blob: b7d6da1f75257ff007243b5cec710ace73ba6ff2
1 | /* |
2 | * MPEG-4 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 | |
31 | struct Mp4vParseContext { |
32 | ParseContext pc; |
33 | Mpeg4DecContext dec_ctx; |
34 | int first_picture; |
35 | }; |
36 | |
37 | int 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 */ |
76 | static 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); |
91 | if (ret < -1) |
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 | |
115 | static 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 | |
128 | static 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 | |
154 | AVCodecParser 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 | }; |
162 |