---
libavcodec/ac3_parser.c | 37 ++++++++++++++++++++-----------------
1 file changed, 20 insertions(+), 17 deletions(-)
diff --git a/libavcodec/ac3_parser.c b/libavcodec/ac3_parser.c
index 66dc27f..30a7130 100644
--- a/libavcodec/ac3_parser.c
+++ b/libavcodec/ac3_parser.c
@@ -75,29 +75,31 @@ int avpriv_ac3_parse_header(BitstreamContext *bcp,
AC3HeaderInfo *hdr)
if(hdr->bitstream_id <= 10) {
/* Normal AC-3 */
- hdr->crc1 = bitstream_read(&bc, 16);
- hdr->sr_code = bitstream_read(&bc, 2);
+ // bitsream_prefetch(&bc, 29); 29 bits already present due _peek
+ hdr->crc1 = bitstream_read_cache(&bc, 16);
+ hdr->sr_code = bitstream_read_cache(&bc, 2);
if(hdr->sr_code == 3)
return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
- frame_size_code = bitstream_read(&bc, 6);
+ frame_size_code = bitstream_read_cache(&bc, 6);
if(frame_size_code > 37)
return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
bitstream_skip(&bc, 5); // skip bsid, already got it
- hdr->bitstream_mode = bitstream_read(&bc, 3);
- hdr->channel_mode = bitstream_read(&bc, 3);
+ bitstream_prefetch(&bc, 11);
+ hdr->bitstream_mode = bitstream_read_cache(&bc, 3);
+ hdr->channel_mode = bitstream_read_cache(&bc, 3);
if(hdr->channel_mode == AC3_CHMODE_STEREO) {
- hdr->dolby_surround_mode = bitstream_read(&bc, 2);
+ hdr->dolby_surround_mode = bitstream_read_cache(&bc, 2);
} else {
if((hdr->channel_mode & 1) && hdr->channel_mode != AC3_CHMODE_MONO)
- hdr->center_mix_level = center_levels[bitstream_read(&bc,
2)];
+ hdr->center_mix_level =
center_levels[bitstream_read_cache(&bc, 2)];
if(hdr->channel_mode & 4)
- hdr->surround_mix_level = surround_levels[bitstream_read(&bc,
2)];
+ hdr->surround_mix_level =
surround_levels[bitstream_read_cache(&bc, 2)];
}
- hdr->lfe_on = bitstream_read_bit(&bc);
+ hdr->lfe_on = bitstream_read_cache(&bc, 1);
hdr->sr_shift = FFMAX(hdr->bitstream_id, 8) - 8;
hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code] >>
hdr->sr_shift;
@@ -109,31 +111,32 @@ int avpriv_ac3_parse_header(BitstreamContext *bcp,
AC3HeaderInfo *hdr)
} else {
/* Enhanced AC-3 */
hdr->crc1 = 0;
- hdr->frame_type = bitstream_read(&bc, 2);
+ // bitsream_prefetch(&bc, 29); 29 bits already present due _peek
+ hdr->frame_type = bitstream_read_cache(&bc, 2);
if(hdr->frame_type == EAC3_FRAME_TYPE_RESERVED)
return AAC_AC3_PARSE_ERROR_FRAME_TYPE;
- hdr->substreamid = bitstream_read(&bc, 3);
+ hdr->substreamid = bitstream_read_cache(&bc, 3);
- hdr->frame_size = (bitstream_read(&bc, 11) + 1) << 1;
+ hdr->frame_size = (bitstream_read_cache(&bc, 11) + 1) << 1;
if(hdr->frame_size < AC3_HEADER_SIZE)
return AAC_AC3_PARSE_ERROR_FRAME_SIZE;
- hdr->sr_code = bitstream_read(&bc, 2);
+ hdr->sr_code = bitstream_read_cache(&bc, 2);
if (hdr->sr_code == 3) {
- int sr_code2 = bitstream_read(&bc, 2);
+ int sr_code2 = bitstream_read_cache(&bc, 2);
if(sr_code2 == 3)
return AAC_AC3_PARSE_ERROR_SAMPLE_RATE;
hdr->sample_rate = ff_ac3_sample_rate_tab[sr_code2] / 2;
hdr->sr_shift = 1;
} else {
- hdr->num_blocks = eac3_blocks[bitstream_read(&bc, 2)];
+ hdr->num_blocks = eac3_blocks[bitstream_read_cache(&bc, 2)];
hdr->sample_rate = ff_ac3_sample_rate_tab[hdr->sr_code];
hdr->sr_shift = 0;
}
- hdr->channel_mode = bitstream_read(&bc, 3);
- hdr->lfe_on = bitstream_read_bit(&bc);
+ hdr->channel_mode = bitstream_read_cache(&bc, 3);
+ hdr->lfe_on = bitstream_read_cache(&bc, 1);
hdr->bit_rate = (uint32_t)(8.0 * hdr->frame_size * hdr->sample_rate /
(hdr->num_blocks * 256.0));
--
2.6.1
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