/**
* Find the end of the current frame in the bitstream.
* @return the position of the first byte of the next frame, or -1
*/
int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
{
int i;
uint32_t state = pc->state;
/* EOF considered as end of frame */
if (buf_size == 0)
return 0;
/*
0 frame start -> 1/4
1 first_SEQEXT -> 0/2
2 first field start -> 3/0
3 second_SEQEXT -> 2/0
4 searching end
*/
for (i = 0; i < buf_size; i++) {
av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
if (pc->frame_start_found & 1) {
if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
pc->frame_start_found--;
else if (state == EXT_START_CODE + 2) {
if ((buf[i] & 3) == 3)
pc->frame_start_found = 0;
else
pc->frame_start_found = (pc->frame_start_found + 1) & 3;
}
state++;
} else {
i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
i++;
pc->frame_start_found = 4;
}
if (state == SEQ_END_CODE) {
pc->frame_start_found = 0;
pc->state=-1;
return i+1;
}
if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
pc->frame_start_found = 0;
if (pc->frame_start_found < 4 && state == EXT_START_CODE)
pc->frame_start_found++;
if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
pc->frame_start_found = 0;
pc->state = -1;
return i - 3;
}
}
if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
ff_fetch_timestamp(s, i - 3, 1);
}
}
}
pc->state = state;
return END_NOT_FOUND;
}
/**
*
* @param buf input
* @param buf_size input length, to signal EOF, this should be 0 (so that the last frame can be output)
* @param pts input presentation timestamp
* @param dts input decoding timestamp
* @param poutbuf will contain a pointer to the first byte of the output frame
* @param poutbuf_size will contain the length of the output frame
* @return the number of bytes of the input bitstream used
*
* Example:
* @code
* while(in_len){
* len = av_parser_parse(myparser, AVCodecContext, &data, &size,
* in_data, in_len,
* pts, dts);
* in_data += len;
* in_len -= len;
*
* if(size)
* decode_frame(data, size);
* }
* @endcode
*/
int av_parser_parse( AVCodecParserContext *s, AVCodecContext *avctx, uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size, int64_t pts, int64_t dts )
{
LogStr("Init");
int index, i;
uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
if (buf_size == 0)
{
/* padding is always necessary even if EOF, so we add it here */
memset(dummy_buf, 0, sizeof(dummy_buf));
buf = dummy_buf;
}
else
{
/* add a new packet descriptor */
if (pts != AV_NOPTS_VALUE || dts != AV_NOPTS_VALUE)
{
i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
s->cur_frame_start_index = i;
s->cur_frame_offset[i] = s->cur_offset;
s->cur_frame_end[i] = s->cur_offset + buf_size;
s->cur_frame_pts[i] = pts;
s->cur_frame_dts[i] = dts;
}
}
if (s->fetch_timestamp)
{
s->fetch_timestamp = 0;
s->last_pts = s->pts;
s->last_dts = s->dts;
ff_fetch_timestamp(s, 0, 0);
}
/* WARNING: the returned index can be negative */
index = s->parser->parser_parse(s, avctx, (const uint8_t **) poutbuf, poutbuf_size, buf, buf_size);
//av_log(NULL, AV_LOG_DEBUG, "parser: in:%"PRId64", %"PRId64", out:%"PRId64", %"PRId64", in:%d out:%d id:%d\n", pts, dts, s->last_pts, s->last_dts, buf_size, *poutbuf_size, avctx->codec_id);
/* update the file pointer */
if (*poutbuf_size)
{
/* fill the data for the current frame */
s->frame_offset = s->next_frame_offset;
/* offset of the next frame */
s->next_frame_offset = s->cur_offset + index;
s->fetch_timestamp = 1;
}
if (index < 0)
{
index = 0;
}
s->cur_offset += index;
LogStr("Exit");
return index;
}
int av_parser_parse2(AVCodecParserContext *s,
AVCodecContext *avctx,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size,
int64_t pts, int64_t dts,
int64_t pos)
{
int index, i;
uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
if(!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
s->next_frame_offset =
s->cur_offset = pos;
s->flags |= PARSER_FLAG_FETCHED_OFFSET;
}
if (buf_size == 0) {
/* padding is always necessary even if EOF, so we add it here */
memset(dummy_buf, 0, sizeof(dummy_buf));
buf = dummy_buf;
} else if (s->cur_offset + buf_size !=
s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
/* add a new packet descriptor */
i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
s->cur_frame_start_index = i;
s->cur_frame_offset[i] = s->cur_offset;
s->cur_frame_end[i] = s->cur_offset + buf_size;
s->cur_frame_pts[i] = pts;
s->cur_frame_dts[i] = dts;
s->cur_frame_pos[i] = pos;
}
if (s->fetch_timestamp){
s->fetch_timestamp=0;
s->last_pts = s->pts;
s->last_dts = s->dts;
s->last_pos = s->pos;
ff_fetch_timestamp(s, 0, 0);
}
/* WARNING: the returned index can be negative */
index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
/* update the file pointer */
if (*poutbuf_size) {
/* fill the data for the current frame */
s->frame_offset = s->next_frame_offset;
/* offset of the next frame */
s->next_frame_offset = s->cur_offset + index;
s->fetch_timestamp=1;
}
if (index < 0)
index = 0;
s->cur_offset += index;
return index;
}
