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2ba45a60 DM |
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 | ||
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); | |
f6fa7814 | 91 | if (ret < -1) |
2ba45a60 DM |
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 | }; |