ffmpeg/libavcodec/lcldec.c

   1 /*
   2  * LCL (LossLess Codec Library) Codec
   3  * Copyright (c) 2002-2004 Roberto Togni
   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  * LCL (LossLess Codec Library) Video Codec
  25  * Decoder for MSZH and ZLIB codecs
  26  * Experimental encoder for ZLIB RGB24
  27  *
  28  * Fourcc: MSZH, ZLIB
  29  *
  30  * Original Win32 dll:
  31  * Ver2.23 By Kenji Oshima 2000.09.20
  32  * avimszh.dll, avizlib.dll
  33  *
  34  * A description of the decoding algorithm can be found here:
  35  *   http://www.pcisys.net/~melanson/codecs
  36  *
  37  * Supports: BGR24 (RGB 24bpp)
  38  *
  39  */
  40
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43
  44 #include "libavutil/mem.h"
  45 #include "libavutil/pixdesc.h"
  46 #include "avcodec.h"
  47 #include "bytestream.h"
  48 #include "internal.h"
  49 #include "lcl.h"
  50
  51 #if CONFIG_ZLIB_DECODER
  52 #include <zlib.h>
  53 #endif
  54
  55 /*
  56  * Decoder context
  57  */
  58 typedef struct LclDecContext {
  59     // Image type
  60     int imgtype;
  61     // Compression type
  62     int compression;
  63     // Flags
  64     int flags;
  65     // Decompressed data size
  66     unsigned int decomp_size;
  67     // Decompression buffer
  68     unsigned char* decomp_buf;
  69 #if CONFIG_ZLIB_DECODER
  70     z_stream zstream;
  71 #endif
  72 } LclDecContext;
  73
  74
  75 /**
  76  * @param srcptr compressed source buffer, must be padded with at least 5 extra bytes
  77  * @param destptr must be padded sufficiently for av_memcpy_backptr
  78  */
  79 static unsigned int mszh_decomp(const unsigned char * srcptr, int srclen, unsigned char * destptr, unsigned int destsize)
  80 {
  81     unsigned char *destptr_bak = destptr;
  82     unsigned char *destptr_end = destptr + destsize;
  83     const unsigned char *srcptr_end = srcptr + srclen;
  84     unsigned mask = *srcptr++;
  85     unsigned maskbit = 0x80;
  86
  87     while (srcptr < srcptr_end && destptr < destptr_end) {
  88         if (!(mask & maskbit)) {
  89             memcpy(destptr, srcptr, 4);
  90             destptr += 4;
  91             srcptr += 4;
  92         } else {
  93             unsigned ofs = bytestream_get_le16(&srcptr);
  94             unsigned cnt = (ofs >> 11) + 1;
  95             ofs &= 0x7ff;
  96             ofs = FFMIN(ofs, destptr - destptr_bak);
  97             cnt *= 4;
  98             cnt = FFMIN(cnt, destptr_end - destptr);
  99             if (ofs) {
 100                 av_memcpy_backptr(destptr, ofs, cnt);
 101             } else {
 102                 // Not known what the correct behaviour is, but
 103                 // this at least avoids uninitialized data.
 104                 memset(destptr, 0, cnt);
 105             }
 106             destptr += cnt;
 107         }
 108         maskbit >>= 1;
 109         if (!maskbit) {
 110             mask = *srcptr++;
 111             while (!mask) {
 112                 if (destptr_end - destptr < 32 || srcptr_end - srcptr < 32) break;
 113                 memcpy(destptr, srcptr, 32);
 114                 destptr += 32;
 115                 srcptr += 32;
 116                 mask = *srcptr++;
 117             }
 118             maskbit = 0x80;
 119         }
 120     }
 121
 122     return destptr - destptr_bak;
 123 }
 124
 125
 126 #if CONFIG_ZLIB_DECODER
 127 /**
 128  * @brief decompress a zlib-compressed data block into decomp_buf
 129  * @param src compressed input buffer
 130  * @param src_len data length in input buffer
 131  * @param offset offset in decomp_buf
 132  * @param expected expected decompressed length
 133  */
 134 static int zlib_decomp(AVCodecContext *avctx, const uint8_t *src, int src_len, int offset, int expected)
 135 {
 136     LclDecContext *c = avctx->priv_data;
 137     int zret = inflateReset(&c->zstream);
 138     if (zret != Z_OK) {
 139         av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", zret);
 140         return AVERROR_UNKNOWN;
 141     }
 142     c->zstream.next_in = (uint8_t *)src;
 143     c->zstream.avail_in = src_len;
 144     c->zstream.next_out = c->decomp_buf + offset;
 145     c->zstream.avail_out = c->decomp_size - offset;
 146     zret = inflate(&c->zstream, Z_FINISH);
 147     if (zret != Z_OK && zret != Z_STREAM_END) {
 148         av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", zret);
 149         return AVERROR_UNKNOWN;
 150     }
 151     if (expected != (unsigned int)c->zstream.total_out) {
 152         av_log(avctx, AV_LOG_ERROR, "Decoded size differs (%d != %lu)\n",
 153                expected, c->zstream.total_out);
 154         return AVERROR_UNKNOWN;
 155     }
 156     return c->zstream.total_out;
 157 }
 158 #endif
 159
 160
 161 /*
 162  *
 163  * Decode a frame
 164  *
 165  */
 166 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt)
 167 {
 168     AVFrame *frame = data;
 169     const uint8_t *buf = avpkt->data;
 170     int buf_size = avpkt->size;
 171     LclDecContext * const c = avctx->priv_data;
 172     unsigned int pixel_ptr;
 173     int row, col;
 174     unsigned char *encoded = avpkt->data, *outptr;
 175     uint8_t *y_out, *u_out, *v_out;
 176     unsigned int width = avctx->width; // Real image width
 177     unsigned int height = avctx->height; // Real image height
 178     unsigned int mszh_dlen;
 179     unsigned char yq, y1q, uq, vq;
 180     int uqvq, ret;
 181     unsigned int mthread_inlen, mthread_outlen;
 182     unsigned int len = buf_size;
 183     int linesize;
 184
 185     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
 186         return ret;
 187
 188     outptr = frame->data[0]; // Output image pointer
 189
 190     /* Decompress frame */
 191     switch (avctx->codec_id) {
 192     case AV_CODEC_ID_MSZH:
 193         switch (c->compression) {
 194         case COMP_MSZH:
 195             if (c->imgtype == IMGTYPE_RGB24 && len == FFALIGN(width * 3, 4) * height ||
 196                 c->imgtype == IMGTYPE_YUV111 && len == width * height * 3) {
 197                 ;
 198             } else if (c->flags & FLAG_MULTITHREAD) {
 199                 mthread_inlen = AV_RL32(buf);
 200                 if (len < 8) {
 201                     av_log(avctx, AV_LOG_ERROR, "len %d is too small\n", len);
 202                     return AVERROR_INVALIDDATA;
 203                 }
 204                 mthread_inlen = FFMIN(mthread_inlen, len - 8);
 205                 mthread_outlen = AV_RL32(buf + 4);
 206                 mthread_outlen = FFMIN(mthread_outlen, c->decomp_size);
 207                 mszh_dlen = mszh_decomp(buf + 8, mthread_inlen, c->decomp_buf, c->decomp_size);
 208                 if (mthread_outlen != mszh_dlen) {
 209                     av_log(avctx, AV_LOG_ERROR, "Mthread1 decoded size differs (%d != %d)\n",
 210                            mthread_outlen, mszh_dlen);
 211                     return AVERROR_INVALIDDATA;
 212                 }
 213                 mszh_dlen = mszh_decomp(buf + 8 + mthread_inlen, len - 8 - mthread_inlen,
 214                                         c->decomp_buf + mthread_outlen, c->decomp_size - mthread_outlen);
 215                 if (mthread_outlen != mszh_dlen) {
 216                     av_log(avctx, AV_LOG_ERROR, "Mthread2 decoded size differs (%d != %d)\n",
 217                            mthread_outlen, mszh_dlen);
 218                     return AVERROR_INVALIDDATA;
 219                 }
 220                 encoded = c->decomp_buf;
 221                 len = c->decomp_size;
 222             } else {
 223                 mszh_dlen = mszh_decomp(buf, len, c->decomp_buf, c->decomp_size);
 224                 if (c->decomp_size != mszh_dlen) {
 225                     av_log(avctx, AV_LOG_ERROR, "Decoded size differs (%d != %d)\n",
 226                            c->decomp_size, mszh_dlen);
 227                     return AVERROR_INVALIDDATA;
 228                 }
 229                 encoded = c->decomp_buf;
 230                 len = mszh_dlen;
 231             }
 232             break;
 233         case COMP_MSZH_NOCOMP: {
 234             int bppx2;
 235             switch (c->imgtype) {
 236             case IMGTYPE_YUV111:
 237             case IMGTYPE_RGB24:
 238                 bppx2 = 6;
 239                 break;
 240             case IMGTYPE_YUV422:
 241             case IMGTYPE_YUV211:
 242                 bppx2 = 4;
 243                 break;
 244             case IMGTYPE_YUV411:
 245             case IMGTYPE_YUV420:
 246                 bppx2 = 3;
 247                 break;
 248             default:
 249                 bppx2 = 0; // will error out below
 250                 break;
 251             }
 252             if (len < ((width * height * bppx2) >> 1))
 253                 return AVERROR_INVALIDDATA;
 254             break;
 255         }
 256         default:
 257             av_log(avctx, AV_LOG_ERROR, "BUG! Unknown MSZH compression in frame decoder.\n");
 258             return AVERROR_INVALIDDATA;
 259         }
 260         break;
 261 #if CONFIG_ZLIB_DECODER
 262     case AV_CODEC_ID_ZLIB:
 263         /* Using the original dll with normal compression (-1) and RGB format
 264          * gives a file with ZLIB fourcc, but frame is really uncompressed.
 265          * To be sure that's true check also frame size */
 266         if (c->compression == COMP_ZLIB_NORMAL && c->imgtype == IMGTYPE_RGB24 &&
 267             len == width * height * 3) {
 268             if (c->flags & FLAG_PNGFILTER) {
 269                 memcpy(c->decomp_buf, buf, len);
 270                 encoded = c->decomp_buf;
 271             } else {
 272                 break;
 273             }
 274         } else if (c->flags & FLAG_MULTITHREAD) {
 275             mthread_inlen = AV_RL32(buf);
 276             mthread_inlen = FFMIN(mthread_inlen, len - 8);
 277             mthread_outlen = AV_RL32(buf + 4);
 278             mthread_outlen = FFMIN(mthread_outlen, c->decomp_size);
 279             ret = zlib_decomp(avctx, buf + 8, mthread_inlen, 0, mthread_outlen);
 280             if (ret < 0) return ret;
 281             ret = zlib_decomp(avctx, buf + 8 + mthread_inlen, len - 8 - mthread_inlen,
 282                               mthread_outlen, mthread_outlen);
 283             if (ret < 0) return ret;
 284         } else {
 285             int ret = zlib_decomp(avctx, buf, len, 0, c->decomp_size);
 286             if (ret < 0) return ret;
 287         }
 288         encoded = c->decomp_buf;
 289         len = c->decomp_size;
 290         break;
 291 #endif
 292     default:
 293         av_log(avctx, AV_LOG_ERROR, "BUG! Unknown codec in frame decoder compression switch.\n");
 294         return AVERROR_INVALIDDATA;
 295     }
 296
 297
 298     /* Apply PNG filter */
 299     if (avctx->codec_id == AV_CODEC_ID_ZLIB && (c->flags & FLAG_PNGFILTER)) {
 300         switch (c->imgtype) {
 301         case IMGTYPE_YUV111:
 302         case IMGTYPE_RGB24:
 303             for (row = 0; row < height; row++) {
 304                 pixel_ptr = row * width * 3;
 305                 yq = encoded[pixel_ptr++];
 306                 uqvq = AV_RL16(encoded+pixel_ptr);
 307                 pixel_ptr += 2;
 308                 for (col = 1; col < width; col++) {
 309                     encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
 310                     uqvq -= AV_RL16(encoded+pixel_ptr+1);
 311                     AV_WL16(encoded+pixel_ptr+1, uqvq);
 312                     pixel_ptr += 3;
 313                 }
 314             }
 315             break;
 316         case IMGTYPE_YUV422:
 317             for (row = 0; row < height; row++) {
 318                 pixel_ptr = row * width * 2;
 319                 yq = uq = vq =0;
 320                 for (col = 0; col < width/4; col++) {
 321                     encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
 322                     encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
 323                     encoded[pixel_ptr+2] = yq -= encoded[pixel_ptr+2];
 324                     encoded[pixel_ptr+3] = yq -= encoded[pixel_ptr+3];
 325                     encoded[pixel_ptr+4] = uq -= encoded[pixel_ptr+4];
 326                     encoded[pixel_ptr+5] = uq -= encoded[pixel_ptr+5];
 327                     encoded[pixel_ptr+6] = vq -= encoded[pixel_ptr+6];
 328                     encoded[pixel_ptr+7] = vq -= encoded[pixel_ptr+7];
 329                     pixel_ptr += 8;
 330                 }
 331             }
 332             break;
 333         case IMGTYPE_YUV411:
 334             for (row = 0; row < height; row++) {
 335                 pixel_ptr = row * width / 2 * 3;
 336                 yq = uq = vq =0;
 337                 for (col = 0; col < width/4; col++) {
 338                     encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
 339                     encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
 340                     encoded[pixel_ptr+2] = yq -= encoded[pixel_ptr+2];
 341                     encoded[pixel_ptr+3] = yq -= encoded[pixel_ptr+3];
 342                     encoded[pixel_ptr+4] = uq -= encoded[pixel_ptr+4];
 343                     encoded[pixel_ptr+5] = vq -= encoded[pixel_ptr+5];
 344                     pixel_ptr += 6;
 345                 }
 346             }
 347             break;
 348         case IMGTYPE_YUV211:
 349             for (row = 0; row < height; row++) {
 350                 pixel_ptr = row * width * 2;
 351                 yq = uq = vq =0;
 352                 for (col = 0; col < width/2; col++) {
 353                     encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
 354                     encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
 355                     encoded[pixel_ptr+2] = uq -= encoded[pixel_ptr+2];
 356                     encoded[pixel_ptr+3] = vq -= encoded[pixel_ptr+3];
 357                     pixel_ptr += 4;
 358                 }
 359             }
 360             break;
 361         case IMGTYPE_YUV420:
 362             for (row = 0; row < height/2; row++) {
 363                 pixel_ptr = row * width * 3;
 364                 yq = y1q = uq = vq =0;
 365                 for (col = 0; col < width/2; col++) {
 366                     encoded[pixel_ptr] = yq -= encoded[pixel_ptr];
 367                     encoded[pixel_ptr+1] = yq -= encoded[pixel_ptr+1];
 368                     encoded[pixel_ptr+2] = y1q -= encoded[pixel_ptr+2];
 369                     encoded[pixel_ptr+3] = y1q -= encoded[pixel_ptr+3];
 370                     encoded[pixel_ptr+4] = uq -= encoded[pixel_ptr+4];
 371                     encoded[pixel_ptr+5] = vq -= encoded[pixel_ptr+5];
 372                     pixel_ptr += 6;
 373                 }
 374             }
 375             break;
 376         default:
 377             av_log(avctx, AV_LOG_ERROR, "BUG! Unknown imagetype in pngfilter switch.\n");
 378             return AVERROR_INVALIDDATA;
 379         }
 380     }
 381
 382     /* Convert colorspace */
 383     y_out = frame->data[0] + (height - 1) * frame->linesize[0];
 384     u_out = frame->data[1] + (height - 1) * frame->linesize[1];
 385     v_out = frame->data[2] + (height - 1) * frame->linesize[2];
 386     switch (c->imgtype) {
 387     case IMGTYPE_YUV111:
 388         for (row = 0; row < height; row++) {
 389             for (col = 0; col < width; col++) {
 390                 y_out[col] = *encoded++;
 391                 u_out[col] = *encoded++ + 128;
 392                 v_out[col] = *encoded++ + 128;
 393             }
 394             y_out -= frame->linesize[0];
 395             u_out -= frame->linesize[1];
 396             v_out -= frame->linesize[2];
 397         }
 398         break;
 399     case IMGTYPE_YUV422:
 400         for (row = 0; row < height; row++) {
 401             for (col = 0; col < width - 3; col += 4) {
 402                 memcpy(y_out + col, encoded, 4);
 403                 encoded += 4;
 404                 u_out[ col >> 1     ] = *encoded++ + 128;
 405                 u_out[(col >> 1) + 1] = *encoded++ + 128;
 406                 v_out[ col >> 1     ] = *encoded++ + 128;
 407                 v_out[(col >> 1) + 1] = *encoded++ + 128;
 408             }
 409             y_out -= frame->linesize[0];
 410             u_out -= frame->linesize[1];
 411             v_out -= frame->linesize[2];
 412         }
 413         break;
 414     case IMGTYPE_RGB24:
 415         linesize = len < FFALIGN(3 * width, 4) * height ? 3 * width : FFALIGN(3 * width, 4);
 416         for (row = height - 1; row >= 0; row--) {
 417             pixel_ptr = row * frame->linesize[0];
 418             memcpy(outptr + pixel_ptr, encoded, 3 * width);
 419             encoded += linesize;
 420         }
 421         break;
 422     case IMGTYPE_YUV411:
 423         for (row = 0; row < height; row++) {
 424             for (col = 0; col < width - 3; col += 4) {
 425                 memcpy(y_out + col, encoded, 4);
 426                 encoded += 4;
 427                 u_out[col >> 2] = *encoded++ + 128;
 428                 v_out[col >> 2] = *encoded++ + 128;
 429             }
 430             y_out -= frame->linesize[0];
 431             u_out -= frame->linesize[1];
 432             v_out -= frame->linesize[2];
 433         }
 434         break;
 435     case IMGTYPE_YUV211:
 436         for (row = 0; row < height; row++) {
 437             for (col = 0; col < width - 1; col += 2) {
 438                 memcpy(y_out + col, encoded, 2);
 439                 encoded += 2;
 440                 u_out[col >> 1] = *encoded++ + 128;
 441                 v_out[col >> 1] = *encoded++ + 128;
 442             }
 443             y_out -= frame->linesize[0];
 444             u_out -= frame->linesize[1];
 445             v_out -= frame->linesize[2];
 446         }
 447         break;
 448     case IMGTYPE_YUV420:
 449         u_out = frame->data[1] + ((height >> 1) - 1) * frame->linesize[1];
 450         v_out = frame->data[2] + ((height >> 1) - 1) * frame->linesize[2];
 451         for (row = 0; row < height - 1; row += 2) {
 452             for (col = 0; col < width - 1; col += 2) {
 453                 memcpy(y_out + col, encoded, 2);
 454                 encoded += 2;
 455                 memcpy(y_out + col - frame->linesize[0], encoded, 2);
 456                 encoded += 2;
 457                 u_out[col >> 1] = *encoded++ + 128;
 458                 v_out[col >> 1] = *encoded++ + 128;
 459             }
 460             y_out -= frame->linesize[0] << 1;
 461             u_out -= frame->linesize[1];
 462             v_out -= frame->linesize[2];
 463         }
 464         break;
 465     default:
 466         av_log(avctx, AV_LOG_ERROR, "BUG! Unknown imagetype in image decoder.\n");
 467         return AVERROR_INVALIDDATA;
 468     }
 469
 470     *got_frame = 1;
 471
 472     /* always report that the buffer was completely consumed */
 473     return buf_size;
 474 }
 475
 476 /*
 477  *
 478  * Init lcl decoder
 479  *
 480  */
 481 static av_cold int decode_init(AVCodecContext *avctx)
 482 {
 483     LclDecContext * const c = avctx->priv_data;
 484     unsigned int basesize = avctx->width * avctx->height;
 485     unsigned int max_basesize = FFALIGN(avctx->width,  4) *
 486                                 FFALIGN(avctx->height, 4);
 487     unsigned int max_decomp_size;
 488     int subsample_h, subsample_v;
 489
 490     if (avctx->extradata_size < 8) {
 491         av_log(avctx, AV_LOG_ERROR, "Extradata size too small.\n");
 492         return AVERROR_INVALIDDATA;
 493     }
 494
 495     /* Check codec type */
 496     if ((avctx->codec_id == AV_CODEC_ID_MSZH  && avctx->extradata[7] != CODEC_MSZH) ||
 497         (avctx->codec_id == AV_CODEC_ID_ZLIB  && avctx->extradata[7] != CODEC_ZLIB)) {
 498         av_log(avctx, AV_LOG_ERROR, "Codec id and codec type mismatch. This should not happen.\n");
 499     }
 500
 501     /* Detect image type */
 502     switch (c->imgtype = avctx->extradata[4]) {
 503     case IMGTYPE_YUV111:
 504         c->decomp_size = basesize * 3;
 505         max_decomp_size = max_basesize * 3;
 506         avctx->pix_fmt = AV_PIX_FMT_YUV444P;
 507         av_log(avctx, AV_LOG_DEBUG, "Image type is YUV 1:1:1.\n");
 508         break;
 509     case IMGTYPE_YUV422:
 510         c->decomp_size = basesize * 2;
 511         max_decomp_size = max_basesize * 2;
 512         avctx->pix_fmt = AV_PIX_FMT_YUV422P;
 513         av_log(avctx, AV_LOG_DEBUG, "Image type is YUV 4:2:2.\n");
 514         if (avctx->width % 4) {
 515             avpriv_request_sample(avctx, "Unsupported dimensions\n");
 516             return AVERROR_INVALIDDATA;
 517         }
 518         break;
 519     case IMGTYPE_RGB24:
 520         c->decomp_size = basesize * 3;
 521         max_decomp_size = max_basesize * 3;
 522         avctx->pix_fmt = AV_PIX_FMT_BGR24;
 523         av_log(avctx, AV_LOG_DEBUG, "Image type is RGB 24.\n");
 524         break;
 525     case IMGTYPE_YUV411:
 526         c->decomp_size = basesize / 2 * 3;
 527         max_decomp_size = max_basesize / 2 * 3;
 528         avctx->pix_fmt = AV_PIX_FMT_YUV411P;
 529         av_log(avctx, AV_LOG_DEBUG, "Image type is YUV 4:1:1.\n");
 530         break;
 531     case IMGTYPE_YUV211:
 532         c->decomp_size = basesize * 2;
 533         max_decomp_size = max_basesize * 2;
 534         avctx->pix_fmt = AV_PIX_FMT_YUV422P;
 535         av_log(avctx, AV_LOG_DEBUG, "Image type is YUV 2:1:1.\n");
 536         break;
 537     case IMGTYPE_YUV420:
 538         c->decomp_size = basesize / 2 * 3;
 539         max_decomp_size = max_basesize / 2 * 3;
 540         avctx->pix_fmt = AV_PIX_FMT_YUV420P;
 541         av_log(avctx, AV_LOG_DEBUG, "Image type is YUV 4:2:0.\n");
 542         break;
 543     default:
 544         av_log(avctx, AV_LOG_ERROR, "Unsupported image format %d.\n", c->imgtype);
 545         return AVERROR_INVALIDDATA;
 546     }
 547
 548     av_pix_fmt_get_chroma_sub_sample(avctx->pix_fmt, &subsample_h, &subsample_v);
 549     if (avctx->width % (1<<subsample_h) || avctx->height % (1<<subsample_v)) {
 550         avpriv_request_sample(avctx, "Unsupported dimensions\n");
 551         return AVERROR_INVALIDDATA;
 552     }
 553
 554     /* Detect compression method */
 555     c->compression = (int8_t)avctx->extradata[5];
 556     switch (avctx->codec_id) {
 557     case AV_CODEC_ID_MSZH:
 558         switch (c->compression) {
 559         case COMP_MSZH:
 560             av_log(avctx, AV_LOG_DEBUG, "Compression enabled.\n");
 561             break;
 562         case COMP_MSZH_NOCOMP:
 563             c->decomp_size = 0;
 564             av_log(avctx, AV_LOG_DEBUG, "No compression.\n");
 565             break;
 566         default:
 567             av_log(avctx, AV_LOG_ERROR, "Unsupported compression format for MSZH (%d).\n", c->compression);
 568             return AVERROR_INVALIDDATA;
 569         }
 570         break;
 571 #if CONFIG_ZLIB_DECODER
 572     case AV_CODEC_ID_ZLIB:
 573         switch (c->compression) {
 574         case COMP_ZLIB_HISPEED:
 575             av_log(avctx, AV_LOG_DEBUG, "High speed compression.\n");
 576             break;
 577         case COMP_ZLIB_HICOMP:
 578             av_log(avctx, AV_LOG_DEBUG, "High compression.\n");
 579             break;
 580         case COMP_ZLIB_NORMAL:
 581             av_log(avctx, AV_LOG_DEBUG, "Normal compression.\n");
 582             break;
 583         default:
 584             if (c->compression < Z_NO_COMPRESSION || c->compression > Z_BEST_COMPRESSION) {
 585                 av_log(avctx, AV_LOG_ERROR, "Unsupported compression level for ZLIB: (%d).\n", c->compression);
 586                 return AVERROR_INVALIDDATA;
 587             }
 588             av_log(avctx, AV_LOG_DEBUG, "Compression level for ZLIB: (%d).\n", c->compression);
 589         }
 590         break;
 591 #endif
 592     default:
 593         av_log(avctx, AV_LOG_ERROR, "BUG! Unknown codec in compression switch.\n");
 594         return AVERROR_INVALIDDATA;
 595     }
 596
 597     /* Allocate decompression buffer */
 598     if (c->decomp_size) {
 599         if (!(c->decomp_buf = av_malloc(max_decomp_size))) {
 600             av_log(avctx, AV_LOG_ERROR, "Can't allocate decompression buffer.\n");
 601             return AVERROR(ENOMEM);
 602         }
 603     }
 604
 605     /* Detect flags */
 606     c->flags = avctx->extradata[6];
 607     if (c->flags & FLAG_MULTITHREAD)
 608         av_log(avctx, AV_LOG_DEBUG, "Multithread encoder flag set.\n");
 609     if (c->flags & FLAG_NULLFRAME)
 610         av_log(avctx, AV_LOG_DEBUG, "Nullframe insertion flag set.\n");
 611     if (avctx->codec_id == AV_CODEC_ID_ZLIB && (c->flags & FLAG_PNGFILTER))
 612         av_log(avctx, AV_LOG_DEBUG, "PNG filter flag set.\n");
 613     if (c->flags & FLAGMASK_UNUSED)
 614         av_log(avctx, AV_LOG_ERROR, "Unknown flag set (%d).\n", c->flags);
 615
 616     /* If needed init zlib */
 617 #if CONFIG_ZLIB_DECODER
 618     if (avctx->codec_id == AV_CODEC_ID_ZLIB) {
 619         int zret;
 620         c->zstream.zalloc = Z_NULL;
 621         c->zstream.zfree = Z_NULL;
 622         c->zstream.opaque = Z_NULL;
 623         zret = inflateInit(&c->zstream);
 624         if (zret != Z_OK) {
 625             av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
 626             av_freep(&c->decomp_buf);
 627             return AVERROR_UNKNOWN;
 628         }
 629     }
 630 #endif
 631
 632     return 0;
 633 }
 634
 635 /*
 636  *
 637  * Uninit lcl decoder
 638  *
 639  */
 640 static av_cold int decode_end(AVCodecContext *avctx)
 641 {
 642     LclDecContext * const c = avctx->priv_data;
 643
 644     av_freep(&c->decomp_buf);
 645 #if CONFIG_ZLIB_DECODER
 646     if (avctx->codec_id == AV_CODEC_ID_ZLIB)
 647         inflateEnd(&c->zstream);
 648 #endif
 649
 650     return 0;
 651 }
 652
 653 #if CONFIG_MSZH_DECODER
 654 AVCodec ff_mszh_decoder = {
 655     .name           = "mszh",
 656     .long_name      = NULL_IF_CONFIG_SMALL("LCL (LossLess Codec Library) MSZH"),
 657     .type           = AVMEDIA_TYPE_VIDEO,
 658     .id             = AV_CODEC_ID_MSZH,
 659     .priv_data_size = sizeof(LclDecContext),
 660     .init           = decode_init,
 661     .close          = decode_end,
 662     .decode         = decode_frame,
 663     .capabilities   = CODEC_CAP_DR1,
 664 };
 665 #endif
 666
 667 #if CONFIG_ZLIB_DECODER
 668 AVCodec ff_zlib_decoder = {
 669     .name           = "zlib",
 670     .long_name      = NULL_IF_CONFIG_SMALL("LCL (LossLess Codec Library) ZLIB"),
 671     .type           = AVMEDIA_TYPE_VIDEO,
 672     .id             = AV_CODEC_ID_ZLIB,
 673     .priv_data_size = sizeof(LclDecContext),
 674     .init           = decode_init,
 675     .close          = decode_end,
 676     .decode         = decode_frame,
 677     .capabilities   = CODEC_CAP_DR1,
 678 };
 679 #endif