#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
/**
- * 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;
- }
}
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)
{
}
/**
- * Common function to parse AC3 or E-AC3 frame header
+ * Common function to parse AC-3 or E-AC-3 frame header
*/
static int parse_frame_header(AC3DecodeContext *s)
{
AC3HeaderInfo hdr;
- GetBitContext *gbc = &s->gbc;
int err;
- err = ff_ac3_parse_header(gbc, &hdr);
+ err = ff_ac3_parse_header(&s->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->channel_in_cpl[s->lfe_ch] = 0;
}
+ if(hdr.bitstream_id > 10)
+ return AC3_PARSE_ERROR_BSID;
+
return ac3_parse_header(s);
}
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;
tbap = bap[i];
switch (tbap) {
case 0:
- coeffs[i] = (av_random(&s->dith_state) & 0x7FFFFF) - 4194304;
+ coeffs[i] = (av_random(&s->dith_state) & 0x7FFFFF) - 0x400000;
break;
case 1:
if (s->channel_in_cpl[ch]) {
if (!got_cplchan) {
get_transform_coeffs_ch(s, CPL_CH, &m);
- uncouple_channels(s);
+ calc_transform_coeffs_cpl(s);
got_cplchan = 1;
}
end = s->end_freq[CPL_CH];
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;
}
/**
- * 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;
/* coupling strategy */
if (get_bits1(gbc)) {
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
- cpl_in_use = get_bits1(gbc);
- if (cpl_in_use) {
+ s->cpl_in_use[blk] = get_bits1(gbc);
+ if (s->cpl_in_use[blk]) {
/* coupling in use */
int cpl_begin_freq, cpl_end_freq;
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] = 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) {
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");
+ if (!err && decode_audio_block(s, blk)) {
+ av_log(avctx, AV_LOG_ERROR, "error decoding the audio block\n");
}
/* interleave output samples */
.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/52 / AC-3"),
};
projects / ffmpeg / blobdiff