/*
* 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 <string.h>
#include "libavutil/crc.h"
-#include "libavutil/random.h"
-#include "avcodec.h"
#include "ac3_parser.h"
-#include "bitstream.h"
-#include "dsputil.h"
#include "ac3dec.h"
+#include "ac3dec_data.h"
-/** Maximum possible frame size when the specification limit is ignored */
-#define AC3_MAX_FRAME_SIZE 21695
+/** Large enough for maximum possible frame size when the specification limit is ignored */
+#define AC3_FRAME_BUFFER_SIZE 32768
/**
- * Table of bin locations for rematrixing bands
- * reference: Section 7.5.2 Rematrixing : Frequency Band Definitions
+ * table for ungrouping 3 values in 7 bits.
+ * used for exponents and bap=2 mantissas
*/
-static const uint8_t rematrix_band_tab[5] = { 13, 25, 37, 61, 253 };
-
-/** 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 */
{
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 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;
- }
}
ff_mdct_init(&s->imdct_512, 9, 1);
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->downmixed = 1;
/* allocate context input buffer */
- if (avctx->error_resilience >= FF_ER_CAREFUL) {
- s->input_buffer = av_mallocz(AC3_MAX_FRAME_SIZE + FF_INPUT_BUFFER_PADDING_SIZE);
+ if (avctx->error_recognition >= 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;
- int err, i;
-
- err = ff_ac3_parse_header(gbc, &hdr);
- if(err)
- return err;
-
- if(hdr.bitstream_id > 10)
- return AC3_PARSE_ERROR_BSID;
-
- /* 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;
- }
+ int i;
/* read the rest of the bsi. read twice for dual mono mode. */
i = !(s->channel_mode);
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);
+ }
+}
+
/**
* Set stereo downmixing coefficients based on frame header info.
* reference: Section 7.8.2 Downmixing Into Two Channels
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[nf][0] = s->downmix_coeffs[nf+1][1] = smix;
}
- /* calculate adjustment needed for each channel to avoid clipping */
- s->downmix_coeff_adjust[0] = s->downmix_coeff_adjust[1] = 0.0f;
+ /* 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_coeff_adjust[0] += s->downmix_coeffs[i][0];
- s->downmix_coeff_adjust[1] += s->downmix_coeffs[i][1];
+ 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;
}
- s->downmix_coeff_adjust[0] = 1.0f / s->downmix_coeff_adjust[0];
- s->downmix_coeff_adjust[1] = 1.0f / s->downmix_coeff_adjust[1];
}
/**
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;
} mant_groups;
/**
- * Get the transform coefficients for a particular channel
+ * Decode the transform coefficients for a particular channel
* reference: Section 7.3 Quantization and Decoding of Mantissas
*/
-static void 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;
tbap = bap[i];
switch (tbap) {
case 0:
- coeffs[i] = (av_random(&s->dith_state) & 0x7FFFFF) - 4194304;
+ coeffs[i] = (av_lfg_get(&s->dith_state) & 0x7FFFFF) - 0x400000;
break;
case 1:
}
}
+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.
+ * Decode the transform coefficients.
*/
-static void 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 */
- get_transform_coeffs_ch(s, ch, &m);
+ 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) {
- get_transform_coeffs_ch(s, CPL_CH, &m);
- 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];
while(++end < 256);
}
- /* if any channel doesn't use dithering, zero appropriate coefficients */
- if(!s->dither_all)
- remove_dithering(s);
+ /* zero the dithered coefficients for appropriate channels */
+ remove_dithering(s);
}
/**
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++) {
+ 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;
}
}
-/**
- * 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.
static inline void do_imdct(AC3DecodeContext *s, int channels)
{
int ch;
+ 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,
- float samples[AC3_MAX_CHANNELS][256], int ch_offset)
+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;
-
- for(i=0; i<256; i++) {
- v0 = v1 = 0.0f;
- for(j=0; j<s->fbw_channels; j++) {
- v0 += samples[j+ch_offset][i] * s->downmix_coeffs[j][0];
- v1 += samples[j+ch_offset][i] * s->downmix_coeffs[j][1];
+ 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 *= s->downmix_coeff_adjust[0];
- v1 *= s->downmix_coeff_adjust[1];
- if(s->output_mode == AC3_CHMODE_MONO) {
- samples[ch_offset][i] = (v0 + v1) * LEVEL_MINUS_3DB;
- } else if(s->output_mode == AC3_CHMODE_STEREO) {
- samples[ ch_offset][i] = v0;
- samples[1+ch_offset][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.
+ * Decode a single audio block from the AC-3 bitstream.
*/
-static int ac3_parse_audio_block(AC3DecodeContext *s, int blk)
+static int decode_audio_block(AC3DecodeContext *s, int blk)
{
int fbw_channels = s->fbw_channels;
int channel_mode = s->channel_mode;
/* block switch flags */
different_transforms = 0;
- 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;
+ 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) {
+ for (ch = 1; ch <= fbw_channels; ch++) {
+ s->dither_flag[ch] = get_bits1(gbc);
+ }
}
/* 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)) {
+ if (s->eac3 ? s->cpl_strategy_exists[blk] : get_bits1(gbc)) {
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
- cpl_in_use = get_bits1(gbc);
- if (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;
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) {
+ memcpy(s->cpl_band_struct,
+ &ff_eac3_default_cpl_band_struct[cpl_begin_freq+1],
+ s->num_cpl_subbands-1);
}
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];
}
- } else if (!blk) {
- av_log(s->avctx, AV_LOG_ERROR, "new coupling strategy must be present in block 0\n");
- return -1;
- } else {
- cpl_in_use = s->cpl_in_use[blk-1];
}
- s->cpl_in_use[blk] = cpl_in_use;
+ cpl_in_use = s->cpl_in_use[blk];
/* coupling coordinates */
if (cpl_in_use) {
for (ch = 1; ch <= fbw_channels; ch++) {
if (s->channel_in_cpl[ch]) {
- if (get_bits1(gbc)) {
+ if ((s->eac3 && s->first_cpl_coords[ch]) || get_bits1(gbc)) {
int master_cpl_coord, cpl_coord_exp, cpl_coord_mant;
+ s->first_cpl_coords[ch] = 0;
cpl_coords_exist = 1;
master_cpl_coord = 3 * get_bits(gbc, 2);
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
av_log(s->avctx, AV_LOG_ERROR, "new coupling coordinates must be present in block 0\n");
return -1;
}
+ } else {
+ /* channel not in coupling */
+ s->first_cpl_coords[ch] = 1;
}
}
/* phase flags */
/* stereo rematrixing strategy and band structure */
if (channel_mode == AC3_CHMODE_STEREO) {
- if (get_bits1(gbc)) {
+ if ((s->eac3 && !blk) || get_bits1(gbc)) {
s->num_rematrixing_bands = 4;
if(cpl_in_use && s->start_freq[CPL_CH] <= 61)
s->num_rematrixing_bands -= 1 + (s->start_freq[CPL_CH] == 37);
}
/* exponent strategies for each channel */
- 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->eac3)
+ 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;
}
}
/* 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=!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 (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;
+ }
}
/* signal-to-noise ratio offsets and fast gains (signal-to-mask ratios) */
- if (get_bits1(gbc)) {
- int csnr;
- csnr = (get_bits(gbc, 6) - 15) << 4;
- for (ch = !cpl_in_use; ch <= s->channels; ch++) { /* snr offset and fast gain */
- s->snr_offset[ch] = (csnr + get_bits(gbc, 4)) << 2;
+ if(!s->eac3 || !blk){
+ if(s->snr_offset_strategy && get_bits1(gbc)) {
+ int snr = 0;
+ int csnr;
+ csnr = (get_bits(gbc, 6) - 15) << 4;
+ for (i = ch = !cpl_in_use; ch <= s->channels; ch++) {
+ /* snr offset */
+ if (ch == i || s->snr_offset_strategy == 2)
+ snr = (csnr + get_bits(gbc, 4)) << 2;
+ /* run at least last bit allocation stage if snr offset changes */
+ if(blk && s->snr_offset[ch] != snr) {
+ bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 1);
+ }
+ s->snr_offset[ch] = snr;
+
+ /* fast gain (normal AC-3 only) */
+ if (!s->eac3) {
+ 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) {
+ 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);
}
- 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;
+ } 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 (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) {
+ if (s->first_cpl_leak || get_bits1(gbc)) {
+ int fl = get_bits(gbc, 3);
+ int sl = get_bits(gbc, 3);
+ /* run last 2 bit allocation stages for coupling channel if
+ coupling leak changes */
+ if(blk && (fl != s->bit_alloc_params.cpl_fast_leak ||
+ sl != s->bit_alloc_params.cpl_slow_leak)) {
+ bit_alloc_stages[CPL_CH] = FFMAX(bit_alloc_stages[CPL_CH], 2);
+ }
+ s->bit_alloc_params.cpl_fast_leak = fl;
+ s->bit_alloc_params.cpl_slow_leak = sl;
+ } else if (!s->eac3 && !blk) {
av_log(s->avctx, AV_LOG_ERROR, "new coupling leak info must be present in block 0\n");
return -1;
}
+ s->first_cpl_leak = 0;
}
/* delta bit allocation information */
- if (get_bits1(gbc)) {
+ if (s->dba_syntax && get_bits1(gbc)) {
/* delta bit allocation exists (strategy) */
for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
s->dba_mode[ch] = get_bits(gbc, 2);
}
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,
- ff_ac3_bap_tab, 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. */
- get_transform_coeffs(s);
+ 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)
} else {
gain *= s->dynamic_range[0];
}
- for(i=0; i<256; i++) {
- s->transform_coeffs[ch][i] = s->fixed_coeffs[ch][i] * gain;
- }
+ s->dsp.int32_to_float_fmul_scalar(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
}
/* downmix and MDCT. order depends on whether block switching is used for
do_imdct(s, s->channels);
if(downmix_output) {
- ac3_downmix(s, s->output, 0);
+ s->dsp.ac3_downmix(s->output, s->downmix_coeffs, s->out_channels, s->fbw_channels, 256);
}
} else {
if(downmix_output) {
- ac3_downmix(s, s->transform_coeffs, 1);
+ s->dsp.ac3_downmix(s->transform_coeffs+1, s->downmix_coeffs, s->out_channels, s->fbw_channels, 256);
}
- if(!s->downmixed) {
+ if(downmix_output && !s->downmixed) {
s->downmixed = 1;
- ac3_downmix(s, s->delay, 0);
+ s->dsp.ac3_downmix(s->delay, s->downmix_coeffs, s->out_channels, s->fbw_channels, 128);
}
do_imdct(s, s->out_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;
- }
- s->dsp.float_to_int16(s->int_output[ch], s->output[ch], 256);
- }
-
return 0;
}
{
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 */
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_MAX_FRAME_SIZE));
+ 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 */
*data_size = 0;
- err = ac3_parse_header(s);
+ err = parse_frame_header(s);
/* check that reported frame size fits in input buffer */
if(s->frame_size > buf_size) {
}
/* check for crc mismatch */
- if(err != AC3_PARSE_ERROR_FRAME_SIZE && avctx->error_resilience >= FF_ER_CAREFUL) {
+ if(err != AC3_PARSE_ERROR_FRAME_SIZE && avctx->error_recognition >= 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;
s->output_mode = s->out_channels == 1 ? AC3_CHMODE_MONO : AC3_CHMODE_STEREO;
}
- /* parse the audio blocks */
+ /* decode the audio blocks */
for (blk = 0; blk < s->num_blocks; blk++) {
- if (!err && ac3_parse_audio_block(s, blk)) {
- av_log(avctx, AV_LOG_ERROR, "error parsing the audio block\n");
+ 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");
}
-
- /* interleave output samples */
- 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 = s->num_blocks * 256 * avctx->channels * sizeof (int16_t);
return s->frame_size;
.init = ac3_decode_init,
.close = ac3_decode_end,
.decode = ac3_decode_frame,
- .long_name = "ATSC A/52 / AC-3",
+ .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52A (AC-3)"),
+};
+
+AVCodec eac3_decoder = {
+ .name = "eac3",
+ .type = CODEC_TYPE_AUDIO,
+ .id = CODEC_ID_EAC3,
+ .priv_data_size = sizeof (AC3DecodeContext),
+ .init = ac3_decode_init,
+ .close = ac3_decode_end,
+ .decode = ac3_decode_frame,
+ .long_name = NULL_IF_CONFIG_SMALL("ATSC A/52B (AC-3, E-AC-3)"),
};