---
libavcodec/ac3dec.c | 28 +++++++++++++++-------------
libavcodec/bitstream.h | 4 +---
2 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/libavcodec/ac3dec.c b/libavcodec/ac3dec.c
index b1548ed..dcc0625 100644
--- a/libavcodec/ac3dec.c
+++ b/libavcodec/ac3dec.c
@@ -219,34 +219,36 @@ static int ac3_parse_header(AC3DecodeContext *s)
/* read the rest of the bsi. read twice for dual mono mode. */
i = !s->channel_mode;
do {
+ bitstream_prefetch(&bc, 32);
bitstream_skip(&bc, 5); // skip dialog normalization
- if (bitstream_read_bit(&bc))
+ if (bitstream_read_cache(&bc, 1))
bitstream_skip(&bc, 8); // skip compression
- if (bitstream_read_bit(&bc))
+ if (bitstream_read_cache(&bc, 1))
bitstream_skip(&bc, 8); // skip language code
- if (bitstream_read_bit(&bc))
+ if (bitstream_read_cache(&bc, 1))
bitstream_skip(&bc, 7); // skip audio production information
} while (i--);
bitstream_skip(&bc, 2); // skip copyright bit and original bitstream bit
/* skip the timecodes or parse the Alternate Bit Stream Syntax */
+ bitstream_prefetch(&bc, 32);
if (s->bitstream_id != 6) {
- if (bitstream_read_bit(&bc))
+ if (bitstream_read_cache(&bc, 1))
bitstream_skip(&bc, 14); // skip timecode1
- if (bitstream_read_bit(&bc))
+ if (bitstream_read_cache(&bc, 1))
bitstream_skip(&bc, 14); // skip timecode2
} else {
- if (bitstream_read_bit(&bc)) {
- s->preferred_downmix = bitstream_read(&bc, 2);
- s->center_mix_level_ltrt = bitstream_read(&bc, 3);
- s->surround_mix_level_ltrt = av_clip(bitstream_read(&bc, 3), 3, 7);
- s->center_mix_level = bitstream_read(&bc, 3);
- s->surround_mix_level = av_clip(bitstream_read(&bc, 3), 3, 7);
+ if (bitstream_read_cache(&bc, 1)) {
+ s->preferred_downmix = bitstream_read_cache(&bc, 2);
+ s->center_mix_level_ltrt = bitstream_read_cache(&bc, 3);
+ s->surround_mix_level_ltrt = av_clip(bitstream_read_cache(&bc, 3),
3, 7);
+ s->center_mix_level = bitstream_read_cache(&bc, 3);
+ s->surround_mix_level = av_clip(bitstream_read_cache(&bc, 3),
3, 7);
}
if (bitstream_read_bit(&bc)) {
- s->dolby_surround_ex_mode = bitstream_read(&bc, 2);
- s->dolby_headphone_mode = bitstream_read(&bc, 2);
+ s->dolby_surround_ex_mode = bitstream_read_cache(&bc, 2);
+ s->dolby_headphone_mode = bitstream_read_cache(&bc, 2);
bitstream_skip(&bc, 10); // skip adconvtyp (1), xbsi2 (8), encinfo
(1)
}
}
diff --git a/libavcodec/bitstream.h b/libavcodec/bitstream.h
index 1196a55..ffb90d8 100644
--- a/libavcodec/bitstream.h
+++ b/libavcodec/bitstream.h
@@ -71,11 +71,9 @@ static inline void refill_32(BitstreamContext *bc)
bc->bits_left += 32;
}
-/* Make sure that the cache contains at least n bits */
+/* Make sure that the cache contains at least n bits, n has to be in the 0-32
range */
static inline void bitstream_prefetch(BitstreamContext *bc, unsigned n)
{
- refill_32(bc);
-
if (bc->bits_left < n)
refill_32(bc);
}
--
2.6.1
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