libavcodec/scpr.c

   1 /*
   2  * ScreenPressor decoder
   3  *
   4  * Copyright (c) 2017 Paul B Mahol
   5  *
   6  * This file is part of FFmpeg.
   7  *
   8  * FFmpeg is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * FFmpeg is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with FFmpeg; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  21  */
  22
  23 #include <stdio.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26
  27 #include "avcodec.h"
  28 #include "bytestream.h"
  29 #include "codec_internal.h"
  30 #include "internal.h"
  31 #include "scpr.h"
  32 #include "scpr3.h"
  33
  34 #define TOP  0x01000000
  35 #define BOT    0x010000
  36
  37 #include "scpr3.c"
  38
  39 static void init_rangecoder(RangeCoder *rc, GetByteContext *gb)
  40 {
  41     rc->code1 = 0;
  42     rc->range = 0xFFFFFFFFU;
  43     rc->code  = bytestream2_get_be32(gb);
  44 }
  45
  46 static void reinit_tables(SCPRContext *s)
  47 {
  48     int comp, i, j;
  49
  50     for (comp = 0; comp < 3; comp++) {
  51         for (j = 0; j < 4096; j++) {
  52             if (s->pixel_model[comp][j].total_freq != 256) {
  53                 for (i = 0; i < 256; i++)
  54                     s->pixel_model[comp][j].freq[i] = 1;
  55                 for (i = 0; i < 16; i++)
  56                     s->pixel_model[comp][j].lookup[i] = 16;
  57                 s->pixel_model[comp][j].total_freq = 256;
  58             }
  59         }
  60     }
  61
  62     for (j = 0; j < 6; j++) {
  63         uint32_t *p = s->run_model[j];
  64         for (i = 0; i < 256; i++)
  65             p[i] = 1;
  66         p[256] = 256;
  67     }
  68
  69     for (j = 0; j < 6; j++) {
  70         uint32_t *op = s->op_model[j];
  71         for (i = 0; i < 6; i++)
  72             op[i] = 1;
  73         op[6] = 6;
  74     }
  75
  76     for (i = 0; i < 256; i++) {
  77         s->range_model[i] = 1;
  78         s->count_model[i] = 1;
  79     }
  80     s->range_model[256] = 256;
  81     s->count_model[256] = 256;
  82
  83     for (i = 0; i < 5; i++) {
  84         s->fill_model[i] = 1;
  85     }
  86     s->fill_model[5] = 5;
  87
  88     for (j = 0; j < 4; j++) {
  89         for (i = 0; i < 16; i++) {
  90             s->sxy_model[j][i] = 1;
  91         }
  92         s->sxy_model[j][16] = 16;
  93     }
  94
  95     for (i = 0; i < 512; i++) {
  96         s->mv_model[0][i] = 1;
  97         s->mv_model[1][i] = 1;
  98     }
  99     s->mv_model[0][512] = 512;
 100     s->mv_model[1][512] = 512;
 101 }
 102
 103 static int decode(GetByteContext *gb, RangeCoder *rc, uint32_t cumFreq, uint32_t freq, uint32_t total_freq)
 104 {
 105     rc->code -= cumFreq * rc->range;
 106     rc->range *= freq;
 107
 108     while (rc->range < TOP && bytestream2_get_bytes_left(gb) > 0) {
 109         uint32_t byte = bytestream2_get_byteu(gb);
 110         rc->code = (rc->code << 8) | byte;
 111         rc->range <<= 8;
 112     }
 113
 114     return 0;
 115 }
 116
 117 static int get_freq(RangeCoder *rc, uint32_t total_freq, uint32_t *freq)
 118 {
 119     if (total_freq == 0)
 120         return AVERROR_INVALIDDATA;
 121
 122     rc->range = rc->range / total_freq;
 123
 124     if (rc->range == 0)
 125         return AVERROR_INVALIDDATA;
 126
 127     *freq = rc->code / rc->range;
 128
 129     return 0;
 130 }
 131
 132 static int decode0(GetByteContext *gb, RangeCoder *rc, uint32_t cumFreq, uint32_t freq, uint32_t total_freq)
 133 {
 134     uint32_t t;
 135
 136     if (total_freq == 0)
 137         return AVERROR_INVALIDDATA;
 138
 139     t = rc->range * (uint64_t)cumFreq / total_freq;
 140
 141     rc->code1 += t + 1;
 142     rc->range = rc->range * (uint64_t)(freq + cumFreq) / total_freq - (t + 1);
 143
 144     while (rc->range < TOP && bytestream2_get_bytes_left(gb) > 0) {
 145         uint32_t byte = bytestream2_get_byteu(gb);
 146         rc->code = (rc->code << 8) | byte;
 147         rc->code1 <<= 8;
 148         rc->range <<= 8;
 149     }
 150
 151     return 0;
 152 }
 153
 154 static int get_freq0(RangeCoder *rc, uint32_t total_freq, uint32_t *freq)
 155 {
 156     if (rc->range == 0)
 157         return AVERROR_INVALIDDATA;
 158
 159     *freq = total_freq * (uint64_t)(rc->code - rc->code1) / rc->range;
 160
 161     return 0;
 162 }
 163
 164 static int decode_value(SCPRContext *s, uint32_t *cnt, uint32_t maxc, uint32_t step, uint32_t *rval)
 165 {
 166     GetByteContext *gb = &s->gb;
 167     RangeCoder *rc = &s->rc;
 168     uint32_t totfr = cnt[maxc];
 169     uint32_t value;
 170     uint32_t c = 0, cumfr = 0, cnt_c = 0;
 171     int i, ret;
 172
 173     if ((ret = s->get_freq(rc, totfr, &value)) < 0)
 174         return ret;
 175
 176     while (c < maxc) {
 177         cnt_c = cnt[c];
 178         if (value >= cumfr + cnt_c)
 179             cumfr += cnt_c;
 180         else
 181             break;
 182         c++;
 183     }
 184
 185     if (c >= maxc)
 186         return AVERROR_INVALIDDATA;
 187
 188     if ((ret = s->decode(gb, rc, cumfr, cnt_c, totfr)) < 0)
 189         return ret;
 190
 191     cnt[c] = cnt_c + step;
 192     totfr += step;
 193     if (totfr > BOT) {
 194         totfr = 0;
 195         for (i = 0; i < maxc; i++) {
 196             uint32_t nc = (cnt[i] >> 1) + 1;
 197             cnt[i] = nc;
 198             totfr += nc;
 199         }
 200     }
 201
 202     cnt[maxc] = totfr;
 203     *rval = c;
 204
 205     return 0;
 206 }
 207
 208 static int decode_unit(SCPRContext *s, PixelModel *pixel, uint32_t step, uint32_t *rval)
 209 {
 210     GetByteContext *gb = &s->gb;
 211     RangeCoder *rc = &s->rc;
 212     uint32_t totfr = pixel->total_freq;
 213     uint32_t value, x = 0, cumfr = 0, cnt_x = 0;
 214     int i, j, ret, c, cnt_c;
 215
 216     if ((ret = s->get_freq(rc, totfr, &value)) < 0)
 217         return ret;
 218
 219     while (x < 16) {
 220         cnt_x = pixel->lookup[x];
 221         if (value >= cumfr + cnt_x)
 222             cumfr += cnt_x;
 223         else
 224             break;
 225         x++;
 226     }
 227
 228     c = x * 16;
 229     cnt_c = 0;
 230     while (c < 256) {
 231         cnt_c = pixel->freq[c];
 232         if (value >= cumfr + cnt_c)
 233             cumfr += cnt_c;
 234         else
 235             break;
 236         c++;
 237     }
 238     if (x >= 16 || c >= 256) {
 239         return AVERROR_INVALIDDATA;
 240     }
 241
 242     if ((ret = s->decode(gb, rc, cumfr, cnt_c, totfr)) < 0)
 243         return ret;
 244
 245     pixel->freq[c] = cnt_c + step;
 246     pixel->lookup[x] = cnt_x + step;
 247     totfr += step;
 248     if (totfr > BOT) {
 249         totfr = 0;
 250         for (i = 0; i < 256; i++) {
 251             uint32_t nc = (pixel->freq[i] >> 1) + 1;
 252             pixel->freq[i] = nc;
 253             totfr += nc;
 254         }
 255         for (i = 0; i < 16; i++) {
 256             uint32_t sum = 0;
 257             uint32_t i16_17 = i << 4;
 258             for (j = 0; j < 16; j++)
 259                 sum += pixel->freq[i16_17 + j];
 260             pixel->lookup[i] = sum;
 261         }
 262     }
 263     pixel->total_freq = totfr;
 264
 265     *rval = c & s->cbits;
 266
 267     return 0;
 268 }
 269
 270 static int decode_units(SCPRContext *s, uint32_t *r, uint32_t *g, uint32_t *b,
 271                         int *cx, int *cx1)
 272 {
 273     const int cxshift = s->cxshift;
 274     int ret;
 275
 276     ret = decode_unit(s, &s->pixel_model[0][*cx + *cx1], 400, r);
 277     if (ret < 0)
 278         return ret;
 279
 280     *cx1 = (*cx << 6) & 0xFC0;
 281     *cx = *r >> cxshift;
 282     ret = decode_unit(s, &s->pixel_model[1][*cx + *cx1], 400, g);
 283     if (ret < 0)
 284         return ret;
 285
 286     *cx1 = (*cx << 6) & 0xFC0;
 287     *cx = *g >> cxshift;
 288     ret = decode_unit(s, &s->pixel_model[2][*cx + *cx1], 400, b);
 289     if (ret < 0)
 290         return ret;
 291
 292     *cx1 = (*cx << 6) & 0xFC0;
 293     *cx = *b >> cxshift;
 294
 295     return 0;
 296 }
 297
 298 static int decompress_i(AVCodecContext *avctx, uint32_t *dst, int linesize)
 299 {
 300     SCPRContext *s = avctx->priv_data;
 301     GetByteContext *gb = &s->gb;
 302     int cx = 0, cx1 = 0, k = 0;
 303     int run, off, y = 0, x = 0, ret;
 304     uint32_t clr = 0, r, g, b, backstep = linesize - avctx->width;
 305     uint32_t lx, ly, ptype;
 306
 307     reinit_tables(s);
 308     bytestream2_skip(gb, 2);
 309     init_rangecoder(&s->rc, gb);
 310
 311     while (k < avctx->width + 1) {
 312         ret = decode_units(s, &r, &g, &b, &cx, &cx1);
 313         if (ret < 0)
 314             return ret;
 315
 316         ret = decode_value(s, s->run_model[0], 256, 400, &run);
 317         if (ret < 0)
 318             return ret;
 319         if (run <= 0)
 320             return AVERROR_INVALIDDATA;
 321
 322         clr = (b << 16) + (g << 8) + r;
 323         k += run;
 324         while (run-- > 0) {
 325             if (y >= avctx->height)
 326                 return AVERROR_INVALIDDATA;
 327
 328             dst[y * linesize + x] = clr;
 329             lx = x;
 330             ly = y;
 331             x++;
 332             if (x >= avctx->width) {
 333                 x = 0;
 334                 y++;
 335             }
 336         }
 337     }
 338     off = -linesize - 1;
 339     ptype = 0;
 340
 341     while (x < avctx->width && y < avctx->height) {
 342         ret = decode_value(s, s->op_model[ptype], 6, 1000, &ptype);
 343         if (ret < 0)
 344             return ret;
 345         if (ptype == 0) {
 346             ret = decode_units(s, &r, &g, &b, &cx, &cx1);
 347             if (ret < 0)
 348                 return ret;
 349
 350             clr = (b << 16) + (g << 8) + r;
 351         }
 352         if (ptype > 5)
 353             return AVERROR_INVALIDDATA;
 354         ret = decode_value(s, s->run_model[ptype], 256, 400, &run);
 355         if (ret < 0)
 356             return ret;
 357         if (run <= 0)
 358             return AVERROR_INVALIDDATA;
 359
 360         ret = decode_run_i(avctx, ptype, run, &x, &y, clr,
 361                            dst, linesize, &lx, &ly,
 362                            backstep, off, &cx, &cx1);
 363         if (ret < 0)
 364             return ret;
 365     }
 366
 367     return 0;
 368 }
 369
 370 static int decompress_p(AVCodecContext *avctx,
 371                         uint32_t *dst, int linesize,
 372                         uint32_t *prev, int plinesize)
 373 {
 374     SCPRContext *s = avctx->priv_data;
 375     GetByteContext *gb = &s->gb;
 376     int ret, temp = 0, min, max, x, y, cx = 0, cx1 = 0;
 377     int backstep = linesize - avctx->width;
 378
 379     if (bytestream2_get_byte(gb) == 0)
 380         return 1;
 381     bytestream2_skip(gb, 1);
 382     init_rangecoder(&s->rc, gb);
 383
 384     ret  = decode_value(s, s->range_model, 256, 1, &min);
 385     ret |= decode_value(s, s->range_model, 256, 1, &temp);
 386     if (ret < 0)
 387         return ret;
 388
 389     min += temp << 8;
 390     ret  = decode_value(s, s->range_model, 256, 1, &max);
 391     ret |= decode_value(s, s->range_model, 256, 1, &temp);
 392     if (ret < 0)
 393         return ret;
 394
 395     max += temp << 8;
 396     if (min > max || min >= s->nbcount)
 397         return AVERROR_INVALIDDATA;
 398
 399     memset(s->blocks, 0, sizeof(*s->blocks) * s->nbcount);
 400
 401     while (min <= max) {
 402         int fill, count;
 403
 404         ret  = decode_value(s, s->fill_model,  5,   10, &fill);
 405         ret |= decode_value(s, s->count_model, 256, 20, &count);
 406         if (ret < 0)
 407             return ret;
 408         if (count <= 0)
 409             return AVERROR_INVALIDDATA;
 410
 411         while (min < s->nbcount && count-- > 0) {
 412             s->blocks[min++] = fill;
 413         }
 414     }
 415
 416     ret = av_frame_copy(s->current_frame, s->last_frame);
 417     if (ret < 0)
 418         return ret;
 419
 420     for (y = 0; y < s->nby; y++) {
 421         for (x = 0; x < s->nbx; x++) {
 422             int sy1 = 0, sy2 = 16, sx1 = 0, sx2 = 16;
 423
 424             if (s->blocks[y * s->nbx + x] == 0)
 425                 continue;
 426
 427             if (((s->blocks[y * s->nbx + x] - 1) & 1) > 0) {
 428                 ret  = decode_value(s, s->sxy_model[0], 16, 100, &sx1);
 429                 ret |= decode_value(s, s->sxy_model[1], 16, 100, &sy1);
 430                 ret |= decode_value(s, s->sxy_model[2], 16, 100, &sx2);
 431                 ret |= decode_value(s, s->sxy_model[3], 16, 100, &sy2);
 432                 if (ret < 0)
 433                     return ret;
 434
 435                 sx2++;
 436                 sy2++;
 437             }
 438             if (((s->blocks[y * s->nbx + x] - 1) & 2) > 0) {
 439                 int i, j, by = y * 16, bx = x * 16;
 440                 int mvx, mvy;
 441
 442                 ret  = decode_value(s, s->mv_model[0], 512, 100, &mvx);
 443                 ret |= decode_value(s, s->mv_model[1], 512, 100, &mvy);
 444                 if (ret < 0)
 445                     return ret;
 446
 447                 mvx -= 256;
 448                 mvy -= 256;
 449
 450                 if (by + mvy + sy1 < 0 || bx + mvx + sx1 < 0 ||
 451                     by + mvy + sy1 >= avctx->height || bx + mvx + sx1 >= avctx->width)
 452                     return AVERROR_INVALIDDATA;
 453
 454                 for (i = 0; i < sy2 - sy1 && (by + sy1 + i) < avctx->height && (by + mvy + sy1 + i) < avctx->height; i++) {
 455                     for (j = 0; j < sx2 - sx1 && (bx + sx1 + j) < avctx->width && (bx + mvx + sx1 + j) < avctx->width; j++) {
 456                         dst[(by + i + sy1) * linesize + bx + sx1 + j] = prev[(by + mvy + sy1 + i) * plinesize + bx + sx1 + mvx + j];
 457                     }
 458                 }
 459             } else {
 460                 int run, bx = x * 16 + sx1, by = y * 16 + sy1;
 461                 uint32_t r, g, b, clr, ptype = 0;
 462
 463                 if (bx >= avctx->width)
 464                     return AVERROR_INVALIDDATA;
 465
 466                 for (; by < y * 16 + sy2 && by < avctx->height;) {
 467                     ret = decode_value(s, s->op_model[ptype], 6, 1000, &ptype);
 468                     if (ret < 0)
 469                         return ret;
 470                     if (ptype == 0) {
 471                         ret = decode_units(s, &r, &g, &b, &cx, &cx1);
 472                         if (ret < 0)
 473                             return ret;
 474
 475                         clr = (b << 16) + (g << 8) + r;
 476                     }
 477                     if (ptype > 5)
 478                         return AVERROR_INVALIDDATA;
 479                     ret = decode_value(s, s->run_model[ptype], 256, 400, &run);
 480                     if (ret < 0)
 481                         return ret;
 482                     if (run <= 0)
 483                         return AVERROR_INVALIDDATA;
 484
 485                     ret = decode_run_p(avctx, ptype, run, x, y, clr,
 486                                        dst, prev, linesize, plinesize, &bx, &by,
 487                                        backstep, sx1, sx2, &cx, &cx1);
 488                     if (ret < 0)
 489                         return ret;
 490                 }
 491             }
 492         }
 493     }
 494
 495     return 0;
 496 }
 497
 498 static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
 499                         int *got_frame, AVPacket *avpkt)
 500 {
 501     SCPRContext *s = avctx->priv_data;
 502     GetByteContext *gb = &s->gb;
 503     int ret, type;
 504
 505     if (avctx->bits_per_coded_sample == 16) {
 506         if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
 507             return ret;
 508     }
 509
 510     if ((ret = ff_reget_buffer(avctx, s->current_frame, 0)) < 0)
 511         return ret;
 512
 513     bytestream2_init(gb, avpkt->data, avpkt->size);
 514
 515     type = bytestream2_peek_byte(gb);
 516
 517     if (type == 2) {
 518         s->version = 1;
 519         s->get_freq = get_freq0;
 520         s->decode = decode0;
 521         frame->key_frame = 1;
 522         ret = decompress_i(avctx, (uint32_t *)s->current_frame->data[0],
 523                            s->current_frame->linesize[0] / 4);
 524     } else if (type == 18) {
 525         s->version = 2;
 526         s->get_freq = get_freq;
 527         s->decode = decode;
 528         frame->key_frame = 1;
 529         ret = decompress_i(avctx, (uint32_t *)s->current_frame->data[0],
 530                            s->current_frame->linesize[0] / 4);
 531     } else if (type == 34) {
 532         frame->key_frame = 1;
 533         s->version = 3;
 534         ret = decompress_i3(avctx, (uint32_t *)s->current_frame->data[0],
 535                             s->current_frame->linesize[0] / 4);
 536     } else if (type == 17 || type == 33) {
 537         uint32_t clr, *dst = (uint32_t *)s->current_frame->data[0];
 538         int y;
 539
 540         if (bytestream2_get_bytes_left(gb) < 3)
 541             return AVERROR_INVALIDDATA;
 542
 543         frame->key_frame = 1;
 544         bytestream2_skip(gb, 1);
 545         if (avctx->bits_per_coded_sample == 16) {
 546             uint16_t value = bytestream2_get_le16(gb);
 547             int r, g, b;
 548
 549             r = (value      ) & 31;
 550             g = (value >>  5) & 31;
 551             b = (value >> 10) & 31;
 552             clr = (r << 16) + (g << 8) + b;
 553         } else {
 554             clr = bytestream2_get_le24(gb);
 555         }
 556         for (y = 0; y < avctx->height; y++) {
 557             dst[0] = clr;
 558             av_memcpy_backptr((uint8_t*)(dst+1), 4, 4*avctx->width - 4);
 559             dst += s->current_frame->linesize[0] / 4;
 560         }
 561     } else if (type == 0 || type == 1) {
 562         frame->key_frame = 0;
 563
 564         if (s->version == 1 || s->version == 2)
 565             ret = decompress_p(avctx, (uint32_t *)s->current_frame->data[0],
 566                                s->current_frame->linesize[0] / 4,
 567                                (uint32_t *)s->last_frame->data[0],
 568                                s->last_frame->linesize[0] / 4);
 569         else
 570             ret = decompress_p3(avctx, (uint32_t *)s->current_frame->data[0],
 571                                 s->current_frame->linesize[0] / 4,
 572                                 (uint32_t *)s->last_frame->data[0],
 573                                 s->last_frame->linesize[0] / 4);
 574         if (ret == 1)
 575             return avpkt->size;
 576     } else {
 577         return AVERROR_PATCHWELCOME;
 578     }
 579
 580     if (ret < 0)
 581         return ret;
 582
 583     if (bytestream2_get_bytes_left(gb) > 5)
 584         return AVERROR_INVALIDDATA;
 585
 586     if (avctx->bits_per_coded_sample != 16) {
 587         ret = av_frame_ref(frame, s->current_frame);
 588         if (ret < 0)
 589             return ret;
 590     } else {
 591         uint8_t *dst = frame->data[0];
 592         int x, y;
 593
 594         ret = av_frame_copy(frame, s->current_frame);
 595         if (ret < 0)
 596             return ret;
 597
 598         // scale up each sample by 8
 599         for (y = 0; y < avctx->height; y++) {
 600             // If the image is sufficiently aligned, compute 8 samples at once
 601             if (!(((uintptr_t)dst) & 7)) {
 602                 uint64_t *dst64 = (uint64_t *)dst;
 603                 int w = avctx->width>>1;
 604                 for (x = 0; x < w; x++) {
 605                     dst64[x] = (dst64[x] << 3) & 0xFCFCFCFCFCFCFCFCULL;
 606                 }
 607                 x *= 8;
 608             } else
 609                 x = 0;
 610             for (; x < avctx->width * 4; x++) {
 611                 dst[x] = dst[x] << 3;
 612             }
 613             dst += frame->linesize[0];
 614         }
 615     }
 616
 617     frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
 618
 619     FFSWAP(AVFrame *, s->current_frame, s->last_frame);
 620
 621     frame->data[0]     += frame->linesize[0] * (avctx->height - 1);
 622     frame->linesize[0] *= -1;
 623
 624     *got_frame = 1;
 625
 626     return avpkt->size;
 627 }
 628
 629 static av_cold int decode_init(AVCodecContext *avctx)
 630 {
 631     SCPRContext *s = avctx->priv_data;
 632
 633     switch (avctx->bits_per_coded_sample) {
 634     case 16: avctx->pix_fmt = AV_PIX_FMT_RGB0; break;
 635     case 24:
 636     case 32: avctx->pix_fmt = AV_PIX_FMT_BGR0; break;
 637     default:
 638         av_log(avctx, AV_LOG_ERROR, "Unsupported bitdepth %i\n", avctx->bits_per_coded_sample);
 639         return AVERROR_INVALIDDATA;
 640     }
 641
 642     s->get_freq = get_freq0;
 643     s->decode = decode0;
 644
 645     s->cxshift = avctx->bits_per_coded_sample == 16 ? 0 : 2;
 646     s->cbits = avctx->bits_per_coded_sample == 16 ? 0x1F : 0xFF;
 647     s->nbx = (avctx->width + 15) / 16;
 648     s->nby = (avctx->height + 15) / 16;
 649     s->nbcount = s->nbx * s->nby;
 650     s->blocks = av_malloc_array(s->nbcount, sizeof(*s->blocks));
 651     if (!s->blocks)
 652         return AVERROR(ENOMEM);
 653
 654     s->last_frame = av_frame_alloc();
 655     s->current_frame = av_frame_alloc();
 656     if (!s->last_frame || !s->current_frame)
 657         return AVERROR(ENOMEM);
 658
 659     return 0;
 660 }
 661
 662 static av_cold int decode_close(AVCodecContext *avctx)
 663 {
 664     SCPRContext *s = avctx->priv_data;
 665
 666     av_freep(&s->blocks);
 667     av_frame_free(&s->last_frame);
 668     av_frame_free(&s->current_frame);
 669
 670     return 0;
 671 }
 672
 673 const FFCodec ff_scpr_decoder = {
 674     .p.name           = "scpr",
 675     .p.long_name      = NULL_IF_CONFIG_SMALL("ScreenPressor"),
 676     .p.type           = AVMEDIA_TYPE_VIDEO,
 677     .p.id             = AV_CODEC_ID_SCPR,
 678     .priv_data_size   = sizeof(SCPRContext),
 679     .init             = decode_init,
 680     .close            = decode_close,
 681     FF_CODEC_DECODE_CB(decode_frame),
 682     .p.capabilities   = AV_CODEC_CAP_DR1,
 683     .caps_internal    = FF_CODEC_CAP_INIT_THREADSAFE |
 684                         FF_CODEC_CAP_INIT_CLEANUP,
 685 };