FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/mpeg4video_parser.c
Date: 2023-09-24 13:02:57
Exec Total Coverage
Lines: 67 69 97.1%
Functions: 4 4 100.0%
Branches: 40 46 87.0%
Line Branch Exec Source
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 "decode.h"
26 #include "parser.h"
27 #include "mpegvideo.h"
28 #include "mpeg4videodec.h"
29 #include "mpeg4videodefs.h"
30
31 struct Mp4vParseContext {
32 ParseContext pc;
33 Mpeg4DecContext dec_ctx;
34 int first_picture;
35 };
36
37 /**
38 * Find the end of the current frame in the bitstream.
39 * @return the position of the first byte of the next frame, or -1
40 */
41 8488 static int mpeg4_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size)
42 {
43 int vop_found, i;
44 uint32_t state;
45
46 8488 vop_found = pc->frame_start_found;
47 8488 state = pc->state;
48
49 8488 i = 0;
50
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 8488 if (!vop_found) {
51
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 8483 for (i = 0; i < buf_size; i++) {
52 8481 state = (state << 8) | buf[i];
53
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 8481 if (state == VOP_STARTCODE) {
54 1086 i++;
55 1086 vop_found = 1;
56 1086 break;
57 }
58 }
59 }
60
61
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 8488 if (vop_found) {
62 /* EOF considered as end of frame */
63
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 8486 if (buf_size == 0)
64 26 return 0;
65
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 8769521 for (; i < buf_size; i++) {
66 8762134 state = (state << 8) | buf[i];
67
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 8762134 if ((state & 0xFFFFFF00) == 0x100) {
68
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 1103 if (state == SLICE_STARTCODE || state == EXT_STARTCODE)
69 30 continue;
70 1073 pc->frame_start_found = 0;
71 1073 pc->state = -1;
72 1073 return i - 3;
73 }
74 }
75 }
76 7389 pc->frame_start_found = vop_found;
77 7389 pc->state = state;
78 7389 return END_NOT_FOUND;
79 }
80
81 /* XXX: make it use less memory */
82 3578 static int mpeg4_decode_header(AVCodecParserContext *s1, AVCodecContext *avctx,
83 const uint8_t *buf, int buf_size)
84 {
85 3578 struct Mp4vParseContext *pc = s1->priv_data;
86 3578 Mpeg4DecContext *dec_ctx = &pc->dec_ctx;
87 3578 MpegEncContext *s = &dec_ctx->m;
88 3578 GetBitContext gb1, *gb = &gb1;
89 int ret;
90
91 3578 s->avctx = avctx;
92 3578 s->current_picture_ptr = &s->current_picture;
93
94
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 3578 if (avctx->extradata_size && pc->first_picture) {
95 241 init_get_bits(gb, avctx->extradata, avctx->extradata_size * 8);
96 241 ret = ff_mpeg4_decode_picture_header(dec_ctx, gb, 1, 1);
97
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 241 if (ret < 0)
98 ✗ av_log(avctx, AV_LOG_WARNING, "Failed to parse extradata\n");
99 }
100
101 3578 init_get_bits(gb, buf, 8 * buf_size);
102 3578 ret = ff_mpeg4_decode_picture_header(dec_ctx, gb, 0, 1);
103
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 3578 if (s->width && (!avctx->width || !avctx->height ||
104
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 3513 !avctx->coded_width || !avctx->coded_height)) {
105 13 ret = ff_set_dimensions(avctx, s->width, s->height);
106
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 13 if (ret < 0)
107 ✗ return ret;
108 }
109
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 3578 if((s1->flags & PARSER_FLAG_USE_CODEC_TS) && s->avctx->framerate.num>0 && ret>=0){
110 av_assert1(s1->pts == AV_NOPTS_VALUE);
111 av_assert1(s1->dts == AV_NOPTS_VALUE);
112
113 874 s1->pts = av_rescale_q(s->time, (AVRational){1, s->avctx->framerate.num}, (AVRational){1, 1200000});
114 }
115
116 3578 s1->pict_type = s->pict_type;
117 3578 pc->first_picture = 0;
118 3578 return ret;
119 }
120
121 333 static av_cold int mpeg4video_parse_init(AVCodecParserContext *s)
122 {
123 333 struct Mp4vParseContext *pc = s->priv_data;
124
125 333 pc->first_picture = 1;
126 333 pc->dec_ctx.m.quant_precision = 5;
127 333 pc->dec_ctx.m.slice_context_count = 1;
128 333 pc->dec_ctx.showed_packed_warning = 1;
129 333 return 0;
130 }
131
132 10967 static int mpeg4video_parse(AVCodecParserContext *s,
133 AVCodecContext *avctx,
134 const uint8_t **poutbuf, int *poutbuf_size,
135 const uint8_t *buf, int buf_size)
136 {
137 10967 ParseContext *pc = s->priv_data;
138 int next;
139
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 10967 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
141 2479 next = buf_size;
142 } else {
143 8488 next = mpeg4_find_frame_end(pc, buf, buf_size);
144
145
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 8488 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
146 7389 *poutbuf = NULL;
147 7389 *poutbuf_size = 0;
148 7389 return buf_size;
149 }
150 }
151 3578 mpeg4_decode_header(s, avctx, buf, buf_size);
152
153 3578 *poutbuf = buf;
154 3578 *poutbuf_size = buf_size;
155 3578 return next;
156 }
157
158 const AVCodecParser ff_mpeg4video_parser = {
159 .codec_ids = { AV_CODEC_ID_MPEG4 },
160 .priv_data_size = sizeof(struct Mp4vParseContext),
161 .parser_init = mpeg4video_parse_init,
162 .parser_parse = mpeg4video_parse,
163 .parser_close = ff_parse_close,
164 };
165