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mpegaudiodec: change granule skip code to avoid false checked bitstream reader errors. 

Code ported from qatar/master, please see there for per line authorship.
Main authors AFAIK are Ronald and Justin. I have no authorship on this.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
This commit is contained in:
Michael Niedermayer 2012-03-01 06:07:36 +01:00
parent 436f866f92
commit a057ef6923
1 changed files with 20 additions and 15 deletions
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35
libavcodec/mpegaudiodec.c
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@ -1386,6 +1386,7 @@ static int mp_decode_layer3(MPADecodeContext *s)
}
if (!s->adu_mode) {
int skip;
const uint8_t *ptr = s->gb.buffer + (get_bits_count(&s->gb)>>3);
int extrasize = av_clip(get_bits_left(&s->gb) >> 3, 0, EXTRABYTES);
assert((get_bits_count(&s->gb) & 7) == 0);
@ -1399,25 +1400,29 @@ static int mp_decode_layer3(MPADecodeContext *s)
#if !UNCHECKED_BITSTREAM_READER
s->gb.size_in_bits_plus8 += FFMAX(extrasize, LAST_BUF_SIZE - s->last_buf_size) * 8;
#endif
skip_bits_long(&s->gb, 8*(s->last_buf_size - main_data_begin));
s->last_buf_size <<= 3;
for (gr = 0; gr < nb_granules && (s->last_buf_size >> 3) < main_data_begin; gr++) {
for (ch = 0; ch < s->nb_channels; ch++) {
g = &s->granules[ch][gr];
s->last_buf_size += g->part2_3_length;
memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));
}
}
skip = s->last_buf_size - 8 * main_data_begin;
if (skip >= s->gb.size_in_bits && s->in_gb.buffer) {
skip_bits_long(&s->in_gb, skip - s->gb.size_in_bits);
s->gb = s->in_gb;
s->in_gb.buffer = NULL;
} else {
skip_bits_long(&s->gb, skip);
}
} else {
gr = 0;
}
for (gr = 0; gr < nb_granules; gr++) {
for (; gr < nb_granules; gr++) {
for (ch = 0; ch < s->nb_channels; ch++) {
g = &s->granules[ch][gr];
if (get_bits_count(&s->gb) < 0) {
av_log(s->avctx, AV_LOG_DEBUG, "mdb:%d, lastbuf:%d skipping granule %d\n",
main_data_begin, s->last_buf_size, gr);
skip_bits_long(&s->gb, g->part2_3_length);
memset(g->sb_hybrid, 0, sizeof(g->sb_hybrid));
if (get_bits_count(&s->gb) >= s->gb.size_in_bits && s->in_gb.buffer) {
skip_bits_long(&s->in_gb, get_bits_count(&s->gb) - s->gb.size_in_bits);
s->gb = s->in_gb;
s->in_gb.buffer = NULL;
}
continue;
}
bits_pos = get_bits_count(&s->gb);
if (!s->lsf) {