.3.3 Expansion of Mantissas for Symmetrical Quantization
+ * Tables 7.19 to 7.23
*/
-static void generate_quantizers_table(int16_t quantizers[], int level, int length)
+static inline float
+symmetric_dequant(int code, int levels)
{
- int i;
-
- for (i = 0; i < length; i++)
- quantizers[i] = ((2 * i - level + 1) << 15) / level;
-}
-
-static void generate_quantizers_table_1(int16_t quantizers[], int level, int length1, int length2, int size)
-{
- int i, j;
- int16_t v;
-
- for (i = 0; i < length1; i++) {
- v = ((2 * i - level + 1) << 15) / level;
- for (j = 0; j < length2; j++)
- quantizers[i * length2 + j] = v;
- }
-
- for (i = length1 * length2; i < size; i++)
- quantizers[i] = 0;
-}
-
-static void generate_quantizers_table_2(int16_t quantizers[], int level, int length1, int length2, int size)
-{
- int i, j;
- int16_t v;
-
- for (i = 0; i < length1; i++) {
- v = ((2 * (i % level) - level + 1) << 15) / level;
- for (j = 0; j < length2; j++)
- quantizers[i * length2 + j] = v;
- }
-
- for (i = length1 * length2; i < size; i++)
- quantizers[i] = 0;
-
-}
-
-static void generate_quantizers_table_3(int16_t quantizers[], int level, int length1, int length2, int size)
-{
- int i, j;
-
- for (i = 0; i < length1; i++)
- for (j = 0; j < length2; j++)
- quantizers[i * length2 + j] = ((2 * (j % level) - level + 1) << 15) / level;
-
- for (i = length1 * length2; i < size; i++)
- quantizers[i] = 0;
+ return (code - (levels >> 1)) * (2.0f / levels);
}
/*
{
int i;
- /* Quantizer ungrouping tables. */
- // for level-3 quantizers
- generate_quantizers_table_1(l3_quantizers_1, 3, 3, 9, 32);
- generate_quantizers_table_2(l3_quantizers_2, 3, 9, 3, 32);
- generate_quantizers_table_3(l3_quantizers_3, 3, 9, 3, 32);
-
- //for level-5 quantizers
- generate_quantizers_table_1(l5_quantizers_1, 5, 5, 25, 128);
- generate_quantizers_table_2(l5_quantizers_2, 5, 25, 5, 128);
- generate_quantizers_table_3(l5_quantizers_3, 5, 25, 5, 128);
-
- //for level-7 quantizers
- generate_quantizers_table(l7_quantizers, 7, 7);
+ /* 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);
+ }
- //for level-4 quantizers
- generate_quantizers_table_2(l11_quantizers_1, 11, 11, 11, 128);
- generate_quantizers_table_3(l11_quantizers_2, 11, 11, 11, 128);
+ /* 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);
+ }
- //for level-15 quantizers
- generate_quantizers_table(l15_quantizers, 15, 15);
- /* End Quantizer ungrouping tables. */
+ /* 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
+ /* 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 + 15));
+ 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_tbl[i][0] = i / 25;
- exp_ungroup_tbl[i][1] = (i % 25) / 5;
- exp_ungroup_tbl[i][2] = (i % 25) % 5;
+ 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)
{
AC3DecodeContext *ctx = avctx->priv_data;
+ ctx->avctx = avctx;
ac3_common_init();
ac3_tables_init();
dsputil_init(&ctx->dsp, avctx);
av_init_random(0, &ctx->dith_state);
- return 0;
-}
-/*********** END INIT FUNCTIONS ***********/
-
-/* Parse the 'sync_info' from the ac3 bitstream.
- * This function extracts the sync_info from ac3 bitstream.
- * GetBitContext within AC3DecodeContext must point to
- * start of the synchronized ac3 bitstream.
- *
- * @param ctx AC3DecodeContext
- * @return Returns framesize, returns 0 if fscod, frmsizecod or bsid is not valid
- */
-static int ac3_parse_sync_info(AC3DecodeContext *ctx)
-{
- GetBitContext *gb = &ctx->gb;
- int frmsizecod, bsid;
-
- skip_bits(gb, 16); //skip the sync_word, sync_info->sync_word = get_bits(gb, 16);
- ctx->crc1 = get_bits(gb, 16);
- ctx->fscod = get_bits(gb, 2);
- if (ctx->fscod == 0x03)
- return 0;
- frmsizecod = get_bits(gb, 6);
- if (frmsizecod >= 38)
- return 0;
- ctx->sampling_rate = ff_ac3_freqs[ctx->fscod];
- ctx->bit_rate = ff_ac3_bitratetab[frmsizecod >> 1];
-
- /* we include it here in order to determine validity of ac3 frame */
- bsid = get_bits(gb, 5);
- if (bsid > 0x08)
- return 0;
- skip_bits(gb, 3); //skip the bsmod, bsi->bsmod = get_bits(gb, 3);
-
- switch (ctx->fscod) {
- case 0x00:
- ctx->frame_size = 4 * ctx->bit_rate;
- return ctx->frame_size;
- case 0x01:
- ctx->frame_size = 2 * (320 * ctx->bit_rate / 147 + (frmsizecod & 1));
- return ctx->frame_size;
- case 0x02:
- ctx->frame_size = 6 * ctx->bit_rate;
- return ctx->frame_size;
+ /* 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;
}
-/* Parse bsi from ac3 bitstream.
- * This function extracts the bitstream information (bsi) from ac3 bitstream.
- *
- * @param ctx AC3DecodeContext after processed by ac3_parse_sync_info
+/**
+ * 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 void ac3_parse_bsi(AC3DecodeContext *ctx)
+static int ac3_parse_header(AC3DecodeContext *ctx)
{
+ AC3HeaderInfo hdr;
GetBitContext *gb = &ctx->gb;
- int i;
-
- ctx->cmixlev = 0;
- ctx->surmixlev = 0;
- ctx->dsurmod = 0;
- ctx->nfchans = 0;
- ctx->cpldeltbae = DBA_NONE;
- ctx->cpldeltnseg = 0;
- for (i = 0; i < 5; i++) {
- ctx->deltbae[i] = DBA_NONE;
- ctx->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
}
- ctx->dynrng = 1.0;
- ctx->dynrng2 = 1.0;
-
- ctx->acmod = get_bits(gb, 3);
- ctx->nfchans = nfchans_tbl[ctx->acmod];
-
- if (ctx->acmod & 0x01 && ctx->acmod != 0x01)
- ctx->cmixlev = get_bits(gb, 2);
- if (ctx->acmod & 0x04)
- ctx->surmixlev = get_bits(gb, 2);
- if (ctx->acmod == 0x02)
- ctx->dsurmod = get_bits(gb, 2);
-
- ctx->lfeon = get_bits1(gb);
+ skip_bits1(gb); // skip lfeon
+ /* read the rest of the bsi. read twice for dual mono mode. */
i = !(ctx->acmod);
do {
- skip_bits(gb, 5); //skip dialog normalization
+ 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, 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))
- skip_bits(gb, 14); //skip timecode1
+ skip_bits(gb, 14); //skip timecode1 / xbsi1
if (get_bits1(gb))
- skip_bits(gb, 14); //skip timecode2
+ skip_bits(gb, 14); //skip timecode2 / xbsi2
+ /* skip additional bitstream info */
if (get_bits1(gb)) {
- i = get_bits(gb, 6); //additional bsi length
+ i = get_bits(gb, 6);
do {
skip_bits(gb, 8);
} while(i--);
}
+
+ /* 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.
- * This function decodes the coded exponents according to exponent strategy
- * and stores them in the decoded exponents buffer.
- *
- * @param[in] gb GetBitContext which points to start of coded exponents
- * @param[in] expstr Exponent coding strategy
- * @param[in] ngrps Number of grouped exponents
- * @param[in] absexp Absolute exponent or DC exponent
- * @param[out] dexps Decoded exponents are stored in dexps
+ * Decode the grouped exponents according to exponent strategy.
+ * reference: Section 7.1.3 Exponent Decoding
*/
static void decode_exponents(GetBitContext *gb, int expstr, int ngrps,
- uint8_t absexp, uint8_t *dexps)
+ uint8_t absexp, int8_t *dexps)
{
int i, j, grp, grpsize;
int dexp[256];
grpsize = expstr + (expstr == EXP_D45);
for(grp=0,i=0; grp<ngrps; grp++) {
expacc = get_bits(gb, 7);
- dexp[i++] = exp_ungroup_tbl[expacc][0];
- dexp[i++] = exp_ungroup_tbl[expacc][1];
- dexp[i++] = exp_ungroup_tbl[expacc][2];
+ dexp[i++] = exp_ungroup_tab[expacc][0];
+ dexp[i++] = exp_ungroup_tab[expacc][1];
+ dexp[i++] = exp_ungroup_tab[expacc][2];
}
/* convert to absolute exps and expand groups */
}
}
-/* Performs bit allocation.
- * This function performs bit allocation for the requested chanenl.
+/**
+ * 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_allocation(AC3DecodeContext *ctx, int chnl)
+static void uncouple_channels(AC3DecodeContext *ctx)
{
- int fgain, snroffset;
-
- if (chnl == 5) {
- fgain = ff_fgaintab[ctx->cplfgaincod];
- snroffset = (((ctx->csnroffst - 15) << 4) + ctx->cplfsnroffst) << 2;
- ac3_parametric_bit_allocation(&ctx->bit_alloc_params, ctx->cplbap,
- ctx->dcplexps, ctx->cplstrtmant,
- ctx->cplendmant, snroffset, fgain, 0,
- ctx->cpldeltbae, ctx->cpldeltnseg,
- ctx->cpldeltoffst, ctx->cpldeltlen,
- ctx->cpldeltba);
- }
- else if (chnl == 6) {
- fgain = ff_fgaintab[ctx->lfefgaincod];
- snroffset = (((ctx->csnroffst - 15) << 4) + ctx->lfefsnroffst) << 2;
- ac3_parametric_bit_allocation(&ctx->bit_alloc_params, ctx->lfebap,
- ctx->dlfeexps, 0, 7, snroffset, fgain, 1,
- DBA_NONE, 0, NULL, NULL, NULL);
- }
- else {
- fgain = ff_fgaintab[ctx->fgaincod[chnl]];
- snroffset = (((ctx->csnroffst - 15) << 4) + ctx->fsnroffst[chnl]) << 2;
- ac3_parametric_bit_allocation(&ctx->bit_alloc_params, ctx->bap[chnl],
- ctx->dexps[chnl], 0, ctx->endmant[chnl],
- snroffset, fgain, 0, ctx->deltbae[chnl],
- ctx->deltnseg[chnl], ctx->deltoffst[chnl],
- ctx->deltlen[chnl], ctx->deltba[chnl]);
+ int i, j, ch, bnd, subbnd;
+
+ 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;
+ }
+ i++;
+ }
+ } while(ctx->cplbndstrc[subbnd]);
}
}
-typedef struct { /* grouped mantissas for 3-level 5-leve and 11-level quantization */
- int16_t l3_quantizers[3];
- int16_t l5_quantizers[3];
- int16_t l11_quantizers[2];
- 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;
-/* 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)
-{
- GetBitContext *gb = &ctx->gb;
- int ch, start, end, cplbndstrc, bnd, gcode, tbap;
- float cplcos[5], cplcoeff;
- uint8_t *exps = ctx->dcplexps;
- uint8_t *bap = ctx->cplbap;
-
- cplbndstrc = ctx->cplbndstrc;
- start = ctx->cplstrtmant;
- bnd = 0;
-
- while (start < ctx->cplendmant) {
- end = start + 12;
- while (cplbndstrc & 1) {
- end += 12;
- cplbndstrc >>= 1;
- }
- cplbndstrc >>= 1;
- for (ch = 0; ch < ctx->nfchans; ch++)
- cplcos[ch] = ctx->chcoeffs[ch] * ctx->cplco[ch][bnd];
- bnd++;
-
- while (start < end) {
- tbap = bap[start];
- switch(tbap) {
- case 0:
- for (ch = 0; ch < ctx->nfchans; ch++)
- if (((ctx->chincpl) >> ch) & 1) {
- if ((ctx->dithflag >> ch) & 1) {
- cplcoeff = (av_random(&ctx->dith_state) & 0xFFFF) * scale_factors[exps[start]];
- ctx->transform_coeffs[ch + 1][start] = cplcoeff * cplcos[ch] * LEVEL_MINUS_3DB;
- } else
- ctx->transform_coeffs[ch + 1][start] = 0;
- }
- start++;
- continue;
- case 1:
- if (m->l3ptr > 2) {
- gcode = get_bits(gb, 5);
- m->l3_quantizers[0] = l3_quantizers_1[gcode];
- m->l3_quantizers[1] = l3_quantizers_2[gcode];
- m->l3_quantizers[2] = l3_quantizers_3[gcode];
- m->l3ptr = 0;
- }
- cplcoeff = m->l3_quantizers[m->l3ptr++] * scale_factors[exps[start]];
- break;
-
- case 2:
- if (m->l5ptr > 2) {
- gcode = get_bits(gb, 7);
- m->l5_quantizers[0] = l5_quantizers_1[gcode];
- m->l5_quantizers[1] = l5_quantizers_2[gcode];
- m->l5_quantizers[2] = l5_quantizers_3[gcode];
- m->l5ptr = 0;
- }
- cplcoeff = m->l5_quantizers[m->l5ptr++] * scale_factors[exps[start]];
- break;
-
- case 3:
- cplcoeff = l7_quantizers[get_bits(gb, 3)] * scale_factors[exps[start]];
- break;
-
- case 4:
- if (m->l11ptr > 1) {
- gcode = get_bits(gb, 7);
- m->l11_quantizers[0] = l11_quantizers_1[gcode];
- m->l11_quantizers[1] = l11_quantizers_2[gcode];
- m->l11ptr = 0;
- }
- cplcoeff = m->l11_quantizers[m->l11ptr++] * scale_factors[exps[start]];
- break;
-
- case 5:
- cplcoeff = l15_quantizers[get_bits(gb, 4)] * scale_factors[exps[start]];
- break;
-
- default:
- cplcoeff = (get_sbits(gb, qntztab[tbap]) << (16 - qntztab[tbap])) * scale_factors[exps[start]];
- }
- for (ch = 0; ch < ctx->nfchans; ch++)
- if ((ctx->chincpl >> ch) & 1)
- ctx->transform_coeffs[ch + 1][start] = cplcoeff * cplcos[ch];
- start++;
- }
- }
-
- return 0;
-}
-
-/* Get the transform coefficients for particular channel */
static int get_transform_coeffs_ch(AC3DecodeContext *ctx, int ch_index, mant_groups *m)
{
GetBitContext *gb = &ctx->gb;
- int i, gcode, tbap, dithflag, end;
+ int i, gcode, tbap, start, end;
uint8_t *exps;
uint8_t *bap;
float *coeffs;
- float factors[25];
-
- for (i = 0; i < 25; i++)
- factors[i] = scale_factors[i] * ctx->chcoeffs[ch_index];
-
- if (ch_index != -1) { /* fbw channels */
- dithflag = (ctx->dithflag >> ch_index) & 1;
- exps = ctx->dexps[ch_index];
- bap = ctx->bap[ch_index];
- coeffs = ctx->transform_coeffs[ch_index + 1];
- end = ctx->endmant[ch_index];
- } else if (ch_index == -1) {
- dithflag = 0;
- exps = ctx->dlfeexps;
- bap = ctx->lfebap;
- coeffs = ctx->transform_coeffs[0];
- end = 7;
- }
+ 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 = 0; i < end; i++) {
+ for (i = start; i < end; i++) {
tbap = bap[i];
switch (tbap) {
case 0:
- if (!dithflag) {
- coeffs[i] = 0;
- continue;
- }
- else {
- coeffs[i] = (av_random(&ctx->dith_state) & 0xFFFF) * factors[exps[i]];
- coeffs[i] *= LEVEL_MINUS_3DB;
- continue;
- }
+ coeffs[i] = ((av_random(&ctx->dith_state) & 0xFFFF) / 65535.0f) - 0.5f;
+ break;
case 1:
- if (m->l3ptr > 2) {
+ if(m->b1ptr > 2) {
gcode = get_bits(gb, 5);
- m->l3_quantizers[0] = l3_quantizers_1[gcode];
- m->l3_quantizers[1] = l3_quantizers_2[gcode];
- m->l3_quantizers[2] = l3_quantizers_3[gcode];
- 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;
}
- coeffs[i] = m->l3_quantizers[m->l3ptr++] * factors[exps[i]];
- continue;
+ coeffs[i] = m->b1_mant[m->b1ptr++];
+ break;
case 2:
- if (m->l5ptr > 2) {
+ if(m->b2ptr > 2) {
gcode = get_bits(gb, 7);
- m->l5_quantizers[0] = l5_quantizers_1[gcode];
- m->l5_quantizers[1] = l5_quantizers_2[gcode];
- m->l5_quantizers[2] = l5_quantizers_3[gcode];
- 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;
}
- coeffs[i] = m->l5_quantizers[m->l5ptr++] * factors[exps[i]];
- continue;
+ coeffs[i] = m->b2_mant[m->b2ptr++];
+ break;
case 3:
- coeffs[i] = l7_quantizers[get_bits(gb, 3)] * factors[exps[i]];
- 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);
- m->l11_quantizers[0] = l11_quantizers_1[gcode];
- m->l11_quantizers[1] = l11_quantizers_2[gcode];
- m->l11ptr = 0;
+ m->b4_mant[0] = b4_mantissas[gcode][0];
+ m->b4_mant[1] = b4_mantissas[gcode][1];
+ m->b4ptr = 0;
}
- coeffs[i] = m->l11_quantizers[m->l11ptr++] * factors[exps[i]];
- continue;
+ coeffs[i] = m->b4_mant[m->b4ptr++];
+ break;
case 5:
- coeffs[i] = l15_quantizers[get_bits(gb, 4)] * factors[exps[i]];
- continue;
+ coeffs[i] = b5_mantissas[get_bits(gb, 4)];
+ break;
default:
- coeffs[i] = (get_sbits(gb, qntztab[tbap]) << (16 - qntztab[tbap])) * factors[exps[i]];
- continue;
+ /* asymmetric dequantization */
+ coeffs[i] = get_sbits(gb, qntztab[tbap]) * scale_factors[qntztab[tbap]-1];
+ break;
}
+ coeffs[i] *= scale_factors[exps[i]];
}
return 0;
}
-/* Get the transform coefficients.
- * This function extracts the tranform coefficients form the ac3 bitstream.
- * This function is called after bit allocation is performed.
+/**
+ * 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;
+ int ch, end;
int got_cplchan = 0;
mant_groups m;
- m.l3ptr = m.l5ptr = m.l11ptr = 3;
+ m.b1ptr = m.b2ptr = m.b4ptr = 3;
- for (i = 0; i < ctx->nfchans; i++) {
- /* transform coefficients for individual channel */
- if (get_transform_coeffs_ch(ctx, i, &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 ((ctx->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)) {
- av_log(NULL, AV_LOG_ERROR, "error in decoupling channels\n");
+ 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 = ctx->cplendmant;
- } else
- end = ctx->endmant[i];
+ end = ctx->endmant[CPL_CH];
+ } else {
+ end = ctx->endmant[ch];
+ }
do
- ctx->transform_coeffs[i + 1][end] = 0;
+ ctx->transform_coeffs[ch][end] = 0;
while(++end < 256);
}
- if (ctx->lfeon) {
- if (get_transform_coeffs_ch(ctx, -1, &m))
- return -1;
- for (i = 7; i < 256; i++) {
- ctx->transform_coeffs[0][i] = 0;
- }
- }
- return 0;
-}
+ /* if any channel doesn't use dithering, zero appropriate coefficients */
+ if(!ctx->dither_all)
+ remove_dithering(ctx);
-/* Rematrixing routines. */
-static void do_rematrixing1(AC3DecodeContext *ctx, int start, int end)
-{
- float tmp0, tmp1;
-
- while (start < end) {
- tmp0 = ctx->transform_coeffs[1][start];
- tmp1 = ctx->transform_coeffs[2][start];
- ctx->transform_coeffs[1][start] = tmp0 + tmp1;
- ctx->transform_coeffs[2][start] = tmp0 - tmp1;
- start++;
- }
+ return 0;
}
+/**
+ * Stereo rematrixing.
+ * reference: Section 7.5.4 Rematrixing : Decoding Technique
+ */
static void do_rematrixing(AC3DecodeContext *ctx)
{
- int bnd1 = 13, bnd2 = 25, bnd3 = 37, bnd4 = 61;
+ int bnd, i;
int end, bndend;
+ float tmp0, tmp1;
- end = FFMIN(ctx->endmant[0], ctx->endmant[1]);
-
- if (ctx->rematflg & 1)
- do_rematrixing1(ctx, bnd1, bnd2);
-
- if (ctx->rematflg & 2)
- do_rematrixing1(ctx, bnd2, bnd3);
-
- bndend = bnd4;
- if (bndend > end) {
- bndend = end;
- if (ctx->rematflg & 4)
- do_rematrixing1(ctx, bnd3, bndend);
- } else {
- if (ctx->rematflg & 4)
- do_rematrixing1(ctx, bnd3, bnd4);
- if (ctx->rematflg & 8)
- do_rematrixing1(ctx, bnd4, end);
- }
-}
-
-/* This function sets the normalized channel coefficients.
- * Transform coefficients are multipllied by the channel
- * coefficients to get normalized transform coefficients.
- */
-static void get_downmix_coeffs(AC3DecodeContext *ctx)
-{
- int from = ctx->acmod;
- int to = ctx->blkoutput;
- float clev = clevs[ctx->cmixlev];
- float slev = slevs[ctx->surmixlev];
- float nf = 1.0; //normalization factor for downmix coeffs
- int i;
-
- if (!ctx->acmod) {
- ctx->chcoeffs[0] = 2 * ctx->dynrng;
- ctx->chcoeffs[1] = 2 * ctx->dynrng2;
- } else {
- for (i = 0; i < ctx->nfchans; i++)
- ctx->chcoeffs[i] = 2 * ctx->dynrng;
- }
-
- if (to == AC3_OUTPUT_UNMODIFIED)
- return;
-
- switch (from) {
- case AC3_ACMOD_DUALMONO:
- switch (to) {
- case AC3_OUTPUT_MONO:
- case AC3_OUTPUT_STEREO: /* We Assume that sum of both mono channels is requested */
- nf = 0.5;
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[1] *= nf;
- break;
- }
- break;
- case AC3_ACMOD_MONO:
- switch (to) {
- case AC3_OUTPUT_STEREO:
- nf = LEVEL_MINUS_3DB;
- ctx->chcoeffs[0] *= nf;
- break;
- }
- break;
- case AC3_ACMOD_STEREO:
- switch (to) {
- case AC3_OUTPUT_MONO:
- nf = LEVEL_MINUS_3DB;
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[1] *= nf;
- break;
- }
- break;
- case AC3_ACMOD_3F:
- switch (to) {
- case AC3_OUTPUT_MONO:
- nf = LEVEL_MINUS_3DB / (1.0 + clev);
- ctx->chcoeffs[0] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[2] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[1] *= ((nf * clev * LEVEL_MINUS_3DB) / 2.0);
- break;
- case AC3_OUTPUT_STEREO:
- nf = 1.0 / (1.0 + clev);
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[2] *= nf;
- ctx->chcoeffs[1] *= (nf * clev);
- break;
- }
- break;
- case AC3_ACMOD_2F1R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- nf = 2.0 * LEVEL_MINUS_3DB / (2.0 + slev);
- ctx->chcoeffs[0] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[1] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[2] *= (nf * slev * LEVEL_MINUS_3DB);
- break;
- case AC3_OUTPUT_STEREO:
- nf = 1.0 / (1.0 + (slev * LEVEL_MINUS_3DB));
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[1] *= nf;
- ctx->chcoeffs[2] *= (nf * slev * LEVEL_MINUS_3DB);
- break;
- case AC3_OUTPUT_DOLBY:
- nf = 1.0 / (1.0 + LEVEL_MINUS_3DB);
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[1] *= nf;
- ctx->chcoeffs[2] *= (nf * LEVEL_MINUS_3DB);
- break;
- }
- break;
- case AC3_ACMOD_3F1R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- nf = LEVEL_MINUS_3DB / (1.0 + clev + (slev / 2.0));
- ctx->chcoeffs[0] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[2] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[1] *= (nf * clev * LEVEL_PLUS_3DB);
- ctx->chcoeffs[3] *= (nf * slev * LEVEL_MINUS_3DB);
- break;
- case AC3_OUTPUT_STEREO:
- nf = 1.0 / (1.0 + clev + (slev * LEVEL_MINUS_3DB));
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[2] *= nf;
- ctx->chcoeffs[1] *= (nf * clev);
- ctx->chcoeffs[3] *= (nf * slev * LEVEL_MINUS_3DB);
- break;
- case AC3_OUTPUT_DOLBY:
- nf = 1.0 / (1.0 + (2.0 * LEVEL_MINUS_3DB));
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[1] *= nf;
- ctx->chcoeffs[1] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[3] *= (nf * LEVEL_MINUS_3DB);
- break;
- }
- break;
- case AC3_ACMOD_2F2R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- nf = LEVEL_MINUS_3DB / (1.0 + slev);
- ctx->chcoeffs[0] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[1] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[2] *= (nf * slev * LEVEL_MINUS_3DB);
- ctx->chcoeffs[3] *= (nf * slev * LEVEL_MINUS_3DB);
- break;
- case AC3_OUTPUT_STEREO:
- nf = 1.0 / (1.0 + slev);
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[1] *= nf;
- ctx->chcoeffs[2] *= (nf * slev);
- ctx->chcoeffs[3] *= (nf * slev);
- break;
- case AC3_OUTPUT_DOLBY:
- nf = 1.0 / (1.0 + (2.0 * LEVEL_MINUS_3DB));
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[1] *= nf;
- ctx->chcoeffs[2] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[3] *= (nf * LEVEL_MINUS_3DB);
- break;
- }
- break;
- case AC3_ACMOD_3F2R:
- switch (to) {
- case AC3_OUTPUT_MONO:
- nf = LEVEL_MINUS_3DB / (1.0 + clev + slev);
- ctx->chcoeffs[0] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[2] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[1] *= (nf * clev * LEVEL_PLUS_3DB);
- ctx->chcoeffs[3] *= (nf * slev * LEVEL_MINUS_3DB);
- ctx->chcoeffs[4] *= (nf * slev * LEVEL_MINUS_3DB);
- break;
- case AC3_OUTPUT_STEREO:
- nf = 1.0 / (1.0 + clev + slev);
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[2] *= nf;
- ctx->chcoeffs[1] *= (nf * clev);
- ctx->chcoeffs[3] *= (nf * slev);
- ctx->chcoeffs[4] *= (nf * slev);
- break;
- case AC3_OUTPUT_DOLBY:
- nf = 1.0 / (1.0 + (3.0 * LEVEL_MINUS_3DB));
- ctx->chcoeffs[0] *= nf;
- ctx->chcoeffs[1] *= nf;
- ctx->chcoeffs[1] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[3] *= (nf * LEVEL_MINUS_3DB);
- ctx->chcoeffs[4] *= (nf * LEVEL_MINUS_3DB);
- break;
- }
- break;
- }
-}
-
-/*********** BEGIN DOWNMIX FUNCTIONS ***********/
-static inline void mix_dualmono_to_mono(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->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->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->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->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->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->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)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->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_2f_1r_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->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_dolby(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->output;
-
- for (i = 0; i < 256; i++) {
- output[1][i] -= output[3][i];
- output[2][i] += output[3][i];
- }
- memset(output[3], 0, sizeof(output[3]));
-}
-
-static inline void mix_3f_1r_to_mono(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->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_3f_1r_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->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]);
- }
- 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->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]);
- }
- 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->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)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->output;
-
- 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]));
-}
-
-static inline void mix_2f_2r_to_dolby(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->output;
-
- 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]));
-}
-
-static inline void mix_3f_2r_to_mono(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->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]));
-}
-
-static inline void mix_3f_2r_to_stereo(AC3DecodeContext *ctx)
-{
- int i;
- float (*output)[BLOCK_SIZE] = ctx->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]);
- }
- 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->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]));
-}
-/*********** END DOWNMIX FUNCTIONS ***********/
+ end = FFMIN(ctx->endmant[1], ctx->endmant[2]);
-/* Downmix the output.
- * This function downmixes the output when the number of input
- * channels is not equal to the number of output channels requested.
- */
-static void do_downmix(AC3DecodeContext *ctx)
-{
- int from = ctx->acmod;
- int to = ctx->blkoutput;
-
- if (to == AC3_OUTPUT_UNMODIFIED)
- return;
-
- switch (from) {
- case AC3_ACMOD_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_ACMOD_MONO:
- switch (to) {
- case AC3_OUTPUT_STEREO:
- upmix_mono_to_stereo(ctx);
- break;
- }
- break;
- case AC3_ACMOD_STEREO:
- switch (to) {
- case AC3_OUTPUT_MONO:
- mix_stereo_to_mono(ctx);
- break;
- }
- break;
- case AC3_ACMOD_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_ACMOD_2F1R:
- 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_ACMOD_3F1R:
- 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;
+ 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_ACMOD_2F2R:
- 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;
- }
- break;
- case AC3_ACMOD_3F2R:
- 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;
- }
- break;
+ }
}
}
-/* This function performs the imdct on 256 sample transform
- * coefficients.
+/**
+ * Perform the 256-point IMDCT
*/
static void do_imdct_256(AC3DecodeContext *ctx, int chindex)
{
int i, k;
- float x[128];
+ DECLARE_ALIGNED_16(float, x[128]);
FFTComplex z[2][64];
float *o_ptr = ctx->tmp_output;
}
}
-/* IMDCT Transform. */
+/**
+ * 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 ch;
+ int nchans;
- if (ctx->blkoutput & AC3_OUTPUT_LFEON) {
- ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output,
- ctx->transform_coeffs[0], ctx->tmp_imdct);
- }
- for (ch=1; ch<=ctx->nfchans; ch++) {
- if ((ctx->blksw >> (ch-1)) & 1)
+ /* 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 (ch=1; ch<=nchans; ch++) {
+ if (ctx->blksw[ch]) {
do_imdct_256(ctx, ch);
- else
+ } else {
ctx->imdct_512.fft.imdct_calc(&ctx->imdct_512, ctx->tmp_output,
ctx->transform_coeffs[ch],
ctx->tmp_imdct);
-
- ctx->dsp.vector_fmul_add_add(ctx->output[ch], ctx->tmp_output,
- ctx->window, ctx->delay[ch], 384, 256, 1);
- ctx->dsp.vector_fmul_reverse(ctx->delay[ch], ctx->tmp_output+256,
+ }
+ /* 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);
}
}
-/* Parse the audio block from ac3 bitstream.
- * This function extract the audio block from the ac3 bitstream
- * and produces the output for the block. This function must
- * be called for each of the six audio block in the ac3 bitstream.
+/**
+ * Downmix the output to mono or stereo.
*/
-static int ac3_parse_audio_block(AC3DecodeContext * ctx)
+static void ac3_downmix(float samples[AC3_MAX_CHANNELS][256], int nfchans,
+ int output_mode, float coef[AC3_MAX_CHANNELS][2])
+{
+ 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;
+ }
+ }
+}
+
+/**
+ * Parse an audio block from AC-3 bitstream.
+ */
+static int ac3_parse_audio_block(AC3DecodeContext *ctx, int blk)
{
int nfchans = ctx->nfchans;
int acmod = ctx->acmod;
- int i, bnd, rbnd, seg, grpsize;
+ int i, bnd, seg, ch;
GetBitContext *gb = &ctx->gb;
- int bit_alloc_flags = 0;
- uint8_t *dexps;
- int mstrcplco, cplcoexp, cplcomant;
- int dynrng, chbwcod, ngrps, cplabsexp, skipl;
-
- ctx->blksw = 0;
- for (i = 0; i < nfchans; i++) /*block switch flag */
- ctx->blksw |= get_bits1(gb) << i;
-
- ctx->dithflag = 0;
- for (i = 0; i < nfchans; i++) /* dithering flag */
- ctx->dithflag |= get_bits1(gb) << i;
-
- if (get_bits1(gb)) { /* dynamic range */
- dynrng = get_sbits(gb, 8);
- ctx->dynrng = ((((dynrng & 0x1f) | 0x20) << 13) * scale_factors[3 - (dynrng >> 5)]);
- }
+ uint8_t bit_alloc_stages[AC3_MAX_CHANNELS];
- if (acmod == 0x00 && get_bits1(gb)) { /* dynamic range 1+1 mode */
- dynrng = get_sbits(gb, 8);
- ctx->dynrng2 = ((((dynrng & 0x1f) | 0x20) << 13) * scale_factors[3 - (dynrng >> 5)]);
- }
+ memset(bit_alloc_stages, 0, AC3_MAX_CHANNELS);
- get_downmix_coeffs(ctx);
+ /* block switch flags */
+ for (ch = 1; ch <= nfchans; ch++)
+ ctx->blksw[ch] = get_bits1(gb);
- if (get_bits1(gb)) { /* coupling strategy */
- ctx->cplinu = get_bits1(gb);
- ctx->cplbndstrc = 0;
- ctx->chincpl = 0;
- if (ctx->cplinu) { /* coupling in use */
- for (i = 0; i < nfchans; i++)
- ctx->chincpl |= get_bits1(gb) << i;
-
- if (acmod == 0x02)
- ctx->phsflginu = get_bits1(gb); //phase flag in use
+ /* 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;
+ }
- ctx->cplbegf = get_bits(gb, 4);
- ctx->cplendf = get_bits(gb, 4);
+ /* 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--);
- if (3 + ctx->cplendf - ctx->cplbegf < 0) {
- av_log(NULL, AV_LOG_ERROR, "cplendf = %d < cplbegf = %d\n", ctx->cplendf, ctx->cplbegf);
+ /* 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;
}
-
- ctx->ncplbnd = ctx->ncplsubnd = 3 + ctx->cplendf - ctx->cplbegf;
- ctx->cplstrtmant = ctx->cplbegf * 12 + 37;
- ctx->cplendmant = ctx->cplendf * 12 + 73;
- for (i = 0; i < ctx->ncplsubnd - 1; i++) /* coupling band structure */
+ 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 |= 1 << i;
+ ctx->cplbndstrc[bnd] = 1;
ctx->ncplbnd--;
}
+ }
+ } else {
+ /* coupling not in use */
+ for (ch = 1; ch <= nfchans; ch++)
+ ctx->chincpl[ch] = 0;
}
}
+ /* coupling coordinates */
if (ctx->cplinu) {
- ctx->cplcoe = 0;
+ int cplcoe = 0;
- for (i = 0; i < nfchans; i++)
- if ((ctx->chincpl) >> i & 1)
- if (get_bits1(gb)) { /* coupling co-ordinates */
- ctx->cplcoe |= 1 << i;
+ for (ch = 1; ch <= nfchans; ch++) {
+ if (ctx->chincpl[ch]) {
+ if (get_bits1(gb)) {
+ int mstrcplco, cplcoexp, cplcomant;
+ cplcoe = 1;
mstrcplco = 3 * get_bits(gb, 2);
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;
- ctx->cplco[i][bnd] = cplcomant * scale_factors[cplcoexp + mstrcplco];
+ ctx->cplco[ch][bnd] = (cplcomant + 16.0f) / 32.0f;
+ ctx->cplco[ch][bnd] *= scale_factors[cplcoexp + mstrcplco];
}
}
-
- if (acmod == 0x02 && ctx->phsflginu && (ctx->cplcoe & 1 || ctx->cplcoe & 2))
- for (bnd = 0; bnd < ctx->ncplbnd; bnd++)
+ }
+ }
+ /* phase flags */
+ if (acmod == AC3_ACMOD_STEREO && ctx->phsflginu && cplcoe) {
+ for (bnd = 0; bnd < ctx->ncplbnd; bnd++) {
if (get_bits1(gb))
- ctx->cplco[1][bnd] = -ctx->cplco[1][bnd];
+ ctx->cplco[2][bnd] = -ctx->cplco[2][bnd];
+ }
+ }
}
- if (acmod == 0x02) {/* rematrixing */
+ /* stereo rematrixing strategy and band structure */
+ if (acmod == AC3_ACMOD_STEREO) {
ctx->rematstr = get_bits1(gb);
if (ctx->rematstr) {
- ctx->rematflg = 0;
-
- if (!(ctx->cplinu) || ctx->cplbegf > 2)
- for (rbnd = 0; rbnd < 4; rbnd++)
- ctx->rematflg |= get_bits1(gb) << rbnd;
- if (ctx->cplbegf > 0 && ctx->cplbegf <= 2 && ctx->cplinu)
- for (rbnd = 0; rbnd < 3; rbnd++)
- ctx->rematflg |= get_bits1(gb) << rbnd;
- if (ctx->cplbegf == 0 && ctx->cplinu)
- for (rbnd = 0; rbnd < 2; rbnd++)
- ctx->rematflg |= get_bits1(gb) << rbnd;
+ 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);
}
}
- ctx->cplexpstr = EXP_REUSE;
- ctx->lfeexpstr = EXP_REUSE;
- if (ctx->cplinu) /* coupling exponent strategy */
- ctx->cplexpstr = get_bits(gb, 2);
- for (i = 0; i < nfchans; i++) /* channel exponent strategy */
- ctx->chexpstr[i] = get_bits(gb, 2);
- if (ctx->lfeon) /* lfe exponent strategy */
- ctx->lfeexpstr = get_bits1(gb);
-
- for (i = 0; i < nfchans; i++) /* channel bandwidth code */
- if (ctx->chexpstr[i] != EXP_REUSE) {
- if ((ctx->chincpl >> i) & 1)
- ctx->endmant[i] = ctx->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 {
- chbwcod = get_bits(gb, 6);
+ int chbwcod = get_bits(gb, 6);
if (chbwcod > 60) {
- av_log(NULL, AV_LOG_ERROR, "chbwcod = %d > 60", chbwcod);
+ av_log(ctx->avctx, AV_LOG_ERROR, "chbwcod = %d > 60", chbwcod);
return -1;
}
- ctx->endmant[i] = chbwcod * 3 + 73;
+ ctx->endmant[ch] = chbwcod * 3 + 73;
}
+ if(blk > 0 && ctx->endmant[ch] != prev)
+ memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
}
-
- if (ctx->cplexpstr != EXP_REUSE) {/* coupling exponents */
- bit_alloc_flags = 64;
- cplabsexp = get_bits(gb, 4) << 1;
- ngrps = (ctx->cplendmant - ctx->cplstrtmant) / (3 << (ctx->cplexpstr - 1));
- decode_exponents(gb, ctx->cplexpstr, ngrps, cplabsexp, ctx->dcplexps + ctx->cplstrtmant);
}
-
- for (i = 0; i < nfchans; i++) /* fbw channel exponents */
- if (ctx->chexpstr[i] != EXP_REUSE) {
- bit_alloc_flags |= 1 << i;
- grpsize = 3 << (ctx->chexpstr[i] - 1);
- ngrps = (ctx->endmant[i] + grpsize - 4) / grpsize;
- dexps = ctx->dexps[i];
- dexps[0] = get_bits(gb, 4);
- decode_exponents(gb, ctx->chexpstr[i], ngrps, dexps[0], dexps + 1);
- skip_bits(gb, 2); /* skip gainrng */
+ 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 */
}
-
- if (ctx->lfeexpstr != EXP_REUSE) { /* lfe exponents */
- bit_alloc_flags |= 32;
- ctx->dlfeexps[0] = get_bits(gb, 4);
- decode_exponents(gb, ctx->lfeexpstr, 2, ctx->dlfeexps[0], ctx->dlfeexps + 1);
}
- if (get_bits1(gb)) { /* bit allocation information */
- bit_alloc_flags = 127;
- ctx->sdcycod = get_bits(gb, 2);
- ctx->fdcycod = get_bits(gb, 2);
- ctx->sgaincod = get_bits(gb, 2);
- ctx->dbpbcod = get_bits(gb, 2);
- ctx->floorcod = get_bits(gb, 3);
+ /* 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 (get_bits1(gb)) { /* snroffset */
- bit_alloc_flags = 127;
- ctx->csnroffst = get_bits(gb, 6);
- if (ctx->cplinu) { /* coupling fine snr offset and fast gain code */
- ctx->cplfsnroffst = get_bits(gb, 4);
- ctx->cplfgaincod = get_bits(gb, 3);
- }
- for (i = 0; i < nfchans; i++) { /* channel fine snr offset and fast gain code */
- ctx->fsnroffst[i] = get_bits(gb, 4);
- ctx->fgaincod[i] = get_bits(gb, 3);
- }
- if (ctx->lfeon) { /* lfe fine snr offset and fast gain code */
- ctx->lfefsnroffst = get_bits(gb, 4);
- ctx->lfefgaincod = get_bits(gb, 3);
+ /* 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 (ctx->cplinu && get_bits1(gb)) { /* coupling leak information */
- bit_alloc_flags |= 64;
- ctx->cplfleak = get_bits(gb, 3);
- ctx->cplsleak = 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)) { /* delta bit allocation information */
- bit_alloc_flags = 127;
-
- if (ctx->cplinu) {
- ctx->cpldeltbae = get_bits(gb, 2);
- if (ctx->cpldeltbae == DBA_RESERVED) {
- av_log(NULL, AV_LOG_ERROR, "coupling delta bit allocation strategy reserved\n");
- return -1;
- }
- }
-
- for (i = 0; i < nfchans; i++) {
- ctx->deltbae[i] = get_bits(gb, 2);
- if (ctx->deltbae[i] == DBA_RESERVED) {
- av_log(NULL, AV_LOG_ERROR, "delta bit allocation strategy reserved\n");
+ /* 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);
}
-
- if (ctx->cplinu)
- if (ctx->cpldeltbae == DBA_NEW) { /*coupling delta offset, len and bit allocation */
- ctx->cpldeltnseg = get_bits(gb, 3);
- for (seg = 0; seg <= ctx->cpldeltnseg; seg++) {
- ctx->cpldeltoffst[seg] = get_bits(gb, 5);
- ctx->cpldeltlen[seg] = get_bits(gb, 4);
- ctx->cpldeltba[seg] = get_bits(gb, 3);
- }
- }
-
- for (i = 0; i < nfchans; i++)
- if (ctx->deltbae[i] == DBA_NEW) {/*channel delta offset, len and bit allocation */
- ctx->deltnseg[i] = get_bits(gb, 3);
- for (seg = 0; seg <= ctx->deltnseg[i]; seg++) {
- ctx->deltoffst[i][seg] = get_bits(gb, 5);
- ctx->deltlen[i][seg] = get_bits(gb, 4);
- ctx->deltba[i][seg] = 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);
}
}
+ }
+ } else if(blk == 0) {
+ for(ch=0; ch<=ctx->nchans; ch++) {
+ ctx->deltbae[ch] = DBA_NONE;
+ }
}
- if (bit_alloc_flags) {
- /* set bit allocation parameters */
- ctx->bit_alloc_params.fscod = ctx->fscod;
- ctx->bit_alloc_params.halfratecod = 0;
- ctx->bit_alloc_params.sdecay = ff_sdecaytab[ctx->sdcycod];
- ctx->bit_alloc_params.fdecay = ff_fdecaytab[ctx->fdcycod];
- ctx->bit_alloc_params.sgain = ff_sgaintab[ctx->sgaincod];
- ctx->bit_alloc_params.dbknee = ff_dbkneetab[ctx->dbpbcod];
- ctx->bit_alloc_params.floor = ff_floortab[ctx->floorcod];
- ctx->bit_alloc_params.cplfleak = ctx->cplfleak;
- ctx->bit_alloc_params.cplsleak = ctx->cplsleak;
-
- if (ctx->chincpl && (bit_alloc_flags & 64))
- do_bit_allocation(ctx, 5);
- for (i = 0; i < nfchans; i++)
- if ((bit_alloc_flags >> i) & 1)
- do_bit_allocation(ctx, i);
- if (ctx->lfeon && (bit_alloc_flags & 32))
- do_bit_allocation(ctx, 6);
+ /* 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]);
+ }
+ 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]);
+ }
+ 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 (get_bits1(gb)) { /* unused dummy data */
- skipl = get_bits(gb, 9);
+ /* 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;
}
/* recover coefficients if rematrixing is in use */
- if (ctx->rematflg)
+ if(ctx->acmod == AC3_ACMOD_STEREO)
do_rematrixing(ctx);
- 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;
+ }
+ }
do_imdct(ctx);
- return 0;
-}
+ /* 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);
+ }
-static inline int16_t convert(int32_t i)
-{
- if (i > 0x43c07fff)
- return 32767;
- else if (i <= 0x43bf8000)
- return -32768;
- else
- return (i - 0x43c00000);
+ /* 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);
+ }
+
+ return 0;
}
-/* Decode ac3 frame.
- *
- * @param avctx Pointer to AVCodecContext
- * @param data Pointer to pcm smaples
- * @param data_size Set to number of pcm samples produced by decoding
- * @param buf Data to be decoded
- * @param buf_size Size of the buffer
+/**
+ * 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;
int16_t *out_samples = (int16_t *)data;
- int i, j, k, start;
- int32_t *int_ptr[6];
-
- for (i = 0; i < 6; i++)
- int_ptr[i] = (int32_t *)(&ctx->output[i]);
+ int i, blk, ch, err;
- //Initialize the GetBitContext with the start of valid AC3 Frame.
+ /* 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)) {
- av_log(avctx, AV_LOG_ERROR, "\n");
- *data_size = 0;
- return buf_size;
+ /* parse the syncinfo */
+ err = ac3_parse_header(ctx);
+ if(err) {
+ switch(err) {
+ case AC3_PARSE_ERROR_SYNC:
+ av_log(avctx, AV_LOG_ERROR, "frame sync error\n");
+ break;
+ case AC3_PARSE_ERROR_BSID:
+ av_log(avctx, AV_LOG_ERROR, "invalid bitstream id\n");
+ break;
+ case AC3_PARSE_ERROR_SAMPLE_RATE:
+ av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n");
+ break;
+ case AC3_PARSE_ERROR_FRAME_SIZE:
+ av_log(avctx, AV_LOG_ERROR, "invalid frame size\n");
+ break;
+ default:
+ av_log(avctx, AV_LOG_ERROR, "invalid header\n");
+ break;
+ }
+ 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;
- if (avctx->channels == 0) {
- ctx->blkoutput |= AC3_OUTPUT_UNMODIFIED;
- if (ctx->lfeon)
- ctx->blkoutput |= AC3_OUTPUT_LFEON;
- avctx->channels = ctx->nfchans + ctx->lfeon;
+ /* check that reported frame size fits in input buffer */
+ if(ctx->frame_size > buf_size) {
+ av_log(avctx, AV_LOG_ERROR, "incomplete frame\n");
+ return -1;
}
- else if (avctx->channels == 1)
- ctx->blkoutput |= AC3_OUTPUT_MONO;
- else if (avctx->channels == 2) {
- if (ctx->dsurmod == 0x02)
- ctx->blkoutput |= AC3_OUTPUT_DOLBY;
- else
- ctx->blkoutput |= AC3_OUTPUT_STEREO;
+
+ /* channel config */
+ ctx->out_channels = ctx->nchans;
+ if (avctx->channels == 0) {
+ 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;
}
- else {
- if (avctx->channels < (ctx->nfchans + ctx->lfeon))
- av_log(avctx, AV_LOG_INFO, "ac3_decoder: AC3 Source Channels Are Less Then Specified %d: Output to %d Channels\n",avctx->channels, ctx->nfchans + ctx->lfeon);
- ctx->blkoutput |= AC3_OUTPUT_UNMODIFIED;
- if (ctx->lfeon)
- ctx->blkoutput |= AC3_OUTPUT_LFEON;
- avctx->channels = ctx->nfchans + ctx->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 < NB_BLOCKS; i++) {
- if (ac3_parse_audio_block(ctx)) {
+ /* 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->frame_size;
}
- start = (ctx->blkoutput & AC3_OUTPUT_LFEON) ? 0 : 1;
- for (k = 0; k < BLOCK_SIZE; k++)
- for (j = start; j <= avctx->channels; j++)
- *(out_samples++) = convert(int_ptr[j][k]);
+ for (i = 0; i < 256; i++)
+ for (ch = 0; ch < ctx->out_channels; ch++)
+ *(out_samples++) = ctx->int_output[ch][i];
}
- *data_size = NB_BLOCKS * BLOCK_SIZE * avctx->channels * sizeof (int16_t);
+ *data_size = NB_BLOCKS * 256 * avctx->channels * sizeof (int16_t);
return ctx->frame_size;
}
-/* Uninitialize ac3 decoder.
+/**
+ * Uninitialize the AC-3 decoder.
*/
static int ac3_decode_end(AVCodecContext *avctx)
{
.close = ac3_decode_end,
.decode = ac3_decode_frame,
};
-
projects / ffmpeg / blobdiff