---
libavcodec/ac3dec.c | 100 ++++++++++++++++++++++++++++++++--------------------
1 file changed, 61 insertions(+), 39 deletions(-)
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index dcc0625..d0628ab 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -715,10 +715,12 @@ static void decode_band_structure(BitstreamContext *bc,
int blk, int eac3,
n_subbands = end_subband - start_subband;
+
+ bitstream_prefetch(bc, 23);
/* decode band structure from bitstream or use default */
- if (!eac3 || bitstream_read_bit(bc)) {
+ if (!eac3 || bitstream_read_cache(bc, 1)) {
for (subbnd = 0; subbnd < n_subbands - 1; subbnd++) {
- coded_band_struct[subbnd] = bitstream_read_bit(bc);
+ coded_band_struct[subbnd] = bitstream_read_cache(bc, 1);
}
band_struct = coded_band_struct;
} else if (!blk) {
@@ -759,21 +761,23 @@ static inline int spx_strategy(AC3DecodeContext *s, int
blk)
int dst_start_freq, dst_end_freq, src_start_freq,
start_subband, end_subband, ch;
+ bitstream_prefetch(bc, 15);
+
/* determine which channels use spx */
if (s->channel_mode == AC3_CHMODE_MONO) {
s->channel_uses_spx[1] = 1;
} else {
for (ch = 1; ch <= fbw_channels; ch++)
- s->channel_uses_spx[ch] = bitstream_read_bit(bc);
+ s->channel_uses_spx[ch] = bitstream_read_cache(bc, 1);
}
/* get the frequency bins of the spx copy region and the spx start
and end subbands */
- dst_start_freq = bitstream_read(bc, 2);
- start_subband = bitstream_read(bc, 3) + 2;
+ dst_start_freq = bitstream_read_cache(bc, 2);
+ start_subband = bitstream_read_cache(bc, 3) + 2;
if (start_subband > 7)
start_subband += start_subband - 7;
- end_subband = bitstream_read(bc, 3) + 5;
+ end_subband = bitstream_read_cache(bc, 3) + 5;
if (end_subband > 7)
end_subband += end_subband - 7;
dst_start_freq = dst_start_freq * 12 + 25;
@@ -817,9 +821,11 @@ static inline void spx_coordinates(AC3DecodeContext *s)
float spx_blend;
int bin, master_spx_coord;
+ bitstream_prefetch(bc, 7);
+
s->first_spx_coords[ch] = 0;
- spx_blend = bitstream_read(bc, 5) * (1.0f / 32);
- master_spx_coord = bitstream_read(bc, 2) * 3;
+ spx_blend = bitstream_read_cache(bc, 5) * (1.0f / 32);
+ master_spx_coord = bitstream_read_cache(bc, 2) * 3;
bin = s->spx_src_start_freq;
for (bnd = 0; bnd < s->num_spx_bands; bnd++) {
@@ -827,6 +833,8 @@ static inline void spx_coordinates(AC3DecodeContext *s)
int spx_coord_exp, spx_coord_mant;
float nratio, sblend, nblend, spx_coord;
+ bitstream_prefetch(bc, 6);
+
/* calculate blending factors */
bandsize = s->spx_band_sizes[bnd];
nratio = ((float)((bin + (bandsize >> 1))) /
s->spx_dst_end_freq) - spx_blend;
@@ -837,8 +845,8 @@ static inline void spx_coordinates(AC3DecodeContext *s)
bin += bandsize;
/* decode spx coordinates */
- spx_coord_exp = bitstream_read(bc, 4);
- spx_coord_mant = bitstream_read(bc, 2);
+ spx_coord_exp = bitstream_read_cache(bc, 4);
+ spx_coord_mant = bitstream_read_cache(bc, 2);
if (spx_coord_exp == 15) spx_coord_mant <<= 1;
else spx_coord_mant += 4;
spx_coord_mant <<= (25 - spx_coord_exp - master_spx_coord);
@@ -862,9 +870,11 @@ static inline int coupling_strategy(AC3DecodeContext *s,
int blk, uint8_t *bit_a
int channel_mode = s->channel_mode;
int ch;
+ bitstream_prefetch(bc, 14);
+
memset(bit_alloc_stages, 3, AC3_MAX_CHANNELS);
if (!s->eac3)
- s->cpl_in_use[blk] = bitstream_read_bit(bc);
+ s->cpl_in_use[blk] = bitstream_read_cache(bc, 1);
if (s->cpl_in_use[blk]) {
/* coupling in use */
int cpl_start_subband, cpl_end_subband;
@@ -875,7 +885,7 @@ static inline int coupling_strategy(AC3DecodeContext *s,
int blk, uint8_t *bit_a
}
/* check for enhanced coupling */
- if (s->eac3 && bitstream_read_bit(bc)) {
+ if (s->eac3 && bitstream_read_cache(bc, 1)) {
/* TODO: parse enhanced coupling strategy info */
avpriv_request_sample(s->avctx, "Enhanced coupling");
return AVERROR_PATCHWELCOME;
@@ -892,12 +902,12 @@ static inline int coupling_strategy(AC3DecodeContext *s,
int blk, uint8_t *bit_a
/* phase flags in use */
if (channel_mode == AC3_CHMODE_STEREO)
- s->phase_flags_in_use = bitstream_read_bit(bc);
+ s->phase_flags_in_use = bitstream_read_cache(bc, 1);
/* coupling frequency range */
cpl_start_subband = bitstream_read(bc, 4);
cpl_end_subband = s->spx_in_use ? (s->spx_src_start_freq - 37) / 12 :
- bitstream_read(bc, 4) + 3;
+ bitstream_read_cache(bc, 4) + 3;
if (cpl_start_subband >= cpl_end_subband) {
av_log(s->avctx, AV_LOG_ERROR, "invalid coupling range (%d >=
%d)\n",
cpl_start_subband, cpl_end_subband);
@@ -938,8 +948,9 @@ static inline int coupling_coordinates(AC3DecodeContext *s,
int blk)
cpl_coords_exist = 1;
master_cpl_coord = 3 * bitstream_read(bc, 2);
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
- cpl_coord_exp = bitstream_read(bc, 4);
- cpl_coord_mant = bitstream_read(bc, 4);
+ bitstream_prefetch(bc, 8);
+ cpl_coord_exp = bitstream_read_cache(bc, 4);
+ cpl_coord_mant = bitstream_read_cache(bc, 4);
if (cpl_coord_exp == 15)
s->cpl_coords[ch][bnd] = cpl_coord_mant << 22;
else
@@ -983,8 +994,9 @@ static int decode_audio_block(AC3DecodeContext *s, int blk)
/* block switch flags */
different_transforms = 0;
if (s->block_switch_syntax) {
+ bitstream_prefetch(bc, 7);
for (ch = 1; ch <= fbw_channels; ch++) {
- s->block_switch[ch] = bitstream_read_bit(bc);
+ s->block_switch[ch] = bitstream_read_cache(bc, 1);
if (ch > 1 && s->block_switch[ch] != s->block_switch[1])
different_transforms = 1;
}
@@ -992,18 +1004,21 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
/* dithering flags */
if (s->dither_flag_syntax) {
+ bitstream_prefetch(bc, 7);
for (ch = 1; ch <= fbw_channels; ch++) {
- s->dither_flag[ch] = bitstream_read_bit(bc);
+ s->dither_flag[ch] = bitstream_read_cache(bc, 1);
}
}
+ bitstream_prefetch(bc, 20);
+
/* dynamic range */
i = !s->channel_mode;
do {
- if (bitstream_read_bit(bc)) {
+ if (bitstream_read_cache(bc, 1)) {
/* Allow asymmetric application of DRC when drc_scale > 1.
Amplification of quiet sounds is enhanced */
- float range = dynamic_range_tab[bitstream_read(bc, 8)];
+ float range = dynamic_range_tab[bitstream_read_cache(bc, 8)];
if (range > 1.0 || s->drc_scale <= 1.0)
s->dynamic_range[i] = powf(range, s->drc_scale);
else
@@ -1014,8 +1029,8 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
} while (i--);
/* spectral extension strategy */
- if (s->eac3 && (!blk || bitstream_read_bit(bc))) {
- s->spx_in_use = bitstream_read_bit(bc);
+ if (s->eac3 && (!blk || bitstream_read_cache(bc, 1))) {
+ s->spx_in_use = bitstream_read_cache(bc, 1);
if (s->spx_in_use) {
if ((ret = spx_strategy(s, blk)) < 0)
return ret;
@@ -1053,9 +1068,11 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
return ret;
}
+ bitstream_prefetch(bc, 21);
+
/* stereo rematrixing strategy and band structure */
if (channel_mode == AC3_CHMODE_STEREO) {
- if ((s->eac3 && !blk) || bitstream_read_bit(bc)) {
+ if ((s->eac3 && !blk) || bitstream_read_cache(bc, 1)) {
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);
@@ -1063,7 +1080,7 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
s->num_rematrixing_bands--;
}
for (bnd = 0; bnd < s->num_rematrixing_bands; bnd++)
- s->rematrixing_flags[bnd] = bitstream_read_bit(bc);
+ s->rematrixing_flags[bnd] = bitstream_read_cache(bc, 1);
} else if (!blk) {
av_log(s->avctx, AV_LOG_WARNING, "Warning: "
"new rematrixing strategy not present in block 0\n");
@@ -1074,7 +1091,7 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
/* exponent strategies for each channel */
for (ch = !cpl_in_use; ch <= s->channels; ch++) {
if (!s->eac3)
- s->exp_strategy[blk][ch] = bitstream_read(bc, 2 - (ch ==
s->lfe_ch));
+ s->exp_strategy[blk][ch] = bitstream_read_cache(bc, 2 - (ch ==
s->lfe_ch));
if (s->exp_strategy[blk][ch] != EXP_REUSE)
bit_alloc_stages[ch] = 3;
}
@@ -1125,12 +1142,13 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
/* bit allocation information */
if (s->bit_allocation_syntax) {
- if (bitstream_read_bit(bc)) {
- s->bit_alloc_params.slow_decay =
ff_ac3_slow_decay_tab[bitstream_read(bc, 2)] >> s->bit_alloc_params.sr_shift;
- s->bit_alloc_params.fast_decay =
ff_ac3_fast_decay_tab[bitstream_read(bc, 2)] >> s->bit_alloc_params.sr_shift;
- s->bit_alloc_params.slow_gain =
ff_ac3_slow_gain_tab[bitstream_read(bc, 2)];
- s->bit_alloc_params.db_per_bit =
ff_ac3_db_per_bit_tab[bitstream_read(bc, 2)];
- s->bit_alloc_params.floor =
ff_ac3_floor_tab[bitstream_read(bc, 3)];
+ bitstream_prefetch(bc, 12);
+ if (bitstream_read_cache(bc, 1)) {
+ s->bit_alloc_params.slow_decay =
ff_ac3_slow_decay_tab[bitstream_read_cache(bc, 2)] >>
s->bit_alloc_params.sr_shift;
+ s->bit_alloc_params.fast_decay =
ff_ac3_fast_decay_tab[bitstream_read_cache(bc, 2)] >>
s->bit_alloc_params.sr_shift;
+ s->bit_alloc_params.slow_gain =
ff_ac3_slow_gain_tab[bitstream_read_cache(bc, 2)];
+ s->bit_alloc_params.db_per_bit =
ff_ac3_db_per_bit_tab[bitstream_read_cache(bc, 2)];
+ s->bit_alloc_params.floor =
ff_ac3_floor_tab[bitstream_read_cache(bc, 3)];
for (ch = !cpl_in_use; ch <= s->channels; ch++)
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
} else if (!blk) {
@@ -1192,9 +1210,10 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
/* coupling leak information */
if (cpl_in_use) {
- if (s->first_cpl_leak || bitstream_read_bit(bc)) {
- int fl = bitstream_read(bc, 3);
- int sl = bitstream_read(bc, 3);
+ bitstream_prefetch(bc, 7);
+ if (s->first_cpl_leak || bitstream_read_cache(bc, 1)) {
+ int fl = bitstream_read_cache(bc, 3);
+ int sl = bitstream_read_cache(bc, 3);
/* run last 2 bit allocation stages for coupling channel if
coupling leak changes */
if (blk && (fl != s->bit_alloc_params.cpl_fast_leak ||
@@ -1214,8 +1233,9 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
/* delta bit allocation information */
if (s->dba_syntax && bitstream_read_bit(bc)) {
/* delta bit allocation exists (strategy) */
+ bitstream_prefetch(bc, 14);
for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
- s->dba_mode[ch] = bitstream_read(bc, 2);
+ s->dba_mode[ch] = bitstream_read_cache(bc, 2);
if (s->dba_mode[ch] == DBA_RESERVED) {
av_log(s->avctx, AV_LOG_ERROR, "delta bit allocation strategy
reserved\n");
return AVERROR_INVALIDDATA;
@@ -1223,13 +1243,15 @@ static int decode_audio_block(AC3DecodeContext *s, int
blk)
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
}
/* channel delta offset, len and bit allocation */
+ bitstream_prefetch(bc, 15);
for (ch = !cpl_in_use; ch <= fbw_channels; ch++) {
if (s->dba_mode[ch] == DBA_NEW) {
- s->dba_nsegs[ch] = bitstream_read(bc, 3) + 1;
+ s->dba_nsegs[ch] = bitstream_read_cache(bc, 3) + 1;
for (seg = 0; seg < s->dba_nsegs[ch]; seg++) {
- s->dba_offsets[ch][seg] = bitstream_read(bc, 5);
- s->dba_lengths[ch][seg] = bitstream_read(bc, 4);
- s->dba_values[ch][seg] = bitstream_read(bc, 3);
+ bitstream_prefetch(bc, 15);
+ s->dba_offsets[ch][seg] = bitstream_read_cache(bc, 5);
+ s->dba_lengths[ch][seg] = bitstream_read_cache(bc, 4);
+ s->dba_values[ch][seg] = bitstream_read_cache(bc, 3);
}
/* run last 2 bit allocation stages if new dba values */
bit_alloc_stages[ch] = FFMAX(bit_alloc_stages[ch], 2);
--
2.6.1
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