-static int find_start_code(const uint8_t **pbuf_ptr, const uint8_t *buf_end)
-{
- const uint8_t *buf_ptr;
- unsigned int state=0xFFFFFFFF, v;
- int val;
-
- buf_ptr = *pbuf_ptr;
- while (buf_ptr < buf_end) {
- v = *buf_ptr++;
- if (state == 0x000001) {
- state = ((state << 8) | v) & 0xffffff;
- val = state;
- goto found;
- }
- state = ((state << 8) | v) & 0xffffff;
- }
- val = -1;
- found:
- *pbuf_ptr = buf_ptr;
- return val;
-}
-
-/* XXX: merge with libavcodec ? */
-#define MPEG1_FRAME_RATE_BASE 1001
-
-static const int frame_rate_tab[16] = {
- 0,
- 24000,
- 24024,
- 25025,
- 30000,
- 30030,
- 50050,
- 60000,
- 60060,
- // Xing's 15fps: (9)
- 15015,
- // libmpeg3's "Unofficial economy rates": (10-13)
- 5005,
- 10010,
- 12012,
- 15015,
- // random, just to avoid segfault !never encode these
- 25025,
- 25025,
-};
-
-static void mpegvideo_extract_headers(AVCodecParserContext *s,
- AVCodecContext *avctx,
- const uint8_t *buf, int buf_size)
-{
- ParseContext1 *pc = s->priv_data;
- const uint8_t *buf_end;
- int32_t start_code;
- int frame_rate_index, ext_type, bytes_left;
- int frame_rate_ext_n, frame_rate_ext_d;
- int picture_structure, top_field_first, repeat_first_field, progressive_frame;
- int horiz_size_ext, vert_size_ext;
-
- s->repeat_pict = 0;
- buf_end = buf + buf_size;
- while (buf < buf_end) {
- start_code = find_start_code(&buf, buf_end);
- bytes_left = buf_end - buf;
- switch(start_code) {
- case PICTURE_START_CODE:
- if (bytes_left >= 2) {
- s->pict_type = (buf[1] >> 3) & 7;
- }
- break;
- case SEQ_START_CODE:
- if (bytes_left >= 4) {
- pc->width = (buf[0] << 4) | (buf[1] >> 4);
- pc->height = ((buf[1] & 0x0f) << 8) | buf[2];
- avcodec_set_dimensions(avctx, pc->width, pc->height);
- frame_rate_index = buf[3] & 0xf;
- pc->frame_rate = avctx->frame_rate = frame_rate_tab[frame_rate_index];
- avctx->frame_rate_base = MPEG1_FRAME_RATE_BASE;
- avctx->codec_id = CODEC_ID_MPEG1VIDEO;
- avctx->sub_id = 1;
- }
- break;
- case EXT_START_CODE:
- if (bytes_left >= 1) {
- ext_type = (buf[0] >> 4);
- switch(ext_type) {
- case 0x1: /* sequence extension */
- if (bytes_left >= 6) {
- horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7);
- vert_size_ext = (buf[2] >> 5) & 3;
- frame_rate_ext_n = (buf[5] >> 5) & 3;
- frame_rate_ext_d = (buf[5] & 0x1f);
- pc->progressive_sequence = buf[1] & (1 << 3);
- avctx->has_b_frames= buf[5] >> 7;
-
- pc->width |=(horiz_size_ext << 12);
- pc->height |=( vert_size_ext << 12);
- avcodec_set_dimensions(avctx, pc->width, pc->height);
- avctx->frame_rate = pc->frame_rate * (frame_rate_ext_n + 1);
- avctx->frame_rate_base = MPEG1_FRAME_RATE_BASE * (frame_rate_ext_d + 1);
- avctx->codec_id = CODEC_ID_MPEG2VIDEO;
- avctx->sub_id = 2; /* forces MPEG2 */
- }
- break;
- case 0x8: /* picture coding extension */
- if (bytes_left >= 5) {
- picture_structure = buf[2]&3;
- top_field_first = buf[3] & (1 << 7);
- repeat_first_field = buf[3] & (1 << 1);
- progressive_frame = buf[4] & (1 << 7);
-
- /* check if we must repeat the frame */
- if (repeat_first_field) {
- if (pc->progressive_sequence) {
- if (top_field_first)
- s->repeat_pict = 4;
- else
- s->repeat_pict = 2;
- } else if (progressive_frame) {
- s->repeat_pict = 1;
- }
- }
-
- /* the packet only represents half a frame
- XXX,FIXME maybe find a different solution */
- if(picture_structure != 3)
- s->repeat_pict = -1;
- }
- break;
- }
- }
- break;
- case -1:
- goto the_end;
- default:
- /* we stop parsing when we encounter a slice. It ensures
- that this function takes a negligible amount of time */
- if (start_code >= SLICE_MIN_START_CODE &&
- start_code <= SLICE_MAX_START_CODE)
- goto the_end;
- break;
- }
- }
- the_end: ;
-}
-
-static int mpegvideo_parse(AVCodecParserContext *s,
- AVCodecContext *avctx,
- uint8_t **poutbuf, int *poutbuf_size,
- const uint8_t *buf, int buf_size)
-{
- ParseContext1 *pc1 = s->priv_data;
- ParseContext *pc= &pc1->pc;
- int next;
-
- next= ff_mpeg1_find_frame_end(pc, buf, buf_size);
-
- if (ff_combine_frame(pc, next, (uint8_t **)&buf, &buf_size) < 0) {
- *poutbuf = NULL;
- *poutbuf_size = 0;
- return buf_size;
- }
- /* we have a full frame : we just parse the first few MPEG headers
- to have the full timing information. The time take by this
- function should be negligible for uncorrupted streams */
- mpegvideo_extract_headers(s, avctx, buf, buf_size);
-#if 0
- printf("pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",
- s->pict_type, (double)avctx->frame_rate / avctx->frame_rate_base, s->repeat_pict);
-#endif
-
- *poutbuf = (uint8_t *)buf;
- *poutbuf_size = buf_size;
- return next;
-}
-