2 * MPEG1 / MPEG2 video parser
3 * Copyright (c) 2000,2001 Fabrice Bellard
4 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "mpegvideo.h"
26 static void mpegvideo_extract_headers(AVCodecParserContext *s,
27 AVCodecContext *avctx,
28 const uint8_t *buf, int buf_size)
30 ParseContext1 *pc = s->priv_data;
31 const uint8_t *buf_end = buf + buf_size;
33 int frame_rate_index, ext_type, bytes_left;
34 int frame_rate_ext_n, frame_rate_ext_d;
35 int picture_structure, top_field_first, repeat_first_field, progressive_frame;
36 int horiz_size_ext, vert_size_ext, bit_rate_ext;
38 //FIXME replace the crap with get_bits()
41 while (buf < buf_end) {
43 buf= ff_find_start_code(buf, buf_end, &start_code);
44 bytes_left = buf_end - buf;
46 case PICTURE_START_CODE:
47 if (bytes_left >= 2) {
48 s->pict_type = (buf[1] >> 3) & 7;
52 if (bytes_left >= 7) {
53 pc->width = (buf[0] << 4) | (buf[1] >> 4);
54 pc->height = ((buf[1] & 0x0f) << 8) | buf[2];
55 if(!avctx->width || !avctx->height || !avctx->coded_width || !avctx->coded_height){
56 avcodec_set_dimensions(avctx, pc->width, pc->height);
59 frame_rate_index = buf[3] & 0xf;
60 pc->frame_rate.den = avctx->time_base.den = ff_frame_rate_tab[frame_rate_index].num;
61 pc->frame_rate.num = avctx->time_base.num = ff_frame_rate_tab[frame_rate_index].den;
62 avctx->bit_rate = ((buf[4]<<10) | (buf[5]<<2) | (buf[6]>>6))*400;
63 avctx->codec_id = CODEC_ID_MPEG1VIDEO;
68 if (bytes_left >= 1) {
69 ext_type = (buf[0] >> 4);
71 case 0x1: /* sequence extension */
72 if (bytes_left >= 6) {
73 horiz_size_ext = ((buf[1] & 1) << 1) | (buf[2] >> 7);
74 vert_size_ext = (buf[2] >> 5) & 3;
75 bit_rate_ext = ((buf[2] & 0x1F)<<7) | (buf[3]>>1);
76 frame_rate_ext_n = (buf[5] >> 5) & 3;
77 frame_rate_ext_d = (buf[5] & 0x1f);
78 pc->progressive_sequence = buf[1] & (1 << 3);
79 avctx->has_b_frames= !(buf[5] >> 7);
81 pc->width |=(horiz_size_ext << 12);
82 pc->height |=( vert_size_ext << 12);
83 avctx->bit_rate += (bit_rate_ext << 18) * 400;
85 avcodec_set_dimensions(avctx, pc->width, pc->height);
86 avctx->time_base.den = pc->frame_rate.den * (frame_rate_ext_n + 1) * 2;
87 avctx->time_base.num = pc->frame_rate.num * (frame_rate_ext_d + 1);
88 avctx->codec_id = CODEC_ID_MPEG2VIDEO;
89 avctx->sub_id = 2; /* forces MPEG2 */
92 case 0x8: /* picture coding extension */
93 if (bytes_left >= 5) {
94 picture_structure = buf[2]&3;
95 top_field_first = buf[3] & (1 << 7);
96 repeat_first_field = buf[3] & (1 << 1);
97 progressive_frame = buf[4] & (1 << 7);
99 /* check if we must repeat the frame */
101 if (repeat_first_field) {
102 if (pc->progressive_sequence) {
107 } else if (progressive_frame) {
119 /* we stop parsing when we encounter a slice. It ensures
120 that this function takes a negligible amount of time */
121 if (start_code >= SLICE_MIN_START_CODE &&
122 start_code <= SLICE_MAX_START_CODE)
130 static int mpegvideo_parse(AVCodecParserContext *s,
131 AVCodecContext *avctx,
132 const uint8_t **poutbuf, int *poutbuf_size,
133 const uint8_t *buf, int buf_size)
135 ParseContext1 *pc1 = s->priv_data;
136 ParseContext *pc= &pc1->pc;
139 if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
142 next= ff_mpeg1_find_frame_end(pc, buf, buf_size, s);
144 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
151 /* we have a full frame : we just parse the first few MPEG headers
152 to have the full timing information. The time take by this
153 function should be negligible for uncorrupted streams */
154 mpegvideo_extract_headers(s, avctx, buf, buf_size);
156 printf("pict_type=%d frame_rate=%0.3f repeat_pict=%d\n",
157 s->pict_type, (double)avctx->time_base.den / avctx->time_base.num, s->repeat_pict);
161 *poutbuf_size = buf_size;
165 static int mpegvideo_split(AVCodecContext *avctx,
166 const uint8_t *buf, int buf_size)
171 for(i=0; i<buf_size; i++){
172 state= (state<<8) | buf[i];
173 if(state != 0x1B3 && state != 0x1B5 && state < 0x200 && state >= 0x100)
179 AVCodecParser ff_mpegvideo_parser = {
180 { CODEC_ID_MPEG1VIDEO, CODEC_ID_MPEG2VIDEO },
181 sizeof(ParseContext1),