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path: root/libavcodec/fmvc.c (plain)
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1/*
2 * FM Screen Capture Codec decoder
3 *
4 * Copyright (c) 2017 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 <stdio.h>
24#include <stdlib.h>
25#include <string.h>
26
27#include "avcodec.h"
28#include "bytestream.h"
29#include "internal.h"
30
31#define BLOCK_HEIGHT 112u
32#define BLOCK_WIDTH 84u
33
34typedef struct InterBlock {
35 int w, h;
36 int size;
37 int xor;
38} InterBlock;
39
40typedef struct FMVCContext {
41 GetByteContext gb;
42 PutByteContext pb;
43 uint8_t *buffer;
44 size_t buffer_size;
45 uint8_t *pbuffer;
46 size_t pbuffer_size;
47 int stride;
48 int bpp;
49 int yb, xb;
50 InterBlock *blocks;
51 int nb_blocks;
52} FMVCContext;
53
54static int decode_type2(GetByteContext *gb, PutByteContext *pb)
55{
56 unsigned repeat = 0, first = 1, opcode = 0;
57 int i, len, pos;
58
59 while (bytestream2_get_bytes_left(gb) > 0) {
60 GetByteContext gbc;
61
62 while (bytestream2_get_bytes_left(gb) > 0) {
63 if (first) {
64 first = 0;
65 if (bytestream2_peek_byte(gb) > 17) {
66 len = bytestream2_get_byte(gb) - 17;
67 if (len < 4) {
68 do {
69 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
70 --len;
71 } while (len);
72 opcode = bytestream2_peek_byte(gb);
73 continue;
74 } else {
75 do {
76 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
77 --len;
78 } while (len);
79 opcode = bytestream2_peek_byte(gb);
80 if (opcode < 0x10) {
81 bytestream2_skip(gb, 1);
82 pos = - (opcode >> 2) - 4 * bytestream2_get_byte(gb) - 2049;
83
84 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
85 bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
86
87 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
88 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
89 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
90 len = opcode & 3;
91 if (!len) {
92 repeat = 1;
93 } else {
94 do {
95 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
96 --len;
97 } while (len);
98 opcode = bytestream2_peek_byte(gb);
99 }
100 continue;
101 }
102 }
103 repeat = 0;
104 }
105 repeat = 1;
106 }
107 if (repeat) {
108 repeat = 0;
109 opcode = bytestream2_peek_byte(gb);
110 if (opcode < 0x10) {
111 bytestream2_skip(gb, 1);
112 if (!opcode) {
113 if (!bytestream2_peek_byte(gb)) {
114 do {
115 bytestream2_skip(gb, 1);
116 opcode += 255;
117 } while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0);
118 }
119 opcode += bytestream2_get_byte(gb) + 15;
120 }
121 bytestream2_put_le32(pb, bytestream2_get_le32(gb));
122 for (i = opcode - 1; i > 0; --i)
123 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
124 opcode = bytestream2_peek_byte(gb);
125 if (opcode < 0x10) {
126 bytestream2_skip(gb, 1);
127 pos = - (opcode >> 2) - 4 * bytestream2_get_byte(gb) - 2049;
128
129 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
130 bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
131
132 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
133 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
134 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
135 len = opcode & 3;
136 if (!len) {
137 repeat = 1;
138 } else {
139 do {
140 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
141 --len;
142 } while (len);
143 opcode = bytestream2_peek_byte(gb);
144 }
145 continue;
146 }
147 }
148 }
149
150 if (opcode >= 0x40) {
151 bytestream2_skip(gb, 1);
152 pos = - ((opcode >> 2) & 7) - 1 - 8 * bytestream2_get_byte(gb);
153 len = (opcode >> 5) - 1;
154
155 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
156 bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
157
158 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
159 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
160 do {
161 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
162 --len;
163 } while (len);
164
165 len = opcode & 3;
166
167 if (!len) {
168 repeat = 1;
169 } else {
170 do {
171 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
172 --len;
173 } while (len);
174 opcode = bytestream2_peek_byte(gb);
175 }
176 continue;
177 } else if (opcode < 0x20) {
178 break;
179 }
180 len = opcode & 0x1F;
181 bytestream2_skip(gb, 1);
182 if (!len) {
183 if (!bytestream2_peek_byte(gb)) {
184 do {
185 bytestream2_skip(gb, 1);
186 len += 255;
187 } while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0);
188 }
189 len += bytestream2_get_byte(gb) + 31;
190 }
191 i = bytestream2_get_le16(gb);
192 pos = - (i >> 2) - 1;
193
194 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
195 bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
196
197 if (len < 6 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) {
198 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
199 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
200 do {
201 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
202 --len;
203 } while (len);
204 } else {
205 bytestream2_put_le32(pb, bytestream2_get_le32(&gbc));
206 for (len = len - 2; len; --len)
207 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
208 }
209 len = i & 3;
210 if (!len) {
211 repeat = 1;
212 } else {
213 do {
214 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
215 --len;
216 } while (len);
217 opcode = bytestream2_peek_byte(gb);
218 }
219 }
220 bytestream2_skip(gb, 1);
221 if (opcode < 0x10) {
222 pos = -(opcode >> 2) - 1 - 4 * bytestream2_get_byte(gb);
223
224 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
225 bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
226
227 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
228 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
229 len = opcode & 3;
230 if (!len) {
231 repeat = 1;
232 } else {
233 do {
234 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
235 --len;
236 } while (len);
237 opcode = bytestream2_peek_byte(gb);
238 }
239 continue;
240 }
241 len = opcode & 7;
242 if (!len) {
243 if (!bytestream2_peek_byte(gb)) {
244 do {
245 bytestream2_skip(gb, 1);
246 len += 255;
247 } while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0);
248 }
249 len += bytestream2_get_byte(gb) + 7;
250 }
251 i = bytestream2_get_le16(gb);
252 pos = bytestream2_tell_p(pb) - 2048 * (opcode & 8);
253 pos = pos - (i >> 2);
254 if (pos == bytestream2_tell_p(pb))
255 break;
256
257 pos = pos - 0x4000;
258 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
259 bytestream2_seek(&gbc, pos, SEEK_SET);
260
261 if (len < 6 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) {
262 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
263 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
264 do {
265 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
266 --len;
267 } while (len);
268 } else {
269 bytestream2_put_le32(pb, bytestream2_get_le32(&gbc));
270 for (len = len - 2; len; --len)
271 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
272 }
273
274 len = i & 3;
275 if (!len) {
276 repeat = 1;
277 } else {
278 do {
279 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
280 --len;
281 } while (len);
282 opcode = bytestream2_peek_byte(gb);
283 }
284 }
285
286 return 0;
287}
288
289static int decode_type1(GetByteContext *gb, PutByteContext *pb)
290{
291 unsigned opcode = 0, len;
292 int high = 0;
293 int i, pos;
294
295 while (bytestream2_get_bytes_left(gb) > 0) {
296 GetByteContext gbc;
297
298 while (bytestream2_get_bytes_left(gb) > 0) {
299 while (bytestream2_get_bytes_left(gb) > 0) {
300 opcode = bytestream2_get_byte(gb);
301 high = opcode >= 0x20;
302 if (high)
303 break;
304 if (opcode)
305 break;
306 opcode = bytestream2_get_byte(gb);
307 if (opcode < 0xF8) {
308 opcode = opcode + 32;
309 break;
310 }
311 i = opcode - 0xF8;
312 if (i) {
313 len = 256;
314 do {
315 len *= 2;
316 --i;
317 } while (i);
318 } else {
319 len = 280;
320 }
321 do {
322 bytestream2_put_le32(pb, bytestream2_get_le32(gb));
323 bytestream2_put_le32(pb, bytestream2_get_le32(gb));
324 len -= 8;
325 } while (len && bytestream2_get_bytes_left(gb) > 0);
326 }
327
328 if (!high) {
329 do {
330 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
331 --opcode;
332 } while (opcode && bytestream2_get_bytes_left(gb) > 0);
333
334 while (bytestream2_get_bytes_left(gb) > 0) {
335 GetByteContext gbc;
336
337 opcode = bytestream2_get_byte(gb);
338 if (opcode >= 0x20)
339 break;
340 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
341
342 pos = -(opcode | 32 * bytestream2_get_byte(gb)) - 1;
343 bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
344 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
345 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
346 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
347 bytestream2_put_byte(pb, bytestream2_get_byte(gb));
348 }
349 }
350 high = 0;
351 if (opcode < 0x40)
352 break;
353 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
354 pos = (-((opcode & 0x1F) | 32 * bytestream2_get_byte(gb)) - 1);
355 bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos, SEEK_SET);
356 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
357 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
358 len = (opcode >> 5) - 1;
359 do {
360 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
361 --len;
362 } while (len && bytestream2_get_bytes_left(&gbc) > 0);
363 }
364 len = opcode & 0x1F;
365 if (!len) {
366 if (!bytestream2_peek_byte(gb)) {
367 do {
368 bytestream2_skip(gb, 1);
369 len += 255;
370 } while (!bytestream2_peek_byte(gb) && bytestream2_get_bytes_left(gb) > 0);
371 }
372 len += bytestream2_get_byte(gb) + 31;
373 }
374 pos = -bytestream2_get_byte(gb);
375 bytestream2_init(&gbc, pb->buffer_start, pb->buffer_end - pb->buffer_start);
376 bytestream2_seek(&gbc, bytestream2_tell_p(pb) + pos - (bytestream2_get_byte(gb) << 8), SEEK_SET);
377 if (bytestream2_tell_p(pb) == bytestream2_tell(&gbc))
378 break;
379 if (len < 5 || bytestream2_tell_p(pb) - bytestream2_tell(&gbc) < 4) {
380 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
381 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
382 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
383 } else {
384 bytestream2_put_le32(pb, bytestream2_get_le32(&gbc));
385 len--;
386 }
387 do {
388 bytestream2_put_byte(pb, bytestream2_get_byte(&gbc));
389 len--;
390 } while (len && bytestream2_get_bytes_left(&gbc) > 0);
391 }
392
393 return 0;
394}
395
396static int decode_frame(AVCodecContext *avctx,
397 void *data, int *got_frame,
398 AVPacket *avpkt)
399{
400 FMVCContext *s = avctx->priv_data;
401 GetByteContext *gb = &s->gb;
402 PutByteContext *pb = &s->pb;
403 AVFrame *frame = data;
404 int ret, y, x;
405
406 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
407 return ret;
408
409 bytestream2_init(gb, avpkt->data, avpkt->size);
410 bytestream2_skip(gb, 2);
411
412 frame->key_frame = !!bytestream2_get_le16(gb);
413 frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
414
415 if (frame->key_frame) {
416 const uint8_t *src;
417 int type, size;
418 uint8_t *dst;
419
420 type = bytestream2_get_le16(gb);
421 size = bytestream2_get_le16(gb);
422 if (size > bytestream2_get_bytes_left(gb))
423 return AVERROR_INVALIDDATA;
424
425 bytestream2_init_writer(pb, s->buffer, s->buffer_size);
426 if (type == 1) {
427 decode_type1(gb, pb);
428 } else if (type == 2){
429 decode_type2(gb, pb);
430 } else {
431 avpriv_report_missing_feature(avctx, "compression %d", type);
432 return AVERROR_PATCHWELCOME;
433 }
434
435 src = s->buffer;
436 dst = frame->data[0] + (avctx->height - 1) * frame->linesize[0];
437 for (y = 0; y < avctx->height; y++) {
438 memcpy(dst, src, avctx->width * s->bpp);
439 dst -= frame->linesize[0];
440 src += s->stride * 4;
441 }
442 } else {
443 int block, nb_blocks, type, k, l;
444 uint8_t *ssrc, *ddst;
445 const uint32_t *src;
446 uint32_t *dst;
447
448 for (block = 0; block < s->nb_blocks; block++)
449 s->blocks[block].xor = 0;
450
451 nb_blocks = bytestream2_get_le16(gb);
452 if (nb_blocks > s->nb_blocks)
453 return AVERROR_INVALIDDATA;
454
455 bytestream2_init_writer(pb, s->pbuffer, s->pbuffer_size);
456
457 type = bytestream2_get_le16(gb);
458 for (block = 0; block < nb_blocks; block++) {
459 int size, offset, start = 0;
460
461 offset = bytestream2_get_le16(gb);
462 if (offset > s->nb_blocks)
463 return AVERROR_INVALIDDATA;
464
465 size = bytestream2_get_le16(gb);
466 if (size > bytestream2_get_bytes_left(gb))
467 return AVERROR_INVALIDDATA;
468
469 start = bytestream2_tell_p(pb);
470 if (type == 1) {
471 decode_type1(gb, pb);
472 } else if (type == 2){
473 decode_type2(gb, pb);
474 } else {
475 avpriv_report_missing_feature(avctx, "compression %d", type);
476 return AVERROR_PATCHWELCOME;
477 }
478
479 if (s->blocks[offset].size * 4 != bytestream2_tell_p(pb) - start)
480 return AVERROR_INVALIDDATA;
481
482 s->blocks[offset].xor = 1;
483 }
484
485 src = (const uint32_t *)s->pbuffer;
486 dst = (uint32_t *)s->buffer;
487
488 for (block = 0, y = 0; y < s->yb; y++) {
489 int block_h = s->blocks[block].h;
490 uint32_t *rect = dst;
491
492 for (x = 0; x < s->xb; x++) {
493 int block_w = s->blocks[block].w;
494 uint32_t *row = dst;
495
496 block_h = s->blocks[block].h;
497 if (s->blocks[block].xor) {
498 for (k = 0; k < block_h; k++) {
499 uint32_t *column = dst;
500 for (l = 0; l < block_w; l++) {
501 *dst++ ^= *src++;
502 }
503 dst = &column[s->stride];
504 }
505 }
506 dst = &row[block_w];
507 ++block;
508 }
509 dst = &rect[block_h * s->stride];
510 }
511
512 ssrc = s->buffer;
513 ddst = frame->data[0] + (avctx->height - 1) * frame->linesize[0];
514 for (y = 0; y < avctx->height; y++) {
515 memcpy(ddst, ssrc, avctx->width * s->bpp);
516 ddst -= frame->linesize[0];
517 ssrc += s->stride * 4;
518 }
519 }
520
521 *got_frame = 1;
522
523 return avpkt->size;
524}
525
526static av_cold int decode_init(AVCodecContext *avctx)
527{
528 FMVCContext *s = avctx->priv_data;
529 int i, j, m, block = 0, h = BLOCK_HEIGHT, w = BLOCK_WIDTH;
530
531 switch (avctx->bits_per_coded_sample) {
532 case 16: avctx->pix_fmt = AV_PIX_FMT_RGB555; break;
533 case 24: avctx->pix_fmt = AV_PIX_FMT_BGR24; break;
534 case 32: avctx->pix_fmt = AV_PIX_FMT_BGRA; break;
535 default:
536 av_log(avctx, AV_LOG_ERROR, "Unsupported bitdepth %i\n", avctx->bits_per_coded_sample);
537 return AVERROR_INVALIDDATA;
538 }
539
540 s->stride = (avctx->width * avctx->bits_per_coded_sample + 31) / 32;
541 s->xb = s->stride / BLOCK_WIDTH;
542 m = s->stride % BLOCK_WIDTH;
543 if (m) {
544 if (m < 37) {
545 w = m + BLOCK_WIDTH;
546 } else {
547 w = m;
548 s->xb++;
549 }
550 }
551
552 s->yb = avctx->height / BLOCK_HEIGHT;
553 m = avctx->height % BLOCK_HEIGHT;
554 if (m) {
555 if (m < 49) {
556 h = m + BLOCK_HEIGHT;
557 } else {
558 h = m;
559 s->yb++;
560 }
561 }
562
563 s->nb_blocks = s->xb * s->yb;
564 s->blocks = av_calloc(s->nb_blocks, sizeof(*s->blocks));
565 if (!s->blocks)
566 return AVERROR(ENOMEM);
567
568 for (i = 0; i < s->yb; i++) {
569 for (j = 0; j < s->xb; j++) {
570 if (i != (s->yb - 1) || j != (s->xb - 1)) {
571 if (i == s->yb - 1) {
572 s->blocks[block].w = BLOCK_WIDTH;
573 s->blocks[block].h = h;
574 s->blocks[block].size = BLOCK_WIDTH * h;
575 } else if (j == s->xb - 1) {
576 s->blocks[block].w = w;
577 s->blocks[block].h = BLOCK_HEIGHT;
578 s->blocks[block].size = BLOCK_HEIGHT * w;
579 } else {
580 s->blocks[block].w = BLOCK_WIDTH;
581 s->blocks[block].h = BLOCK_HEIGHT;
582 s->blocks[block].size = BLOCK_WIDTH * BLOCK_HEIGHT;
583 }
584 } else {
585 s->blocks[block].w = w;
586 s->blocks[block].h = h;
587 s->blocks[block].size = w * h;
588 }
589 block++;
590 }
591 }
592
593 s->bpp = avctx->bits_per_coded_sample >> 3;
594 s->buffer_size = avctx->width * avctx->height * 4;
595 s->pbuffer_size = avctx->width * avctx->height * 4;
596 s->buffer = av_malloc(s->buffer_size);
597 s->pbuffer = av_malloc(s->pbuffer_size);
598 if (!s->buffer || !s->pbuffer)
599 return AVERROR(ENOMEM);
600
601 return 0;
602}
603
604static av_cold int decode_close(AVCodecContext *avctx)
605{
606 FMVCContext *s = avctx->priv_data;
607
608 av_freep(&s->buffer);
609 av_freep(&s->pbuffer);
610 av_freep(&s->blocks);
611
612 return 0;
613}
614
615AVCodec ff_fmvc_decoder = {
616 .name = "fmvc",
617 .long_name = NULL_IF_CONFIG_SMALL("FM Screen Capture Codec"),
618 .type = AVMEDIA_TYPE_VIDEO,
619 .id = AV_CODEC_ID_FMVC,
620 .priv_data_size = sizeof(FMVCContext),
621 .init = decode_init,
622 .close = decode_close,
623 .decode = decode_frame,
624 .capabilities = AV_CODEC_CAP_DR1,
625 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
626 FF_CODEC_CAP_INIT_CLEANUP,
627};
628
generated by cgit at 2024-05-17 02:04:48 (GMT)