FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/mss3.c
Date: 2021-09-26 18:22:30
Exec Total Coverage
Lines: 0 467 0.0%
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1 /*
2 * Microsoft Screen 3 (aka Microsoft ATC Screen) decoder
3 * Copyright (c) 2012 Konstantin Shishkov
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 * Microsoft Screen 3 (aka Microsoft ATC Screen) decoder
25 */
26
27 #include "avcodec.h"
28 #include "bytestream.h"
29 #include "internal.h"
30 #include "mathops.h"
31 #include "mss34dsp.h"
32
33 #define HEADER_SIZE 27
34
35 #define MODEL2_SCALE 13
36 #define MODEL_SCALE 15
37 #define MODEL256_SEC_SCALE 9
38
39 typedef struct Model2 {
40 int upd_val, till_rescale;
41 unsigned zero_freq, zero_weight;
42 unsigned total_freq, total_weight;
43 } Model2;
44
45 typedef struct Model {
46 int weights[16], freqs[16];
47 int num_syms;
48 int tot_weight;
49 int upd_val, max_upd_val, till_rescale;
50 } Model;
51
52 typedef struct Model256 {
53 int weights[256], freqs[256];
54 int tot_weight;
55 int secondary[68];
56 int sec_size;
57 int upd_val, max_upd_val, till_rescale;
58 } Model256;
59
60 #define RAC_BOTTOM 0x01000000
61 typedef struct RangeCoder {
62 const uint8_t *src, *src_end;
63
64 uint32_t range, low;
65 int got_error;
66 } RangeCoder;
67
68 enum BlockType {
69 FILL_BLOCK = 0,
70 IMAGE_BLOCK,
71 DCT_BLOCK,
72 HAAR_BLOCK,
73 SKIP_BLOCK
74 };
75
76 typedef struct BlockTypeContext {
77 int last_type;
78 Model bt_model[5];
79 } BlockTypeContext;
80
81 typedef struct FillBlockCoder {
82 int fill_val;
83 Model coef_model;
84 } FillBlockCoder;
85
86 typedef struct ImageBlockCoder {
87 Model256 esc_model, vec_entry_model;
88 Model vec_size_model;
89 Model vq_model[125];
90 } ImageBlockCoder;
91
92 typedef struct DCTBlockCoder {
93 int *prev_dc;
94 ptrdiff_t prev_dc_stride;
95 int prev_dc_height;
96 int quality;
97 uint16_t qmat[64];
98 Model dc_model;
99 Model2 sign_model;
100 Model256 ac_model;
101 } DCTBlockCoder;
102
103 typedef struct HaarBlockCoder {
104 int quality, scale;
105 Model256 coef_model;
106 Model coef_hi_model;
107 } HaarBlockCoder;
108
109 typedef struct MSS3Context {
110 AVCodecContext *avctx;
111 AVFrame *pic;
112
113 int got_error;
114 RangeCoder coder;
115 BlockTypeContext btype[3];
116 FillBlockCoder fill_coder[3];
117 ImageBlockCoder image_coder[3];
118 DCTBlockCoder dct_coder[3];
119 HaarBlockCoder haar_coder[3];
120
121 int dctblock[64];
122 int hblock[16 * 16];
123 } MSS3Context;
124
125
126 static void model2_reset(Model2 *m)
127 {
128 m->zero_weight = 1;
129 m->total_weight = 2;
130 m->zero_freq = 0x1000;
131 m->total_freq = 0x2000;
132 m->upd_val = 4;
133 m->till_rescale = 4;
134 }
135
136 static void model2_update(Model2 *m, int bit)
137 {
138 unsigned scale;
139
140 if (!bit)
141 m->zero_weight++;
142 m->till_rescale--;
143 if (m->till_rescale)
144 return;
145
146 m->total_weight += m->upd_val;
147 if (m->total_weight > 0x2000) {
148 m->total_weight = (m->total_weight + 1) >> 1;
149 m->zero_weight = (m->zero_weight + 1) >> 1;
150 if (m->total_weight == m->zero_weight)
151 m->total_weight = m->zero_weight + 1;
152 }
153 m->upd_val = m->upd_val * 5 >> 2;
154 if (m->upd_val > 64)
155 m->upd_val = 64;
156 scale = 0x80000000u / m->total_weight;
157 m->zero_freq = m->zero_weight * scale >> 18;
158 m->total_freq = m->total_weight * scale >> 18;
159 m->till_rescale = m->upd_val;
160 }
161
162 static void model_update(Model *m, int val)
163 {
164 int i, sum = 0;
165 unsigned scale;
166
167 m->weights[val]++;
168 m->till_rescale--;
169 if (m->till_rescale)
170 return;
171 m->tot_weight += m->upd_val;
172
173 if (m->tot_weight > 0x8000) {
174 m->tot_weight = 0;
175 for (i = 0; i < m->num_syms; i++) {
176 m->weights[i] = (m->weights[i] + 1) >> 1;
177 m->tot_weight += m->weights[i];
178 }
179 }
180 scale = 0x80000000u / m->tot_weight;
181 for (i = 0; i < m->num_syms; i++) {
182 m->freqs[i] = sum * scale >> 16;
183 sum += m->weights[i];
184 }
185
186 m->upd_val = m->upd_val * 5 >> 2;
187 if (m->upd_val > m->max_upd_val)
188 m->upd_val = m->max_upd_val;
189 m->till_rescale = m->upd_val;
190 }
191
192 static void model_reset(Model *m)
193 {
194 int i;
195
196 m->tot_weight = 0;
197 for (i = 0; i < m->num_syms - 1; i++)
198 m->weights[i] = 1;
199 m->weights[m->num_syms - 1] = 0;
200
201 m->upd_val = m->num_syms;
202 m->till_rescale = 1;
203 model_update(m, m->num_syms - 1);
204 m->till_rescale =
205 m->upd_val = (m->num_syms + 6) >> 1;
206 }
207
208 static av_cold void model_init(Model *m, int num_syms)
209 {
210 m->num_syms = num_syms;
211 m->max_upd_val = 8 * num_syms + 48;
212
213 model_reset(m);
214 }
215
216 static void model256_update(Model256 *m, int val)
217 {
218 int i, sum = 0;
219 unsigned scale;
220 int send, sidx = 1;
221
222 m->weights[val]++;
223 m->till_rescale--;
224 if (m->till_rescale)
225 return;
226 m->tot_weight += m->upd_val;
227
228 if (m->tot_weight > 0x8000) {
229 m->tot_weight = 0;
230 for (i = 0; i < 256; i++) {
231 m->weights[i] = (m->weights[i] + 1) >> 1;
232 m->tot_weight += m->weights[i];
233 }
234 }
235 scale = 0x80000000u / m->tot_weight;
236 m->secondary[0] = 0;
237 for (i = 0; i < 256; i++) {
238 m->freqs[i] = sum * scale >> 16;
239 sum += m->weights[i];
240 send = m->freqs[i] >> MODEL256_SEC_SCALE;
241 while (sidx <= send)
242 m->secondary[sidx++] = i - 1;
243 }
244 while (sidx < m->sec_size)
245 m->secondary[sidx++] = 255;
246
247 m->upd_val = m->upd_val * 5 >> 2;
248 if (m->upd_val > m->max_upd_val)
249 m->upd_val = m->max_upd_val;
250 m->till_rescale = m->upd_val;
251 }
252
253 static void model256_reset(Model256 *m)
254 {
255 int i;
256
257 for (i = 0; i < 255; i++)
258 m->weights[i] = 1;
259 m->weights[255] = 0;
260
261 m->tot_weight = 0;
262 m->upd_val = 256;
263 m->till_rescale = 1;
264 model256_update(m, 255);
265 m->till_rescale =
266 m->upd_val = (256 + 6) >> 1;
267 }
268
269 static av_cold void model256_init(Model256 *m)
270 {
271 m->max_upd_val = 8 * 256 + 48;
272 m->sec_size = (1 << 6) + 2;
273
274 model256_reset(m);
275 }
276
277 static void rac_init(RangeCoder *c, const uint8_t *src, int size)
278 {
279 int i;
280
281 c->src = src;
282 c->src_end = src + size;
283 c->low = 0;
284 for (i = 0; i < FFMIN(size, 4); i++)
285 c->low = (c->low << 8) | *c->src++;
286 c->range = 0xFFFFFFFF;
287 c->got_error = 0;
288 }
289
290 static void rac_normalise(RangeCoder *c)
291 {
292 for (;;) {
293 c->range <<= 8;
294 c->low <<= 8;
295 if (c->src < c->src_end) {
296 c->low |= *c->src++;
297 } else if (!c->low) {
298 c->got_error = 1;
299 c->low = 1;
300 }
301 if (c->low > c->range) {
302 c->got_error = 1;
303 c->low = 1;
304 }
305 if (c->range >= RAC_BOTTOM)
306 return;
307 }
308 }
309
310 static int rac_get_bit(RangeCoder *c)
311 {
312 int bit;
313
314 c->range >>= 1;
315
316 bit = (c->range <= c->low);
317 if (bit)
318 c->low -= c->range;
319
320 if (c->range < RAC_BOTTOM)
321 rac_normalise(c);
322
323 return bit;
324 }
325
326 static int rac_get_bits(RangeCoder *c, int nbits)
327 {
328 int val;
329
330 c->range >>= nbits;
331 val = c->low / c->range;
332 c->low -= c->range * val;
333
334 if (c->range < RAC_BOTTOM)
335 rac_normalise(c);
336
337 return val;
338 }
339
340 static int rac_get_model2_sym(RangeCoder *c, Model2 *m)
341 {
342 int bit, helper;
343
344 helper = m->zero_freq * (c->range >> MODEL2_SCALE);
345 bit = (c->low >= helper);
346 if (bit) {
347 c->low -= helper;
348 c->range -= helper;
349 } else {
350 c->range = helper;
351 }
352
353 if (c->range < RAC_BOTTOM)
354 rac_normalise(c);
355
356 model2_update(m, bit);
357
358 return bit;
359 }
360
361 static int rac_get_model_sym(RangeCoder *c, Model *m)
362 {
363 int val;
364 int end, end2;
365 unsigned prob, prob2, helper;
366
367 prob = 0;
368 prob2 = c->range;
369 c->range >>= MODEL_SCALE;
370 val = 0;
371 end = m->num_syms >> 1;
372 end2 = m->num_syms;
373 do {
374 helper = m->freqs[end] * c->range;
375 if (helper <= c->low) {
376 val = end;
377 prob = helper;
378 } else {
379 end2 = end;
380 prob2 = helper;
381 }
382 end = (end2 + val) >> 1;
383 } while (end != val);
384 c->low -= prob;
385 c->range = prob2 - prob;
386 if (c->range < RAC_BOTTOM)
387 rac_normalise(c);
388
389 model_update(m, val);
390
391 return val;
392 }
393
394 static int rac_get_model256_sym(RangeCoder *c, Model256 *m)
395 {
396 int val;
397 int start, end;
398 int ssym;
399 unsigned prob, prob2, helper;
400
401 prob2 = c->range;
402 c->range >>= MODEL_SCALE;
403
404 helper = c->low / c->range;
405 ssym = helper >> MODEL256_SEC_SCALE;
406 val = m->secondary[ssym];
407
408 end = start = m->secondary[ssym + 1] + 1;
409 while (end > val + 1) {
410 ssym = (end + val) >> 1;
411 if (m->freqs[ssym] <= helper) {
412 end = start;
413 val = ssym;
414 } else {
415 end = (end + val) >> 1;
416 start = ssym;
417 }
418 }
419 prob = m->freqs[val] * c->range;
420 if (val != 255)
421 prob2 = m->freqs[val + 1] * c->range;
422
423 c->low -= prob;
424 c->range = prob2 - prob;
425 if (c->range < RAC_BOTTOM)
426 rac_normalise(c);
427
428 model256_update(m, val);
429
430 return val;
431 }
432
433 static int decode_block_type(RangeCoder *c, BlockTypeContext *bt)
434 {
435 bt->last_type = rac_get_model_sym(c, &bt->bt_model[bt->last_type]);
436
437 return bt->last_type;
438 }
439
440 static int decode_coeff(RangeCoder *c, Model *m)
441 {
442 int val, sign;
443
444 val = rac_get_model_sym(c, m);
445 if (val) {
446 sign = rac_get_bit(c);
447 if (val > 1) {
448 val--;
449 val = (1 << val) + rac_get_bits(c, val);
450 }
451 if (!sign)
452 val = -val;
453 }
454
455 return val;
456 }
457
458 static void decode_fill_block(RangeCoder *c, FillBlockCoder *fc,
459 uint8_t *dst, ptrdiff_t stride, int block_size)
460 {
461 int i;
462
463 fc->fill_val += decode_coeff(c, &fc->coef_model);
464
465 for (i = 0; i < block_size; i++, dst += stride)
466 memset(dst, fc->fill_val, block_size);
467 }
468
469 static void decode_image_block(RangeCoder *c, ImageBlockCoder *ic,
470 uint8_t *dst, ptrdiff_t stride, int block_size)
471 {
472 int i, j;
473 int vec_size;
474 int vec[4];
475 int prev_line[16];
476 int A, B, C;
477
478 vec_size = rac_get_model_sym(c, &ic->vec_size_model) + 2;
479 for (i = 0; i < vec_size; i++)
480 vec[i] = rac_get_model256_sym(c, &ic->vec_entry_model);
481 for (; i < 4; i++)
482 vec[i] = 0;
483 memset(prev_line, 0, sizeof(prev_line));
484
485 for (j = 0; j < block_size; j++) {
486 A = 0;
487 B = 0;
488 for (i = 0; i < block_size; i++) {
489 C = B;
490 B = prev_line[i];
491 A = rac_get_model_sym(c, &ic->vq_model[A + B * 5 + C * 25]);
492
493 prev_line[i] = A;
494 if (A < 4)
495 dst[i] = vec[A];
496 else
497 dst[i] = rac_get_model256_sym(c, &ic->esc_model);
498 }
499 dst += stride;
500 }
501 }
502
503 static int decode_dct(RangeCoder *c, DCTBlockCoder *bc, int *block,
504 int bx, int by)
505 {
506 int skip, val, sign, pos = 1, zz_pos, dc;
507 int blk_pos = bx + by * bc->prev_dc_stride;
508
509 memset(block, 0, sizeof(*block) * 64);
510
511 dc = decode_coeff(c, &bc->dc_model);
512 if (by) {
513 if (bx) {
514 int l, tl, t;
515
516 l = bc->prev_dc[blk_pos - 1];
517 tl = bc->prev_dc[blk_pos - 1 - bc->prev_dc_stride];
518 t = bc->prev_dc[blk_pos - bc->prev_dc_stride];
519
520 if (FFABS(t - tl) <= FFABS(l - tl))
521 dc += l;
522 else
523 dc += t;
524 } else {
525 dc += bc->prev_dc[blk_pos - bc->prev_dc_stride];
526 }
527 } else if (bx) {
528 dc += bc->prev_dc[bx - 1];
529 }
530 bc->prev_dc[blk_pos] = dc;
531 block[0] = dc * bc->qmat[0];
532
533 while (pos < 64) {
534 val = rac_get_model256_sym(c, &bc->ac_model);
535 if (!val)
536 return 0;
537 if (val == 0xF0) {
538 pos += 16;
539 continue;
540 }
541 skip = val >> 4;
542 val = val & 0xF;
543 if (!val)
544 return -1;
545 pos += skip;
546 if (pos >= 64)
547 return -1;
548
549 sign = rac_get_model2_sym(c, &bc->sign_model);
550 if (val > 1) {
551 val--;
552 val = (1 << val) + rac_get_bits(c, val);
553 }
554 if (!sign)
555 val = -val;
556
557 zz_pos = ff_zigzag_direct[pos];
558 block[zz_pos] = val * bc->qmat[zz_pos];
559 pos++;
560 }
561
562 return pos == 64 ? 0 : -1;
563 }
564
565 static void decode_dct_block(RangeCoder *c, DCTBlockCoder *bc,
566 uint8_t *dst, ptrdiff_t stride, int block_size,
567 int *block, int mb_x, int mb_y)
568 {
569 int i, j;
570 int bx, by;
571 int nblocks = block_size >> 3;
572
573 bx = mb_x * nblocks;
574 by = mb_y * nblocks;
575
576 for (j = 0; j < nblocks; j++) {
577 for (i = 0; i < nblocks; i++) {
578 if (decode_dct(c, bc, block, bx + i, by + j)) {
579 c->got_error = 1;
580 return;
581 }
582 ff_mss34_dct_put(dst + i * 8, stride, block);
583 }
584 dst += 8 * stride;
585 }
586 }
587
588 static void decode_haar_block(RangeCoder *c, HaarBlockCoder *hc,
589 uint8_t *dst, ptrdiff_t stride,
590 int block_size, int *block)
591 {
592 const int hsize = block_size >> 1;
593 int A, B, C, D, t1, t2, t3, t4;
594 int i, j;
595
596 for (j = 0; j < block_size; j++) {
597 for (i = 0; i < block_size; i++) {
598 if (i < hsize && j < hsize)
599 block[i] = rac_get_model256_sym(c, &hc->coef_model);
600 else
601 block[i] = decode_coeff(c, &hc->coef_hi_model);
602 block[i] *= hc->scale;
603 }
604 block += block_size;
605 }
606 block -= block_size * block_size;
607
608 for (j = 0; j < hsize; j++) {
609 for (i = 0; i < hsize; i++) {
610 A = block[i];
611 B = block[i + hsize];
612 C = block[i + hsize * block_size];
613 D = block[i + hsize * block_size + hsize];
614
615 t1 = A - B;
616 t2 = C - D;
617 t3 = A + B;
618 t4 = C + D;
619 dst[i * 2] = av_clip_uint8(t1 - t2);
620 dst[i * 2 + stride] = av_clip_uint8(t1 + t2);
621 dst[i * 2 + 1] = av_clip_uint8(t3 - t4);
622 dst[i * 2 + 1 + stride] = av_clip_uint8(t3 + t4);
623 }
624 block += block_size;
625 dst += stride * 2;
626 }
627 }
628
629 static void reset_coders(MSS3Context *ctx, int quality)
630 {
631 int i, j;
632
633 for (i = 0; i < 3; i++) {
634 ctx->btype[i].last_type = SKIP_BLOCK;
635 for (j = 0; j < 5; j++)
636 model_reset(&ctx->btype[i].bt_model[j]);
637 ctx->fill_coder[i].fill_val = 0;
638 model_reset(&ctx->fill_coder[i].coef_model);
639 model256_reset(&ctx->image_coder[i].esc_model);
640 model256_reset(&ctx->image_coder[i].vec_entry_model);
641 model_reset(&ctx->image_coder[i].vec_size_model);
642 for (j = 0; j < 125; j++)
643 model_reset(&ctx->image_coder[i].vq_model[j]);
644 if (ctx->dct_coder[i].quality != quality) {
645 ctx->dct_coder[i].quality = quality;
646 ff_mss34_gen_quant_mat(ctx->dct_coder[i].qmat, quality, !i);
647 }
648 memset(ctx->dct_coder[i].prev_dc, 0,
649 sizeof(*ctx->dct_coder[i].prev_dc) *
650 ctx->dct_coder[i].prev_dc_stride *
651 ctx->dct_coder[i].prev_dc_height);
652 model_reset(&ctx->dct_coder[i].dc_model);
653 model2_reset(&ctx->dct_coder[i].sign_model);
654 model256_reset(&ctx->dct_coder[i].ac_model);
655 if (ctx->haar_coder[i].quality != quality) {
656 ctx->haar_coder[i].quality = quality;
657 ctx->haar_coder[i].scale = 17 - 7 * quality / 50;
658 }
659 model_reset(&ctx->haar_coder[i].coef_hi_model);
660 model256_reset(&ctx->haar_coder[i].coef_model);
661 }
662 }
663
664 static av_cold void init_coders(MSS3Context *ctx)
665 {
666 int i, j;
667
668 for (i = 0; i < 3; i++) {
669 for (j = 0; j < 5; j++)
670 model_init(&ctx->btype[i].bt_model[j], 5);
671 model_init(&ctx->fill_coder[i].coef_model, 12);
672 model256_init(&ctx->image_coder[i].esc_model);
673 model256_init(&ctx->image_coder[i].vec_entry_model);
674 model_init(&ctx->image_coder[i].vec_size_model, 3);
675 for (j = 0; j < 125; j++)
676 model_init(&ctx->image_coder[i].vq_model[j], 5);
677 model_init(&ctx->dct_coder[i].dc_model, 12);
678 model256_init(&ctx->dct_coder[i].ac_model);
679 model_init(&ctx->haar_coder[i].coef_hi_model, 12);
680 model256_init(&ctx->haar_coder[i].coef_model);
681 }
682 }
683
684 static int mss3_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
685 AVPacket *avpkt)
686 {
687 const uint8_t *buf = avpkt->data;
688 int buf_size = avpkt->size;
689 MSS3Context *c = avctx->priv_data;
690 RangeCoder *acoder = &c->coder;
691 GetByteContext gb;
692 uint8_t *dst[3];
693 int dec_width, dec_height, dec_x, dec_y, quality, keyframe;
694 int x, y, i, mb_width, mb_height, blk_size, btype;
695 int ret;
696
697 if (buf_size < HEADER_SIZE) {
698 av_log(avctx, AV_LOG_ERROR,
699 "Frame should have at least %d bytes, got %d instead\n",
700 HEADER_SIZE, buf_size);
701 return AVERROR_INVALIDDATA;
702 }
703
704 bytestream2_init(&gb, buf, buf_size);
705 keyframe = bytestream2_get_be32(&gb);
706 if (keyframe & ~0x301) {
707 av_log(avctx, AV_LOG_ERROR, "Invalid frame type %X\n", keyframe);
708 return AVERROR_INVALIDDATA;
709 }
710 keyframe = !(keyframe & 1);
711 bytestream2_skip(&gb, 6);
712 dec_x = bytestream2_get_be16(&gb);
713 dec_y = bytestream2_get_be16(&gb);
714 dec_width = bytestream2_get_be16(&gb);
715 dec_height = bytestream2_get_be16(&gb);
716
717 if (dec_x + dec_width > avctx->width ||
718 dec_y + dec_height > avctx->height ||
719 (dec_width | dec_height) & 0xF) {
720 av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d +%d,%d\n",
721 dec_width, dec_height, dec_x, dec_y);
722 return AVERROR_INVALIDDATA;
723 }
724 bytestream2_skip(&gb, 4);
725 quality = bytestream2_get_byte(&gb);
726 if (quality < 1 || quality > 100) {
727 av_log(avctx, AV_LOG_ERROR, "Invalid quality setting %d\n", quality);
728 return AVERROR_INVALIDDATA;
729 }
730 bytestream2_skip(&gb, 4);
731
732 if (keyframe && !bytestream2_get_bytes_left(&gb)) {
733 av_log(avctx, AV_LOG_ERROR, "Keyframe without data found\n");
734 return AVERROR_INVALIDDATA;
735 }
736 if (!keyframe && c->got_error)
737 return buf_size;
738 c->got_error = 0;
739
740 if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)
741 return ret;
742 c->pic->key_frame = keyframe;
743 c->pic->pict_type = keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
744 if (!bytestream2_get_bytes_left(&gb)) {
745 if ((ret = av_frame_ref(data, c->pic)) < 0)
746 return ret;
747 *got_frame = 1;
748
749 return buf_size;
750 }
751
752 reset_coders(c, quality);
753
754 rac_init(acoder, buf + HEADER_SIZE, buf_size - HEADER_SIZE);
755
756 mb_width = dec_width >> 4;
757 mb_height = dec_height >> 4;
758 dst[0] = c->pic->data[0] + dec_x + dec_y * c->pic->linesize[0];
759 dst[1] = c->pic->data[1] + dec_x / 2 + (dec_y / 2) * c->pic->linesize[1];
760 dst[2] = c->pic->data[2] + dec_x / 2 + (dec_y / 2) * c->pic->linesize[2];
761 for (y = 0; y < mb_height; y++) {
762 for (x = 0; x < mb_width; x++) {
763 for (i = 0; i < 3; i++) {
764 blk_size = 8 << !i;
765
766 btype = decode_block_type(acoder, c->btype + i);
767 switch (btype) {
768 case FILL_BLOCK:
769 decode_fill_block(acoder, c->fill_coder + i,
770 dst[i] + x * blk_size,
771 c->pic->linesize[i], blk_size);
772 break;
773 case IMAGE_BLOCK:
774 decode_image_block(acoder, c->image_coder + i,
775 dst[i] + x * blk_size,
776 c->pic->linesize[i], blk_size);
777 break;
778 case DCT_BLOCK:
779 decode_dct_block(acoder, c->dct_coder + i,
780 dst[i] + x * blk_size,
781 c->pic->linesize[i], blk_size,
782 c->dctblock, x, y);
783 break;
784 case HAAR_BLOCK:
785 decode_haar_block(acoder, c->haar_coder + i,
786 dst[i] + x * blk_size,
787 c->pic->linesize[i], blk_size,
788 c->hblock);
789 break;
790 }
791 if (c->got_error || acoder->got_error) {
792 av_log(avctx, AV_LOG_ERROR, "Error decoding block %d,%d\n",
793 x, y);
794 c->got_error = 1;
795 return AVERROR_INVALIDDATA;
796 }
797 }
798 }
799 dst[0] += c->pic->linesize[0] * 16;
800 dst[1] += c->pic->linesize[1] * 8;
801 dst[2] += c->pic->linesize[2] * 8;
802 }
803
804 if ((ret = av_frame_ref(data, c->pic)) < 0)
805 return ret;
806
807 *got_frame = 1;
808
809 return buf_size;
810 }
811
812 static av_cold int mss3_decode_end(AVCodecContext *avctx)
813 {
814 MSS3Context * const c = avctx->priv_data;
815 int i;
816
817 av_frame_free(&c->pic);
818 for (i = 0; i < 3; i++)
819 av_freep(&c->dct_coder[i].prev_dc);
820
821 return 0;
822 }
823
824 static av_cold int mss3_decode_init(AVCodecContext *avctx)
825 {
826 MSS3Context * const c = avctx->priv_data;
827 int i;
828
829 c->avctx = avctx;
830
831 if ((avctx->width & 0xF) || (avctx->height & 0xF)) {
832 av_log(avctx, AV_LOG_ERROR,
833 "Image dimensions should be a multiple of 16.\n");
834 return AVERROR_INVALIDDATA;
835 }
836
837 c->got_error = 0;
838 for (i = 0; i < 3; i++) {
839 int b_width = avctx->width >> (2 + !!i);
840 int b_height = avctx->height >> (2 + !!i);
841 c->dct_coder[i].prev_dc_stride = b_width;
842 c->dct_coder[i].prev_dc_height = b_height;
843 c->dct_coder[i].prev_dc = av_malloc(sizeof(*c->dct_coder[i].prev_dc) *
844 b_width * b_height);
845 if (!c->dct_coder[i].prev_dc) {
846 av_log(avctx, AV_LOG_ERROR, "Cannot allocate buffer\n");
847 return AVERROR(ENOMEM);
848 }
849 }
850
851 c->pic = av_frame_alloc();
852 if (!c->pic)
853 return AVERROR(ENOMEM);
854
855 avctx->pix_fmt = AV_PIX_FMT_YUV420P;
856
857 init_coders(c);
858
859 return 0;
860 }
861
862 const AVCodec ff_msa1_decoder = {
863 .name = "msa1",
864 .long_name = NULL_IF_CONFIG_SMALL("MS ATC Screen"),
865 .type = AVMEDIA_TYPE_VIDEO,
866 .id = AV_CODEC_ID_MSA1,
867 .priv_data_size = sizeof(MSS3Context),
868 .init = mss3_decode_init,
869 .close = mss3_decode_end,
870 .decode = mss3_decode_frame,
871 .capabilities = AV_CODEC_CAP_DR1,
872 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
873 };
874