FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavformat/mxg.c
Date: 2026-04-24 19:58:39
Exec Total Coverage
Lines: 114 131 87.0%
Functions: 5 5 100.0%
Branches: 62 86 72.1%
Line Branch Exec Source
1 /*
2 * MxPEG clip file demuxer
3 * Copyright (c) 2010 Anatoly Nenashev
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "libavutil/channel_layout.h"
23 #include "libavutil/internal.h"
24 #include "libavutil/intreadwrite.h"
25 #include "libavutil/mem.h"
26 #include "libavcodec/mjpeg.h"
27 #include "avformat.h"
28 #include "demux.h"
29 #include "internal.h"
30 #include "avio.h"
31
32 #define DEFAULT_PACKET_SIZE 1024
33 #define OVERREAD_SIZE 3
34
35 typedef struct MXGContext {
36 uint8_t *buffer;
37 uint8_t *buffer_ptr;
38 uint8_t *soi_ptr;
39 unsigned int buffer_size;
40 int64_t dts;
41 unsigned int cache_size;
42 } MXGContext;
43
44 1 static int mxg_read_header(AVFormatContext *s)
45 {
46 AVStream *video_st, *audio_st;
47 1 MXGContext *mxg = s->priv_data;
48
49 /* video parameters will be extracted from the compressed bitstream */
50 1 video_st = avformat_new_stream(s, NULL);
51
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 1 if (!video_st)
52 ✗ return AVERROR(ENOMEM);
53 1 video_st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
54 1 video_st->codecpar->codec_id = AV_CODEC_ID_MXPEG;
55 1 avpriv_set_pts_info(video_st, 64, 1, 1000000);
56
57 1 audio_st = avformat_new_stream(s, NULL);
58
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 1 if (!audio_st)
59 ✗ return AVERROR(ENOMEM);
60 1 audio_st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
61 1 audio_st->codecpar->codec_id = AV_CODEC_ID_PCM_ALAW;
62 1 audio_st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
63 1 audio_st->codecpar->sample_rate = 8000;
64 1 audio_st->codecpar->bits_per_coded_sample = 8;
65 1 audio_st->codecpar->block_align = 1;
66 1 avpriv_set_pts_info(audio_st, 64, 1, 1000000);
67
68 1 mxg->soi_ptr = mxg->buffer_ptr = mxg->buffer = 0;
69 1 mxg->buffer_size = 0;
70 1 mxg->dts = AV_NOPTS_VALUE;
71 1 mxg->cache_size = 0;
72
73 1 return 0;
74 }
75
76 8365 static uint8_t* mxg_find_startmarker(uint8_t *p, uint8_t *end)
77 {
78
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 139149 for (; p < end - 3; p += 4) {
79 138625 uint32_t x = AV_RN32(p);
80
81
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 138625 if (x & (~(x+0x01010101)) & 0x80808080) {
82
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 7841 if (p[0] == 0xff) {
83 1627 return p;
84
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 6214 } else if (p[1] == 0xff) {
85 1718 return p+1;
86
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 4496 } else if (p[2] == 0xff) {
87 2815 return p+2;
88
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 1681 } else if (p[3] == 0xff) {
89 1681 return p+3;
90 }
91 }
92 }
93
94
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 1274 for (; p < end; ++p) {
95
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 763 if (*p == 0xff) return p;
96 }
97
98 511 return end;
99 }
100
101 590 static int mxg_update_cache(AVFormatContext *s, unsigned int cache_size)
102 {
103 590 MXGContext *mxg = s->priv_data;
104 590 unsigned int current_pos = mxg->buffer_ptr - mxg->buffer;
105 unsigned int soi_pos;
106 uint8_t *buffer;
107 int ret;
108
109 /* reallocate internal buffer */
110
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 590 if (current_pos > current_pos + cache_size)
111 ✗ return AVERROR(ENOMEM);
112 590 soi_pos = mxg->soi_ptr - mxg->buffer;
113 590 buffer = av_fast_realloc(mxg->buffer, &mxg->buffer_size,
114 590 current_pos + cache_size +
115 AV_INPUT_BUFFER_PADDING_SIZE);
116
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 590 if (!buffer)
117 ✗ return AVERROR(ENOMEM);
118 590 mxg->buffer = buffer;
119 590 mxg->buffer_ptr = mxg->buffer + current_pos;
120
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 590 if (mxg->soi_ptr) mxg->soi_ptr = mxg->buffer + soi_pos;
121
122 /* get data */
123 590 ret = avio_read(s->pb, mxg->buffer_ptr + mxg->cache_size,
124 590 cache_size - mxg->cache_size);
125
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 590 if (ret < 0)
126 ✗ return ret;
127
128 590 mxg->cache_size += ret;
129
130 590 memset(mxg->buffer_ptr + mxg->cache_size, 0, AV_INPUT_BUFFER_PADDING_SIZE);
131
132 590 return ret;
133 }
134
135 32 static int mxg_read_packet(AVFormatContext *s, AVPacket *pkt)
136 {
137 int ret;
138 unsigned int size;
139 uint8_t *startmarker_ptr, *end, *search_end, marker;
140 32 MXGContext *mxg = s->priv_data;
141
142
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 8366 while (!avio_feof(s->pb) && !s->pb->error){
143
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 8365 if (mxg->cache_size <= OVERREAD_SIZE) {
144 /* update internal buffer */
145 560 ret = mxg_update_cache(s, DEFAULT_PACKET_SIZE + OVERREAD_SIZE);
146
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 560 if (ret < 0)
147 ✗ return ret;
148 }
149 8365 end = mxg->buffer_ptr + mxg->cache_size;
150
151 /* find start marker - 0xff */
152
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 8365 if (mxg->cache_size > OVERREAD_SIZE) {
153 8365 search_end = end - OVERREAD_SIZE;
154 8365 startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end);
155 } else {
156 ✗ search_end = end;
157 ✗ startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end);
158 ✗ if (startmarker_ptr >= search_end - 1 ||
159 ✗ *(startmarker_ptr + 1) != EOI) break;
160 }
161
162
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 8365 if (startmarker_ptr != search_end) { /* start marker found */
163 7854 marker = *(startmarker_ptr + 1);
164 7854 mxg->buffer_ptr = startmarker_ptr + 2;
165 7854 mxg->cache_size = end - mxg->buffer_ptr;
166
167
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 7854 if (marker == SOI) {
168 31 mxg->soi_ptr = startmarker_ptr;
169
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 7823 } else if (marker == EOI) {
170
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 30 if (!mxg->soi_ptr) {
171 ✗ av_log(s, AV_LOG_WARNING, "Found EOI before SOI, skipping\n");
172 ✗ continue;
173 }
174
175 30 size = mxg->buffer_ptr - mxg->soi_ptr;
176 30 ret = av_new_packet(pkt, size);
177
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 30 if (ret < 0)
178 ✗ return ret;
179 30 memcpy(pkt->data, mxg->soi_ptr, size);
180
181 30 pkt->pts = pkt->dts = mxg->dts;
182 30 pkt->stream_index = 0;
183
184
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 30 if (mxg->soi_ptr - mxg->buffer > mxg->cache_size) {
185
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 14 if (mxg->cache_size > 0) {
186 14 memmove(mxg->buffer, mxg->buffer_ptr, mxg->cache_size);
187 }
188
189 14 mxg->buffer_ptr = mxg->buffer;
190 }
191 30 mxg->soi_ptr = 0;
192
193 30 return pkt->size;
194
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 7793 } else if ( (SOF0 <= marker && marker <= SOF15) ||
195
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 128 (SOS <= marker && marker <= COM) ) {
196 /* all other markers that start marker segment also contain
197 length value (see specification for JPEG Annex B.1) */
198 133 size = AV_RB16(mxg->buffer_ptr);
199
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 133 if (size < 2)
200 ✗ return AVERROR(EINVAL);
201
202
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 133 if (mxg->cache_size < size) {
203 30 ret = mxg_update_cache(s, size);
204
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 30 if (ret < 0)
205 ✗ return ret;
206 30 startmarker_ptr = mxg->buffer_ptr - 2;
207 30 mxg->cache_size = 0;
208 } else {
209 103 mxg->cache_size -= size;
210 }
211
212 133 mxg->buffer_ptr += size;
213
214
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 133 if (marker == APP13 && size >= 16) { /* audio data */
215 1 ret = av_new_packet(pkt, size - 14);
216
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 1 if (ret < 0)
217 ✗ return ret;
218 1 memcpy(pkt->data, startmarker_ptr + 16, size - 14);
219
220 /* time (GMT) of first sample in usec since 1970, little-endian */
221 1 pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8);
222 1 pkt->stream_index = 1;
223
224
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 1 if (startmarker_ptr - mxg->buffer > mxg->cache_size) {
225
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 1 if (mxg->cache_size > 0) {
226 ✗ memcpy(mxg->buffer, mxg->buffer_ptr, mxg->cache_size);
227 }
228 1 mxg->buffer_ptr = mxg->buffer;
229 }
230
231 1 return pkt->size;
232
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 132 } else if (marker == COM && size >= 18 &&
233
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 63 !strncmp(startmarker_ptr + 4, "MXF", 3)) {
234 /* time (GMT) of video frame in usec since 1970, little-endian */
235 31 mxg->dts = AV_RL64(startmarker_ptr + 12);
236 }
237 }
238 } else {
239 /* start marker not found */
240 511 mxg->buffer_ptr = search_end;
241 511 mxg->cache_size = OVERREAD_SIZE;
242 }
243 }
244
245 1 return AVERROR_EOF;
246 }
247
248 1 static int mxg_close(struct AVFormatContext *s)
249 {
250 1 MXGContext *mxg = s->priv_data;
251 1 av_freep(&mxg->buffer);
252 1 return 0;
253 }
254
255 const FFInputFormat ff_mxg_demuxer = {
256 .p.name = "mxg",
257 .p.long_name = NULL_IF_CONFIG_SMALL("MxPEG clip"),
258 .p.extensions = "mxg",
259 .priv_data_size = sizeof(MXGContext),
260 .read_header = mxg_read_header,
261 .read_packet = mxg_read_packet,
262 .read_close = mxg_close,
263 };
264