FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/mxg.c
Date: 2022-11-26 13:19:19
Exec Total Coverage
Lines: 113 130 86.9%
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 "libavcodec/mjpeg.h"
26 #include "avformat.h"
27 #include "internal.h"
28 #include "avio.h"
29
30 #define DEFAULT_PACKET_SIZE 1024
31 #define OVERREAD_SIZE 3
32
33 typedef struct MXGContext {
34 uint8_t *buffer;
35 uint8_t *buffer_ptr;
36 uint8_t *soi_ptr;
37 unsigned int buffer_size;
38 int64_t dts;
39 unsigned int cache_size;
40 } MXGContext;
41
42 1 static int mxg_read_header(AVFormatContext *s)
43 {
44 AVStream *video_st, *audio_st;
45 1 MXGContext *mxg = s->priv_data;
46
47 /* video parameters will be extracted from the compressed bitstream */
48 1 video_st = avformat_new_stream(s, NULL);
49
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1 if (!video_st)
50 return AVERROR(ENOMEM);
51 1 video_st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
52 1 video_st->codecpar->codec_id = AV_CODEC_ID_MXPEG;
53 1 avpriv_set_pts_info(video_st, 64, 1, 1000000);
54
55 1 audio_st = avformat_new_stream(s, NULL);
56
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1 if (!audio_st)
57 return AVERROR(ENOMEM);
58 1 audio_st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
59 1 audio_st->codecpar->codec_id = AV_CODEC_ID_PCM_ALAW;
60 1 audio_st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
61 1 audio_st->codecpar->sample_rate = 8000;
62 1 audio_st->codecpar->bits_per_coded_sample = 8;
63 1 audio_st->codecpar->block_align = 1;
64 1 avpriv_set_pts_info(audio_st, 64, 1, 1000000);
65
66 1 mxg->soi_ptr = mxg->buffer_ptr = mxg->buffer = 0;
67 1 mxg->buffer_size = 0;
68 1 mxg->dts = AV_NOPTS_VALUE;
69 1 mxg->cache_size = 0;
70
71 1 return 0;
72 }
73
74 8365 static uint8_t* mxg_find_startmarker(uint8_t *p, uint8_t *end)
75 {
76
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139149 for (; p < end - 3; p += 4) {
77 138625 uint32_t x = AV_RN32(p);
78
79
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138625 if (x & (~(x+0x01010101)) & 0x80808080) {
80
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7841 if (p[0] == 0xff) {
81 1627 return p;
82
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6214 } else if (p[1] == 0xff) {
83 1718 return p+1;
84
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4496 } else if (p[2] == 0xff) {
85 2815 return p+2;
86
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1681 } else if (p[3] == 0xff) {
87 1681 return p+3;
88 }
89 }
90 }
91
92
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1274 for (; p < end; ++p) {
93
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763 if (*p == 0xff) return p;
94 }
95
96 511 return end;
97 }
98
99 590 static int mxg_update_cache(AVFormatContext *s, unsigned int cache_size)
100 {
101 590 MXGContext *mxg = s->priv_data;
102 590 unsigned int current_pos = mxg->buffer_ptr - mxg->buffer;
103 unsigned int soi_pos;
104 uint8_t *buffer;
105 int ret;
106
107 /* reallocate internal buffer */
108
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590 if (current_pos > current_pos + cache_size)
109 return AVERROR(ENOMEM);
110 590 soi_pos = mxg->soi_ptr - mxg->buffer;
111 590 buffer = av_fast_realloc(mxg->buffer, &mxg->buffer_size,
112 590 current_pos + cache_size +
113 AV_INPUT_BUFFER_PADDING_SIZE);
114
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590 if (!buffer)
115 return AVERROR(ENOMEM);
116 590 mxg->buffer = buffer;
117 590 mxg->buffer_ptr = mxg->buffer + current_pos;
118
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590 if (mxg->soi_ptr) mxg->soi_ptr = mxg->buffer + soi_pos;
119
120 /* get data */
121 590 ret = avio_read(s->pb, mxg->buffer_ptr + mxg->cache_size,
122 590 cache_size - mxg->cache_size);
123
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590 if (ret < 0)
124 return ret;
125
126 590 mxg->cache_size += ret;
127
128 590 return ret;
129 }
130
131 32 static int mxg_read_packet(AVFormatContext *s, AVPacket *pkt)
132 {
133 int ret;
134 unsigned int size;
135 uint8_t *startmarker_ptr, *end, *search_end, marker;
136 32 MXGContext *mxg = s->priv_data;
137
138
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8366 while (!avio_feof(s->pb) && !s->pb->error){
139
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8365 if (mxg->cache_size <= OVERREAD_SIZE) {
140 /* update internal buffer */
141 560 ret = mxg_update_cache(s, DEFAULT_PACKET_SIZE + OVERREAD_SIZE);
142
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560 if (ret < 0)
143 return ret;
144 }
145 8365 end = mxg->buffer_ptr + mxg->cache_size;
146
147 /* find start marker - 0xff */
148
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8365 if (mxg->cache_size > OVERREAD_SIZE) {
149 8365 search_end = end - OVERREAD_SIZE;
150 8365 startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end);
151 } else {
152 search_end = end;
153 startmarker_ptr = mxg_find_startmarker(mxg->buffer_ptr, search_end);
154 if (startmarker_ptr >= search_end - 1 ||
155 *(startmarker_ptr + 1) != EOI) break;
156 }
157
158
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8365 if (startmarker_ptr != search_end) { /* start marker found */
159 7854 marker = *(startmarker_ptr + 1);
160 7854 mxg->buffer_ptr = startmarker_ptr + 2;
161 7854 mxg->cache_size = end - mxg->buffer_ptr;
162
163
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7854 if (marker == SOI) {
164 31 mxg->soi_ptr = startmarker_ptr;
165
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7823 } else if (marker == EOI) {
166
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30 if (!mxg->soi_ptr) {
167 av_log(s, AV_LOG_WARNING, "Found EOI before SOI, skipping\n");
168 continue;
169 }
170
171 30 size = mxg->buffer_ptr - mxg->soi_ptr;
172 30 ret = av_new_packet(pkt, size);
173
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30 if (ret < 0)
174 return ret;
175 30 memcpy(pkt->data, mxg->soi_ptr, size);
176
177 30 pkt->pts = pkt->dts = mxg->dts;
178 30 pkt->stream_index = 0;
179
180
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30 if (mxg->soi_ptr - mxg->buffer > mxg->cache_size) {
181
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14 if (mxg->cache_size > 0) {
182 14 memmove(mxg->buffer, mxg->buffer_ptr, mxg->cache_size);
183 }
184
185 14 mxg->buffer_ptr = mxg->buffer;
186 }
187 30 mxg->soi_ptr = 0;
188
189 30 return pkt->size;
190
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7793 } else if ( (SOF0 <= marker && marker <= SOF15) ||
191
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128 (SOS <= marker && marker <= COM) ) {
192 /* all other markers that start marker segment also contain
193 length value (see specification for JPEG Annex B.1) */
194 133 size = AV_RB16(mxg->buffer_ptr);
195
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133 if (size < 2)
196 return AVERROR(EINVAL);
197
198
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133 if (mxg->cache_size < size) {
199 30 ret = mxg_update_cache(s, size);
200
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30 if (ret < 0)
201 return ret;
202 30 startmarker_ptr = mxg->buffer_ptr - 2;
203 30 mxg->cache_size = 0;
204 } else {
205 103 mxg->cache_size -= size;
206 }
207
208 133 mxg->buffer_ptr += size;
209
210
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133 if (marker == APP13 && size >= 16) { /* audio data */
211 1 ret = av_new_packet(pkt, size - 14);
212
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1 if (ret < 0)
213 return ret;
214 1 memcpy(pkt->data, startmarker_ptr + 16, size - 14);
215
216 /* time (GMT) of first sample in usec since 1970, little-endian */
217 1 pkt->pts = pkt->dts = AV_RL64(startmarker_ptr + 8);
218 1 pkt->stream_index = 1;
219
220
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1 if (startmarker_ptr - mxg->buffer > mxg->cache_size) {
221
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1 if (mxg->cache_size > 0) {
222 memcpy(mxg->buffer, mxg->buffer_ptr, mxg->cache_size);
223 }
224 1 mxg->buffer_ptr = mxg->buffer;
225 }
226
227 1 return pkt->size;
228
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132 } else if (marker == COM && size >= 18 &&
229
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63 !strncmp(startmarker_ptr + 4, "MXF", 3)) {
230 /* time (GMT) of video frame in usec since 1970, little-endian */
231 31 mxg->dts = AV_RL64(startmarker_ptr + 12);
232 }
233 }
234 } else {
235 /* start marker not found */
236 511 mxg->buffer_ptr = search_end;
237 511 mxg->cache_size = OVERREAD_SIZE;
238 }
239 }
240
241 1 return AVERROR_EOF;
242 }
243
244 1 static int mxg_close(struct AVFormatContext *s)
245 {
246 1 MXGContext *mxg = s->priv_data;
247 1 av_freep(&mxg->buffer);
248 1 return 0;
249 }
250
251 const AVInputFormat ff_mxg_demuxer = {
252 .name = "mxg",
253 .long_name = NULL_IF_CONFIG_SMALL("MxPEG clip"),
254 .priv_data_size = sizeof(MXGContext),
255 .read_header = mxg_read_header,
256 .read_packet = mxg_read_packet,
257 .read_close = mxg_close,
258 .extensions = "mxg",
259 };
260