FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavformat/idcin.c
Date: 2026-04-24 19:58:39
Exec Total Coverage
Lines: 119 165 72.1%
Functions: 3 4 75.0%
Branches: 62 114 54.4%
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1 /*
2 * id Quake II CIN File Demuxer
3 * Copyright (c) 2003 The FFmpeg project
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 /**
23 * @file
24 * id Quake II CIN file demuxer by Mike Melanson (melanson@pcisys.net)
25 * For more information about the id CIN format, visit:
26 * http://www.csse.monash.edu.au/~timf/
27 *
28 * CIN is a somewhat quirky and ill-defined format. Here are some notes
29 * for anyone trying to understand the technical details of this format:
30 *
31 * The format has no definite file signature. This is problematic for a
32 * general-purpose media player that wants to automatically detect file
33 * types. However, a CIN file does start with 5 32-bit numbers that
34 * specify audio and video parameters. This demuxer gets around the lack
35 * of file signature by performing sanity checks on those parameters.
36 * Probabilistically, this is a reasonable solution since the number of
37 * valid combinations of the 5 parameters is a very small subset of the
38 * total 160-bit number space.
39 *
40 * Refer to the function idcin_probe() for the precise A/V parameters
41 * that this demuxer allows.
42 *
43 * Next, each audio and video frame has a duration of 1/14 sec. If the
44 * audio sample rate is a multiple of the common frequency 22050 Hz it will
45 * divide evenly by 14. However, if the sample rate is 11025 Hz:
46 * 11025 (samples/sec) / 14 (frames/sec) = 787.5 (samples/frame)
47 * The way the CIN stores audio in this case is by storing 787 sample
48 * frames in the first audio frame and 788 sample frames in the second
49 * audio frame. Therefore, the total number of bytes in an audio frame
50 * is given as:
51 * audio frame #0: 787 * (bytes/sample) * (# channels) bytes in frame
52 * audio frame #1: 788 * (bytes/sample) * (# channels) bytes in frame
53 * audio frame #2: 787 * (bytes/sample) * (# channels) bytes in frame
54 * audio frame #3: 788 * (bytes/sample) * (# channels) bytes in frame
55 *
56 * Finally, not all id CIN creation tools agree on the resolution of the
57 * color palette, apparently. Some creation tools specify red, green, and
58 * blue palette components in terms of 6-bit VGA color DAC values which
59 * range from 0..63. Other tools specify the RGB components as full 8-bit
60 * values that range from 0..255. Since there are no markers in the file to
61 * differentiate between the two variants, this demuxer uses the following
62 * heuristic:
63 * - load the 768 palette bytes from disk
64 * - assume that they will need to be shifted left by 2 bits to
65 * transform them from 6-bit values to 8-bit values
66 * - scan through all 768 palette bytes
67 * - if any bytes exceed 63, do not shift the bytes at all before
68 * transmitting them to the video decoder
69 */
70
71 #include "libavutil/channel_layout.h"
72 #include "libavutil/imgutils.h"
73 #include "libavutil/intreadwrite.h"
74 #include "avformat.h"
75 #include "demux.h"
76 #include "internal.h"
77
78 #define HUFFMAN_TABLE_SIZE (64 * 1024)
79 #define IDCIN_FPS 14
80
81 typedef struct IdcinDemuxContext {
82 int video_stream_index;
83 int audio_stream_index;
84 int audio_chunk_size1;
85 int audio_chunk_size2;
86 int block_align;
87
88 /* demux state variables */
89 int current_audio_chunk;
90 int next_chunk_is_video;
91 int audio_present;
92 int64_t first_pkt_pos;
93 } IdcinDemuxContext;
94
95 7480 static int idcin_probe(const AVProbeData *p)
96 {
97 unsigned int number, sample_rate;
98 unsigned int w, h;
99 int i;
100
101 /*
102 * This is what you could call a "probabilistic" file check: id CIN
103 * files don't have a definite file signature. In lieu of such a marker,
104 * perform sanity checks on the 5 32-bit header fields:
105 * width, height: greater than 0, less than or equal to 1024
106 * audio sample rate: greater than or equal to 8000, less than or
107 * equal to 48000, or 0 for no audio
108 * audio sample width (bytes/sample): 0 for no audio, or 1 or 2
109 * audio channels: 0 for no audio, or 1 or 2
110 */
111
112 /* check we have enough data to do all checks, otherwise the
113 0-padding may cause a wrong recognition */
114
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 7480 if (p->buf_size < 20 + HUFFMAN_TABLE_SIZE + 12)
115 6405 return 0;
116
117 /* check the video width */
118 1075 w = AV_RL32(&p->buf[0]);
119
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 1075 if ((w == 0) || (w > 1024))
120 1071 return 0;
121
122 /* check the video height */
123 4 h = AV_RL32(&p->buf[4]);
124
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 4 if ((h == 0) || (h > 1024))
125 3 return 0;
126
127 /* check the audio sample rate */
128 1 sample_rate = AV_RL32(&p->buf[8]);
129
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 1 if (sample_rate && (sample_rate < 8000 || sample_rate > 48000))
130 ✗ return 0;
131
132 /* check the audio bytes/sample */
133 1 number = AV_RL32(&p->buf[12]);
134
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 1 if (number > 2 || sample_rate && !number)
135 ✗ return 0;
136
137 /* check the audio channels */
138 1 number = AV_RL32(&p->buf[16]);
139
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 1 if (number > 2 || sample_rate && !number)
140 ✗ return 0;
141
142 1 i = 20 + HUFFMAN_TABLE_SIZE;
143
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 1 if (AV_RL32(&p->buf[i]) == 1)
144 1 i += 768;
145
146
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 1 if (i+12 > p->buf_size || AV_RL32(&p->buf[i+8]) != w*h)
147 ✗ return 1;
148
149 /* return half certainty since this check is a bit sketchy */
150 1 return AVPROBE_SCORE_EXTENSION;
151 }
152
153 1 static int idcin_read_header(AVFormatContext *s)
154 {
155 1 AVIOContext *pb = s->pb;
156 1 IdcinDemuxContext *idcin = s->priv_data;
157 AVStream *st;
158 unsigned int width, height;
159 unsigned int sample_rate, bytes_per_sample, channels;
160 int ret;
161
162 /* get the 5 header parameters */
163 1 width = avio_rl32(pb);
164 1 height = avio_rl32(pb);
165 1 sample_rate = avio_rl32(pb);
166 1 bytes_per_sample = avio_rl32(pb);
167 1 channels = avio_rl32(pb);
168
169
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 1 if (s->pb->eof_reached) {
170 ✗ av_log(s, AV_LOG_ERROR, "incomplete header\n");
171 ✗ return s->pb->error ? s->pb->error : AVERROR_EOF;
172 }
173
174
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 1 if (av_image_check_size(width, height, 0, s) < 0)
175 ✗ return AVERROR_INVALIDDATA;
176
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 1 if (sample_rate > 0) {
177
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 1 if (sample_rate < 14 || sample_rate > INT_MAX) {
178 ✗ av_log(s, AV_LOG_ERROR, "invalid sample rate: %u\n", sample_rate);
179 ✗ return AVERROR_INVALIDDATA;
180 }
181
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 1 if (bytes_per_sample < 1 || bytes_per_sample > 2) {
182 ✗ av_log(s, AV_LOG_ERROR, "invalid bytes per sample: %u\n",
183 bytes_per_sample);
184 ✗ return AVERROR_INVALIDDATA;
185 }
186
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 1 if (channels < 1 || channels > 2) {
187 ✗ av_log(s, AV_LOG_ERROR, "invalid channels: %u\n", channels);
188 ✗ return AVERROR_INVALIDDATA;
189 }
190 1 idcin->audio_present = 1;
191 } else {
192 /* if sample rate is 0, assume no audio */
193 ✗ idcin->audio_present = 0;
194 }
195
196 1 st = avformat_new_stream(s, NULL);
197
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 1 if (!st)
198 ✗ return AVERROR(ENOMEM);
199 1 avpriv_set_pts_info(st, 33, 1, IDCIN_FPS);
200 1 st->start_time = 0;
201 1 idcin->video_stream_index = st->index;
202 1 st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
203 1 st->codecpar->codec_id = AV_CODEC_ID_IDCIN;
204 1 st->codecpar->codec_tag = 0; /* no fourcc */
205 1 st->codecpar->width = width;
206 1 st->codecpar->height = height;
207
208 /* load up the Huffman tables into extradata */
209
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 1 if ((ret = ff_get_extradata(s, st->codecpar, pb, HUFFMAN_TABLE_SIZE)) < 0)
210 ✗ return ret;
211
212
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 1 if (idcin->audio_present) {
213 1 idcin->audio_present = 1;
214 1 st = avformat_new_stream(s, NULL);
215
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 1 if (!st)
216 ✗ return AVERROR(ENOMEM);
217 1 avpriv_set_pts_info(st, 63, 1, sample_rate);
218 1 st->start_time = 0;
219 1 idcin->audio_stream_index = st->index;
220 1 st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
221 1 st->codecpar->codec_tag = 1;
222 1 av_channel_layout_default(&st->codecpar->ch_layout, channels);
223 1 st->codecpar->sample_rate = sample_rate;
224 1 st->codecpar->bits_per_coded_sample = bytes_per_sample * 8;
225 1 st->codecpar->bit_rate = sample_rate * bytes_per_sample * 8 * channels;
226 1 st->codecpar->block_align = idcin->block_align = bytes_per_sample * channels;
227
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 1 if (bytes_per_sample == 1)
228 ✗ st->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
229 else
230 1 st->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
231
232
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 1 if (sample_rate % 14 != 0) {
233 ✗ idcin->audio_chunk_size1 = (sample_rate / 14) *
234 ✗ bytes_per_sample * channels;
235 ✗ idcin->audio_chunk_size2 = (sample_rate / 14 + 1) *
236 ✗ bytes_per_sample * channels;
237 } else {
238 1 idcin->audio_chunk_size1 = idcin->audio_chunk_size2 =
239 1 (sample_rate / 14) * bytes_per_sample * channels;
240 }
241 1 idcin->current_audio_chunk = 0;
242 }
243
244 1 idcin->next_chunk_is_video = 1;
245 1 idcin->first_pkt_pos = avio_tell(s->pb);
246
247 1 return 0;
248 }
249
250 105 static int idcin_read_packet(AVFormatContext *s,
251 AVPacket *pkt)
252 {
253 int ret;
254 unsigned int command;
255 unsigned int chunk_size;
256 105 IdcinDemuxContext *idcin = s->priv_data;
257 105 AVIOContext *pb = s->pb;
258 int i;
259 int palette_scale;
260 unsigned char r, g, b;
261 unsigned char palette_buffer[768];
262 uint32_t palette[256];
263
264
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 105 if (avio_feof(s->pb))
265 ✗ return s->pb->error ? s->pb->error : AVERROR_EOF;
266
267
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 105 if (idcin->next_chunk_is_video) {
268 53 command = avio_rl32(pb);
269
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 53 if (command == 2) {
270 ✗ return AVERROR_INVALIDDATA;
271
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 53 } else if (command == 1) {
272 /* trigger a palette change */
273 1 ret = avio_read(pb, palette_buffer, 768);
274
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 1 if (ret < 0) {
275 ✗ return ret;
276
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 1 } else if (ret != 768) {
277 ✗ av_log(s, AV_LOG_ERROR, "incomplete packet\n");
278 ✗ return AVERROR_INVALIDDATA;
279 }
280 /* scale the palette as necessary */
281 1 palette_scale = 2;
282
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 1 for (i = 0; i < 768; i++)
283
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 1 if (palette_buffer[i] > 63) {
284 1 palette_scale = 0;
285 1 break;
286 }
287
288
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 257 for (i = 0; i < 256; i++) {
289 256 r = palette_buffer[i * 3 ] << palette_scale;
290 256 g = palette_buffer[i * 3 + 1] << palette_scale;
291 256 b = palette_buffer[i * 3 + 2] << palette_scale;
292 256 palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | (b);
293
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 256 if (palette_scale == 2)
294 ✗ palette[i] |= palette[i] >> 6 & 0x30303;
295 }
296 }
297
298
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 53 if (s->pb->eof_reached) {
299 ✗ av_log(s, AV_LOG_ERROR, "incomplete packet\n");
300 ✗ return s->pb->error ? s->pb->error : AVERROR_EOF;
301 }
302 53 chunk_size = avio_rl32(pb);
303
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 53 if (chunk_size < 4 || chunk_size > INT_MAX - 4) {
304 ✗ av_log(s, AV_LOG_ERROR, "invalid chunk size: %u\n", chunk_size);
305 ✗ return AVERROR_INVALIDDATA;
306 }
307 /* skip the number of decoded bytes (always equal to width * height) */
308 53 avio_skip(pb, 4);
309 53 chunk_size -= 4;
310 53 ret= av_get_packet(pb, pkt, chunk_size);
311
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 53 if (ret < 0)
312 ✗ return ret;
313
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 53 else if (ret != chunk_size) {
314 1 av_log(s, AV_LOG_ERROR, "incomplete packet\n");
315 1 return AVERROR_INVALIDDATA;
316 }
317
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 52 if (command == 1) {
318 uint8_t *pal;
319
320 1 pal = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
321 AVPALETTE_SIZE);
322
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 1 if (!pal) {
323 ✗ return AVERROR(ENOMEM);
324 }
325 1 memcpy(pal, palette, AVPALETTE_SIZE);
326 1 pkt->flags |= AV_PKT_FLAG_KEY;
327 }
328 52 pkt->stream_index = idcin->video_stream_index;
329 52 pkt->duration = 1;
330 } else {
331 /* send out the audio chunk */
332
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 52 if (idcin->current_audio_chunk)
333 26 chunk_size = idcin->audio_chunk_size2;
334 else
335 26 chunk_size = idcin->audio_chunk_size1;
336 52 ret= av_get_packet(pb, pkt, chunk_size);
337
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 52 if (ret < 0)
338 ✗ return ret;
339 52 pkt->stream_index = idcin->audio_stream_index;
340 52 pkt->duration = chunk_size / idcin->block_align;
341
342 52 idcin->current_audio_chunk ^= 1;
343 }
344
345
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 104 if (idcin->audio_present)
346 104 idcin->next_chunk_is_video ^= 1;
347
348 104 return 0;
349 }
350
351 ✗ static int idcin_read_seek(AVFormatContext *s, int stream_index,
352 int64_t timestamp, int flags)
353 {
354 ✗ IdcinDemuxContext *idcin = s->priv_data;
355
356 ✗ if (idcin->first_pkt_pos > 0) {
357 ✗ int64_t ret = avio_seek(s->pb, idcin->first_pkt_pos, SEEK_SET);
358 ✗ if (ret < 0)
359 ✗ return ret;
360 ✗ avpriv_update_cur_dts(s, s->streams[idcin->video_stream_index], 0);
361 ✗ idcin->next_chunk_is_video = 1;
362 ✗ idcin->current_audio_chunk = 0;
363 ✗ return 0;
364 }
365 ✗ return -1;
366 }
367
368 const FFInputFormat ff_idcin_demuxer = {
369 .p.name = "idcin",
370 .p.long_name = NULL_IF_CONFIG_SMALL("id Cinematic"),
371 .p.flags = AVFMT_NO_BYTE_SEEK,
372 .priv_data_size = sizeof(IdcinDemuxContext),
373 .read_probe = idcin_probe,
374 .read_header = idcin_read_header,
375 .read_packet = idcin_read_packet,
376 .read_seek = idcin_read_seek,
377 };
378