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d59591fb02
contains the first picture startcode that commences in the PES packet, instead of the first access unit that commences in the PES packet. Fix the parser to handle that properly. This was a very long standing bug ... The change to the seek regressions is because the mpeg ts muxer stores too many invalid and randomized timestamps which overflow the 4 entry buffer we use in the parser. Originally committed as revision 13643 to svn://svn.ffmpeg.org/ffmpeg/trunk
183 lines
6.9 KiB
C
183 lines
6.9 KiB
C
/*
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* MPEG1 / MPEG2 video parser
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* Copyright (c) 2000,2001 Fabrice Bellard.
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* Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "parser.h"
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#include "mpegvideo.h"
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static void mpegvideo_extract_headers(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t *buf, int buf_size)
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{
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ParseContext1 *pc = s->priv_data;
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const uint8_t *buf_end;
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const uint8_t *buf_start= buf;
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uint32_t start_code;
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int frame_rate_index, ext_type, bytes_left;
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int frame_rate_ext_n, frame_rate_ext_d;
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int picture_structure, top_field_first, repeat_first_field, progressive_frame;
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int horiz_size_ext, vert_size_ext, bit_rate_ext;
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//FIXME replace the crap with get_bits()
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s->repeat_pict = 0;
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buf_end = buf + buf_size;
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while (buf < buf_end) {
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start_code= -1;
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buf= ff_find_start_code(buf, buf_end, &start_code);
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bytes_left = buf_end - buf;
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switch(start_code) {
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case PICTURE_START_CODE:
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ff_fetch_timestamp(s, buf-buf_start-4, 1);
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if (bytes_left >= 2) {
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s->pict_type = (buf[1] >> 3) & 7;
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}
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break;
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case SEQ_START_CODE:
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if (bytes_left >= 7) {
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pc->width = (buf[0] << 4) | (buf[1] >> 4);
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pc->height = ((buf[1] & 0x0f) << 8) | buf[2];
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avcodec_set_dimensions(avctx, pc->width, pc->height);
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frame_rate_index = buf[3] & 0xf;
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pc->frame_rate.den = avctx->time_base.den = ff_frame_rate_tab[frame_rate_index].num;
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pc->frame_rate.num = avctx->time_base.num = ff_frame_rate_tab[frame_rate_index].den;
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avctx->bit_rate = ((buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6))*400;
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avctx->codec_id = CODEC_ID_MPEG1VIDEO;
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avctx->sub_id = 1;
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}
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break;
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case EXT_START_CODE:
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if (bytes_left >= 1) {
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ext_type = (buf[0] >> 4);
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switch(ext_type) {
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case 0x1: /* sequence extension */
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if (bytes_left >= 6) {
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horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7);
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vert_size_ext = (buf[2] >> 5) & 3;
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bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1);
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frame_rate_ext_n = (buf[5] >> 5) & 3;
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frame_rate_ext_d = (buf[5] & 0x1f);
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pc->progressive_sequence = buf[1] & (1 << 3);
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avctx->has_b_frames= !(buf[5] >> 7);
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pc->width |=(horiz_size_ext << 12);
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pc->height |=( vert_size_ext << 12);
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avctx->bit_rate += (bit_rate_ext << 18) * 400;
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avcodec_set_dimensions(avctx, pc->width, pc->height);
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avctx->time_base.den = pc->frame_rate.den * (frame_rate_ext_n + 1);
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avctx->time_base.num = pc->frame_rate.num * (frame_rate_ext_d + 1);
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avctx->codec_id = CODEC_ID_MPEG2VIDEO;
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avctx->sub_id = 2; /* forces MPEG2 */
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}
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break;
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case 0x8: /* picture coding extension */
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if (bytes_left >= 5) {
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picture_structure = buf[2]&3;
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top_field_first = buf[3] & (1 << 7);
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repeat_first_field = buf[3] & (1 << 1);
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progressive_frame = buf[4] & (1 << 7);
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/* check if we must repeat the frame */
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if (repeat_first_field) {
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if (pc->progressive_sequence) {
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if (top_field_first)
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s->repeat_pict = 4;
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else
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s->repeat_pict = 2;
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} else if (progressive_frame) {
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s->repeat_pict = 1;
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}
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}
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}
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break;
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}
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}
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break;
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case -1:
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goto the_end;
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default:
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/* we stop parsing when we encounter a slice. It ensures
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that this function takes a negligible amount of time */
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if (start_code >= SLICE_MIN_START_CODE &&
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start_code <= SLICE_MAX_START_CODE)
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goto the_end;
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break;
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}
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}
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the_end: ;
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}
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static int mpegvideo_parse(AVCodecParserContext *s,
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AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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ParseContext1 *pc1 = s->priv_data;
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ParseContext *pc= &pc1->pc;
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int next;
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if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
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next= buf_size;
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}else{
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next= ff_mpeg1_find_frame_end(pc, buf, buf_size);
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if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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}
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/* we have a full frame : we just parse the first few MPEG headers
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to have the full timing information. The time take by this
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function should be negligible for uncorrupted streams */
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mpegvideo_extract_headers(s, avctx, buf, buf_size);
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#if 0
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printf("pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",
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s->pict_type, (double)avctx->time_base.den / avctx->time_base.num, s->repeat_pict);
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#endif
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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static int mpegvideo_split(AVCodecContext *avctx,
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const uint8_t *buf, int buf_size)
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{
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int i;
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uint32_t state= -1;
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for(i=0; i<buf_size; i++){
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state= (state<<8) | buf[i];
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if(state != 0x1B3 && state != 0x1B5 && state < 0x200 && state >= 0x100)
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return i-3;
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}
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return 0;
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}
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AVCodecParser mpegvideo_parser = {
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{ CODEC_ID_MPEG1VIDEO, CODEC_ID_MPEG2VIDEO },
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sizeof(ParseContext1),
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NULL,
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mpegvideo_parse,
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ff_parse1_close,
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};
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