Imported Debian version 2.5.3~trusty1
[deb_ffmpeg.git] / ffmpeg / libavcodec / mpeg4video_parser.c
CommitLineData
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1/*
2 * MPEG4 Video frame extraction
3 * Copyright (c) 2003 Fabrice Bellard
4 * Copyright (c) 2003 Michael Niedermayer
5 *
6 * This file is part of FFmpeg.
7 *
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.
12 *
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.
17 *
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
21 */
22
23#define UNCHECKED_BITSTREAM_READER 1
24
25#include "internal.h"
26#include "parser.h"
27#include "mpegvideo.h"
28#include "mpeg4video.h"
29#include "mpeg4video_parser.h"
30
31struct Mp4vParseContext {
32 ParseContext pc;
33 Mpeg4DecContext dec_ctx;
34 int first_picture;
35};
36
37int ff_mpeg4_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
38{
39 int vop_found, i;
40 uint32_t state;
41
42 vop_found = pc->frame_start_found;
43 state = pc->state;
44
45 i = 0;
46 if (!vop_found) {
47 for (i = 0; i < buf_size; i++) {
48 state = (state << 8) | buf[i];
49 if (state == 0x1B6) {
50 i++;
51 vop_found = 1;
52 break;
53 }
54 }
55 }
56
57 if (vop_found) {
58 /* EOF considered as end of frame */
59 if (buf_size == 0)
60 return 0;
61 for (; i < buf_size; i++) {
62 state = (state << 8) | buf[i];
63 if ((state & 0xFFFFFF00) == 0x100) {
64 pc->frame_start_found = 0;
65 pc->state = -1;
66 return i - 3;
67 }
68 }
69 }
70 pc->frame_start_found = vop_found;
71 pc->state = state;
72 return END_NOT_FOUND;
73}
74
75/* XXX: make it use less memory */
76static int mpeg4_decode_header(AVCodecParserContext *s1, AVCodecContext *avctx,
77 const uint8_t *buf, int buf_size)
78{
79 struct Mp4vParseContext *pc = s1->priv_data;
80 Mpeg4DecContext *dec_ctx = &pc->dec_ctx;
81 MpegEncContext *s = &dec_ctx->m;
82 GetBitContext gb1, *gb = &gb1;
83 int ret;
84
85 s->avctx = avctx;
86 s->current_picture_ptr = &s->current_picture;
87
88 if (avctx->extradata_size && pc->first_picture) {
89 init_get_bits(gb, avctx->extradata, avctx->extradata_size * 8);
90 ret = ff_mpeg4_decode_picture_header(dec_ctx, gb);
f6fa7814 91 if (ret < -1)
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92 av_log(avctx, AV_LOG_WARNING, "Failed to parse extradata\n");
93 }
94
95 init_get_bits(gb, buf, 8 * buf_size);
96 ret = ff_mpeg4_decode_picture_header(dec_ctx, gb);
97 if (s->width && (!avctx->width || !avctx->height ||
98 !avctx->coded_width || !avctx->coded_height)) {
99 ret = ff_set_dimensions(avctx, s->width, s->height);
100 if (ret < 0)
101 return ret;
102 }
103 if((s1->flags & PARSER_FLAG_USE_CODEC_TS) && s->avctx->time_base.den>0 && ret>=0){
104 av_assert1(s1->pts == AV_NOPTS_VALUE);
105 av_assert1(s1->dts == AV_NOPTS_VALUE);
106
107 s1->pts = av_rescale_q(s->time, (AVRational){1, s->avctx->time_base.den}, (AVRational){1, 1200000});
108 }
109
110 s1->pict_type = s->pict_type;
111 pc->first_picture = 0;
112 return ret;
113}
114
115static av_cold int mpeg4video_parse_init(AVCodecParserContext *s)
116{
117 struct Mp4vParseContext *pc = s->priv_data;
118
119 ff_mpeg4videodec_static_init();
120
121 pc->first_picture = 1;
122 pc->dec_ctx.m.quant_precision = 5;
123 pc->dec_ctx.m.slice_context_count = 1;
124 pc->dec_ctx.showed_packed_warning = 1;
125 return 0;
126}
127
128static int mpeg4video_parse(AVCodecParserContext *s,
129 AVCodecContext *avctx,
130 const uint8_t **poutbuf, int *poutbuf_size,
131 const uint8_t *buf, int buf_size)
132{
133 ParseContext *pc = s->priv_data;
134 int next;
135
136 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
137 next = buf_size;
138 } else {
139 next = ff_mpeg4_find_frame_end(pc, buf, buf_size);
140
141 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
142 *poutbuf = NULL;
143 *poutbuf_size = 0;
144 return buf_size;
145 }
146 }
147 mpeg4_decode_header(s, avctx, buf, buf_size);
148
149 *poutbuf = buf;
150 *poutbuf_size = buf_size;
151 return next;
152}
153
154AVCodecParser ff_mpeg4video_parser = {
155 .codec_ids = { AV_CODEC_ID_MPEG4 },
156 .priv_data_size = sizeof(struct Mp4vParseContext),
157 .parser_init = mpeg4video_parse_init,
158 .parser_parse = mpeg4video_parse,
159 .parser_close = ff_parse_close,
160 .split = ff_mpeg4video_split,
161};