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1 /*
2  * Copyright (c) 2012 Konstantin Shishkov
3  *
4  * This file is part of FFmpeg.
5  *
6  * FFmpeg is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2.1 of the License, or (at your option) any later version.
10  *
11  * FFmpeg is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with FFmpeg; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19  */
20 
21 /**
22  * @file
23  * Common functions for Microsoft Screen 1 and 2
24  */
25 
26 #include <inttypes.h>
27 
28 #include "libavutil/intfloat.h"
29 #include "libavutil/intreadwrite.h"
30 #include "avcodec.h"
31 #include "mss12.h"
32 
33 enum SplitMode {
34     SPLIT_VERT = 0,
35     SPLIT_HOR,
36     SPLIT_NONE
37 };
38 
39 static const int sec_order_sizes[4] = { 1, 7, 6, 1 };
40 
41 enum ContextDirection {
42     TOP_LEFT = 0,
43     TOP,
44     TOP_RIGHT,
45     LEFT
46 };
47 
model_calc_threshold(Model * m)48 static int model_calc_threshold(Model *m)
49 {
50     int thr;
51 
52     thr = 2 * m->weights[m->num_syms] - 1;
53     thr = ((thr >> 1) + 4 * m->cum_prob[0]) / thr;
54 
55     return FFMIN(thr, 0x3FFF);
56 }
57 
model_reset(Model * m)58 static void model_reset(Model *m)
59 {
60     int i;
61 
62     for (i = 0; i <= m->num_syms; i++) {
63         m->weights[i]  = 1;
64         m->cum_prob[i] = m->num_syms - i;
65     }
66     m->weights[0] = 0;
67     for (i = 0; i < m->num_syms; i++)
68         m->idx2sym[i + 1] = i;
69 }
70 
model_init(Model * m,int num_syms,int thr_weight)71 static av_cold void model_init(Model *m, int num_syms, int thr_weight)
72 {
73     m->num_syms   = num_syms;
74     m->thr_weight = thr_weight;
75     m->threshold  = num_syms * thr_weight;
76 }
77 
model_rescale_weights(Model * m)78 static void model_rescale_weights(Model *m)
79 {
80     int i;
81     int cum_prob;
82 
83     if (m->thr_weight == THRESH_ADAPTIVE)
84         m->threshold = model_calc_threshold(m);
85     while (m->cum_prob[0] > m->threshold) {
86         cum_prob = 0;
87         for (i = m->num_syms; i >= 0; i--) {
88             m->cum_prob[i] = cum_prob;
89             m->weights[i]  = (m->weights[i] + 1) >> 1;
90             cum_prob      += m->weights[i];
91         }
92     }
93 }
94 
ff_mss12_model_update(Model * m,int val)95 void ff_mss12_model_update(Model *m, int val)
96 {
97     int i;
98 
99     if (m->weights[val] == m->weights[val - 1]) {
100         for (i = val; m->weights[i - 1] == m->weights[val]; i--);
101         if (i != val) {
102             int sym1, sym2;
103 
104             sym1 = m->idx2sym[val];
105             sym2 = m->idx2sym[i];
106 
107             m->idx2sym[val]  = sym2;
108             m->idx2sym[i]    = sym1;
109 
110             val = i;
111         }
112     }
113     m->weights[val]++;
114     for (i = val - 1; i >= 0; i--)
115         m->cum_prob[i]++;
116     model_rescale_weights(m);
117 }
118 
pixctx_reset(PixContext * ctx)119 static void pixctx_reset(PixContext *ctx)
120 {
121     int i, j;
122 
123     if (!ctx->special_initial_cache)
124         for (i = 0; i < ctx->cache_size; i++)
125             ctx->cache[i] = i;
126     else {
127         ctx->cache[0] = 1;
128         ctx->cache[1] = 2;
129         ctx->cache[2] = 4;
130     }
131 
132     model_reset(&ctx->cache_model);
133     model_reset(&ctx->full_model);
134 
135     for (i = 0; i < 15; i++)
136         for (j = 0; j < 4; j++)
137             model_reset(&ctx->sec_models[i][j]);
138 }
139 
pixctx_init(PixContext * ctx,int cache_size,int full_model_syms,int special_initial_cache)140 static av_cold void pixctx_init(PixContext *ctx, int cache_size,
141                                 int full_model_syms, int special_initial_cache)
142 {
143     int i, j, k, idx;
144 
145     ctx->cache_size            = cache_size + 4;
146     ctx->num_syms              = cache_size;
147     ctx->special_initial_cache = special_initial_cache;
148 
149     model_init(&ctx->cache_model, ctx->num_syms + 1, THRESH_LOW);
150     model_init(&ctx->full_model, full_model_syms, THRESH_HIGH);
151 
152     for (i = 0, idx = 0; i < 4; i++)
153         for (j = 0; j < sec_order_sizes[i]; j++, idx++)
154             for (k = 0; k < 4; k++)
155                 model_init(&ctx->sec_models[idx][k], 2 + i,
156                            i ? THRESH_LOW : THRESH_ADAPTIVE);
157 }
158 
decode_pixel(ArithCoder * acoder,PixContext * pctx,uint8_t * ngb,int num_ngb,int any_ngb)159 static av_always_inline int decode_pixel(ArithCoder *acoder, PixContext *pctx,
160                                          uint8_t *ngb, int num_ngb, int any_ngb)
161 {
162     int i, val, pix;
163 
164     if (acoder->overread > MAX_OVERREAD)
165         return AVERROR_INVALIDDATA;
166     val = acoder->get_model_sym(acoder, &pctx->cache_model);
167     if (val < pctx->num_syms) {
168         if (any_ngb) {
169             int idx, j;
170 
171             idx = 0;
172             for (i = 0; i < pctx->cache_size; i++) {
173                 for (j = 0; j < num_ngb; j++)
174                     if (pctx->cache[i] == ngb[j])
175                         break;
176                 if (j == num_ngb) {
177                     if (idx == val)
178                         break;
179                     idx++;
180                 }
181             }
182             val = FFMIN(i, pctx->cache_size - 1);
183         }
184         pix = pctx->cache[val];
185     } else {
186         pix = acoder->get_model_sym(acoder, &pctx->full_model);
187         for (i = 0; i < pctx->cache_size - 1; i++)
188             if (pctx->cache[i] == pix)
189                 break;
190         val = i;
191     }
192     if (val) {
193         for (i = val; i > 0; i--)
194             pctx->cache[i] = pctx->cache[i - 1];
195         pctx->cache[0] = pix;
196     }
197 
198     return pix;
199 }
200 
decode_pixel_in_context(ArithCoder * acoder,PixContext * pctx,uint8_t * src,ptrdiff_t stride,int x,int y,int has_right)201 static int decode_pixel_in_context(ArithCoder *acoder, PixContext *pctx,
202                                    uint8_t *src, ptrdiff_t stride, int x, int y,
203                                    int has_right)
204 {
205     uint8_t neighbours[4];
206     uint8_t ref_pix[4];
207     int nlen;
208     int layer = 0, sub;
209     int pix;
210     int i, j;
211 
212     if (!y) {
213         memset(neighbours, src[-1], 4);
214     } else {
215         neighbours[TOP] = src[-stride];
216         if (!x) {
217             neighbours[TOP_LEFT] = neighbours[LEFT] = neighbours[TOP];
218         } else {
219             neighbours[TOP_LEFT] = src[-stride - 1];
220             neighbours[    LEFT] = src[-1];
221         }
222         if (has_right)
223             neighbours[TOP_RIGHT] = src[-stride + 1];
224         else
225             neighbours[TOP_RIGHT] = neighbours[TOP];
226     }
227 
228     sub = 0;
229     if (x >= 2 && src[-2] == neighbours[LEFT])
230         sub  = 1;
231     if (y >= 2 && src[-2 * stride] == neighbours[TOP])
232         sub |= 2;
233 
234     nlen = 1;
235     ref_pix[0] = neighbours[0];
236     for (i = 1; i < 4; i++) {
237         for (j = 0; j < nlen; j++)
238             if (ref_pix[j] == neighbours[i])
239                 break;
240         if (j == nlen)
241             ref_pix[nlen++] = neighbours[i];
242     }
243 
244     switch (nlen) {
245     case 1:
246         layer = 0;
247         break;
248     case 2:
249         if (neighbours[TOP] == neighbours[TOP_LEFT]) {
250             if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT])
251                 layer = 1;
252             else if (neighbours[LEFT] == neighbours[TOP_LEFT])
253                 layer = 2;
254             else
255                 layer = 3;
256         } else if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT]) {
257             if (neighbours[LEFT] == neighbours[TOP_LEFT])
258                 layer = 4;
259             else
260                 layer = 5;
261         } else if (neighbours[LEFT] == neighbours[TOP_LEFT]) {
262             layer = 6;
263         } else {
264             layer = 7;
265         }
266         break;
267     case 3:
268         if (neighbours[TOP] == neighbours[TOP_LEFT])
269             layer = 8;
270         else if (neighbours[TOP_RIGHT] == neighbours[TOP_LEFT])
271             layer = 9;
272         else if (neighbours[LEFT] == neighbours[TOP_LEFT])
273             layer = 10;
274         else if (neighbours[TOP_RIGHT] == neighbours[TOP])
275             layer = 11;
276         else if (neighbours[TOP] == neighbours[LEFT])
277             layer = 12;
278         else
279             layer = 13;
280         break;
281     case 4:
282         layer = 14;
283         break;
284     }
285 
286     pix = acoder->get_model_sym(acoder,
287                                 &pctx->sec_models[layer][sub]);
288     if (pix < nlen)
289         return ref_pix[pix];
290     else
291         return decode_pixel(acoder, pctx, ref_pix, nlen, 1);
292 }
293 
decode_region(ArithCoder * acoder,uint8_t * dst,uint8_t * rgb_dst,int x,int y,int width,int height,ptrdiff_t stride,ptrdiff_t rgb_stride,PixContext * pctx,const uint32_t * pal)294 static int decode_region(ArithCoder *acoder, uint8_t *dst, uint8_t *rgb_dst,
295                          int x, int y, int width, int height, ptrdiff_t stride,
296                          ptrdiff_t rgb_stride, PixContext *pctx,
297                          const uint32_t *pal)
298 {
299     int i, j, p;
300 
301     rgb_stride = rgb_dst ? rgb_stride : 0;
302     rgb_dst    = rgb_dst ? rgb_dst + x * 3 + y * rgb_stride : NULL;
303     dst += x + y * stride;
304 
305     for (j = 0; j < height; j++) {
306         for (i = 0; i < width; i++) {
307             if (!i && !j)
308                 p = decode_pixel(acoder, pctx, NULL, 0, 0);
309             else
310                 p = decode_pixel_in_context(acoder, pctx, dst + i, stride,
311                                             i, j, width - i - 1);
312             if (p < 0)
313                 return p;
314             dst[i] = p;
315 
316             if (rgb_dst)
317                 AV_WB24(rgb_dst + i * 3, pal[p]);
318         }
319         dst     += stride;
320         rgb_dst  = FF_PTR_ADD(rgb_dst, rgb_stride);
321     }
322 
323     return 0;
324 }
325 
copy_rectangles(MSS12Context const * c,int x,int y,int width,int height)326 static void copy_rectangles(MSS12Context const *c,
327                             int x, int y, int width, int height)
328 {
329     int j;
330 
331     if (c->last_rgb_pic)
332         for (j = y; j < y + height; j++) {
333             memcpy(c->rgb_pic      + j * c->rgb_stride + x * 3,
334                    c->last_rgb_pic + j * c->rgb_stride + x * 3,
335                    width * 3);
336             memcpy(c->pal_pic      + j * c->pal_stride + x,
337                    c->last_pal_pic + j * c->pal_stride + x,
338                    width);
339         }
340 }
341 
motion_compensation(MSS12Context const * c,int x,int y,int width,int height)342 static int motion_compensation(MSS12Context const *c,
343                                int x, int y, int width, int height)
344 {
345     if (x + c->mvX < 0 || x + c->mvX + width  > c->avctx->width  ||
346         y + c->mvY < 0 || y + c->mvY + height > c->avctx->height ||
347         !c->rgb_pic)
348         return -1;
349     else {
350         uint8_t *dst     = c->pal_pic + x     + y * c->pal_stride;
351         uint8_t *rgb_dst = c->rgb_pic + x * 3 + y * c->rgb_stride;
352         uint8_t *src;
353         uint8_t *rgb_src;
354         int j;
355         x += c->mvX;
356         y += c->mvY;
357         if (c->last_rgb_pic) {
358             src     = c->last_pal_pic + x +     y * c->pal_stride;
359             rgb_src = c->last_rgb_pic + x * 3 + y * c->rgb_stride;
360         } else {
361             src     = c->pal_pic + x     + y * c->pal_stride;
362             rgb_src = c->rgb_pic + x * 3 + y * c->rgb_stride;
363         }
364         for (j = 0; j < height; j++) {
365             memmove(dst, src, width);
366             memmove(rgb_dst, rgb_src, width * 3);
367             dst     += c->pal_stride;
368             src     += c->pal_stride;
369             rgb_dst += c->rgb_stride;
370             rgb_src += c->rgb_stride;
371         }
372     }
373     return 0;
374 }
375 
decode_region_masked(MSS12Context const * c,ArithCoder * acoder,uint8_t * dst,ptrdiff_t stride,uint8_t * mask,ptrdiff_t mask_stride,int x,int y,int width,int height,PixContext * pctx)376 static int decode_region_masked(MSS12Context const *c, ArithCoder *acoder,
377                                 uint8_t *dst, ptrdiff_t stride, uint8_t *mask,
378                                 ptrdiff_t mask_stride, int x, int y,
379                                 int width, int height,
380                                 PixContext *pctx)
381 {
382     int i, j, p;
383     uint8_t *rgb_dst = c->rgb_pic + x * 3 + y * c->rgb_stride;
384 
385     dst  += x + y * stride;
386     mask += x + y * mask_stride;
387 
388     for (j = 0; j < height; j++) {
389         for (i = 0; i < width; i++) {
390             if (c->avctx->err_recognition & AV_EF_EXPLODE &&
391                 ( c->rgb_pic && mask[i] != 0x01 && mask[i] != 0x02 && mask[i] != 0x04 ||
392                  !c->rgb_pic && mask[i] != 0x80 && mask[i] != 0xFF))
393                 return -1;
394 
395             if (mask[i] == 0x02) {
396                 copy_rectangles(c, x + i, y + j, 1, 1);
397             } else if (mask[i] == 0x04) {
398                 if (motion_compensation(c, x + i, y + j, 1, 1))
399                     return -1;
400             } else if (mask[i] != 0x80) {
401                 if (!i && !j)
402                     p = decode_pixel(acoder, pctx, NULL, 0, 0);
403                 else
404                     p = decode_pixel_in_context(acoder, pctx, dst + i, stride,
405                                                 i, j, width - i - 1);
406                 if (p < 0)
407                     return p;
408                 dst[i] = p;
409                 if (c->rgb_pic)
410                     AV_WB24(rgb_dst + i * 3, c->pal[p]);
411             }
412         }
413         dst     += stride;
414         mask    += mask_stride;
415         rgb_dst += c->rgb_stride;
416     }
417 
418     return 0;
419 }
420 
slicecontext_init(SliceContext * sc,int version,int full_model_syms)421 static av_cold void slicecontext_init(SliceContext *sc,
422                                       int version, int full_model_syms)
423 {
424     model_init(&sc->intra_region, 2, THRESH_ADAPTIVE);
425     model_init(&sc->inter_region, 2, THRESH_ADAPTIVE);
426     model_init(&sc->split_mode,   3, THRESH_HIGH);
427     model_init(&sc->edge_mode,    2, THRESH_HIGH);
428     model_init(&sc->pivot,        3, THRESH_LOW);
429 
430     pixctx_init(&sc->intra_pix_ctx, 8, full_model_syms, 0);
431 
432     pixctx_init(&sc->inter_pix_ctx, version ? 3 : 2,
433                 full_model_syms, version ? 1 : 0);
434 }
435 
ff_mss12_slicecontext_reset(SliceContext * sc)436 void ff_mss12_slicecontext_reset(SliceContext *sc)
437 {
438     model_reset(&sc->intra_region);
439     model_reset(&sc->inter_region);
440     model_reset(&sc->split_mode);
441     model_reset(&sc->edge_mode);
442     model_reset(&sc->pivot);
443     pixctx_reset(&sc->intra_pix_ctx);
444     pixctx_reset(&sc->inter_pix_ctx);
445 }
446 
decode_pivot(SliceContext * sc,ArithCoder * acoder,int base)447 static int decode_pivot(SliceContext *sc, ArithCoder *acoder, int base)
448 {
449     int val, inv;
450 
451     inv = acoder->get_model_sym(acoder, &sc->edge_mode);
452     val = acoder->get_model_sym(acoder, &sc->pivot) + 1;
453 
454     if (val > 2) {
455         if ((base + 1) / 2 - 2 <= 0)
456             return -1;
457 
458         val = acoder->get_number(acoder, (base + 1) / 2 - 2) + 3;
459     }
460 
461     if ((unsigned)val >= base)
462         return -1;
463 
464     return inv ? base - val : val;
465 }
466 
decode_region_intra(SliceContext * sc,ArithCoder * acoder,int x,int y,int width,int height)467 static int decode_region_intra(SliceContext *sc, ArithCoder *acoder,
468                                int x, int y, int width, int height)
469 {
470     MSS12Context const *c = sc->c;
471     int mode;
472 
473     mode = acoder->get_model_sym(acoder, &sc->intra_region);
474 
475     if (!mode) {
476         int i, j, pix, rgb_pix;
477         ptrdiff_t stride     = c->pal_stride;
478         ptrdiff_t rgb_stride = c->rgb_stride;
479         uint8_t *dst     = c->pal_pic + x     + y * stride;
480         uint8_t *rgb_dst = c->rgb_pic ? c->rgb_pic + x * 3 + y * rgb_stride : NULL;
481 
482         pix     = decode_pixel(acoder, &sc->intra_pix_ctx, NULL, 0, 0);
483         if (pix < 0)
484             return pix;
485         rgb_pix = c->pal[pix];
486         for (i = 0; i < height; i++, dst += stride) {
487             memset(dst, pix, width);
488             if (rgb_dst) {
489                 for (j = 0; j < width * 3; j += 3)
490                     AV_WB24(rgb_dst + j, rgb_pix);
491                 rgb_dst += rgb_stride;
492             }
493         }
494     } else {
495         return decode_region(acoder, c->pal_pic, c->rgb_pic,
496                              x, y, width, height, c->pal_stride, c->rgb_stride,
497                              &sc->intra_pix_ctx, &c->pal[0]);
498     }
499 
500     return 0;
501 }
502 
decode_region_inter(SliceContext * sc,ArithCoder * acoder,int x,int y,int width,int height)503 static int decode_region_inter(SliceContext *sc, ArithCoder *acoder,
504                                int x, int y, int width, int height)
505 {
506     MSS12Context const *c = sc->c;
507     int mode;
508 
509     mode = acoder->get_model_sym(acoder, &sc->inter_region);
510 
511     if (!mode) {
512         mode = decode_pixel(acoder, &sc->inter_pix_ctx, NULL, 0, 0);
513         if (mode < 0)
514             return mode;
515 
516         if (c->avctx->err_recognition & AV_EF_EXPLODE &&
517             ( c->rgb_pic && mode != 0x01 && mode != 0x02 && mode != 0x04 ||
518              !c->rgb_pic && mode != 0x80 && mode != 0xFF))
519             return -1;
520 
521         if (mode == 0x02)
522             copy_rectangles(c, x, y, width, height);
523         else if (mode == 0x04)
524             return motion_compensation(c, x, y, width, height);
525         else if (mode != 0x80)
526             return decode_region_intra(sc, acoder, x, y, width, height);
527     } else {
528         if (decode_region(acoder, c->mask, NULL,
529                           x, y, width, height, c->mask_stride, 0,
530                           &sc->inter_pix_ctx, &c->pal[0]) < 0)
531             return -1;
532         return decode_region_masked(c, acoder, c->pal_pic,
533                                     c->pal_stride, c->mask,
534                                     c->mask_stride,
535                                     x, y, width, height,
536                                     &sc->intra_pix_ctx);
537     }
538 
539     return 0;
540 }
541 
ff_mss12_decode_rect(SliceContext * sc,ArithCoder * acoder,int x,int y,int width,int height)542 int ff_mss12_decode_rect(SliceContext *sc, ArithCoder *acoder,
543                          int x, int y, int width, int height)
544 {
545     int mode, pivot;
546     if (acoder->overread > MAX_OVERREAD)
547         return AVERROR_INVALIDDATA;
548 
549     mode = acoder->get_model_sym(acoder, &sc->split_mode);
550 
551     switch (mode) {
552     case SPLIT_VERT:
553         if ((pivot = decode_pivot(sc, acoder, height)) < 1)
554             return -1;
555         if (ff_mss12_decode_rect(sc, acoder, x, y, width, pivot))
556             return -1;
557         if (ff_mss12_decode_rect(sc, acoder, x, y + pivot, width, height - pivot))
558             return -1;
559         break;
560     case SPLIT_HOR:
561         if ((pivot = decode_pivot(sc, acoder, width)) < 1)
562             return -1;
563         if (ff_mss12_decode_rect(sc, acoder, x, y, pivot, height))
564             return -1;
565         if (ff_mss12_decode_rect(sc, acoder, x + pivot, y, width - pivot, height))
566             return -1;
567         break;
568     case SPLIT_NONE:
569         if (sc->c->keyframe)
570             return decode_region_intra(sc, acoder, x, y, width, height);
571         else
572             return decode_region_inter(sc, acoder, x, y, width, height);
573     default:
574         return -1;
575     }
576 
577     return 0;
578 }
579 
ff_mss12_decode_init(MSS12Context * c,int version,SliceContext * sc1,SliceContext * sc2)580 av_cold int ff_mss12_decode_init(MSS12Context *c, int version,
581                                  SliceContext* sc1, SliceContext *sc2)
582 {
583     AVCodecContext *avctx = c->avctx;
584     int i;
585 
586     if (avctx->extradata_size < 52 + 256 * 3) {
587         av_log(avctx, AV_LOG_ERROR, "Insufficient extradata size %d\n",
588                avctx->extradata_size);
589         return AVERROR_INVALIDDATA;
590     }
591 
592     if (AV_RB32(avctx->extradata) < avctx->extradata_size) {
593         av_log(avctx, AV_LOG_ERROR,
594                "Insufficient extradata size: expected %"PRIu32" got %d\n",
595                AV_RB32(avctx->extradata),
596                avctx->extradata_size);
597         return AVERROR_INVALIDDATA;
598     }
599 
600     avctx->coded_width  = FFMAX(AV_RB32(avctx->extradata + 20), avctx->width);
601     avctx->coded_height = FFMAX(AV_RB32(avctx->extradata + 24), avctx->height);
602     if (avctx->coded_width > 4096 || avctx->coded_height > 4096) {
603         av_log(avctx, AV_LOG_ERROR, "Frame dimensions %dx%d too large",
604                avctx->coded_width, avctx->coded_height);
605         return AVERROR_INVALIDDATA;
606     }
607     if (avctx->coded_width < 1 || avctx->coded_height < 1) {
608         av_log(avctx, AV_LOG_ERROR, "Frame dimensions %dx%d too small",
609                avctx->coded_width, avctx->coded_height);
610         return AVERROR_INVALIDDATA;
611     }
612 
613     av_log(avctx, AV_LOG_DEBUG, "Encoder version %"PRIu32".%"PRIu32"\n",
614            AV_RB32(avctx->extradata + 4), AV_RB32(avctx->extradata + 8));
615     if (version != AV_RB32(avctx->extradata + 4) > 1) {
616         av_log(avctx, AV_LOG_ERROR,
617                "Header version doesn't match codec tag\n");
618         return -1;
619     }
620 
621     c->free_colours = AV_RB32(avctx->extradata + 48);
622     if ((unsigned)c->free_colours > 256) {
623         av_log(avctx, AV_LOG_ERROR,
624                "Incorrect number of changeable palette entries: %d\n",
625                c->free_colours);
626         return AVERROR_INVALIDDATA;
627     }
628     av_log(avctx, AV_LOG_DEBUG, "%d free colour(s)\n", c->free_colours);
629 
630     av_log(avctx, AV_LOG_DEBUG, "Display dimensions %"PRIu32"x%"PRIu32"\n",
631            AV_RB32(avctx->extradata + 12), AV_RB32(avctx->extradata + 16));
632     av_log(avctx, AV_LOG_DEBUG, "Coded dimensions %dx%d\n",
633            avctx->coded_width, avctx->coded_height);
634     av_log(avctx, AV_LOG_DEBUG, "%g frames per second\n",
635            av_int2float(AV_RB32(avctx->extradata + 28)));
636     av_log(avctx, AV_LOG_DEBUG, "Bitrate %"PRIu32" bps\n",
637            AV_RB32(avctx->extradata + 32));
638     av_log(avctx, AV_LOG_DEBUG, "Max. lead time %g ms\n",
639            av_int2float(AV_RB32(avctx->extradata + 36)));
640     av_log(avctx, AV_LOG_DEBUG, "Max. lag time %g ms\n",
641            av_int2float(AV_RB32(avctx->extradata + 40)));
642     av_log(avctx, AV_LOG_DEBUG, "Max. seek time %g ms\n",
643            av_int2float(AV_RB32(avctx->extradata + 44)));
644 
645     if (version) {
646         if (avctx->extradata_size < 60 + 256 * 3) {
647             av_log(avctx, AV_LOG_ERROR,
648                    "Insufficient extradata size %d for v2\n",
649                    avctx->extradata_size);
650             return AVERROR_INVALIDDATA;
651         }
652 
653         c->slice_split = AV_RB32(avctx->extradata + 52);
654         av_log(avctx, AV_LOG_DEBUG, "Slice split %d\n", c->slice_split);
655 
656         c->full_model_syms = AV_RB32(avctx->extradata + 56);
657         if (c->full_model_syms < 2 || c->full_model_syms > 256) {
658             av_log(avctx, AV_LOG_ERROR,
659                    "Incorrect number of used colours %d\n",
660                    c->full_model_syms);
661             return AVERROR_INVALIDDATA;
662         }
663         av_log(avctx, AV_LOG_DEBUG, "Used colours %d\n",
664                c->full_model_syms);
665     } else {
666         c->slice_split     = 0;
667         c->full_model_syms = 256;
668     }
669 
670     for (i = 0; i < 256; i++)
671         c->pal[i] = 0xFFU << 24 | AV_RB24(avctx->extradata + 52 +
672                             (version ? 8 : 0) + i * 3);
673 
674     c->mask_stride = FFALIGN(avctx->width, 16);
675     c->mask        = av_malloc_array(c->mask_stride, avctx->height);
676     if (!c->mask) {
677         av_log(avctx, AV_LOG_ERROR, "Cannot allocate mask plane\n");
678         return AVERROR(ENOMEM);
679     }
680 
681     sc1->c = c;
682     slicecontext_init(sc1, version, c->full_model_syms);
683     if (c->slice_split) {
684         sc2->c = c;
685         slicecontext_init(sc2, version, c->full_model_syms);
686     }
687     c->corrupted = 1;
688 
689     return 0;
690 }
691 
ff_mss12_decode_end(MSS12Context * c)692 av_cold int ff_mss12_decode_end(MSS12Context *c)
693 {
694     av_freep(&c->mask);
695 
696     return 0;
697 }
698