FFmpeg coverage

Line	Branch	Exec	Source
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 "libavutil/mem.h"
28			#include "avcodec.h"
29			#include "bytestream.h"
30			#include "codec_internal.h"
31			#include "decode.h"
32			#include "mathops.h"
33			#include "mss34dsp.h"
34
35			#define HEADER_SIZE 27
36
37			#define MODEL2_SCALE 13
38			#define MODEL_SCALE 15
39			#define MODEL256_SEC_SCALE 9
40
41			typedef struct Model2 {
42			int upd_val, till_rescale;
43			unsigned zero_freq, zero_weight;
44			unsigned total_freq, total_weight;
45			} Model2;
46
47			typedef struct Model {
48			int weights[16], freqs[16];
49			int num_syms;
50			int tot_weight;
51			int upd_val, max_upd_val, till_rescale;
52			} Model;
53
54			typedef struct Model256 {
55			int weights[256], freqs[256];
56			int tot_weight;
57			int secondary[68];
58			int sec_size;
59			int upd_val, max_upd_val, till_rescale;
60			} Model256;
61
62			#define RAC_BOTTOM 0x01000000
63			typedef struct RangeCoder {
64			const uint8_t *src, *src_end;
65
66			uint32_t range, low;
67			int got_error;
68			} RangeCoder;
69
70			enum BlockType {
71			FILL_BLOCK = 0,
72			IMAGE_BLOCK,
73			DCT_BLOCK,
74			HAAR_BLOCK,
75			SKIP_BLOCK
76			};
77
78			typedef struct BlockTypeContext {
79			int last_type;
80			Model bt_model[5];
81			} BlockTypeContext;
82
83			typedef struct FillBlockCoder {
84			int fill_val;
85			Model coef_model;
86			} FillBlockCoder;
87
88			typedef struct ImageBlockCoder {
89			Model256 esc_model, vec_entry_model;
90			Model vec_size_model;
91			Model vq_model[125];
92			} ImageBlockCoder;
93
94			typedef struct DCTBlockCoder {
95			int *prev_dc;
96			ptrdiff_t prev_dc_stride;
97			int prev_dc_height;
98			int quality;
99			uint16_t qmat[64];
100			Model dc_model;
101			Model2 sign_model;
102			Model256 ac_model;
103			} DCTBlockCoder;
104
105			typedef struct HaarBlockCoder {
106			int quality, scale;
107			Model256 coef_model;
108			Model coef_hi_model;
109			} HaarBlockCoder;
110
111			typedef struct MSS3Context {
112			AVCodecContext *avctx;
113			AVFrame *pic;
114
115			int got_error;
116			RangeCoder coder;
117			BlockTypeContext btype[3];
118			FillBlockCoder fill_coder[3];
119			ImageBlockCoder image_coder[3];
120			DCTBlockCoder dct_coder[3];
121			HaarBlockCoder haar_coder[3];
122
123			int dctblock[64];
124			int hblock[16 * 16];
125			} MSS3Context;
126
127
128		✗	static void model2_reset(Model2 *m)
129			{
130		✗	m->zero_weight = 1;
131		✗	m->total_weight = 2;
132		✗	m->zero_freq = 0x1000;
133		✗	m->total_freq = 0x2000;
134		✗	m->upd_val = 4;
135		✗	m->till_rescale = 4;
136		✗	}
137
138		✗	static void model2_update(Model2 *m, int bit)
139			{
140			unsigned scale;
141
142		✗	if (!bit)
143		✗	m->zero_weight++;
144		✗	m->till_rescale--;
145		✗	if (m->till_rescale)
146		✗	return;
147
148		✗	m->total_weight += m->upd_val;
149		✗	if (m->total_weight > 0x2000) {
150		✗	m->total_weight = (m->total_weight + 1) >> 1;
151		✗	m->zero_weight = (m->zero_weight + 1) >> 1;
152		✗	if (m->total_weight == m->zero_weight)
153		✗	m->total_weight = m->zero_weight + 1;
154			}
155		✗	m->upd_val = m->upd_val * 5 >> 2;
156		✗	if (m->upd_val > 64)
157		✗	m->upd_val = 64;
158		✗	scale = 0x80000000u / m->total_weight;
159		✗	m->zero_freq = m->zero_weight * scale >> 18;
160		✗	m->total_freq = m->total_weight * scale >> 18;
161		✗	m->till_rescale = m->upd_val;
162			}
163
164		✗	static void model_update(Model *m, int val)
165			{
166		✗	int i, sum = 0;
167			unsigned scale;
168
169		✗	m->weights[val]++;
170		✗	m->till_rescale--;
171		✗	if (m->till_rescale)
172		✗	return;
173		✗	m->tot_weight += m->upd_val;
174
175		✗	if (m->tot_weight > 0x8000) {
176		✗	m->tot_weight = 0;
177		✗	for (i = 0; i < m->num_syms; i++) {
178		✗	m->weights[i] = (m->weights[i] + 1) >> 1;
179		✗	m->tot_weight += m->weights[i];
180			}
181			}
182		✗	scale = 0x80000000u / m->tot_weight;
183		✗	for (i = 0; i < m->num_syms; i++) {
184		✗	m->freqs[i] = sum * scale >> 16;
185		✗	sum += m->weights[i];
186			}
187
188		✗	m->upd_val = m->upd_val * 5 >> 2;
189		✗	if (m->upd_val > m->max_upd_val)
190		✗	m->upd_val = m->max_upd_val;
191		✗	m->till_rescale = m->upd_val;
192			}
193
194		✗	static void model_reset(Model *m)
195			{
196			int i;
197
198		✗	m->tot_weight = 0;
199		✗	for (i = 0; i < m->num_syms - 1; i++)
200		✗	m->weights[i] = 1;
201		✗	m->weights[m->num_syms - 1] = 0;
202
203		✗	m->upd_val = m->num_syms;
204		✗	m->till_rescale = 1;
205		✗	model_update(m, m->num_syms - 1);
206		✗	m->till_rescale =
207		✗	m->upd_val = (m->num_syms + 6) >> 1;
208		✗	}
209
210		✗	static av_cold void model_init(Model *m, int num_syms)
211			{
212		✗	m->num_syms = num_syms;
213		✗	m->max_upd_val = 8 * num_syms + 48;
214
215		✗	model_reset(m);
216		✗	}
217
218		✗	static void model256_update(Model256 *m, int val)
219			{
220		✗	int i, sum = 0;
221			unsigned scale;
222		✗	int send, sidx = 1;
223
224		✗	m->weights[val]++;
225		✗	m->till_rescale--;
226		✗	if (m->till_rescale)
227		✗	return;
228		✗	m->tot_weight += m->upd_val;
229
230		✗	if (m->tot_weight > 0x8000) {
231		✗	m->tot_weight = 0;
232		✗	for (i = 0; i < 256; i++) {
233		✗	m->weights[i] = (m->weights[i] + 1) >> 1;
234		✗	m->tot_weight += m->weights[i];
235			}
236			}
237		✗	scale = 0x80000000u / m->tot_weight;
238		✗	m->secondary[0] = 0;
239		✗	for (i = 0; i < 256; i++) {
240		✗	m->freqs[i] = sum * scale >> 16;
241		✗	sum += m->weights[i];
242		✗	send = m->freqs[i] >> MODEL256_SEC_SCALE;
243		✗	while (sidx <= send)
244		✗	m->secondary[sidx++] = i - 1;
245			}
246		✗	while (sidx < m->sec_size)
247		✗	m->secondary[sidx++] = 255;
248
249		✗	m->upd_val = m->upd_val * 5 >> 2;
250		✗	if (m->upd_val > m->max_upd_val)
251		✗	m->upd_val = m->max_upd_val;
252		✗	m->till_rescale = m->upd_val;
253			}
254
255		✗	static void model256_reset(Model256 *m)
256			{
257			int i;
258
259		✗	for (i = 0; i < 255; i++)
260		✗	m->weights[i] = 1;
261		✗	m->weights[255] = 0;
262
263		✗	m->tot_weight = 0;
264		✗	m->upd_val = 256;
265		✗	m->till_rescale = 1;
266		✗	model256_update(m, 255);
267		✗	m->till_rescale =
268		✗	m->upd_val = (256 + 6) >> 1;
269		✗	}
270
271		✗	static av_cold void model256_init(Model256 *m)
272			{
273		✗	m->max_upd_val = 8 * 256 + 48;
274		✗	m->sec_size = (1 << 6) + 2;
275
276		✗	model256_reset(m);
277		✗	}
278
279		✗	static void rac_init(RangeCoder *c, const uint8_t *src, int size)
280			{
281			int i;
282
283		✗	c->src = src;
284		✗	c->src_end = src + size;
285		✗	c->low = 0;
286		✗	for (i = 0; i < FFMIN(size, 4); i++)
287		✗	c->low = (c->low << 8) | *c->src++;
288		✗	c->range = 0xFFFFFFFF;
289		✗	c->got_error = 0;
290		✗	}
291
292		✗	static void rac_normalise(RangeCoder *c)
293			{
294			for (;;) {
295		✗	c->range <<= 8;
296		✗	c->low <<= 8;
297		✗	if (c->src < c->src_end) {
298		✗	c->low |= *c->src++;
299		✗	} else if (!c->low) {
300		✗	c->got_error = 1;
301		✗	c->low = 1;
302			}
303		✗	if (c->low > c->range) {
304		✗	c->got_error = 1;
305		✗	c->low = 1;
306			}
307		✗	if (c->range >= RAC_BOTTOM)
308		✗	return;
309			}
310			}
311
312		✗	static int rac_get_bit(RangeCoder *c)
313			{
314			int bit;
315
316		✗	c->range >>= 1;
317
318		✗	bit = (c->range <= c->low);
319		✗	if (bit)
320		✗	c->low -= c->range;
321
322		✗	if (c->range < RAC_BOTTOM)
323		✗	rac_normalise(c);
324
325		✗	return bit;
326			}
327
328		✗	static int rac_get_bits(RangeCoder *c, int nbits)
329			{
330			int val;
331
332		✗	c->range >>= nbits;
333		✗	val = c->low / c->range;
334		✗	c->low -= c->range * val;
335
336		✗	if (c->range < RAC_BOTTOM)
337		✗	rac_normalise(c);
338
339		✗	return val;
340			}
341
342		✗	static int rac_get_model2_sym(RangeCoder *c, Model2 *m)
343			{
344			int bit, helper;
345
346		✗	helper = m->zero_freq * (c->range >> MODEL2_SCALE);
347		✗	bit = (c->low >= helper);
348		✗	if (bit) {
349		✗	c->low -= helper;
350		✗	c->range -= helper;
351			} else {
352		✗	c->range = helper;
353			}
354
355		✗	if (c->range < RAC_BOTTOM)
356		✗	rac_normalise(c);
357
358		✗	model2_update(m, bit);
359
360		✗	return bit;
361			}
362
363		✗	static int rac_get_model_sym(RangeCoder *c, Model *m)
364			{
365			int val;
366			int end, end2;
367			unsigned prob, prob2, helper;
368
369		✗	prob = 0;
370		✗	prob2 = c->range;
371		✗	c->range >>= MODEL_SCALE;
372		✗	val = 0;
373		✗	end = m->num_syms >> 1;
374		✗	end2 = m->num_syms;
375			do {
376		✗	helper = m->freqs[end] * c->range;
377		✗	if (helper <= c->low) {
378		✗	val = end;
379		✗	prob = helper;
380			} else {
381		✗	end2 = end;
382		✗	prob2 = helper;
383			}
384		✗	end = (end2 + val) >> 1;
385		✗	} while (end != val);
386		✗	c->low -= prob;
387		✗	c->range = prob2 - prob;
388		✗	if (c->range < RAC_BOTTOM)
389		✗	rac_normalise(c);
390
391		✗	model_update(m, val);
392
393		✗	return val;
394			}
395
396		✗	static int rac_get_model256_sym(RangeCoder *c, Model256 *m)
397			{
398			int val;
399			int start, end;
400			int ssym;
401			unsigned prob, prob2, helper;
402
403		✗	prob2 = c->range;
404		✗	c->range >>= MODEL_SCALE;
405
406		✗	helper = c->low / c->range;
407		✗	ssym = helper >> MODEL256_SEC_SCALE;
408		✗	val = m->secondary[ssym];
409
410		✗	end = start = m->secondary[ssym + 1] + 1;
411		✗	while (end > val + 1) {
412		✗	ssym = (end + val) >> 1;
413		✗	if (m->freqs[ssym] <= helper) {
414		✗	end = start;
415		✗	val = ssym;
416			} else {
417		✗	end = (end + val) >> 1;
418		✗	start = ssym;
419			}
420			}
421		✗	prob = m->freqs[val] * c->range;
422		✗	if (val != 255)
423		✗	prob2 = m->freqs[val + 1] * c->range;
424
425		✗	c->low -= prob;
426		✗	c->range = prob2 - prob;
427		✗	if (c->range < RAC_BOTTOM)
428		✗	rac_normalise(c);
429
430		✗	model256_update(m, val);
431
432		✗	return val;
433			}
434
435		✗	static int decode_block_type(RangeCoder *c, BlockTypeContext *bt)
436			{
437		✗	bt->last_type = rac_get_model_sym(c, &bt->bt_model[bt->last_type]);
438
439		✗	return bt->last_type;
440			}
441
442		✗	static int decode_coeff(RangeCoder *c, Model *m)
443			{
444			int val, sign;
445
446		✗	val = rac_get_model_sym(c, m);
447		✗	if (val) {
448		✗	sign = rac_get_bit(c);
449		✗	if (val > 1) {
450		✗	val--;
451		✗	val = (1 << val) + rac_get_bits(c, val);
452			}
453		✗	if (!sign)
454		✗	val = -val;
455			}
456
457		✗	return val;
458			}
459
460		✗	static void decode_fill_block(RangeCoder *c, FillBlockCoder *fc,
461			uint8_t *dst, ptrdiff_t stride, int block_size)
462			{
463			int i;
464
465		✗	fc->fill_val += decode_coeff(c, &fc->coef_model);
466
467		✗	for (i = 0; i < block_size; i++, dst += stride)
468		✗	memset(dst, fc->fill_val, block_size);
469		✗	}
470
471		✗	static void decode_image_block(RangeCoder *c, ImageBlockCoder *ic,
472			uint8_t *dst, ptrdiff_t stride, int block_size)
473			{
474			int i, j;
475			int vec_size;
476			int vec[4];
477			int prev_line[16];
478			int A, B, C;
479
480		✗	vec_size = rac_get_model_sym(c, &ic->vec_size_model) + 2;
481		✗	for (i = 0; i < vec_size; i++)
482		✗	vec[i] = rac_get_model256_sym(c, &ic->vec_entry_model);
483		✗	for (; i < 4; i++)
484		✗	vec[i] = 0;
485		✗	memset(prev_line, 0, sizeof(prev_line));
486
487		✗	for (j = 0; j < block_size; j++) {
488		✗	A = 0;
489		✗	B = 0;
490		✗	for (i = 0; i < block_size; i++) {
491		✗	C = B;
492		✗	B = prev_line[i];
493		✗	A = rac_get_model_sym(c, &ic->vq_model[A + B * 5 + C * 25]);
494
495		✗	prev_line[i] = A;
496		✗	if (A < 4)
497		✗	dst[i] = vec[A];
498			else
499		✗	dst[i] = rac_get_model256_sym(c, &ic->esc_model);
500			}
501		✗	dst += stride;
502			}
503		✗	}
504
505		✗	static int decode_dct(RangeCoder *c, DCTBlockCoder *bc, int *block,
506			int bx, int by)
507			{
508		✗	int skip, val, sign, pos = 1, zz_pos, dc;
509		✗	int blk_pos = bx + by * bc->prev_dc_stride;
510
511		✗	memset(block, 0, sizeof(*block) * 64);
512
513		✗	dc = decode_coeff(c, &bc->dc_model);
514		✗	if (by) {
515		✗	if (bx) {
516			int l, tl, t;
517
518		✗	l = bc->prev_dc[blk_pos - 1];
519		✗	tl = bc->prev_dc[blk_pos - 1 - bc->prev_dc_stride];
520		✗	t = bc->prev_dc[blk_pos - bc->prev_dc_stride];
521
522		✗	if (FFABS(t - tl) <= FFABS(l - tl))
523		✗	dc += l;
524			else
525		✗	dc += t;
526			} else {
527		✗	dc += bc->prev_dc[blk_pos - bc->prev_dc_stride];
528			}
529		✗	} else if (bx) {
530		✗	dc += bc->prev_dc[bx - 1];
531			}
532		✗	bc->prev_dc[blk_pos] = dc;
533		✗	block[0] = dc * bc->qmat[0];
534
535		✗	while (pos < 64) {
536		✗	val = rac_get_model256_sym(c, &bc->ac_model);
537		✗	if (!val)
538		✗	return 0;
539		✗	if (val == 0xF0) {
540		✗	pos += 16;
541		✗	continue;
542			}
543		✗	skip = val >> 4;
544		✗	val = val & 0xF;
545		✗	if (!val)
546		✗	return -1;
547		✗	pos += skip;
548		✗	if (pos >= 64)
549		✗	return -1;
550
551		✗	sign = rac_get_model2_sym(c, &bc->sign_model);
552		✗	if (val > 1) {
553		✗	val--;
554		✗	val = (1 << val) + rac_get_bits(c, val);
555			}
556		✗	if (!sign)
557		✗	val = -val;
558
559		✗	zz_pos = ff_zigzag_direct[pos];
560		✗	block[zz_pos] = val * bc->qmat[zz_pos];
561		✗	pos++;
562			}
563
564		✗	return pos == 64 ? 0 : -1;
565			}
566
567		✗	static void decode_dct_block(RangeCoder *c, DCTBlockCoder *bc,
568			uint8_t *dst, ptrdiff_t stride, int block_size,
569			int *block, int mb_x, int mb_y)
570			{
571			int i, j;
572			int bx, by;
573		✗	int nblocks = block_size >> 3;
574
575		✗	bx = mb_x * nblocks;
576		✗	by = mb_y * nblocks;
577
578		✗	for (j = 0; j < nblocks; j++) {
579		✗	for (i = 0; i < nblocks; i++) {
580		✗	if (decode_dct(c, bc, block, bx + i, by + j)) {
581		✗	c->got_error = 1;
582		✗	return;
583			}
584		✗	ff_mss34_dct_put(dst + i * 8, stride, block);
585			}
586		✗	dst += 8 * stride;
587			}
588			}
589
590		✗	static void decode_haar_block(RangeCoder *c, HaarBlockCoder *hc,
591			uint8_t *dst, ptrdiff_t stride,
592			int block_size, int *block)
593			{
594		✗	const int hsize = block_size >> 1;
595			int A, B, C, D, t1, t2, t3, t4;
596			int i, j;
597
598		✗	for (j = 0; j < block_size; j++) {
599		✗	for (i = 0; i < block_size; i++) {
600		✗	if (i < hsize && j < hsize)
601		✗	block[i] = rac_get_model256_sym(c, &hc->coef_model);
602			else
603		✗	block[i] = decode_coeff(c, &hc->coef_hi_model);
604		✗	block[i] *= hc->scale;
605			}
606		✗	block += block_size;
607			}
608		✗	block -= block_size * block_size;
609
610		✗	for (j = 0; j < hsize; j++) {
611		✗	for (i = 0; i < hsize; i++) {
612		✗	A = block[i];
613		✗	B = block[i + hsize];
614		✗	C = block[i + hsize * block_size];
615		✗	D = block[i + hsize * block_size + hsize];
616
617		✗	t1 = A - B;
618		✗	t2 = C - D;
619		✗	t3 = A + B;
620		✗	t4 = C + D;
621		✗	dst[i * 2] = av_clip_uint8(t1 - t2);
622		✗	dst[i * 2 + stride] = av_clip_uint8(t1 + t2);
623		✗	dst[i * 2 + 1] = av_clip_uint8(t3 - t4);
624		✗	dst[i * 2 + 1 + stride] = av_clip_uint8(t3 + t4);
625			}
626		✗	block += block_size;
627		✗	dst += stride * 2;
628			}
629		✗	}
630
631		✗	static void reset_coders(MSS3Context *ctx, int quality)
632			{
633			int i, j;
634
635		✗	for (i = 0; i < 3; i++) {
636		✗	ctx->btype[i].last_type = SKIP_BLOCK;
637		✗	for (j = 0; j < 5; j++)
638		✗	model_reset(&ctx->btype[i].bt_model[j]);
639		✗	ctx->fill_coder[i].fill_val = 0;
640		✗	model_reset(&ctx->fill_coder[i].coef_model);
641		✗	model256_reset(&ctx->image_coder[i].esc_model);
642		✗	model256_reset(&ctx->image_coder[i].vec_entry_model);
643		✗	model_reset(&ctx->image_coder[i].vec_size_model);
644		✗	for (j = 0; j < 125; j++)
645		✗	model_reset(&ctx->image_coder[i].vq_model[j]);
646		✗	if (ctx->dct_coder[i].quality != quality) {
647		✗	ctx->dct_coder[i].quality = quality;
648		✗	ff_mss34_gen_quant_mat(ctx->dct_coder[i].qmat, quality, !i);
649			}
650		✗	memset(ctx->dct_coder[i].prev_dc, 0,
651			sizeof(*ctx->dct_coder[i].prev_dc) *
652		✗	ctx->dct_coder[i].prev_dc_stride *
653		✗	ctx->dct_coder[i].prev_dc_height);
654		✗	model_reset(&ctx->dct_coder[i].dc_model);
655		✗	model2_reset(&ctx->dct_coder[i].sign_model);
656		✗	model256_reset(&ctx->dct_coder[i].ac_model);
657		✗	if (ctx->haar_coder[i].quality != quality) {
658		✗	ctx->haar_coder[i].quality = quality;
659		✗	ctx->haar_coder[i].scale = 17 - 7 * quality / 50;
660			}
661		✗	model_reset(&ctx->haar_coder[i].coef_hi_model);
662		✗	model256_reset(&ctx->haar_coder[i].coef_model);
663			}
664		✗	}
665
666		✗	static av_cold void init_coders(MSS3Context *ctx)
667			{
668			int i, j;
669
670		✗	for (i = 0; i < 3; i++) {
671		✗	for (j = 0; j < 5; j++)
672		✗	model_init(&ctx->btype[i].bt_model[j], 5);
673		✗	model_init(&ctx->fill_coder[i].coef_model, 12);
674		✗	model256_init(&ctx->image_coder[i].esc_model);
675		✗	model256_init(&ctx->image_coder[i].vec_entry_model);
676		✗	model_init(&ctx->image_coder[i].vec_size_model, 3);
677		✗	for (j = 0; j < 125; j++)
678		✗	model_init(&ctx->image_coder[i].vq_model[j], 5);
679		✗	model_init(&ctx->dct_coder[i].dc_model, 12);
680		✗	model256_init(&ctx->dct_coder[i].ac_model);
681		✗	model_init(&ctx->haar_coder[i].coef_hi_model, 12);
682		✗	model256_init(&ctx->haar_coder[i].coef_model);
683			}
684		✗	}
685
686		✗	static int mss3_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
687			int *got_frame, AVPacket *avpkt)
688			{
689		✗	const uint8_t *buf = avpkt->data;
690		✗	int buf_size = avpkt->size;
691		✗	MSS3Context *c = avctx->priv_data;
692		✗	RangeCoder *acoder = &c->coder;
693			GetByteContext gb;
694			uint8_t *dst[3];
695			int dec_width, dec_height, dec_x, dec_y, quality, keyframe;
696			int x, y, i, mb_width, mb_height, blk_size, btype;
697			int ret;
698
699		✗	if (buf_size < HEADER_SIZE) {
700		✗	av_log(avctx, AV_LOG_ERROR,
701			"Frame should have at least %d bytes, got %d instead\n",
702			HEADER_SIZE, buf_size);
703		✗	return AVERROR_INVALIDDATA;
704			}
705
706		✗	bytestream2_init(&gb, buf, buf_size);
707		✗	keyframe = bytestream2_get_be32(&gb);
708		✗	if (keyframe & ~0x301) {
709		✗	av_log(avctx, AV_LOG_ERROR, "Invalid frame type %X\n", keyframe);
710		✗	return AVERROR_INVALIDDATA;
711			}
712		✗	keyframe = !(keyframe & 1);
713		✗	bytestream2_skip(&gb, 6);
714		✗	dec_x = bytestream2_get_be16(&gb);
715		✗	dec_y = bytestream2_get_be16(&gb);
716		✗	dec_width = bytestream2_get_be16(&gb);
717		✗	dec_height = bytestream2_get_be16(&gb);
718
719		✗	if (dec_x + dec_width > avctx->width ||
720		✗	dec_y + dec_height > avctx->height ||
721		✗	(dec_width | dec_height) & 0xF) {
722		✗	av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d +%d,%d\n",
723			dec_width, dec_height, dec_x, dec_y);
724		✗	return AVERROR_INVALIDDATA;
725			}
726		✗	bytestream2_skip(&gb, 4);
727		✗	quality = bytestream2_get_byte(&gb);
728		✗	if (quality < 1 || quality > 100) {
729		✗	av_log(avctx, AV_LOG_ERROR, "Invalid quality setting %d\n", quality);
730		✗	return AVERROR_INVALIDDATA;
731			}
732		✗	bytestream2_skip(&gb, 4);
733
734		✗	if (keyframe && !bytestream2_get_bytes_left(&gb)) {
735		✗	av_log(avctx, AV_LOG_ERROR, "Keyframe without data found\n");
736		✗	return AVERROR_INVALIDDATA;
737			}
738		✗	if (!keyframe && c->got_error)
739		✗	return buf_size;
740		✗	c->got_error = 0;
741
742		✗	if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)
743		✗	return ret;
744		✗	if (keyframe)
745		✗	c->pic->flags |= AV_FRAME_FLAG_KEY;
746			else
747		✗	c->pic->flags &= ~AV_FRAME_FLAG_KEY;
748		✗	c->pic->pict_type = keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
749		✗	if (!bytestream2_get_bytes_left(&gb)) {
750		✗	if ((ret = av_frame_ref(rframe, c->pic)) < 0)
751		✗	return ret;
752		✗	*got_frame = 1;
753
754		✗	return buf_size;
755			}
756
757		✗	reset_coders(c, quality);
758
759		✗	rac_init(acoder, buf + HEADER_SIZE, buf_size - HEADER_SIZE);
760
761		✗	mb_width = dec_width >> 4;
762		✗	mb_height = dec_height >> 4;
763		✗	dst[0] = c->pic->data[0] + dec_x + dec_y * c->pic->linesize[0];
764		✗	dst[1] = c->pic->data[1] + dec_x / 2 + (dec_y / 2) * c->pic->linesize[1];
765		✗	dst[2] = c->pic->data[2] + dec_x / 2 + (dec_y / 2) * c->pic->linesize[2];
766		✗	for (y = 0; y < mb_height; y++) {
767		✗	for (x = 0; x < mb_width; x++) {
768		✗	for (i = 0; i < 3; i++) {
769		✗	blk_size = 8 << !i;
770
771		✗	btype = decode_block_type(acoder, c->btype + i);
772		✗	switch (btype) {
773		✗	case FILL_BLOCK:
774		✗	decode_fill_block(acoder, c->fill_coder + i,
775		✗	dst[i] + x * blk_size,
776		✗	c->pic->linesize[i], blk_size);
777		✗	break;
778		✗	case IMAGE_BLOCK:
779		✗	decode_image_block(acoder, c->image_coder + i,
780		✗	dst[i] + x * blk_size,
781		✗	c->pic->linesize[i], blk_size);
782		✗	break;
783		✗	case DCT_BLOCK:
784		✗	decode_dct_block(acoder, c->dct_coder + i,
785		✗	dst[i] + x * blk_size,
786		✗	c->pic->linesize[i], blk_size,
787		✗	c->dctblock, x, y);
788		✗	break;
789		✗	case HAAR_BLOCK:
790		✗	decode_haar_block(acoder, c->haar_coder + i,
791		✗	dst[i] + x * blk_size,
792		✗	c->pic->linesize[i], blk_size,
793		✗	c->hblock);
794		✗	break;
795			}
796		✗	if (c->got_error || acoder->got_error) {
797		✗	av_log(avctx, AV_LOG_ERROR, "Error decoding block %d,%d\n",
798			x, y);
799		✗	c->got_error = 1;
800		✗	return AVERROR_INVALIDDATA;
801			}
802			}
803			}
804		✗	dst[0] += c->pic->linesize[0] * 16;
805		✗	dst[1] += c->pic->linesize[1] * 8;
806		✗	dst[2] += c->pic->linesize[2] * 8;
807			}
808
809		✗	if ((ret = av_frame_ref(rframe, c->pic)) < 0)
810		✗	return ret;
811
812		✗	*got_frame = 1;
813
814		✗	return buf_size;
815			}
816
817		✗	static av_cold int mss3_decode_end(AVCodecContext *avctx)
818			{
819		✗	MSS3Context * const c = avctx->priv_data;
820			int i;
821
822		✗	av_frame_free(&c->pic);
823		✗	for (i = 0; i < 3; i++)
824		✗	av_freep(&c->dct_coder[i].prev_dc);
825
826		✗	return 0;
827			}
828
829		✗	static av_cold int mss3_decode_init(AVCodecContext *avctx)
830			{
831		✗	MSS3Context * const c = avctx->priv_data;
832			int i;
833
834		✗	c->avctx = avctx;
835
836		✗	if ((avctx->width & 0xF) || (avctx->height & 0xF)) {
837		✗	av_log(avctx, AV_LOG_ERROR,
838			"Image dimensions should be a multiple of 16.\n");
839		✗	return AVERROR_INVALIDDATA;
840			}
841
842		✗	c->got_error = 0;
843		✗	for (i = 0; i < 3; i++) {
844		✗	int b_width = avctx->width >> (2 + !!i);
845		✗	int b_height = avctx->height >> (2 + !!i);
846		✗	c->dct_coder[i].prev_dc_stride = b_width;
847		✗	c->dct_coder[i].prev_dc_height = b_height;
848		✗	c->dct_coder[i].prev_dc = av_malloc(sizeof(*c->dct_coder[i].prev_dc) *
849		✗	b_width * b_height);
850		✗	if (!c->dct_coder[i].prev_dc) {
851		✗	av_log(avctx, AV_LOG_ERROR, "Cannot allocate buffer\n");
852		✗	return AVERROR(ENOMEM);
853			}
854			}
855
856		✗	c->pic = av_frame_alloc();
857		✗	if (!c->pic)
858		✗	return AVERROR(ENOMEM);
859
860		✗	avctx->pix_fmt = AV_PIX_FMT_YUV420P;
861
862		✗	init_coders(c);
863
864		✗	return 0;
865			}
866
867			const FFCodec ff_msa1_decoder = {
868			.p.name = "msa1",
869			CODEC_LONG_NAME("MS ATC Screen"),
870			.p.type = AVMEDIA_TYPE_VIDEO,
871			.p.id = AV_CODEC_ID_MSA1,
872			.priv_data_size = sizeof(MSS3Context),
873			.init = mss3_decode_init,
874			.close = mss3_decode_end,
875			FF_CODEC_DECODE_CB(mss3_decode_frame),
876			.p.capabilities = AV_CODEC_CAP_DR1,
877			.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
878			};
879