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1 /*
2  * Microsoft Screen 2 (aka Windows Media Video V9 Screen) decoder
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  * Microsoft Screen 2 (aka Windows Media Video V9 Screen) decoder
24  */
25 
26 #include "libavutil/avassert.h"
27 #include "codec_internal.h"
28 #include "error_resilience.h"
29 #include "internal.h"
30 #include "mpeg_er.h"
31 #include "mpegvideodec.h"
32 #include "msmpeg4dec.h"
33 #include "qpeldsp.h"
34 #include "vc1.h"
35 #include "wmv2data.h"
36 #include "mss12.h"
37 #include "mss2dsp.h"
38 
39 typedef struct MSS2Context {
40     VC1Context     v;
41     int            split_position;
42     AVFrame       *last_pic;
43     MSS12Context   c;
44     MSS2DSPContext dsp;
45     SliceContext   sc[2];
46 } MSS2Context;
47 
arith2_normalise(ArithCoder * c)48 static void arith2_normalise(ArithCoder *c)
49 {
50     while ((c->high >> 15) - (c->low >> 15) < 2) {
51         if ((c->low ^ c->high) & 0x10000) {
52             c->high  ^= 0x8000;
53             c->value ^= 0x8000;
54             c->low   ^= 0x8000;
55         }
56         c->high  = (uint16_t)c->high  << 8  | 0xFF;
57         c->value = (uint16_t)c->value << 8  | bytestream2_get_byte(c->gbc.gB);
58         c->low   = (uint16_t)c->low   << 8;
59     }
60 }
61 
ARITH_GET_BIT(arith2)62 ARITH_GET_BIT(arith2)
63 
64 /* L. Stuiver and A. Moffat: "Piecewise Integer Mapping for Arithmetic Coding."
65  * In Proc. 8th Data Compression Conference (DCC '98), pp. 3-12, Mar. 1998 */
66 
67 static int arith2_get_scaled_value(int value, int n, int range)
68 {
69     int split = (n << 1) - range;
70 
71     if (value > split)
72         return split + (value - split >> 1);
73     else
74         return value;
75 }
76 
arith2_rescale_interval(ArithCoder * c,int range,int low,int high,int n)77 static void arith2_rescale_interval(ArithCoder *c, int range,
78                                     int low, int high, int n)
79 {
80     int split = (n << 1) - range;
81 
82     if (high > split)
83         c->high = split + (high - split << 1);
84     else
85         c->high = high;
86 
87     c->high += c->low - 1;
88 
89     if (low > split)
90         c->low += split + (low - split << 1);
91     else
92         c->low += low;
93 }
94 
arith2_get_number(ArithCoder * c,int n)95 static int arith2_get_number(ArithCoder *c, int n)
96 {
97     int range = c->high - c->low + 1;
98     int scale = av_log2(range) - av_log2(n);
99     int val;
100 
101     if (n << scale > range)
102         scale--;
103 
104     n <<= scale;
105 
106     val = arith2_get_scaled_value(c->value - c->low, n, range) >> scale;
107 
108     arith2_rescale_interval(c, range, val << scale, (val + 1) << scale, n);
109 
110     arith2_normalise(c);
111 
112     return val;
113 }
114 
arith2_get_prob(ArithCoder * c,int16_t * probs)115 static int arith2_get_prob(ArithCoder *c, int16_t *probs)
116 {
117     int range = c->high - c->low + 1, n = *probs;
118     int scale = av_log2(range) - av_log2(n);
119     int i     = 0, val;
120 
121     if (n << scale > range)
122         scale--;
123 
124     n <<= scale;
125 
126     val = arith2_get_scaled_value(c->value - c->low, n, range) >> scale;
127     while (probs[++i] > val) ;
128 
129     arith2_rescale_interval(c, range,
130                             probs[i] << scale, probs[i - 1] << scale, n);
131 
132     return i;
133 }
134 
ARITH_GET_MODEL_SYM(arith2)135 ARITH_GET_MODEL_SYM(arith2)
136 
137 static int arith2_get_consumed_bytes(ArithCoder *c)
138 {
139     int diff = (c->high >> 16) - (c->low >> 16);
140     int bp   = bytestream2_tell(c->gbc.gB) - 3 << 3;
141     int bits = 1;
142 
143     while (!(diff & 0x80)) {
144         bits++;
145         diff <<= 1;
146     }
147 
148     return (bits + bp + 7 >> 3) + ((c->low >> 16) + 1 == c->high >> 16);
149 }
150 
arith2_init(ArithCoder * c,GetByteContext * gB)151 static void arith2_init(ArithCoder *c, GetByteContext *gB)
152 {
153     c->low           = 0;
154     c->high          = 0xFFFFFF;
155     c->value         = bytestream2_get_be24(gB);
156     c->overread      = 0;
157     c->gbc.gB        = gB;
158     c->get_model_sym = arith2_get_model_sym;
159     c->get_number    = arith2_get_number;
160 }
161 
decode_pal_v2(MSS12Context * ctx,const uint8_t * buf,int buf_size)162 static int decode_pal_v2(MSS12Context *ctx, const uint8_t *buf, int buf_size)
163 {
164     int i, ncol;
165     uint32_t *pal = ctx->pal + 256 - ctx->free_colours;
166 
167     if (!ctx->free_colours)
168         return 0;
169 
170     ncol = *buf++;
171     if (ncol > ctx->free_colours || buf_size < 2 + ncol * 3)
172         return AVERROR_INVALIDDATA;
173     for (i = 0; i < ncol; i++)
174         *pal++ = AV_RB24(buf + 3 * i);
175 
176     return 1 + ncol * 3;
177 }
178 
decode_555(AVCodecContext * avctx,GetByteContext * gB,uint16_t * dst,ptrdiff_t stride,int keyframe,int w,int h)179 static int decode_555(AVCodecContext *avctx, GetByteContext *gB, uint16_t *dst, ptrdiff_t stride,
180                       int keyframe, int w, int h)
181 {
182     int last_symbol = 0, repeat = 0, prev_avail = 0;
183 
184     if (!keyframe) {
185         int x, y, endx, endy, t;
186 
187 #define READ_PAIR(a, b)                 \
188     a  = bytestream2_get_byte(gB) << 4; \
189     t  = bytestream2_get_byte(gB);      \
190     a |= t >> 4;                        \
191     b  = (t & 0xF) << 8;                \
192     b |= bytestream2_get_byte(gB);      \
193 
194         READ_PAIR(x, endx)
195         READ_PAIR(y, endy)
196 
197         if (endx >= w || endy >= h || x > endx || y > endy)
198             return AVERROR_INVALIDDATA;
199         dst += x + stride * y;
200         w    = endx - x + 1;
201         h    = endy - y + 1;
202         if (y)
203             prev_avail = 1;
204     }
205 
206     do {
207         uint16_t *p = dst;
208         do {
209             if (repeat-- < 1) {
210                 int b = bytestream2_get_byte(gB);
211                 if (b < 128)
212                     last_symbol = b << 8 | bytestream2_get_byte(gB);
213                 else if (b > 129) {
214                     repeat = 0;
215                     while (b-- > 130) {
216                         if (repeat >= (INT_MAX >> 8) - 1) {
217                             av_log(avctx, AV_LOG_ERROR, "repeat overflow\n");
218                             return AVERROR_INVALIDDATA;
219                         }
220                         repeat = (repeat << 8) + bytestream2_get_byte(gB) + 1;
221                     }
222                     if (last_symbol == -2) {
223                         int skip = FFMIN((unsigned)repeat, dst + w - p);
224                         repeat -= skip;
225                         p      += skip;
226                     }
227                 } else
228                     last_symbol = 127 - b;
229             }
230             if (last_symbol >= 0)
231                 *p = last_symbol;
232             else if (last_symbol == -1 && prev_avail)
233                 *p = *(p - stride);
234         } while (++p < dst + w);
235         dst       += stride;
236         prev_avail = 1;
237     } while (--h);
238 
239     return 0;
240 }
241 
decode_rle(GetBitContext * gb,uint8_t * pal_dst,ptrdiff_t pal_stride,uint8_t * rgb_dst,ptrdiff_t rgb_stride,uint32_t * pal,int keyframe,int kf_slipt,int slice,int w,int h)242 static int decode_rle(GetBitContext *gb, uint8_t *pal_dst, ptrdiff_t pal_stride,
243                       uint8_t *rgb_dst, ptrdiff_t rgb_stride, uint32_t *pal,
244                       int keyframe, int kf_slipt, int slice, int w, int h)
245 {
246     uint8_t bits[270] = { 0 };
247     uint32_t codes[270];
248     VLC vlc;
249 
250     int current_length = 0, read_codes = 0, next_code = 0, current_codes = 0;
251     int remaining_codes, surplus_codes, i;
252 
253     const int alphabet_size = 270 - keyframe;
254 
255     int last_symbol = 0, repeat = 0, prev_avail = 0;
256 
257     if (!keyframe) {
258         int x, y, clipw, cliph;
259 
260         x     = get_bits(gb, 12);
261         y     = get_bits(gb, 12);
262         clipw = get_bits(gb, 12) + 1;
263         cliph = get_bits(gb, 12) + 1;
264 
265         if (x + clipw > w || y + cliph > h)
266             return AVERROR_INVALIDDATA;
267         pal_dst += pal_stride * y + x;
268         rgb_dst += rgb_stride * y + x * 3;
269         w        = clipw;
270         h        = cliph;
271         if (y)
272             prev_avail = 1;
273     } else {
274         if (slice > 0) {
275             pal_dst   += pal_stride * kf_slipt;
276             rgb_dst   += rgb_stride * kf_slipt;
277             prev_avail = 1;
278             h         -= kf_slipt;
279         } else
280             h = kf_slipt;
281     }
282 
283     /* read explicit codes */
284     do {
285         while (current_codes--) {
286             int symbol = get_bits(gb, 8);
287             if (symbol >= 204 - keyframe)
288                 symbol += 14 - keyframe;
289             else if (symbol > 189)
290                 symbol = get_bits1(gb) + (symbol << 1) - 190;
291             if (bits[symbol])
292                 return AVERROR_INVALIDDATA;
293             bits[symbol]  = current_length;
294             codes[symbol] = next_code++;
295             read_codes++;
296         }
297         current_length++;
298         next_code     <<= 1;
299         remaining_codes = (1 << current_length) - next_code;
300         current_codes   = get_bits(gb, av_ceil_log2(remaining_codes + 1));
301         if (current_length > 22 || current_codes > remaining_codes)
302             return AVERROR_INVALIDDATA;
303     } while (current_codes != remaining_codes);
304 
305     remaining_codes = alphabet_size - read_codes;
306 
307     /* determine the minimum length to fit the rest of the alphabet */
308     while ((surplus_codes = (2 << current_length) -
309                             (next_code << 1) - remaining_codes) < 0) {
310         current_length++;
311         next_code <<= 1;
312     }
313 
314     /* add the rest of the symbols lexicographically */
315     for (i = 0; i < alphabet_size; i++)
316         if (!bits[i]) {
317             if (surplus_codes-- == 0) {
318                 current_length++;
319                 next_code <<= 1;
320             }
321             bits[i]  = current_length;
322             codes[i] = next_code++;
323         }
324 
325     if (next_code != 1 << current_length)
326         return AVERROR_INVALIDDATA;
327 
328     if ((i = init_vlc(&vlc, 9, alphabet_size, bits, 1, 1, codes, 4, 4, 0)) < 0)
329         return i;
330 
331     /* frame decode */
332     do {
333         uint8_t *pp = pal_dst;
334         uint8_t *rp = rgb_dst;
335         do {
336             if (repeat-- < 1) {
337                 int b = get_vlc2(gb, vlc.table, 9, 3);
338                 if (b < 256)
339                     last_symbol = b;
340                 else if (b < 268) {
341                     b -= 256;
342                     if (b == 11)
343                         b = get_bits(gb, 4) + 10;
344 
345                     if (!b)
346                         repeat = 0;
347                     else
348                         repeat = get_bits(gb, b);
349 
350                     repeat += (1 << b) - 1;
351 
352                     if (last_symbol == -2) {
353                         int skip = FFMIN(repeat, pal_dst + w - pp);
354                         repeat -= skip;
355                         pp     += skip;
356                         rp     += skip * 3;
357                     }
358                 } else
359                     last_symbol = 267 - b;
360             }
361             if (last_symbol >= 0) {
362                 *pp = last_symbol;
363                 AV_WB24(rp, pal[last_symbol]);
364             } else if (last_symbol == -1 && prev_avail) {
365                 *pp = *(pp - pal_stride);
366                 memcpy(rp, rp - rgb_stride, 3);
367             }
368             rp += 3;
369         } while (++pp < pal_dst + w);
370         pal_dst   += pal_stride;
371         rgb_dst   += rgb_stride;
372         prev_avail = 1;
373     } while (--h);
374 
375     ff_free_vlc(&vlc);
376     return 0;
377 }
378 
decode_wmv9(AVCodecContext * avctx,const uint8_t * buf,int buf_size,int x,int y,int w,int h,int wmv9_mask)379 static int decode_wmv9(AVCodecContext *avctx, const uint8_t *buf, int buf_size,
380                        int x, int y, int w, int h, int wmv9_mask)
381 {
382     MSS2Context *ctx  = avctx->priv_data;
383     MSS12Context *c   = &ctx->c;
384     VC1Context *v     = avctx->priv_data;
385     MpegEncContext *s = &v->s;
386     AVFrame *f;
387     int ret;
388 
389     ff_mpeg_flush(avctx);
390 
391     if ((ret = init_get_bits8(&s->gb, buf, buf_size)) < 0)
392         return ret;
393 
394     s->loop_filter = avctx->skip_loop_filter < AVDISCARD_ALL;
395 
396     if (ff_vc1_parse_frame_header(v, &s->gb) < 0) {
397         av_log(v->s.avctx, AV_LOG_ERROR, "header error\n");
398         return AVERROR_INVALIDDATA;
399     }
400 
401     if (s->pict_type != AV_PICTURE_TYPE_I) {
402         av_log(v->s.avctx, AV_LOG_ERROR, "expected I-frame\n");
403         return AVERROR_INVALIDDATA;
404     }
405 
406     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
407 
408     if ((ret = ff_mpv_frame_start(s, avctx)) < 0) {
409         av_log(v->s.avctx, AV_LOG_ERROR, "ff_mpv_frame_start error\n");
410         avctx->pix_fmt = AV_PIX_FMT_RGB24;
411         return ret;
412     }
413 
414     ff_mpeg_er_frame_start(s);
415 
416     v->end_mb_x = (w + 15) >> 4;
417     s->end_mb_y = (h + 15) >> 4;
418     if (v->respic & 1)
419         v->end_mb_x = v->end_mb_x + 1 >> 1;
420     if (v->respic & 2)
421         s->end_mb_y = s->end_mb_y + 1 >> 1;
422 
423     ff_vc1_decode_blocks(v);
424 
425     if (v->end_mb_x == s->mb_width && s->end_mb_y == s->mb_height) {
426         ff_er_frame_end(&s->er);
427     } else {
428         av_log(v->s.avctx, AV_LOG_WARNING,
429                "disabling error correction due to block count mismatch %dx%d != %dx%d\n",
430                v->end_mb_x, s->end_mb_y, s->mb_width, s->mb_height);
431     }
432 
433     ff_mpv_frame_end(s);
434 
435     f = s->current_picture.f;
436 
437     if (v->respic == 3) {
438         ctx->dsp.upsample_plane(f->data[0], f->linesize[0], w,      h);
439         ctx->dsp.upsample_plane(f->data[1], f->linesize[1], w+1 >> 1, h+1 >> 1);
440         ctx->dsp.upsample_plane(f->data[2], f->linesize[2], w+1 >> 1, h+1 >> 1);
441     } else if (v->respic)
442         avpriv_request_sample(v->s.avctx,
443                               "Asymmetric WMV9 rectangle subsampling");
444 
445     av_assert0(f->linesize[1] == f->linesize[2]);
446 
447     if (wmv9_mask != -1)
448         ctx->dsp.mss2_blit_wmv9_masked(c->rgb_pic + y * c->rgb_stride + x * 3,
449                                        c->rgb_stride, wmv9_mask,
450                                        c->pal_pic + y * c->pal_stride + x,
451                                        c->pal_stride,
452                                        f->data[0], f->linesize[0],
453                                        f->data[1], f->data[2], f->linesize[1],
454                                        w, h);
455     else
456         ctx->dsp.mss2_blit_wmv9(c->rgb_pic + y * c->rgb_stride + x * 3,
457                                 c->rgb_stride,
458                                 f->data[0], f->linesize[0],
459                                 f->data[1], f->data[2], f->linesize[1],
460                                 w, h);
461 
462     avctx->pix_fmt = AV_PIX_FMT_RGB24;
463 
464     return 0;
465 }
466 
467 struct Rectangle {
468     int coded, x, y, w, h;
469 };
470 
471 #define MAX_WMV9_RECTANGLES 20
472 #define ARITH2_PADDING 2
473 
mss2_decode_frame(AVCodecContext * avctx,AVFrame * frame,int * got_frame,AVPacket * avpkt)474 static int mss2_decode_frame(AVCodecContext *avctx, AVFrame *frame,
475                              int *got_frame, AVPacket *avpkt)
476 {
477     const uint8_t *buf = avpkt->data;
478     int buf_size       = avpkt->size;
479     MSS2Context *ctx = avctx->priv_data;
480     MSS12Context *c  = &ctx->c;
481     GetBitContext gb;
482     GetByteContext gB;
483     ArithCoder acoder;
484 
485     int keyframe, has_wmv9, has_mv, is_rle, is_555, ret;
486 
487     struct Rectangle wmv9rects[MAX_WMV9_RECTANGLES], *r;
488     int used_rects = 0, i, implicit_rect = 0, av_uninit(wmv9_mask);
489 
490     if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
491         return ret;
492 
493     if (keyframe = get_bits1(&gb))
494         skip_bits(&gb, 7);
495     has_wmv9 = get_bits1(&gb);
496     has_mv   = keyframe ? 0 : get_bits1(&gb);
497     is_rle   = get_bits1(&gb);
498     is_555   = is_rle && get_bits1(&gb);
499     if (c->slice_split > 0)
500         ctx->split_position = c->slice_split;
501     else if (c->slice_split < 0) {
502         if (get_bits1(&gb)) {
503             if (get_bits1(&gb)) {
504                 if (get_bits1(&gb))
505                     ctx->split_position = get_bits(&gb, 16);
506                 else
507                     ctx->split_position = get_bits(&gb, 12);
508             } else
509                 ctx->split_position = get_bits(&gb, 8) << 4;
510         } else {
511             if (keyframe)
512                 ctx->split_position = avctx->height / 2;
513         }
514     } else
515         ctx->split_position = avctx->height;
516 
517     if (c->slice_split && (ctx->split_position < 1 - is_555 ||
518                            ctx->split_position > avctx->height - 1))
519         return AVERROR_INVALIDDATA;
520 
521     align_get_bits(&gb);
522     buf      += get_bits_count(&gb) >> 3;
523     buf_size -= get_bits_count(&gb) >> 3;
524 
525     if (buf_size < 1)
526         return AVERROR_INVALIDDATA;
527 
528     if (is_555 && (has_wmv9 || has_mv || c->slice_split && ctx->split_position))
529         return AVERROR_INVALIDDATA;
530 
531     avctx->pix_fmt = is_555 ? AV_PIX_FMT_RGB555 : AV_PIX_FMT_RGB24;
532     if (ctx->last_pic->format != avctx->pix_fmt)
533         av_frame_unref(ctx->last_pic);
534 
535     if (has_wmv9) {
536         bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
537         arith2_init(&acoder, &gB);
538 
539         implicit_rect = !arith2_get_bit(&acoder);
540 
541         while (arith2_get_bit(&acoder)) {
542             if (used_rects == MAX_WMV9_RECTANGLES)
543                 return AVERROR_INVALIDDATA;
544             r = &wmv9rects[used_rects];
545             if (!used_rects)
546                 r->x = arith2_get_number(&acoder, avctx->width);
547             else
548                 r->x = arith2_get_number(&acoder, avctx->width -
549                                          wmv9rects[used_rects - 1].x) +
550                        wmv9rects[used_rects - 1].x;
551             r->y = arith2_get_number(&acoder, avctx->height);
552             r->w = arith2_get_number(&acoder, avctx->width  - r->x) + 1;
553             r->h = arith2_get_number(&acoder, avctx->height - r->y) + 1;
554             used_rects++;
555         }
556 
557         if (implicit_rect && used_rects) {
558             av_log(avctx, AV_LOG_ERROR, "implicit_rect && used_rects > 0\n");
559             return AVERROR_INVALIDDATA;
560         }
561 
562         if (implicit_rect) {
563             wmv9rects[0].x = 0;
564             wmv9rects[0].y = 0;
565             wmv9rects[0].w = avctx->width;
566             wmv9rects[0].h = avctx->height;
567 
568             used_rects = 1;
569         }
570         for (i = 0; i < used_rects; i++) {
571             if (!implicit_rect && arith2_get_bit(&acoder)) {
572                 av_log(avctx, AV_LOG_ERROR, "Unexpected grandchildren\n");
573                 return AVERROR_INVALIDDATA;
574             }
575             if (!i) {
576                 wmv9_mask = arith2_get_bit(&acoder) - 1;
577                 if (!wmv9_mask)
578                     wmv9_mask = arith2_get_number(&acoder, 256);
579             }
580             wmv9rects[i].coded = arith2_get_number(&acoder, 2);
581         }
582 
583         buf      += arith2_get_consumed_bytes(&acoder);
584         buf_size -= arith2_get_consumed_bytes(&acoder);
585         if (buf_size < 1)
586             return AVERROR_INVALIDDATA;
587     }
588 
589     c->mvX = c->mvY = 0;
590     if (keyframe && !is_555) {
591         if ((i = decode_pal_v2(c, buf, buf_size)) < 0)
592             return AVERROR_INVALIDDATA;
593         buf      += i;
594         buf_size -= i;
595     } else if (has_mv) {
596         buf      += 4;
597         buf_size -= 4;
598         if (buf_size < 1)
599             return AVERROR_INVALIDDATA;
600         c->mvX = AV_RB16(buf - 4) - avctx->width;
601         c->mvY = AV_RB16(buf - 2) - avctx->height;
602     }
603 
604     if (c->mvX < 0 || c->mvY < 0) {
605         FFSWAP(uint8_t *, c->pal_pic, c->last_pal_pic);
606 
607         if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
608             return ret;
609 
610         if (ctx->last_pic->data[0]) {
611             av_assert0(frame->linesize[0] == ctx->last_pic->linesize[0]);
612             c->last_rgb_pic = ctx->last_pic->data[0] +
613                               ctx->last_pic->linesize[0] * (avctx->height - 1);
614         } else {
615             av_log(avctx, AV_LOG_ERROR, "Missing keyframe\n");
616             return AVERROR_INVALIDDATA;
617         }
618     } else {
619         if ((ret = ff_reget_buffer(avctx, ctx->last_pic, 0)) < 0)
620             return ret;
621         if ((ret = av_frame_ref(frame, ctx->last_pic)) < 0)
622             return ret;
623 
624         c->last_rgb_pic = NULL;
625     }
626     c->rgb_pic    = frame->data[0] +
627                     frame->linesize[0] * (avctx->height - 1);
628     c->rgb_stride = -frame->linesize[0];
629 
630     frame->key_frame = keyframe;
631     frame->pict_type = keyframe ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
632 
633     if (is_555) {
634         bytestream2_init(&gB, buf, buf_size);
635 
636         if (decode_555(avctx, &gB, (uint16_t *)c->rgb_pic, c->rgb_stride >> 1,
637                        keyframe, avctx->width, avctx->height))
638             return AVERROR_INVALIDDATA;
639 
640         buf_size -= bytestream2_tell(&gB);
641     } else {
642         if (keyframe) {
643             c->corrupted = 0;
644             ff_mss12_slicecontext_reset(&ctx->sc[0]);
645             if (c->slice_split)
646                 ff_mss12_slicecontext_reset(&ctx->sc[1]);
647         }
648         if (is_rle) {
649             if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
650                 return ret;
651             if (ret = decode_rle(&gb, c->pal_pic, c->pal_stride,
652                                  c->rgb_pic, c->rgb_stride, c->pal, keyframe,
653                                  ctx->split_position, 0,
654                                  avctx->width, avctx->height))
655                 return ret;
656             align_get_bits(&gb);
657 
658             if (c->slice_split)
659                 if (ret = decode_rle(&gb, c->pal_pic, c->pal_stride,
660                                      c->rgb_pic, c->rgb_stride, c->pal, keyframe,
661                                      ctx->split_position, 1,
662                                      avctx->width, avctx->height))
663                     return ret;
664 
665             align_get_bits(&gb);
666             buf      += get_bits_count(&gb) >> 3;
667             buf_size -= get_bits_count(&gb) >> 3;
668         } else if (!implicit_rect || wmv9_mask != -1) {
669             if (c->corrupted)
670                 return AVERROR_INVALIDDATA;
671             bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
672             arith2_init(&acoder, &gB);
673             c->keyframe = keyframe;
674             if (c->corrupted = ff_mss12_decode_rect(&ctx->sc[0], &acoder, 0, 0,
675                                                     avctx->width,
676                                                     ctx->split_position))
677                 return AVERROR_INVALIDDATA;
678 
679             buf      += arith2_get_consumed_bytes(&acoder);
680             buf_size -= arith2_get_consumed_bytes(&acoder);
681             if (c->slice_split) {
682                 if (buf_size < 1)
683                     return AVERROR_INVALIDDATA;
684                 bytestream2_init(&gB, buf, buf_size + ARITH2_PADDING);
685                 arith2_init(&acoder, &gB);
686                 if (c->corrupted = ff_mss12_decode_rect(&ctx->sc[1], &acoder, 0,
687                                                         ctx->split_position,
688                                                         avctx->width,
689                                                         avctx->height - ctx->split_position))
690                     return AVERROR_INVALIDDATA;
691 
692                 buf      += arith2_get_consumed_bytes(&acoder);
693                 buf_size -= arith2_get_consumed_bytes(&acoder);
694             }
695         } else
696             memset(c->pal_pic, 0, c->pal_stride * avctx->height);
697     }
698 
699     if (has_wmv9) {
700         for (i = 0; i < used_rects; i++) {
701             int x = wmv9rects[i].x;
702             int y = wmv9rects[i].y;
703             int w = wmv9rects[i].w;
704             int h = wmv9rects[i].h;
705             if (wmv9rects[i].coded) {
706                 int WMV9codedFrameSize;
707                 if (buf_size < 4 || !(WMV9codedFrameSize = AV_RL24(buf)))
708                     return AVERROR_INVALIDDATA;
709                 if (ret = decode_wmv9(avctx, buf + 3, buf_size - 3,
710                                       x, y, w, h, wmv9_mask))
711                     return ret;
712                 buf      += WMV9codedFrameSize + 3;
713                 buf_size -= WMV9codedFrameSize + 3;
714             } else {
715                 uint8_t *dst = c->rgb_pic + y * c->rgb_stride + x * 3;
716                 if (wmv9_mask != -1) {
717                     ctx->dsp.mss2_gray_fill_masked(dst, c->rgb_stride,
718                                                    wmv9_mask,
719                                                    c->pal_pic + y * c->pal_stride + x,
720                                                    c->pal_stride,
721                                                    w, h);
722                 } else {
723                     do {
724                         memset(dst, 0x80, w * 3);
725                         dst += c->rgb_stride;
726                     } while (--h);
727                 }
728             }
729         }
730     }
731 
732     if (buf_size)
733         av_log(avctx, AV_LOG_WARNING, "buffer not fully consumed\n");
734 
735     if (c->mvX < 0 || c->mvY < 0) {
736         av_frame_unref(ctx->last_pic);
737         ret = av_frame_ref(ctx->last_pic, frame);
738         if (ret < 0)
739             return ret;
740     }
741 
742     *got_frame       = 1;
743 
744     return avpkt->size;
745 }
746 
wmv9_init(AVCodecContext * avctx)747 static av_cold int wmv9_init(AVCodecContext *avctx)
748 {
749     VC1Context *v = avctx->priv_data;
750     int ret;
751 
752     v->s.avctx    = avctx;
753 
754     ff_vc1_init_common(v);
755 
756     v->profile = PROFILE_MAIN;
757 
758     v->zz_8x4     = ff_wmv2_scantableA;
759     v->zz_4x8     = ff_wmv2_scantableB;
760     v->res_y411   = 0;
761     v->res_sprite = 0;
762 
763     v->frmrtq_postproc = 7;
764     v->bitrtq_postproc = 31;
765 
766     v->res_x8          = 0;
767     v->multires        = 0;
768     v->res_fasttx      = 1;
769 
770     v->fastuvmc        = 0;
771 
772     v->extended_mv     = 0;
773 
774     v->dquant          = 1;
775     v->vstransform     = 1;
776 
777     v->res_transtab    = 0;
778 
779     v->overlap         = 0;
780 
781     v->resync_marker   = 0;
782     v->rangered        = 0;
783 
784     v->s.max_b_frames = avctx->max_b_frames = 0;
785     v->quantizer_mode = 0;
786 
787     v->finterpflag = 0;
788 
789     v->res_rtm_flag = 1;
790 
791     ff_vc1_init_transposed_scantables(v);
792 
793     if ((ret = ff_msmpeg4_decode_init(avctx)) < 0 ||
794         (ret = ff_vc1_decode_init_alloc_tables(v)) < 0)
795         return ret;
796 
797     /* error concealment */
798     v->s.me.qpel_put = v->s.qdsp.put_qpel_pixels_tab;
799     v->s.me.qpel_avg = v->s.qdsp.avg_qpel_pixels_tab;
800 
801     return 0;
802 }
803 
mss2_decode_end(AVCodecContext * avctx)804 static av_cold int mss2_decode_end(AVCodecContext *avctx)
805 {
806     MSS2Context *const ctx = avctx->priv_data;
807 
808     av_frame_free(&ctx->last_pic);
809 
810     ff_mss12_decode_end(&ctx->c);
811     av_freep(&ctx->c.pal_pic);
812     av_freep(&ctx->c.last_pal_pic);
813     ff_vc1_decode_end(avctx);
814 
815     return 0;
816 }
817 
mss2_decode_init(AVCodecContext * avctx)818 static av_cold int mss2_decode_init(AVCodecContext *avctx)
819 {
820     MSS2Context * const ctx = avctx->priv_data;
821     MSS12Context *c = &ctx->c;
822     int ret;
823     c->avctx = avctx;
824     if (ret = ff_mss12_decode_init(c, 1, &ctx->sc[0], &ctx->sc[1]))
825         return ret;
826     ctx->last_pic   = av_frame_alloc();
827     c->pal_stride   = c->mask_stride;
828     c->pal_pic      = av_mallocz(c->pal_stride * avctx->height);
829     c->last_pal_pic = av_mallocz(c->pal_stride * avctx->height);
830     if (!c->pal_pic || !c->last_pal_pic || !ctx->last_pic) {
831         mss2_decode_end(avctx);
832         return AVERROR(ENOMEM);
833     }
834     if (ret = wmv9_init(avctx)) {
835         mss2_decode_end(avctx);
836         return ret;
837     }
838     ff_mss2dsp_init(&ctx->dsp);
839 
840     avctx->pix_fmt = c->free_colours == 127 ? AV_PIX_FMT_RGB555
841                                             : AV_PIX_FMT_RGB24;
842 
843 
844     return 0;
845 }
846 
847 const FFCodec ff_mss2_decoder = {
848     .p.name         = "mss2",
849     .p.long_name    = NULL_IF_CONFIG_SMALL("MS Windows Media Video V9 Screen"),
850     .p.type         = AVMEDIA_TYPE_VIDEO,
851     .p.id           = AV_CODEC_ID_MSS2,
852     .priv_data_size = sizeof(MSS2Context),
853     .init           = mss2_decode_init,
854     .close          = mss2_decode_end,
855     FF_CODEC_DECODE_CB(mss2_decode_frame),
856     .p.capabilities = AV_CODEC_CAP_DR1,
857     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
858 };
859