@ -125,9 +125,14 @@ static int h263_decode_end(AVCodecContext *avctx)
*/
static int get_consumed_bytes ( MpegEncContext * s , int buf_size ) {
int pos = ( get_bits_count ( & s - > gb ) + 7 ) > > 3 ;
if ( s - > divx_version > = 500 ) {
//we would have to scan through the whole buf to handle the weird reordering ...
return buf_size ;
} else if ( s - > flags & CODEC_FLAG_TRUNCATED ) {
pos - = s - > parse_context . last_index ;
if ( pos < 0 ) pos = 0 ; // padding is not really read so this might be -1
return pos ;
} else {
if ( pos = = 0 ) pos = 1 ; //avoid infinite loops (i doubt thats needed but ...)
if ( pos + 10 > buf_size ) pos = buf_size ; // oops ;)
@ -299,6 +304,43 @@ static int decode_slice(MpegEncContext *s){
return - 1 ;
}
/**
* finds the end of the current frame in the bitstream .
* @ return the position of the first byte of the next frame , or - 1
*/
static int mpeg4_find_frame_end ( MpegEncContext * s , UINT8 * buf , int buf_size ) {
ParseContext * pc = & s - > parse_context ;
int vop_found , i ;
uint32_t state ;
vop_found = pc - > frame_start_found ;
state = pc - > state ;
i = 0 ;
if ( ! vop_found ) {
for ( i = 0 ; i < buf_size ; i + + ) {
state = ( state < < 8 ) | buf [ i ] ;
if ( state = = 0x1B6 ) {
i + + ;
vop_found = 1 ;
break ;
}
}
}
for ( ; i < buf_size ; i + + ) {
state = ( state < < 8 ) | buf [ i ] ;
if ( ( state & 0xFFFFFF00 ) = = 0x100 ) {
pc - > frame_start_found = 0 ;
pc - > state = - 1 ;
return i - 3 ;
}
}
pc - > frame_start_found = vop_found ;
pc - > state = state ;
return - 1 ;
}
static int h263_decode_frame ( AVCodecContext * avctx ,
void * data , int * data_size ,
UINT8 * buf , int buf_size )
@ -325,6 +367,42 @@ uint64_t time= rdtsc();
if ( buf_size = = 0 ) {
return 0 ;
}
if ( s - > flags & CODEC_FLAG_TRUNCATED ) {
int next ;
ParseContext * pc = & s - > parse_context ;
pc - > last_index = pc - > index ;
if ( s - > codec_id = = CODEC_ID_MPEG4 ) {
next = mpeg4_find_frame_end ( s , buf , buf_size ) ;
} else {
fprintf ( stderr , " this codec doesnt support truncated bitstreams \n " ) ;
return - 1 ;
}
if ( next = = - 1 ) {
if ( buf_size + FF_INPUT_BUFFER_PADDING_SIZE + pc - > index > pc - > buffer_size ) {
pc - > buffer_size = buf_size + pc - > index + 10 * 1024 ;
pc - > buffer = realloc ( pc - > buffer , pc - > buffer_size ) ;
}
memcpy ( & pc - > buffer [ pc - > index ] , buf , buf_size ) ;
pc - > index + = buf_size ;
return buf_size ;
}
if ( pc - > index ) {
if ( next + FF_INPUT_BUFFER_PADDING_SIZE + pc - > index > pc - > buffer_size ) {
pc - > buffer_size = next + pc - > index + 10 * 1024 ;
pc - > buffer = realloc ( pc - > buffer , pc - > buffer_size ) ;
}
memcpy ( & pc - > buffer [ pc - > index ] , buf , next + FF_INPUT_BUFFER_PADDING_SIZE ) ;
pc - > index = 0 ;
buf = pc - > buffer ;
buf_size = pc - > last_index + next ;
}
}
retry :
@ -627,7 +705,7 @@ AVCodec mpeg4_decoder = {
NULL ,
h263_decode_end ,
h263_decode_frame ,
CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 ,
CODEC_CAP_DRAW_HORIZ_BAND | CODEC_CAP_DR1 | CODEC_CAP_TRUNCATED ,
} ;
AVCodec h263_decoder = {
Michael Niedermayer
23 years ago