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better padding/stuffing bug autodetection 

Originally committed as revision 1457 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2003-01-13 12:57:39 +00:00
parent 741235ebe9
commit 650faac6de
1 changed files with 9 additions and 5 deletions
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14
libavcodec/h263dec.c
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@ -144,6 +144,8 @@ static int get_consumed_bytes(MpegEncContext *s, int buf_size){
} }
static int decode_slice(MpegEncContext *s){ static int decode_slice(MpegEncContext *s){
const int workaround_bugs= s->workaround_bugs;
s->last_resync_gb= s->gb; s->last_resync_gb= s->gb;
s->first_slice_line= 1; s->first_slice_line= 1;
@ -257,7 +259,9 @@ static int decode_slice(MpegEncContext *s){
const int bits_count= get_bits_count(&s->gb); const int bits_count= get_bits_count(&s->gb);
const int bits_left = s->gb.size*8 - bits_count; const int bits_left = s->gb.size*8 - bits_count;
if(bits_left==0 || bits_left>8){ if(bits_left==0){
s->padding_bug_score+=16;
}else if(bits_left>8){
s->padding_bug_score++; s->padding_bug_score++;
} else if(bits_left != 1){ } else if(bits_left != 1){
int v= show_bits(&s->gb, 8); int v= show_bits(&s->gb, 8);
@ -267,7 +271,7 @@ static int decode_slice(MpegEncContext *s){
s->padding_bug_score--; s->padding_bug_score--;
else else
s->padding_bug_score++; s->padding_bug_score++;
} }
if(s->padding_bug_score > -2) if(s->padding_bug_score > -2)
s->workaround_bugs |= FF_BUG_NO_PADDING; s->workaround_bugs |= FF_BUG_NO_PADDING;
@ -276,7 +280,7 @@ static int decode_slice(MpegEncContext *s){
} }
// handle formats which dont have unique end markers // handle formats which dont have unique end markers
if(s->msmpeg4_version || (s->workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly if(s->msmpeg4_version || (workaround_bugs&FF_BUG_NO_PADDING)){ //FIXME perhaps solve this more cleanly
int left= s->gb.size*8 - get_bits_count(&s->gb); int left= s->gb.size*8 - get_bits_count(&s->gb);
int max_extra=7; int max_extra=7;
@ -285,9 +289,9 @@ static int decode_slice(MpegEncContext *s){
max_extra+= 17; max_extra+= 17;
/* buggy padding but the frame should still end approximately at the bitstream end */ /* buggy padding but the frame should still end approximately at the bitstream end */
if((s->workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3) if((workaround_bugs&FF_BUG_NO_PADDING) && s->error_resilience>=3)
max_extra+= 48; max_extra+= 48;
else if((s->workaround_bugs&FF_BUG_NO_PADDING)) else if((workaround_bugs&FF_BUG_NO_PADDING))
max_extra+= 256*256*256*64; max_extra+= 256*256*256*64;
if(left>max_extra){ if(left>max_extra){