libavcodec/pixlet.c

   1 /*
   2  * Apple Pixlet decoder
   3  * Copyright (c) 2016 Paul B Mahol
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include <stdint.h>
  23
  24 #include "libavutil/imgutils.h"
  25 #include "libavutil/intmath.h"
  26 #include "libavutil/opt.h"
  27
  28 #include "avcodec.h"
  29 #include "bitstream.h"
  30 #include "bytestream.h"
  31 #include "internal.h"
  32 #include "thread.h"
  33 #include "unary.h"
  34
  35 #define NB_LEVELS 4
  36
  37 #define PIXLET_MAGIC 0xDEADBEEF
  38
  39 #define H 0
  40 #define V 1
  41
  42 typedef struct SubBand {
  43     size_t width, height;
  44     size_t size;
  45     size_t x, y;
  46 } SubBand;
  47
  48 typedef struct PixletContext {
  49     AVClass *class;
  50
  51     GetByteContext gb;
  52     BitstreamContext bc;
  53
  54     int levels;
  55     int depth;
  56     size_t w, h;
  57
  58     int16_t *filter[2];
  59     int16_t *prediction;
  60     int64_t scaling[4][2][NB_LEVELS];
  61     SubBand band[4][NB_LEVELS * 3 + 1];
  62 } PixletContext;
  63
  64 static av_cold int pixlet_init(AVCodecContext *avctx)
  65 {
  66     avctx->pix_fmt     = AV_PIX_FMT_YUV420P16;
  67     avctx->color_range = AVCOL_RANGE_JPEG;
  68     return 0;
  69 }
  70
  71 static av_cold int pixlet_close(AVCodecContext *avctx)
  72 {
  73     PixletContext *ctx = avctx->priv_data;
  74
  75     av_freep(&ctx->filter[0]);
  76     av_freep(&ctx->filter[1]);
  77     av_freep(&ctx->prediction);
  78
  79     return 0;
  80 }
  81
  82 static int init_decoder(AVCodecContext *avctx)
  83 {
  84     PixletContext *ctx = avctx->priv_data;
  85     int i, plane;
  86
  87     ctx->filter[0]  = av_malloc_array(ctx->h, sizeof(int16_t));
  88     ctx->filter[1]  = av_malloc_array(FFMAX(ctx->h, ctx->w) + 16, sizeof(int16_t));
  89     ctx->prediction = av_malloc_array((ctx->w >> NB_LEVELS), sizeof(int16_t));
  90     if (!ctx->filter[0] || !ctx->filter[1] || !ctx->prediction)
  91         return AVERROR(ENOMEM);
  92
  93     for (plane = 0; plane < 3; plane++) {
  94         unsigned shift = plane > 0;
  95         size_t w       = ctx->w >> shift;
  96         size_t h       = ctx->h >> shift;
  97
  98         ctx->band[plane][0].width  =  w >> NB_LEVELS;
  99         ctx->band[plane][0].height =  h >> NB_LEVELS;
 100         ctx->band[plane][0].size   = (w >> NB_LEVELS) * (h >> NB_LEVELS);
 101
 102         for (i = 0; i < NB_LEVELS * 3; i++) {
 103             unsigned scale = ctx->levels - (i / 3);
 104
 105             ctx->band[plane][i + 1].width  =  w >> scale;
 106             ctx->band[plane][i + 1].height =  h >> scale;
 107             ctx->band[plane][i + 1].size   = (w >> scale) * (h >> scale);
 108
 109             ctx->band[plane][i + 1].x = (w >> scale) * (((i + 1) % 3) != 2);
 110             ctx->band[plane][i + 1].y = (h >> scale) * (((i + 1) % 3) != 1);
 111         }
 112     }
 113
 114     return 0;
 115 }
 116
 117 static int read_low_coeffs(AVCodecContext *avctx, int16_t *dst, size_t size,
 118                            size_t width, ptrdiff_t stride)
 119 {
 120     PixletContext *ctx = avctx->priv_data;
 121     BitstreamContext *bc = &ctx->bc;
 122     unsigned cnt1, nbits, k, j = 0, i = 0;
 123     int64_t value, state = 3;
 124     int rlen, escape, flag = 0;
 125
 126     while (i < size) {
 127         nbits = FFMIN(ff_clz((state >> 8) + 3) ^ 0x1F, 14);
 128
 129         cnt1 = get_unary(bc, 0, 8);
 130         if (cnt1 < 8) {
 131             value = bitstream_read(bc, nbits);
 132             if (value <= 1) {
 133                 bitstream_unget(bc, value & 1, 1);
 134                 value = 1;
 135             }
 136             escape = value + ((1 << nbits) - 1) * cnt1 - 1;
 137         } else {
 138             escape = bitstream_read(bc, 16);
 139         }
 140
 141         value    = -((escape + flag) & 1) | 1;
 142         dst[j++] = value * ((escape + flag + 1) >> 1);
 143         i++;
 144         if (j == width) {
 145             j    = 0;
 146             dst += stride;
 147         }
 148         state = 120 * (escape + flag) + state - (120 * state >> 8);
 149         flag  = 0;
 150
 151         if (state * 4 > 0xFF || i >= size)
 152             continue;
 153
 154         nbits  = ((state + 8) >> 5) + (state ? ff_clz(state) : 32) - 24;
 155         escape = av_mod_uintp2(16383, nbits);
 156         cnt1   = get_unary(bc, 0, 8);
 157         if (cnt1 > 7) {
 158             rlen = bitstream_read(bc, 16);
 159         } else {
 160             value = bitstream_read(bc, nbits);
 161             if (value <= 1) {
 162                 bitstream_unget(bc, value & 1, 1);
 163                 value = 1;
 164             }
 165             rlen = value + escape * cnt1 - 1;
 166         }
 167
 168         if (i + rlen > size)
 169             return AVERROR_INVALIDDATA;
 170         i += rlen;
 171
 172         for (k = 0; k < rlen; k++) {
 173             dst[j++] = 0;
 174             if (j == width) {
 175                 j    = 0;
 176                 dst += stride;
 177             }
 178         }
 179
 180         state = 0;
 181         flag  = rlen < 0xFFFF ? 1 : 0;
 182     }
 183
 184     bitstream_align(bc);
 185     return bitstream_tell(bc) >> 3;
 186 }
 187
 188 static int read_high_coeffs(AVCodecContext *avctx, uint8_t *src, int16_t *dst,
 189                             int size, int64_t c, int a, int64_t d,
 190                             int width, ptrdiff_t stride)
 191 {
 192     PixletContext *ctx = avctx->priv_data;
 193     BitstreamContext *bc = &ctx->bc;
 194     unsigned cnt1, shbits, rlen, nbits, length, i = 0, j = 0, k;
 195     int ret, escape, pfx, cthulu, yflag, xflag, flag = 0;
 196     int64_t state = 3, value, tmp;
 197
 198     ret = bitstream_init8(bc, src, bytestream2_get_bytes_left(&ctx->gb));
 199     if (ret < 0)
 200         return ret;
 201
 202     cthulu = (a >= 0) + (a ^ (a >> 31)) - (a >> 31);
 203     if (cthulu != 1) {
 204         nbits = 33 - ff_clz(cthulu - 1);
 205         if (nbits > 16)
 206             return AVERROR_INVALIDDATA;
 207     } else {
 208         nbits = 1;
 209     }
 210
 211     length = 25 - nbits;
 212
 213     while (i < size) {
 214         if (state >> 8 != -3)
 215             value = ff_clz((state >> 8) + 3) ^ 0x1F;
 216         else
 217             value = -1;
 218
 219         cnt1 = get_unary(bc, 0, length);
 220         if (cnt1 >= length) {
 221             cnt1 = bitstream_read(bc, nbits);
 222         } else {
 223             pfx    = 14 + (((value - 14) >> 32) & (value - 14));
 224             cnt1  *= (1 << pfx) - 1;
 225
 226             shbits = bitstream_read(bc, pfx);
 227             if (shbits <= 1) {
 228                 bitstream_unget(bc, shbits & 1, 1);
 229                 shbits = 1;
 230             }
 231             cnt1 += shbits - 1;
 232         }
 233
 234         xflag = flag + cnt1;
 235         yflag = xflag;
 236
 237         if (flag + cnt1 == 0) {
 238             value = 0;
 239         } else {
 240             xflag &= 1u;
 241             tmp    = c * ((yflag + 1) >> 1) + (c >> 1);
 242             value  = xflag + (tmp ^ -xflag);
 243         }
 244
 245         i++;
 246         dst[j++] = value;
 247         if (j == width) {
 248             j    = 0;
 249             dst += stride;
 250         }
 251         state += d * yflag - (d * state >> 8);
 252
 253         flag = 0;
 254
 255         if (state * 4 > 0xFF || i >= size)
 256             continue;
 257
 258         pfx    = ((state + 8) >> 5) + (state ? ff_clz(state) : 32) - 24;
 259         escape = av_mod_uintp2(16383, pfx);
 260         cnt1   = get_unary(bc, 0, 8);
 261         if (cnt1 < 8) {
 262             if (pfx < 1 || pfx > 25)
 263                 return AVERROR_INVALIDDATA;
 264
 265             value = bitstream_read(bc, pfx);
 266             if (value <= 1) {
 267                 bitstream_unget(bc, value & 1, 1);
 268                 value = 1;
 269             }
 270             rlen = value + escape * cnt1 - 1;
 271         } else {
 272             if (bitstream_read_bit(bc))
 273                 value = bitstream_read(bc, 16);
 274             else
 275                 value = bitstream_read(bc, 8);
 276
 277             rlen = value + 8 * escape;
 278         }
 279
 280         if (rlen > 0xFFFF || i + rlen > size)
 281             return AVERROR_INVALIDDATA;
 282         i += rlen;
 283
 284         for (k = 0; k < rlen; k++) {
 285             dst[j++] = 0;
 286             if (j == width) {
 287                 j    = 0;
 288                 dst += stride;
 289             }
 290         }
 291
 292         state = 0;
 293         flag  = rlen < 0xFFFF ? 1 : 0;
 294     }
 295
 296     bitstream_align(bc);
 297     return bitstream_tell(bc) >> 3;
 298 }
 299
 300 static int read_highpass(AVCodecContext *avctx, uint8_t *ptr,
 301                          int plane, AVFrame *frame)
 302 {
 303     PixletContext *ctx = avctx->priv_data;
 304     ptrdiff_t stride = frame->linesize[plane] / 2;
 305     int i, ret;
 306
 307     for (i = 0; i < ctx->levels * 3; i++) {
 308         int32_t a = bytestream2_get_be32(&ctx->gb);
 309         int32_t b = bytestream2_get_be32(&ctx->gb);
 310         int32_t c = bytestream2_get_be32(&ctx->gb);
 311         int32_t d = bytestream2_get_be32(&ctx->gb);
 312         int16_t *dest = (int16_t *)frame->data[plane] +
 313                         ctx->band[plane][i + 1].x +
 314                         ctx->band[plane][i + 1].y * stride;
 315         size_t size = ctx->band[plane][i + 1].size;
 316         uint32_t magic = bytestream2_get_be32(&ctx->gb);
 317
 318         if (magic != PIXLET_MAGIC) {
 319             av_log(avctx, AV_LOG_ERROR,
 320                    "wrong magic number: 0x%"PRIX32" for plane %d, band %d\n",
 321                    magic, plane, i);
 322             return AVERROR_INVALIDDATA;
 323         }
 324
 325         ret = read_high_coeffs(avctx, ptr + bytestream2_tell(&ctx->gb), dest,
 326                                size, c, (b >= FFABS(a)) ? b : a, d,
 327                                ctx->band[plane][i + 1].width, stride);
 328         if (ret < 0) {
 329             av_log(avctx, AV_LOG_ERROR,
 330                    "error in highpass coefficients for plane %d, band %d\n",
 331                    plane, i);
 332             return ret;
 333         }
 334         bytestream2_skip(&ctx->gb, ret);
 335     }
 336
 337     return 0;
 338 }
 339
 340 static void line_add_sat_s16(int16_t *dst, const int16_t *src, size_t len)
 341 {
 342     int i;
 343     for (i = 0; i < len; i++) {
 344         int val = dst[i] + src[i];
 345         dst[i] = av_clip_int16(val);
 346     }
 347 }
 348
 349 static void lowpass_prediction(int16_t *dst, int16_t *pred,
 350                                size_t width, size_t height, ptrdiff_t stride)
 351 {
 352     int i, j;
 353
 354     memset(pred, 0, width * sizeof(*pred));
 355
 356     for (i = 0; i < height; i++) {
 357         line_add_sat_s16(pred, dst, width);
 358         dst[0] = pred[0];
 359         for (j = 1; j < width; j++)
 360             dst[j] = pred[j] + dst[j - 1];
 361         dst += stride;
 362     }
 363 }
 364
 365 static void filterfn(int16_t *dest, int16_t *tmp, size_t size, int64_t scale)
 366 {
 367     int16_t *low, *high, *ll, *lh, *hl, *hh;
 368     int hsize, i, j;
 369     int64_t value;
 370
 371     hsize = size >> 1;
 372     low   = tmp + 4;
 373     high  = &low[hsize + 8];
 374
 375     memcpy(low, dest, size);
 376     memcpy(high, dest + hsize, size);
 377
 378     ll = &low[hsize];
 379     lh = &low[hsize];
 380     hl = &high[hsize];
 381     hh = hl;
 382     for (i = 4, j = 2; i; i--, j++, ll--, hh++, lh++, hl--) {
 383         low[i - 5]  = low[j - 1];
 384         lh[0]       = ll[-1];
 385         high[i - 5] = high[j - 2];
 386         hh[0]       = hl[-2];
 387     }
 388
 389     for (i = 0; i < hsize; i++) {
 390         value = (int64_t) low [i + 1] * -INT64_C(325392907)  +
 391                 (int64_t) low [i + 0] *  INT64_C(3687786320) +
 392                 (int64_t) low [i - 1] * -INT64_C(325392907)  +
 393                 (int64_t) high[i + 0] *  INT64_C(1518500249) +
 394                 (int64_t) high[i - 1] *  INT64_C(1518500249);
 395         dest[i * 2] = av_clip_int16(((value >> 32) * scale) >> 32);
 396     }
 397
 398     for (i = 0; i < hsize; i++) {
 399         value = (int64_t) low [i + 2] * -INT64_C(65078576)   +
 400                 (int64_t) low [i + 1] *  INT64_C(1583578880) +
 401                 (int64_t) low [i + 0] *  INT64_C(1583578880) +
 402                 (int64_t) low [i - 1] * -INT64_C(65078576)   +
 403                 (int64_t) high[i + 1] *  INT64_C(303700064)  +
 404                 (int64_t) high[i + 0] * -INT64_C(3644400640) +
 405                 (int64_t) high[i - 1] *  INT64_C(303700064);
 406         dest[i * 2 + 1] = av_clip_int16(((value >> 32) * scale) >> 32);
 407     }
 408 }
 409
 410 static void reconstruction(AVCodecContext *avctx, int16_t *dest,
 411                            size_t width, size_t height, ptrdiff_t stride,
 412                            int64_t *scaling_h, int64_t *scaling_v)
 413 {
 414     PixletContext *ctx = avctx->priv_data;
 415     unsigned scaled_width, scaled_height;
 416     int16_t *ptr, *tmp;
 417     int i, j, k;
 418
 419     scaled_width  = width  >> NB_LEVELS;
 420     scaled_height = height >> NB_LEVELS;
 421     tmp           = ctx->filter[0];
 422
 423     for (i = 0; i < NB_LEVELS; i++) {
 424         int64_t scale_v = scaling_v[i];
 425         int64_t scale_h = scaling_h[i];
 426         scaled_width  <<= 1;
 427         scaled_height <<= 1;
 428
 429         ptr = dest;
 430         for (j = 0; j < scaled_height; j++) {
 431             filterfn(ptr, ctx->filter[1], scaled_width, scale_v);
 432             ptr += stride;
 433         }
 434
 435         for (j = 0; j < scaled_width; j++) {
 436             ptr = dest + j;
 437             for (k = 0; k < scaled_height; k++) {
 438                 tmp[k] = *ptr;
 439                 ptr   += stride;
 440             }
 441
 442             filterfn(tmp, ctx->filter[1], scaled_height, scale_h);
 443
 444             ptr = dest + j;
 445             for (k = 0; k < scaled_height; k++) {
 446                 *ptr = tmp[k];
 447                 ptr += stride;
 448             }
 449         }
 450     }
 451 }
 452
 453 static void postprocess_luma(AVFrame *frame, size_t w, size_t h, int depth)
 454 {
 455     uint16_t *dsty = (uint16_t *)frame->data[0];
 456     int16_t *srcy  = (int16_t *)frame->data[0];
 457     ptrdiff_t stridey = frame->linesize[0] / 2;
 458     int i, j;
 459
 460     for (j = 0; j < h; j++) {
 461         for (i = 0; i < w; i++) {
 462             if (srcy[i] <= 0)
 463                 dsty[i] = 0;
 464             else if (srcy[i] > ((1 << depth) - 1))
 465                 dsty[i] = 65535;
 466             else
 467                 dsty[i] = ((int64_t) srcy[i] * srcy[i] * 65535) /
 468                           ((1 << depth) - 1) / ((1 << depth) - 1);
 469         }
 470         dsty += stridey;
 471         srcy += stridey;
 472     }
 473 }
 474
 475 static void postprocess_chroma(AVFrame *frame, int w, int h, int depth)
 476 {
 477     uint16_t *dstu = (uint16_t *)frame->data[1];
 478     uint16_t *dstv = (uint16_t *)frame->data[2];
 479     int16_t *srcu  = (int16_t *)frame->data[1];
 480     int16_t *srcv  = (int16_t *)frame->data[2];
 481     ptrdiff_t strideu = frame->linesize[1] / 2;
 482     ptrdiff_t stridev = frame->linesize[2] / 2;
 483     const unsigned add = 1 << (depth - 1);
 484     const unsigned shift = 16 - depth;
 485     int i, j;
 486
 487     for (j = 0; j < h; j++) {
 488         for (i = 0; i < w; i++) {
 489             dstu[i] = av_clip_uintp2_c(add + srcu[i], depth) << shift;
 490             dstv[i] = av_clip_uintp2_c(add + srcv[i], depth) << shift;
 491         }
 492         dstu += strideu;
 493         dstv += stridev;
 494         srcu += strideu;
 495         srcv += stridev;
 496     }
 497 }
 498
 499 static int decode_plane(AVCodecContext *avctx, int plane,
 500                         AVPacket *avpkt, AVFrame *frame)
 501 {
 502     PixletContext *ctx = avctx->priv_data;
 503     ptrdiff_t stride   = frame->linesize[plane] / 2;
 504     unsigned shift     = plane > 0;
 505     int16_t *dst;
 506     int i, ret;
 507
 508     for (i = ctx->levels - 1; i >= 0; i--) {
 509         int32_t h = sign_extend(bytestream2_get_be32(&ctx->gb), 32);
 510         int32_t v = sign_extend(bytestream2_get_be32(&ctx->gb), 32);
 511
 512         if (!h || !v)
 513             return AVERROR_INVALIDDATA;
 514
 515         ctx->scaling[plane][H][i] = (1000000ULL << 32) / h;
 516         ctx->scaling[plane][V][i] = (1000000ULL << 32) / v;
 517     }
 518
 519     bytestream2_skip(&ctx->gb, 4);
 520
 521     dst    = (int16_t *)frame->data[plane];
 522     dst[0] = sign_extend(bytestream2_get_be16(&ctx->gb), 16);
 523
 524     ret = bitstream_init8(&ctx->bc, avpkt->data + bytestream2_tell(&ctx->gb),
 525                           bytestream2_get_bytes_left(&ctx->gb));
 526     if (ret < 0)
 527         return ret;
 528
 529     ret = read_low_coeffs(avctx, dst + 1, ctx->band[plane][0].width - 1,
 530                           ctx->band[plane][0].width - 1, 0);
 531     if (ret < 0) {
 532         av_log(avctx, AV_LOG_ERROR,
 533                "error in lowpass coefficients for plane %d, top row\n", plane);
 534         return ret;
 535     }
 536
 537     ret = read_low_coeffs(avctx, dst + stride,
 538                           ctx->band[plane][0].height - 1, 1, stride);
 539     if (ret < 0) {
 540         av_log(avctx, AV_LOG_ERROR,
 541                "error in lowpass coefficients for plane %d, left column\n",
 542                plane);
 543         return ret;
 544     }
 545
 546     ret = read_low_coeffs(avctx, dst + stride + 1,
 547                           (ctx->band[plane][0].width - 1) * (ctx->band[plane][0].height - 1),
 548                           ctx->band[plane][0].width - 1, stride);
 549     if (ret < 0) {
 550         av_log(avctx, AV_LOG_ERROR,
 551                "error in lowpass coefficients for plane %d, rest\n", plane);
 552         return ret;
 553     }
 554
 555     bytestream2_skip(&ctx->gb, ret);
 556     if (bytestream2_get_bytes_left(&ctx->gb) <= 0) {
 557         av_log(avctx, AV_LOG_ERROR, "no bytes left\n");
 558         return AVERROR_INVALIDDATA;
 559     }
 560
 561     ret = read_highpass(avctx, avpkt->data, plane, frame);
 562     if (ret < 0)
 563         return ret;
 564
 565     lowpass_prediction(dst, ctx->prediction, ctx->band[plane][0].width,
 566                        ctx->band[plane][0].height, stride);
 567
 568     reconstruction(avctx, (int16_t *)frame->data[plane], ctx->w >> shift,
 569                    ctx->h >> shift, stride, ctx->scaling[plane][H],
 570                    ctx->scaling[plane][V]);
 571
 572     return 0;
 573 }
 574
 575 static int pixlet_decode_frame(AVCodecContext *avctx, void *data,
 576                                int *got_frame, AVPacket *avpkt)
 577 {
 578     PixletContext *ctx = avctx->priv_data;
 579     int i, w, h, width, height, ret, version;
 580     AVFrame *p = data;
 581     ThreadFrame frame = { .f = data };
 582     uint32_t pktsize;
 583
 584     bytestream2_init(&ctx->gb, avpkt->data, avpkt->size);
 585
 586     pktsize = bytestream2_get_be32(&ctx->gb);
 587     if (pktsize <= 44 || pktsize - 4 > bytestream2_get_bytes_left(&ctx->gb)) {
 588         av_log(avctx, AV_LOG_ERROR, "Invalid packet size %"PRIu32".\n", pktsize);
 589         return AVERROR_INVALIDDATA;
 590     }
 591
 592     version = bytestream2_get_le32(&ctx->gb);
 593     if (version != 1)
 594         avpriv_request_sample(avctx, "Version %d", version);
 595
 596     bytestream2_skip(&ctx->gb, 4);
 597     if (bytestream2_get_be32(&ctx->gb) != 1)
 598         return AVERROR_INVALIDDATA;
 599     bytestream2_skip(&ctx->gb, 4);
 600
 601     width  = bytestream2_get_be32(&ctx->gb);
 602     height = bytestream2_get_be32(&ctx->gb);
 603
 604     w = FFALIGN(width,  1 << (NB_LEVELS + 1));
 605     h = FFALIGN(height, 1 << (NB_LEVELS + 1));
 606
 607     ctx->levels = bytestream2_get_be32(&ctx->gb);
 608     if (ctx->levels != NB_LEVELS)
 609         return AVERROR_INVALIDDATA;
 610     ctx->depth = bytestream2_get_be32(&ctx->gb);
 611     if (ctx->depth < 8 || ctx->depth > 15) {
 612         avpriv_request_sample(avctx, "Depth %d", ctx->depth);
 613         return AVERROR_INVALIDDATA;
 614     }
 615
 616     ret = ff_set_dimensions(avctx, w, h);
 617     if (ret < 0)
 618         return ret;
 619     avctx->width  = width;
 620     avctx->height = height;
 621
 622     /* reinit should dimensions change */
 623     if (ctx->w != w || ctx->h != h) {
 624         pixlet_close(avctx);
 625         ctx->w = w;
 626         ctx->h = h;
 627
 628         ret = init_decoder(avctx);
 629         if (ret < 0) {
 630             pixlet_close(avctx);
 631             ctx->w = 0;
 632             ctx->h = 0;
 633             return ret;
 634         }
 635     }
 636
 637     bytestream2_skip(&ctx->gb, 8);
 638
 639     ret = ff_thread_get_buffer(avctx, &frame, 0);
 640     if (ret < 0)
 641         return ret;
 642
 643     for (i = 0; i < 3; i++) {
 644         ret = decode_plane(avctx, i, avpkt, frame.f);
 645         if (ret < 0)
 646             return ret;
 647         if (avctx->flags & AV_CODEC_FLAG_GRAY)
 648             break;
 649     }
 650
 651     postprocess_luma(frame.f, ctx->w, ctx->h, ctx->depth);
 652     postprocess_chroma(frame.f, ctx->w >> 1, ctx->h >> 1, ctx->depth);
 653
 654     p->pict_type   = AV_PICTURE_TYPE_I;
 655     p->color_range = AVCOL_RANGE_JPEG;
 656     p->key_frame   = 1;
 657
 658     *got_frame = 1;
 659
 660     return pktsize;
 661 }
 662
 663 #if HAVE_THREADS
 664 static int pixlet_init_thread_copy(AVCodecContext *avctx)
 665 {
 666     PixletContext *ctx = avctx->priv_data;
 667
 668     ctx->filter[0]  = NULL;
 669     ctx->filter[1]  = NULL;
 670     ctx->prediction = NULL;
 671     ctx->w = 0;
 672     ctx->h = 0;
 673
 674     return 0;
 675 }
 676 #endif /* HAVE_THREADS */
 677
 678 AVCodec ff_pixlet_decoder = {
 679     .name             = "pixlet",
 680     .long_name        = NULL_IF_CONFIG_SMALL("Apple Pixlet"),
 681     .type             = AVMEDIA_TYPE_VIDEO,
 682     .id               = AV_CODEC_ID_PIXLET,
 683     .init             = pixlet_init,
 684     .init_thread_copy = ONLY_IF_THREADS_ENABLED(pixlet_init_thread_copy),
 685     .close            = pixlet_close,
 686     .decode           = pixlet_decode_frame,
 687     .priv_data_size   = sizeof(PixletContext),
 688     .capabilities     = AV_CODEC_CAP_DR1 |
 689                         AV_CODEC_CAP_FRAME_THREADS,
 690     .caps_internal    = FF_CODEC_CAP_INIT_THREADSAFE |
 691                         FF_CODEC_CAP_INIT_CLEANUP,
 692 };