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making decoding more error robust

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Originally committed as revision 7073 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer
2006-11-14 22:06:28 +00:00
parent 7e5f82dc06
commit ee50a7c1e5
1 changed files with 19 additions and 11 deletions
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30
libavcodec/mpegaudiodec.c
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@ -1748,8 +1748,7 @@ static int huffman_decode(MPADecodeContext *s, GranuleDef *g,
bits_left = end_pos - get_bits_count(&s->gb); bits_left = end_pos - get_bits_count(&s->gb);
//av_log(NULL, AV_LOG_ERROR, "left:%d buf:%p\n", bits_left, s->in_gb.buffer); //av_log(NULL, AV_LOG_ERROR, "left:%d buf:%p\n", bits_left, s->in_gb.buffer);
if (bits_left < 0) { if (bits_left < 0) {
dprintf("bits_left=%d\n", bits_left); av_log(NULL, AV_LOG_ERROR, "bits_left=%d\n", bits_left);
return -1;
} }
skip_bits_long(&s->gb, bits_left); skip_bits_long(&s->gb, bits_left);
@ -2274,20 +2273,28 @@ static int mp_decode_layer3(MPADecodeContext *s)
/* now we get bits from the main_data_begin offset */ /* now we get bits from the main_data_begin offset */
dprintf("seekback: %d\n", main_data_begin); dprintf("seekback: %d\n", main_data_begin);
//av_log(NULL, AV_LOG_ERROR, "backstep:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size); //av_log(NULL, AV_LOG_ERROR, "backstep:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size);
if(main_data_begin > s->last_buf_size){
av_log(NULL, AV_LOG_ERROR, "backstep:%d, lastbuf:%d\n", main_data_begin, s->last_buf_size);
// s->last_buf_size= main_data_begin;
return -1;
}
memcpy(s->last_buf + s->last_buf_size, ptr, EXTRABYTES); memcpy(s->last_buf + s->last_buf_size, ptr, EXTRABYTES);
s->in_gb= s->gb; s->in_gb= s->gb;
init_get_bits(&s->gb, s->last_buf + s->last_buf_size - main_data_begin, main_data_begin*8); init_get_bits(&s->gb, s->last_buf, s->last_buf_size*8);
skip_bits_long(&s->gb, 8*(s->last_buf_size - main_data_begin));
} }
for(gr=0;gr<nb_granules;gr++) { for(gr=0;gr<nb_granules;gr++) {
for(ch=0;ch<s->nb_channels;ch++) { for(ch=0;ch<s->nb_channels;ch++) {
g = &granules[ch][gr]; g = &granules[ch][gr];
if(get_bits_count(&s->gb)<0){
av_log(NULL, AV_LOG_ERROR, "mdb:%d, lastbuf:%d skiping 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); bits_pos = get_bits_count(&s->gb);
@ -2418,9 +2425,7 @@ static int mp_decode_layer3(MPADecodeContext *s)
exponents_from_scale_factors(s, g, exponents); exponents_from_scale_factors(s, g, exponents);
/* read Huffman coded residue */ /* read Huffman coded residue */
if (huffman_decode(s, g, exponents, huffman_decode(s, g, exponents, bits_pos + g->part2_3_length);
bits_pos + g->part2_3_length) < 0)
return -1;
#if defined(DEBUG) #if defined(DEBUG)
sample_dump(0, g->sb_hybrid, 576); sample_dump(0, g->sb_hybrid, 576);
#endif #endif
@ -2446,6 +2451,8 @@ static int mp_decode_layer3(MPADecodeContext *s)
#endif #endif
} }
} /* gr */ } /* gr */
if(get_bits_count(&s->gb)<0)
skip_bits_long(&s->gb, -get_bits_count(&s->gb));
return nb_granules * 18; return nb_granules * 18;
} }
@ -2483,6 +2490,7 @@ static int mp_decode_frame(MPADecodeContext *s,
}else }else
av_log(NULL, AV_LOG_ERROR, "invalid old backstep %d\n", i); av_log(NULL, AV_LOG_ERROR, "invalid old backstep %d\n", i);
s->gb= s->in_gb; s->gb= s->in_gb;
s->in_gb.buffer= NULL;
} }
align_get_bits(&s->gb); align_get_bits(&s->gb);