FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavformat/sga.c
Date: 2025-10-26 07:25:09
Exec Total Coverage
Lines: 72 293 24.6%
Functions: 1 10 10.0%
Branches: 75 230 32.6%
Line Branch Exec Source
1 /*
2 * Digital Pictures SGA game demuxer
3 *
4 * Copyright (C) 2021 Paul B Mahol
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 #include "libavutil/intreadwrite.h"
24 #include "libavutil/avassert.h"
25 #include "libavutil/channel_layout.h"
26 #include "libavutil/internal.h"
27 #include "avformat.h"
28 #include "demux.h"
29 #include "internal.h"
30 #include "avio_internal.h"
31
32 #define SEGA_CD_PCM_NUM 12500000
33 #define SEGA_CD_PCM_DEN 786432
34
35 typedef struct SGADemuxContext {
36 int video_stream_index;
37 int audio_stream_index;
38
39 uint8_t sector[65536 * 2];
40 int sector_headers;
41 int sample_rate;
42 int first_audio_size;
43 int payload_size;
44 int packet_type;
45 int flags;
46 int idx;
47 int left;
48 int64_t pkt_pos;
49 } SGADemuxContext;
50
51 7279 static int sga_probe(const AVProbeData *p)
52 {
53 7279 const uint8_t *src = p->buf;
54 7279 int score = 0, sectors = 1;
55 7279 int last_left = 0;
56 7279 int sample_rate = -1;
57
58
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 7279 if (p->buf_size < 2048)
59 372 return 0;
60
61
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 10243 for (int i = 0; i + 2 < p->buf_size; i += 2048) {
62 8827 int header = AV_RB16(src + i);
63
64
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 8827 if ((header > 0x07FE && header < 0x8100) ||
65
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 3521 (header > 0x8200 && header < 0xA100) ||
66
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 487 (header > 0xA200 && header < 0xC100)) {
67 5491 sectors = 0;
68 5491 break;
69 }
70 }
71
72
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 7580 for (int i = 0; i + 4 < p->buf_size;) {
73 6951 int header = AV_RB16(src + i);
74 6951 int left = AV_RB16(src + i + 2);
75 int offset, type, size;
76
77
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 6951 if (last_left < 0)
78 ✗ return 0;
79
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 6951 if (sectors && header && last_left == 0) {
80
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 270 if (header >> 12) {
81 115 last_left = left;
82 } else {
83 155 last_left = left = header;
84 }
85
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 6681 } else if (sectors && header) {
86 4 left = header;
87 4 last_left -= left;
88
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 4 if (header != 0x7FE && left < 7)
89 ✗ return 0;
90
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 6677 } else if (sectors) {
91
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 1186 if (left <= 8)
92 526 return 0;
93
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 660 i += sectors ? 2048 : left + 4;
94 660 last_left = 0;
95 660 continue;
96 }
97
98
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 5765 if (sectors && (i > 0 && left < 0x7fe) &&
99
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 7 (i + left + 14 < p->buf_size)) {
100 7 offset = i + left + 2;
101
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 5758 } else if (sectors && i > 0) {
102 13 i += 2048;
103 13 last_left -= FFMIN(last_left, 2046);
104 13 continue;
105 } else {
106 5745 offset = 0;
107 5745 last_left = left;
108 }
109
110 5752 header = AV_RB16(src + offset);
111 5752 size = AV_RB16(src + offset + 2) + 4;
112
113
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 110564 while ((header & 0xFF00) == 0) {
114 104812 offset++;
115
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 104812 if (offset + 4 >= p->buf_size)
116 ✗ break;
117 104812 header = AV_RB16(src + offset);
118 104812 size = AV_RB16(src + offset + 2) + 4;
119 }
120
121
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 5752 if (offset + 12 >= p->buf_size)
122 ✗ break;
123
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 5752 if ((header & 0xFF) > 1)
124 5492 return 0;
125 260 type = header >> 8;
126
127
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 260 if (type == 0xAA ||
128
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 260 type == 0xA1 ||
129
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 260 type == 0xA2 ||
130 ✗ type == 0xA3) {
131 int new_rate;
132
133 ✗ if (size <= 12)
134 ✗ return 0;
135 ✗ new_rate = AV_RB16(src + offset + 8);
136 ✗ if (sample_rate < 0)
137 ✗ sample_rate = new_rate;
138 ✗ if (sample_rate == 0 || new_rate != sample_rate)
139 ✗ return 0;
140 ✗ if (src[offset + 10] != 1)
141 ✗ return 0;
142
143 ✗ score += 10;
144
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 260 } else if (type == 0xC1 ||
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 260 type == 0xC6 ||
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 259 type == 0xC7 ||
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 259 type == 0xC8 ||
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 258 type == 0xC9 ||
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 258 type == 0xCB ||
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 258 type == 0xCD ||
151 ✗ type == 0xE7) {
152 2 int nb_pals = src[offset + 9];
153 2 int tiles_w = src[offset + 10];
154 2 int tiles_h = src[offset + 11];
155
156
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 2 if (size <= 12)
157 ✗ return 0;
158
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 2 if (nb_pals == 0 || nb_pals > 4)
159 ✗ return 0;
160
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 2 if (tiles_w == 0 || tiles_w > 80)
161 2 return 0;
162 ✗ if (tiles_h == 0 || tiles_h > 60)
163 ✗ return 0;
164
165 ✗ score += 10;
166
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 258 } else if (header == 0x7FE) {
167 ;
168 } else {
169 258 return 0;
170 }
171
172 ✗ i += sectors ? 2048 : size + 4;
173 ✗ last_left -= FFMIN(last_left, 2046);
174
175 ✗ if (score < 0)
176 ✗ break;
177 }
178
179 629 return av_clip(score, 0, AVPROBE_SCORE_MAX);
180 }
181
182 ✗ static int sga_read_header(AVFormatContext *s)
183 {
184 ✗ SGADemuxContext *sga = s->priv_data;
185 ✗ AVIOContext *pb = s->pb;
186
187 ✗ sga->sector_headers = 1;
188 ✗ sga->first_audio_size = 0;
189 ✗ sga->video_stream_index = -1;
190 ✗ sga->audio_stream_index = -1;
191 ✗ sga->left = 2048;
192 ✗ sga->idx = 0;
193
194 ✗ s->ctx_flags |= AVFMTCTX_NOHEADER;
195
196 ✗ if (pb->seekable & AVIO_SEEKABLE_NORMAL) {
197 ✗ while (!avio_feof(pb)) {
198 ✗ int header = avio_rb16(pb);
199 ✗ int type = header >> 8;
200 ✗ int skip = 2046;
201 int clock;
202
203 ✗ if (!sga->first_audio_size &&
204 ✗ (type == 0xAA ||
205 ✗ type == 0xA1 ||
206 ✗ type == 0xA2 ||
207 type == 0xA3)) {
208 ✗ sga->first_audio_size = avio_rb16(pb);
209 ✗ avio_skip(pb, 4);
210 ✗ clock = avio_rb16(pb);
211 ✗ sga->sample_rate = av_rescale(clock,
212 SEGA_CD_PCM_NUM,
213 SEGA_CD_PCM_DEN);
214 ✗ skip -= 8;
215 }
216 ✗ if ((header > 0x07FE && header < 0x8100) ||
217 ✗ (header > 0x8200 && header < 0xA100) ||
218 ✗ (header > 0xA200 && header < 0xC100)) {
219 ✗ sga->sector_headers = 0;
220 ✗ break;
221 }
222
223 ✗ avio_skip(pb, skip);
224 }
225
226 ✗ avio_seek(pb, 0, SEEK_SET);
227 }
228
229 ✗ return 0;
230 }
231
232 ✗ static void print_stats(AVFormatContext *s, const char *where)
233 {
234 ✗ SGADemuxContext *sga = s->priv_data;
235
236 ✗ av_log(s, AV_LOG_DEBUG, "START %s\n", where);
237 ✗ av_log(s, AV_LOG_DEBUG, "pos: %"PRIX64"\n", avio_tell(s->pb));
238 ✗ av_log(s, AV_LOG_DEBUG, "idx: %X\n", sga->idx);
239 ✗ av_log(s, AV_LOG_DEBUG, "packet_type: %X\n", sga->packet_type);
240 ✗ av_log(s, AV_LOG_DEBUG, "payload_size: %X\n", sga->payload_size);
241 ✗ av_log(s, AV_LOG_DEBUG, "SECTOR: %016"PRIX64"\n", AV_RB64(sga->sector));
242 ✗ av_log(s, AV_LOG_DEBUG, "stream: %X\n", sga->sector[1]);
243 ✗ av_log(s, AV_LOG_DEBUG, "END %s\n", where);
244 ✗ }
245
246 ✗ static void update_type_size(AVFormatContext *s)
247 {
248 ✗ SGADemuxContext *sga = s->priv_data;
249
250 ✗ if (sga->idx >= 4) {
251 ✗ sga->packet_type = sga->sector[0];
252 ✗ sga->payload_size = AV_RB16(sga->sector + 2);
253 } else {
254 ✗ sga->packet_type = 0;
255 ✗ sga->payload_size = 0;
256 }
257 ✗ }
258
259 ✗ static int sga_video_packet(AVFormatContext *s, AVPacket *pkt)
260 {
261 ✗ SGADemuxContext *sga = s->priv_data;
262 int ret;
263
264 ✗ if (sga->payload_size <= 8)
265 ✗ return AVERROR_INVALIDDATA;
266
267 ✗ if (sga->video_stream_index == -1) {
268 AVRational frame_rate;
269
270 ✗ AVStream *st = avformat_new_stream(s, NULL);
271 ✗ if (!st)
272 ✗ return AVERROR(ENOMEM);
273
274 ✗ st->start_time = 0;
275 ✗ st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
276 ✗ st->codecpar->codec_tag = 0;
277 ✗ st->codecpar->codec_id = AV_CODEC_ID_SGA_VIDEO;
278 ✗ sga->video_stream_index = st->index;
279
280 ✗ if (sga->first_audio_size > 0 && sga->sample_rate > 0) {
281 ✗ frame_rate.num = sga->sample_rate;
282 ✗ frame_rate.den = sga->first_audio_size;
283 } else {
284 ✗ frame_rate.num = 15;
285 ✗ frame_rate.den = 1;
286 }
287 ✗ avpriv_set_pts_info(st, 64, frame_rate.den, frame_rate.num);
288 }
289
290 ✗ ret = av_new_packet(pkt, sga->payload_size + 4);
291 ✗ if (ret < 0)
292 ✗ return AVERROR(ENOMEM);
293 ✗ memcpy(pkt->data, sga->sector, sga->payload_size + 4);
294 ✗ av_assert0(sga->idx >= sga->payload_size + 4);
295 ✗ memmove(sga->sector, sga->sector + sga->payload_size + 4, sga->idx - sga->payload_size - 4);
296
297 ✗ pkt->stream_index = sga->video_stream_index;
298 ✗ pkt->duration = 1;
299 ✗ pkt->pos = sga->pkt_pos;
300 ✗ pkt->flags |= sga->flags;
301 ✗ sga->idx -= sga->payload_size + 4;
302 ✗ sga->flags = 0;
303 ✗ update_type_size(s);
304
305 ✗ av_log(s, AV_LOG_DEBUG, "VIDEO PACKET: %d:%016"PRIX64" i:%X\n", pkt->size, AV_RB64(sga->sector), sga->idx);
306
307 ✗ return 0;
308 }
309
310 ✗ static int sga_audio_packet(AVFormatContext *s, AVPacket *pkt)
311 {
312 ✗ SGADemuxContext *sga = s->priv_data;
313 int ret;
314
315 ✗ if (sga->payload_size <= 8)
316 ✗ return AVERROR_INVALIDDATA;
317
318 ✗ if (sga->audio_stream_index == -1) {
319 ✗ AVStream *st = avformat_new_stream(s, NULL);
320 ✗ if (!st)
321 ✗ return AVERROR(ENOMEM);
322
323 ✗ st->start_time = 0;
324 ✗ st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
325 ✗ st->codecpar->codec_tag = 0;
326 ✗ st->codecpar->codec_id = AV_CODEC_ID_PCM_SGA;
327 ✗ st->codecpar->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO;
328 ✗ st->codecpar->sample_rate = av_rescale(AV_RB16(sga->sector + 8),
329 SEGA_CD_PCM_NUM,
330 SEGA_CD_PCM_DEN);
331 ✗ sga->audio_stream_index = st->index;
332
333 ✗ avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);
334 }
335
336 ✗ ret = av_new_packet(pkt, sga->payload_size - 8);
337 ✗ if (ret < 0)
338 ✗ return AVERROR(ENOMEM);
339 ✗ memcpy(pkt->data, sga->sector + 12, sga->payload_size - 8);
340 ✗ av_assert0(sga->idx >= sga->payload_size + 4);
341 ✗ memmove(sga->sector, sga->sector + sga->payload_size + 4, sga->idx - sga->payload_size - 4);
342
343 ✗ pkt->stream_index = sga->audio_stream_index;
344 ✗ pkt->duration = pkt->size;
345 ✗ pkt->pos = sga->pkt_pos;
346 ✗ pkt->flags |= sga->flags;
347 ✗ sga->idx -= sga->payload_size + 4;
348 ✗ sga->flags = 0;
349 ✗ update_type_size(s);
350
351 ✗ av_log(s, AV_LOG_DEBUG, "AUDIO PACKET: %d:%016"PRIX64" i:%X\n", pkt->size, AV_RB64(sga->sector), sga->idx);
352
353 ✗ return 0;
354 }
355
356 ✗ static int sga_packet(AVFormatContext *s, AVPacket *pkt)
357 {
358 ✗ SGADemuxContext *sga = s->priv_data;
359 ✗ int ret = 0;
360
361 ✗ if (sga->packet_type == 0xCD ||
362 ✗ sga->packet_type == 0xCB ||
363 ✗ sga->packet_type == 0xC9 ||
364 ✗ sga->packet_type == 0xC8 ||
365 ✗ sga->packet_type == 0xC7 ||
366 ✗ sga->packet_type == 0xC6 ||
367 ✗ sga->packet_type == 0xC1 ||
368 ✗ sga->packet_type == 0xE7) {
369 ✗ ret = sga_video_packet(s, pkt);
370 ✗ } else if (sga->packet_type == 0xA1 ||
371 ✗ sga->packet_type == 0xA2 ||
372 ✗ sga->packet_type == 0xA3 ||
373 ✗ sga->packet_type == 0xAA) {
374 ✗ ret = sga_audio_packet(s, pkt);
375 } else {
376 ✗ if (sga->idx == 0)
377 ✗ return AVERROR_EOF;
378 ✗ if (sga->sector[0])
379 ✗ return AVERROR_INVALIDDATA;
380 ✗ memmove(sga->sector, sga->sector + 1, sga->idx - 1);
381 ✗ sga->idx--;
382 ✗ return AVERROR(EAGAIN);
383 }
384
385 ✗ return ret;
386 }
387
388 ✗ static int try_packet(AVFormatContext *s, AVPacket *pkt)
389 {
390 ✗ SGADemuxContext *sga = s->priv_data;
391 ✗ int ret = AVERROR(EAGAIN);
392
393 ✗ update_type_size(s);
394 ✗ if (sga->idx >= sga->payload_size + 4) {
395 ✗ print_stats(s, "before sga_packet");
396 ✗ ret = sga_packet(s, pkt);
397 ✗ print_stats(s, "after sga_packet");
398 ✗ if (ret != AVERROR(EAGAIN))
399 ✗ return ret;
400 }
401
402 ✗ return sga->idx < sga->payload_size + 4 ? AVERROR(EAGAIN) : ret;
403 }
404
405 ✗ static int sga_read_packet(AVFormatContext *s, AVPacket *pkt)
406 {
407 ✗ SGADemuxContext *sga = s->priv_data;
408 ✗ AVIOContext *pb = s->pb;
409 ✗ int header, ret = 0;
410
411 ✗ sga->pkt_pos = avio_tell(pb);
412
413 ✗ retry:
414 ✗ update_type_size(s);
415
416 ✗ print_stats(s, "start");
417 ✗ if (avio_feof(pb) &&
418 ✗ (!sga->payload_size || sga->idx < sga->payload_size + 4))
419 ✗ return AVERROR_EOF;
420
421 ✗ if (sga->idx < sga->payload_size + 4) {
422 ✗ ret = ffio_ensure_seekback(pb, 2);
423 ✗ if (ret < 0)
424 ✗ return ret;
425
426 ✗ print_stats(s, "before read header");
427 ✗ header = avio_rb16(pb);
428 ✗ if (!header) {
429 ✗ avio_skip(pb, 2046);
430 ✗ sga->left = 0;
431 ✗ } else if (!avio_feof(pb) &&
432 ✗ ((header >> 15) ||
433 ✗ !sga->sector_headers)) {
434 ✗ avio_seek(pb, -2, SEEK_CUR);
435 ✗ sga->flags = AV_PKT_FLAG_KEY;
436 ✗ sga->left = 2048;
437 } else {
438 ✗ sga->left = 2046;
439 }
440
441 ✗ av_assert0(sga->idx + sga->left < sizeof(sga->sector));
442 ✗ ret = avio_read(pb, sga->sector + sga->idx, sga->left);
443 ✗ if (ret > 0)
444 ✗ sga->idx += ret;
445 ✗ else if (ret != AVERROR_EOF && ret)
446 ✗ return ret;
447 ✗ print_stats(s, "after read header");
448
449 ✗ update_type_size(s);
450 }
451
452 ✗ ret = try_packet(s, pkt);
453 ✗ if (ret == AVERROR(EAGAIN))
454 ✗ goto retry;
455
456 ✗ return ret;
457 }
458
459 ✗ static int sga_seek(AVFormatContext *s, int stream_index,
460 int64_t timestamp, int flags)
461 {
462 ✗ SGADemuxContext *sga = s->priv_data;
463
464 ✗ sga->packet_type = sga->payload_size = sga->idx = 0;
465 ✗ memset(sga->sector, 0, sizeof(sga->sector));
466
467 ✗ return -1;
468 }
469
470 const FFInputFormat ff_sga_demuxer = {
471 .p.name = "sga",
472 .p.long_name = NULL_IF_CONFIG_SMALL("Digital Pictures SGA"),
473 .p.extensions = "sga",
474 .p.flags = AVFMT_GENERIC_INDEX,
475 .priv_data_size = sizeof(SGADemuxContext),
476 .read_probe = sga_probe,
477 .read_header = sga_read_header,
478 .read_packet = sga_read_packet,
479 .read_seek = sga_seek,
480 };
481