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General approach to parsing chunks in VC-1 AP 

Originally committed as revision 7803 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Kostya Shishkov 2007-02-02 06:45:21 +00:00
parent 14c49573d8
commit 77ccd3ba54
1 changed files with 124 additions and 40 deletions
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164
libavcodec/vc1.c
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@ -46,6 +46,19 @@ extern const uint16_t ff_msmp4_mb_i_table[64][2];
#define AC_VLC_BITS 9
static const uint16_t table_mb_intra[64][2];
/** Markers used if VC-1 AP frame data */
//@{
enum VC1Code{
VC1_CODE_RES0 = 0x00000100,
VC1_CODE_ESCAPE = 0x00000103,
VC1_CODE_ENDOFSEQ = 0x0000010A,
VC1_CODE_SLICE,
VC1_CODE_FIELD,
VC1_CODE_FRAME,
VC1_CODE_ENTRYPOINT,
VC1_CODE_SEQHDR,
};
//@}
/** Available Profiles */
//@{
@ -4094,6 +4107,42 @@ static void vc1_decode_blocks(VC1Context *v)
}
}
#define IS_MARKER(x) ((((x) & ~0xFF) == VC1_CODE_RES0) && ((x) != VC1_CODE_ESCAPE))
/** Find VC-1 marker in buffer
* @return position where next marker starts or end of buffer if no marker found
*/
static av_always_inline uint8_t* find_next_marker(uint8_t *src, uint8_t *end)
{
uint32_t mrk = 0xFFFFFFFF;
if(end-src < 4) return end;
while(src < end){
mrk = (mrk << 8) | *src++;
if(IS_MARKER(mrk))
return src-4;
}
return end;
}
static av_always_inline int vc1_unescape_buffer(uint8_t *src, int size, uint8_t *dst)
{
int dsize = 0, i;
if(size < 4){
for(dsize = 0; dsize < size; dsize++) *dst++ = *src++;
return size;
}
for(i = 0; i < size; i++, src++) {
if(src[0] == 3 && i >= 2 && !src[-1] && !src[-2] && i < size-1 && src[1] < 4) {
dst[dsize++] = src[1];
src++;
i++;
} else
dst[dsize++] = *src;
}
return dsize;
}
/** Initialize a VC1/WMV3 decoder
* @todo TODO: Handle VC-1 IDUs (Transport level?)
@ -4145,44 +4194,47 @@ static int vc1_decode_init(AVCodecContext *avctx)
av_log(avctx, AV_LOG_INFO, "Read %i bits in overflow\n", -count);
}
} else { // VC1/WVC1
int edata_size = avctx->extradata_size;
uint8_t *edata = avctx->extradata;
uint8_t *start = avctx->extradata, *end = avctx->extradata + avctx->extradata_size;
uint8_t *next; int size, buf2_size;
uint8_t *buf2 = NULL;
int seq_inited = 0, ep_inited = 0;
if(avctx->extradata_size < 16) {
av_log(avctx, AV_LOG_ERROR, "Extradata size too small: %i\n", edata_size);
av_log(avctx, AV_LOG_ERROR, "Extradata size too small: %i\n", avctx->extradata_size);
return -1;
}
while(edata_size > 8) {
// test if we've found header
if(AV_RB32(edata) == 0x0000010F) {
edata += 4;
edata_size -= 4;
buf2 = av_mallocz(avctx->extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
if(start[0]) start++; // in WVC1 extradata first byte is its size
next = start;
for(; next < end; start = next){
next = find_next_marker(start + 4, end);
size = next - start - 4;
if(size <= 0) continue;
buf2_size = vc1_unescape_buffer(start + 4, size, buf2);
init_get_bits(&gb, buf2, buf2_size * 8);
switch(AV_RB32(start)){
case VC1_CODE_SEQHDR:
if(decode_sequence_header(avctx, &gb) < 0){
av_free(buf2);
return -1;
}
seq_inited = 1;
break;
case VC1_CODE_ENTRYPOINT:
if(decode_entry_point(avctx, &gb) < 0){
av_free(buf2);
return -1;
}
ep_inited = 1;
break;
}
edata_size--;
edata++;
}
init_get_bits(&gb, edata, edata_size*8);
if (decode_sequence_header(avctx, &gb) < 0)
return -1;
while(edata_size > 8) {
// test if we've found entry point
if(AV_RB32(edata) == 0x0000010E) {
edata += 4;
edata_size -= 4;
break;
}
edata_size--;
edata++;
av_free(buf2);
if(!seq_inited || !ep_inited){
av_log(avctx, AV_LOG_ERROR, "Incomplete extradata\n");
return -1;
}
init_get_bits(&gb, edata, edata_size*8);
if (decode_entry_point(avctx, &gb) < 0)
return -1;
}
avctx->has_b_frames= !!(avctx->max_b_frames);
s->low_delay = !avctx->has_b_frames;
@ -4246,17 +4298,49 @@ static int vc1_decode_frame(AVCodecContext *avctx,
s->current_picture_ptr= &s->picture[i];
}
//for advanced profile we need to unescape buffer
//for advanced profile we may need to parse and unescape data
if (avctx->codec_id == CODEC_ID_VC1) {
int i, buf_size2;
buf2 = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
buf_size2 = 0;
for(i = 0; i < buf_size; i++) {
if(buf[i] == 3 && i >= 2 && !buf[i-1] && !buf[i-2] && i < buf_size-1 && buf[i+1] < 4) {
buf2[buf_size2++] = buf[i+1];
i++;
} else
buf2[buf_size2++] = buf[i];
int buf_size2 = 0;
buf2 = av_mallocz(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
if(IS_MARKER(AV_RB32(buf))){ /* frame starts with marker and needs to be parsed */
uint8_t *dst = buf2, *start, *end, *next;
int size;
next = buf;
for(start = buf, end = buf + buf_size; next < end; start = next){
next = find_next_marker(start + 4, end);
size = next - start - 4;
if(size <= 0) continue;
switch(AV_RB32(start)){
case VC1_CODE_FRAME:
buf_size2 = vc1_unescape_buffer(start + 4, size, buf2);
break;
case VC1_CODE_ENTRYPOINT: /* it should be before frame data */
buf_size2 = vc1_unescape_buffer(start + 4, size, buf2);
init_get_bits(&s->gb, buf2, buf_size2*8);
decode_entry_point(avctx, &s->gb);
break;
case VC1_CODE_SLICE:
av_log(avctx, AV_LOG_ERROR, "Sliced decoding is not implemented (yet)\n");
av_free(buf2);
return -1;
}
}
}else if(v->interlace && ((buf[0] & 0xC0) == 0xC0)){ /* WVC1 interlaced stores both fields divided by marker */
uint8_t *divider;
divider = find_next_marker(buf, buf + buf_size);
if((divider == (buf + buf_size)) || AV_RB32(divider) != VC1_CODE_FIELD){
av_log(avctx, AV_LOG_ERROR, "Error in WVC1 interlaced frame\n");
return -1;
}
buf_size2 = vc1_unescape_buffer(buf, divider - buf, buf2);
// TODO
av_free(buf2);return -1;
}else{
buf_size2 = vc1_unescape_buffer(buf, buf_size, buf2);
}
init_get_bits(&s->gb, buf2, buf_size2*8);
} else