FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/mss4.c
Date: 2022-07-05 19:52:29
Exec Total Coverage
Lines: 270 298 90.6%
Branches: 159 186 85.5%

Line Branch Exec Source
1 /*
2 * Microsoft Screen 4 (aka Microsoft Expression Encoder 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 4 (aka Microsoft Titanium Screen 2,
25 * aka Microsoft Expression Encoder Screen) decoder
26 */
27
28 #include "libavutil/thread.h"
29
30 #include "avcodec.h"
31 #include "bytestream.h"
32 #include "codec_internal.h"
33 #include "get_bits.h"
34 #include "internal.h"
35 #include "jpegtables.h"
36 #include "mss34dsp.h"
37 #include "unary.h"
38
39 #define HEADER_SIZE 8
40
41 enum FrameType {
42 INTRA_FRAME = 0,
43 INTER_FRAME,
44 SKIP_FRAME
45 };
46
47 enum BlockType {
48 SKIP_BLOCK = 0,
49 DCT_BLOCK,
50 IMAGE_BLOCK,
51 };
52
53 enum CachePos {
54 LEFT = 0,
55 TOP_LEFT,
56 TOP,
57 };
58
59 static const uint8_t mss4_dc_vlc_lens[2][16] = {
60 { 0, 1, 5, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0 },
61 { 0, 3, 1, 1, 1, 1, 1, 1, 1, 2, 0, 0, 0, 0, 0, 0 }
62 };
63
64 static const uint8_t vec_len_syms[2][4] = {
65 { 4, 2, 3, 1 },
66 { 4, 1, 2, 3 }
67 };
68
69 static const uint8_t mss4_vec_entry_vlc_lens[2][16] = {
70 { 0, 2, 2, 3, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
71 { 0, 1, 5, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
72 };
73
74 static const uint8_t mss4_vec_entry_vlc_syms[2][9] = {
75 { 0, 7, 6, 5, 8, 4, 3, 1, 2 },
76 { 0, 2, 3, 4, 5, 6, 7, 1, 8 }
77 };
78
79 #define MAX_ENTRIES 162
80
81 typedef struct MSS4Context {
82 AVFrame *pic;
83
84 int block[64];
85 uint8_t imgbuf[3][16 * 16];
86
87 int quality;
88 uint16_t quant_mat[2][64];
89
90 int *prev_dc[3];
91 ptrdiff_t dc_stride[3];
92 int dc_cache[4][4];
93
94 int prev_vec[3][4];
95 } MSS4Context;
96
97 static VLC dc_vlc[2], ac_vlc[2];
98 static VLC vec_entry_vlc[2];
99
100 12 static av_cold void mss4_init_vlc(VLC *vlc, unsigned *offset,
101 const uint8_t *lens, const uint8_t *syms)
102 {
103 static VLCElem vlc_buf[2146];
104 uint8_t bits[MAX_ENTRIES];
105 int i, j;
106 12 int idx = 0;
107
108
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204 for (i = 0; i < 16; i++) {
109
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924 for (j = 0; j < lens[i]; j++) {
110 732 bits[idx] = i + 1;
111 732 idx++;
112 }
113 }
114
115 12 vlc->table = &vlc_buf[*offset];
116 12 vlc->table_allocated = FF_ARRAY_ELEMS(vlc_buf) - *offset;
117 12 ff_init_vlc_from_lengths(vlc, FFMIN(bits[idx - 1], 9), idx,
118 bits, 1, syms, 1, 1,
119 0, INIT_VLC_STATIC_OVERLONG, NULL);
120 12 *offset += vlc->table_size;
121 12 }
122
123 2 static av_cold void mss4_init_vlcs(void)
124 {
125
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6 for (unsigned i = 0, offset = 0; i < 2; i++) {
126 4 mss4_init_vlc(&dc_vlc[i], &offset, mss4_dc_vlc_lens[i], NULL);
127
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4 mss4_init_vlc(&ac_vlc[i], &offset,
128 i ? ff_mjpeg_bits_ac_chrominance + 1
129 : ff_mjpeg_bits_ac_luminance + 1,
130 i ? ff_mjpeg_val_ac_chrominance
131 : ff_mjpeg_val_ac_luminance);
132 4 mss4_init_vlc(&vec_entry_vlc[i], &offset, mss4_vec_entry_vlc_lens[i],
133 4 mss4_vec_entry_vlc_syms[i]);
134 }
135 2 }
136
137 /* This function returns values in the range
138 * (-range + 1; -range/2] U [range/2; range - 1)
139 * i.e.
140 * nbits = 0 -> 0
141 * nbits = 1 -> -1, 1
142 * nbits = 2 -> -3, -2, 2, 3
143 */
144 315916 static av_always_inline int get_coeff_bits(GetBitContext *gb, int nbits)
145 {
146 int val;
147
148
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315916 if (!nbits)
149 133329 return 0;
150
151 182587 val = get_bits(gb, nbits);
152
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182587 if (val < (1 << (nbits - 1)))
153 98069 val -= (1 << nbits) - 1;
154
155 182587 return val;
156 }
157
158 180586 static inline int get_coeff(GetBitContext *gb, VLC *vlc)
159 {
160 180586 int val = get_vlc2(gb, vlc->table, vlc->bits, 2);
161
162 180586 return get_coeff_bits(gb, val);
163 }
164
165 85284 static int mss4_decode_dct(GetBitContext *gb, VLC *dc_vlc, VLC *ac_vlc,
166 int *block, int *dc_cache,
167 int bx, int by, uint16_t *quant_mat)
168 {
169 85284 int skip, val, pos = 1, zz_pos, dc;
170
171 85284 memset(block, 0, sizeof(*block) * 64);
172
173 85284 dc = get_coeff(gb, dc_vlc);
174 // DC prediction is the same as in MSS3
175
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85284 if (by) {
176
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84904 if (bx) {
177 int l, tl, t;
178
179 83868 l = dc_cache[LEFT];
180 83868 tl = dc_cache[TOP_LEFT];
181 83868 t = dc_cache[TOP];
182
183
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83868 if (FFABS(t - tl) <= FFABS(l - tl))
184 80876 dc += l;
185 else
186 2992 dc += t;
187 } else {
188 1036 dc += dc_cache[TOP];
189 }
190
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380 } else if (bx) {
191 380 dc += dc_cache[LEFT];
192 }
193 85284 dc_cache[LEFT] = dc;
194 85284 block[0] = dc * quant_mat[0];
195
196
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220682 while (pos < 64) {
197 219785 val = get_vlc2(gb, ac_vlc->table, 9, 2);
198
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219785 if (!val)
199 84387 return 0;
200
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135398 if (val == -1)
201 return -1;
202
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135398 if (val == 0xF0) {
203 68 pos += 16;
204 68 continue;
205 }
206 135330 skip = val >> 4;
207 135330 val = get_coeff_bits(gb, val & 0xF);
208 135330 pos += skip;
209
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135330 if (pos >= 64)
210 return -1;
211
212 135330 zz_pos = ff_zigzag_direct[pos];
213 135330 block[zz_pos] = val * quant_mat[zz_pos];
214 135330 pos++;
215 }
216
217
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897 return pos == 64 ? 0 : -1;
218 }
219
220 14214 static int mss4_decode_dct_block(MSS4Context *c, GetBitContext *gb,
221 uint8_t *dst[3], int mb_x, int mb_y)
222 {
223 int i, j, k, ret;
224 14214 uint8_t *out = dst[0];
225
226
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42642 for (j = 0; j < 2; j++) {
227
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85284 for (i = 0; i < 2; i++) {
228 56856 int xpos = mb_x * 2 + i;
229 56856 c->dc_cache[j][TOP_LEFT] = c->dc_cache[j][TOP];
230 56856 c->dc_cache[j][TOP] = c->prev_dc[0][mb_x * 2 + i];
231 56856 ret = mss4_decode_dct(gb, &dc_vlc[0], &ac_vlc[0], c->block,
232 56856 c->dc_cache[j],
233 56856 xpos, mb_y * 2 + j, c->quant_mat[0]);
234
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56856 if (ret)
235 return ret;
236 56856 c->prev_dc[0][mb_x * 2 + i] = c->dc_cache[j][LEFT];
237
238 56856 ff_mss34_dct_put(out + xpos * 8, c->pic->linesize[0],
239 56856 c->block);
240 }
241 28428 out += 8 * c->pic->linesize[0];
242 }
243
244
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42642 for (i = 1; i < 3; i++) {
245 28428 c->dc_cache[i + 1][TOP_LEFT] = c->dc_cache[i + 1][TOP];
246 28428 c->dc_cache[i + 1][TOP] = c->prev_dc[i][mb_x];
247 28428 ret = mss4_decode_dct(gb, &dc_vlc[1], &ac_vlc[1],
248 28428 c->block, c->dc_cache[i + 1], mb_x, mb_y,
249 28428 c->quant_mat[1]);
250
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28428 if (ret)
251 return ret;
252 28428 c->prev_dc[i][mb_x] = c->dc_cache[i + 1][LEFT];
253
254 28428 ff_mss34_dct_put(c->imgbuf[i], 8, c->block);
255 28428 out = dst[i] + mb_x * 16;
256 // Since the DCT block is coded as YUV420 and the whole frame as YUV444,
257 // we need to scale chroma.
258
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483276 for (j = 0; j < 16; j++) {
259
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4093632 for (k = 0; k < 8; k++)
260 3638784 AV_WN16A(out + k * 2, c->imgbuf[i][k + (j & ~1) * 4] * 0x101);
261 454848 out += c->pic->linesize[i];
262 }
263 }
264
265 14214 return 0;
266 }
267
268 281245 static void read_vec_pos(GetBitContext *gb, int *vec_pos, int *sel_flag,
269 int *sel_len, int *prev)
270 {
271 281245 int i, y_flag = 0;
272
273
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1124980 for (i = 2; i >= 0; i--) {
274
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843735 if (!sel_flag[i]) {
275 192630 vec_pos[i] = 0;
276 192630 continue;
277 }
278
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651105 if ((!i && !y_flag) || get_bits1(gb)) {
279
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554066 if (sel_len[i] > 0) {
280 549560 int pval = prev[i];
281 549560 vec_pos[i] = get_bits(gb, sel_len[i]);
282
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549560 if (vec_pos[i] >= pval)
283 297455 vec_pos[i]++;
284 } else {
285 4506 vec_pos[i] = !prev[i];
286 }
287 554066 y_flag = 1;
288 } else {
289 97039 vec_pos[i] = prev[i];
290 }
291 }
292 281245 }
293
294 8739072 static int get_value_cached(GetBitContext *gb, int vec_pos, uint8_t *vec,
295 int vec_size, int component, int shift, int *prev)
296 {
297
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8739072 if (vec_pos < vec_size)
298 8442194 return vec[vec_pos];
299
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296878 if (!get_bits1(gb))
300 46525 return prev[component];
301 250353 prev[component] = get_bits(gb, 8 - shift) << shift;
302 250353 return prev[component];
303 }
304
305 #define MKVAL(vals) ((vals)[0] | ((vals)[1] << 3) | ((vals)[2] << 6))
306
307 /* Image mode - the hardest to comprehend MSS4 coding mode.
308 *
309 * In this mode all three 16x16 blocks are coded together with a method
310 * remotely similar to the methods employed in MSS1-MSS3.
311 * The idea is that every component has a vector of 1-4 most common symbols
312 * and an escape mode for reading new value from the bitstream. Decoding
313 * consists of retrieving pixel values from the vector or reading new ones
314 * from the bitstream; depending on flags read from the bitstream, these vector
315 * positions can be updated or reused from the state of the previous line
316 * or previous pixel.
317 */
318 11379 static int mss4_decode_image_block(MSS4Context *ctx, GetBitContext *gb,
319 uint8_t *picdst[3], int mb_x, int mb_y)
320 {
321 uint8_t vec[3][4];
322 int vec_len[3];
323 int sel_len[3], sel_flag[3];
324 int i, j, k, mode, split;
325 11379 int prev_vec1 = 0, prev_split = 0;
326 11379 int vals[3] = { 0 };
327 11379 int prev_pix[3] = { 0 };
328 11379 int prev_mode[16] = { 0 };
329 uint8_t *dst[3];
330
331
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11379 const int val_shift = ctx->quality == 100 ? 0 : 2;
332
333
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45516 for (i = 0; i < 3; i++)
334 34137 dst[i] = ctx->imgbuf[i];
335
336
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45516 for (i = 0; i < 3; i++) {
337 34137 vec_len[i] = vec_len_syms[!!i][get_unary(gb, 0, 3)];
338
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129439 for (j = 0; j < vec_len[i]; j++) {
339 95302 vec[i][j] = get_coeff(gb, &vec_entry_vlc[!!i]);
340 95302 vec[i][j] += ctx->prev_vec[i][j];
341 95302 ctx->prev_vec[i][j] = vec[i][j];
342 }
343 34137 sel_flag[i] = vec_len[i] > 1;
344 34137 sel_len[i] = vec_len[i] > 2 ? vec_len[i] - 2 : 0;
345 }
346
347
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193443 for (j = 0; j < 16; j++) {
348
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182064 if (get_bits1(gb)) {
349 56004 split = 0;
350
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56004 if (get_bits1(gb)) {
351 35860 prev_mode[0] = 0;
352 35860 vals[0] = vals[1] = vals[2] = 0;
353 35860 mode = 2;
354 } else {
355 20144 mode = get_bits1(gb);
356
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20144 if (mode)
357 3817 split = get_bits(gb, 4);
358 }
359
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952068 for (i = 0; i < 16; i++) {
360
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896064 if (mode <= 1) {
361 322304 vals[0] = prev_mode[i] & 7;
362 322304 vals[1] = (prev_mode[i] >> 3) & 7;
363 322304 vals[2] = prev_mode[i] >> 6;
364
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322304 if (mode == 1 && i == split) {
365 3817 read_vec_pos(gb, vals, sel_flag, sel_len, vals);
366 }
367
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573760 } else if (mode == 2) {
368
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573760 if (get_bits1(gb))
369 261389 read_vec_pos(gb, vals, sel_flag, sel_len, vals);
370 }
371
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3584256 for (k = 0; k < 3; k++)
372 2688192 *dst[k]++ = get_value_cached(gb, vals[k], vec[k],
373 vec_len[k], k,
374 val_shift, prev_pix);
375 896064 prev_mode[i] = MKVAL(vals);
376 }
377 } else {
378
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126060 if (get_bits1(gb)) {
379 21425 split = get_bits(gb, 4);
380
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21425 if (split >= prev_split)
381 15525 split++;
382 21425 prev_split = split;
383 } else {
384 104635 split = prev_split;
385 }
386
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126060 if (split) {
387 109261 vals[0] = prev_mode[0] & 7;
388 109261 vals[1] = (prev_mode[0] >> 3) & 7;
389 109261 vals[2] = prev_mode[0] >> 6;
390
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437044 for (i = 0; i < 3; i++) {
391
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5442705 for (k = 0; k < split; k++) {
392 5114922 *dst[i]++ = get_value_cached(gb, vals[i], vec[i],
393 vec_len[i], i, val_shift,
394 prev_pix);
395 5114922 prev_mode[k] = MKVAL(vals);
396 }
397 }
398 }
399
400
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126060 if (split != 16) {
401 22314 vals[0] = prev_vec1 & 7;
402 22314 vals[1] = (prev_vec1 >> 3) & 7;
403 22314 vals[2] = prev_vec1 >> 6;
404
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22314 if (get_bits1(gb)) {
405 16039 read_vec_pos(gb, vals, sel_flag, sel_len, vals);
406 16039 prev_vec1 = MKVAL(vals);
407 }
408
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89256 for (i = 0; i < 3; i++) {
409
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1002900 for (k = 0; k < 16 - split; k++) {
410 935958 *dst[i]++ = get_value_cached(gb, vals[i], vec[i],
411 vec_len[i], i, val_shift,
412 prev_pix);
413 935958 prev_mode[split + k] = MKVAL(vals);
414 }
415 }
416 }
417 }
418 }
419
420
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45516 for (i = 0; i < 3; i++)
421
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580329 for (j = 0; j < 16; j++)
422 546192 memcpy(picdst[i] + mb_x * 16 + j * ctx->pic->linesize[i],
423 546192 ctx->imgbuf[i] + j * 16, 16);
424
425 11379 return 0;
426 }
427
428 175050 static inline void mss4_update_dc_cache(MSS4Context *c, int mb_x)
429 {
430 int i;
431
432 175050 c->dc_cache[0][TOP] = c->prev_dc[0][mb_x * 2 + 1];
433 175050 c->dc_cache[0][LEFT] = 0;
434 175050 c->dc_cache[1][TOP] = 0;
435 175050 c->dc_cache[1][LEFT] = 0;
436
437
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525150 for (i = 0; i < 2; i++)
438 350100 c->prev_dc[0][mb_x * 2 + i] = 0;
439
440
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525150 for (i = 1; i < 3; i++) {
441 350100 c->dc_cache[i + 1][TOP] = c->prev_dc[i][mb_x];
442 350100 c->dc_cache[i + 1][LEFT] = 0;
443 350100 c->prev_dc[i][mb_x] = 0;
444 }
445 175050 }
446
447 145 static int mss4_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
448 int *got_frame, AVPacket *avpkt)
449 {
450 145 const uint8_t *buf = avpkt->data;
451 145 int buf_size = avpkt->size;
452 145 MSS4Context *c = avctx->priv_data;
453 GetBitContext gb;
454 GetByteContext bc;
455 uint8_t *dst[3];
456 int width, height, quality, frame_type;
457 int x, y, i, mb_width, mb_height, blk_type;
458 int ret;
459
460
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145 if (buf_size < HEADER_SIZE) {
461 av_log(avctx, AV_LOG_ERROR,
462 "Frame should have at least %d bytes, got %d instead\n",
463 HEADER_SIZE, buf_size);
464 return AVERROR_INVALIDDATA;
465 }
466
467 145 bytestream2_init(&bc, buf, buf_size);
468 145 width = bytestream2_get_be16(&bc);
469 145 height = bytestream2_get_be16(&bc);
470 145 bytestream2_skip(&bc, 2);
471 145 quality = bytestream2_get_byte(&bc);
472 145 frame_type = bytestream2_get_byte(&bc);
473
474
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145 if (width > avctx->width ||
475
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145 height != avctx->height) {
476 av_log(avctx, AV_LOG_ERROR, "Invalid frame dimensions %dx%d\n",
477 width, height);
478 return AVERROR_INVALIDDATA;
479 }
480
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145 if (quality < 1 || quality > 100) {
481 av_log(avctx, AV_LOG_ERROR, "Invalid quality setting %d\n", quality);
482 return AVERROR_INVALIDDATA;
483 }
484
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145 if ((frame_type & ~3) || frame_type == 3) {
485 av_log(avctx, AV_LOG_ERROR, "Invalid frame type %d\n", frame_type);
486 return AVERROR_INVALIDDATA;
487 }
488
489
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145 if (frame_type != SKIP_FRAME && !bytestream2_get_bytes_left(&bc)) {
490 av_log(avctx, AV_LOG_ERROR,
491 "Empty frame found but it is not a skip frame.\n");
492 return AVERROR_INVALIDDATA;
493 }
494 145 mb_width = FFALIGN(width, 16) >> 4;
495 145 mb_height = FFALIGN(height, 16) >> 4;
496
497
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145 if (frame_type != SKIP_FRAME && 8*buf_size < 8*HEADER_SIZE + mb_width*mb_height)
498 return AVERROR_INVALIDDATA;
499
500
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145 if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)
501 return ret;
502 145 c->pic->key_frame = (frame_type == INTRA_FRAME);
503 145 c->pic->pict_type = (frame_type == INTRA_FRAME) ? AV_PICTURE_TYPE_I
504
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145 : AV_PICTURE_TYPE_P;
505
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145 if (frame_type == SKIP_FRAME) {
506 98 *got_frame = 1;
507
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98 if ((ret = av_frame_ref(rframe, c->pic)) < 0)
508 return ret;
509
510 98 return buf_size;
511 }
512
513
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47 if (c->quality != quality) {
514 2 c->quality = quality;
515
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6 for (i = 0; i < 2; i++)
516 4 ff_mss34_gen_quant_mat(c->quant_mat[i], quality, !i);
517 }
518
519
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47 if ((ret = init_get_bits8(&gb, buf + HEADER_SIZE, buf_size - HEADER_SIZE)) < 0)
520 return ret;
521 47 dst[0] = c->pic->data[0];
522 47 dst[1] = c->pic->data[1];
523 47 dst[2] = c->pic->data[2];
524
525 47 memset(c->prev_vec, 0, sizeof(c->prev_vec));
526
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2519 for (y = 0; y < mb_height; y++) {
527 2472 memset(c->dc_cache, 0, sizeof(c->dc_cache));
528
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191736 for (x = 0; x < mb_width; x++) {
529 189264 blk_type = decode012(&gb);
530
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189264 switch (blk_type) {
531 14214 case DCT_BLOCK:
532
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14214 if (mss4_decode_dct_block(c, &gb, dst, x, y) < 0) {
533 av_log(avctx, AV_LOG_ERROR,
534 "Error decoding DCT block %d,%d\n",
535 x, y);
536 return AVERROR_INVALIDDATA;
537 }
538 14214 break;
539 11379 case IMAGE_BLOCK:
540
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11379 if (mss4_decode_image_block(c, &gb, dst, x, y) < 0) {
541 av_log(avctx, AV_LOG_ERROR,
542 "Error decoding VQ block %d,%d\n",
543 x, y);
544 return AVERROR_INVALIDDATA;
545 }
546 11379 break;
547 163671 case SKIP_BLOCK:
548
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163671 if (frame_type == INTRA_FRAME) {
549 av_log(avctx, AV_LOG_ERROR, "Skip block in intra frame\n");
550 return AVERROR_INVALIDDATA;
551 }
552 163671 break;
553 }
554
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189264 if (blk_type != DCT_BLOCK)
555 175050 mss4_update_dc_cache(c, x);
556 }
557 2472 dst[0] += c->pic->linesize[0] * 16;
558 2472 dst[1] += c->pic->linesize[1] * 16;
559 2472 dst[2] += c->pic->linesize[2] * 16;
560 }
561
562
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47 if ((ret = av_frame_ref(rframe, c->pic)) < 0)
563 return ret;
564
565 47 *got_frame = 1;
566
567 47 return buf_size;
568 }
569
570 4 static av_cold int mss4_decode_end(AVCodecContext *avctx)
571 {
572 4 MSS4Context * const c = avctx->priv_data;
573 int i;
574
575 4 av_frame_free(&c->pic);
576
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16 for (i = 0; i < 3; i++)
577 12 av_freep(&c->prev_dc[i]);
578
579 4 return 0;
580 }
581
582 4 static av_cold int mss4_decode_init(AVCodecContext *avctx)
583 {
584 static AVOnce init_static_once = AV_ONCE_INIT;
585 4 MSS4Context * const c = avctx->priv_data;
586 int i;
587
588
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16 for (i = 0; i < 3; i++) {
589
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12 c->dc_stride[i] = FFALIGN(avctx->width, 16) >> (2 + !!i);
590 12 c->prev_dc[i] = av_malloc_array(c->dc_stride[i], sizeof(**c->prev_dc));
591
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12 if (!c->prev_dc[i]) {
592 av_log(avctx, AV_LOG_ERROR, "Cannot allocate buffer\n");
593 return AVERROR(ENOMEM);
594 }
595 }
596
597 4 c->pic = av_frame_alloc();
598
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4 if (!c->pic)
599 return AVERROR(ENOMEM);
600
601 4 avctx->pix_fmt = AV_PIX_FMT_YUV444P;
602
603 4 ff_thread_once(&init_static_once, mss4_init_vlcs);
604
605 4 return 0;
606 }
607
608 const FFCodec ff_mts2_decoder = {
609 .p.name = "mts2",
610 .p.long_name = NULL_IF_CONFIG_SMALL("MS Expression Encoder Screen"),
611 .p.type = AVMEDIA_TYPE_VIDEO,
612 .p.id = AV_CODEC_ID_MTS2,
613 .priv_data_size = sizeof(MSS4Context),
614 .init = mss4_decode_init,
615 .close = mss4_decode_end,
616 FF_CODEC_DECODE_CB(mss4_decode_frame),
617 .p.capabilities = AV_CODEC_CAP_DR1,
618 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
619 };
620