libavcodec/pngdec.c

   1 /*
   2  * PNG image format
   3  * Copyright (c) 2003 Fabrice Bellard.
   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 #include "avcodec.h"
  22 #include "bytestream.h"
  23 #include "png.h"
  24
  25 /* TODO:
  26  * - add 2, 4 and 16 bit depth support
  27  */
  28
  29 #include <zlib.h>
  30
  31 //#define DEBUG
  32
  33 typedef struct PNGDecContext {
  34     uint8_t *bytestream;
  35     uint8_t *bytestream_start;
  36     uint8_t *bytestream_end;
  37     AVFrame picture;
  38
  39     int state;
  40     int width, height;
  41     int bit_depth;
  42     int color_type;
  43     int compression_type;
  44     int interlace_type;
  45     int filter_type;
  46     int channels;
  47     int bits_per_pixel;
  48     int bpp;
  49
  50     uint8_t *image_buf;
  51     int image_linesize;
  52     uint32_t palette[256];
  53     uint8_t *crow_buf;
  54     uint8_t *last_row;
  55     uint8_t *tmp_row;
  56     int pass;
  57     int crow_size; /* compressed row size (include filter type) */
  58     int row_size; /* decompressed row size */
  59     int pass_row_size; /* decompress row size of the current pass */
  60     int y;
  61     z_stream zstream;
  62 } PNGDecContext;
  63
  64 /* Mask to determine which y pixels can be written in a pass */
  65 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
  66     0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
  67 };
  68
  69 /* Mask to determine which pixels to overwrite while displaying */
  70 static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
  71     0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
  72 };
  73
  74 /* NOTE: we try to construct a good looking image at each pass. width
  75    is the original image width. We also do pixel format conversion at
  76    this stage */
  77 static void png_put_interlaced_row(uint8_t *dst, int width,
  78                                    int bits_per_pixel, int pass,
  79                                    int color_type, const uint8_t *src)
  80 {
  81     int x, mask, dsp_mask, j, src_x, b, bpp;
  82     uint8_t *d;
  83     const uint8_t *s;
  84
  85     mask = ff_png_pass_mask[pass];
  86     dsp_mask = png_pass_dsp_mask[pass];
  87     switch(bits_per_pixel) {
  88     case 1:
  89         /* we must initialize the line to zero before writing to it */
  90         if (pass == 0)
  91             memset(dst, 0, (width + 7) >> 3);
  92         src_x = 0;
  93         for(x = 0; x < width; x++) {
  94             j = (x & 7);
  95             if ((dsp_mask << j) & 0x80) {
  96                 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
  97                 dst[x >> 3] |= b << (7 - j);
  98             }
  99             if ((mask << j) & 0x80)
 100                 src_x++;
 101         }
 102         break;
 103     default:
 104         bpp = bits_per_pixel >> 3;
 105         d = dst;
 106         s = src;
 107         if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 108             for(x = 0; x < width; x++) {
 109                 j = x & 7;
 110                 if ((dsp_mask << j) & 0x80) {
 111                     *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
 112                 }
 113                 d += bpp;
 114                 if ((mask << j) & 0x80)
 115                     s += bpp;
 116             }
 117         } else {
 118             for(x = 0; x < width; x++) {
 119                 j = x & 7;
 120                 if ((dsp_mask << j) & 0x80) {
 121                     memcpy(d, s, bpp);
 122                 }
 123                 d += bpp;
 124                 if ((mask << j) & 0x80)
 125                     s += bpp;
 126             }
 127         }
 128         break;
 129     }
 130 }
 131
 132 /* XXX: optimize */
 133 /* NOTE: 'dst' can be equal to 'last' */
 134 static void png_filter_row(uint8_t *dst, int filter_type,
 135                            uint8_t *src, uint8_t *last, int size, int bpp)
 136 {
 137     int i, p;
 138
 139     switch(filter_type) {
 140     case PNG_FILTER_VALUE_NONE:
 141         memcpy(dst, src, size);
 142         break;
 143     case PNG_FILTER_VALUE_SUB:
 144         for(i = 0; i < bpp; i++) {
 145             dst[i] = src[i];
 146         }
 147         for(i = bpp; i < size; i++) {
 148             p = dst[i - bpp];
 149             dst[i] = p + src[i];
 150         }
 151         break;
 152     case PNG_FILTER_VALUE_UP:
 153         for(i = 0; i < size; i++) {
 154             p = last[i];
 155             dst[i] = p + src[i];
 156         }
 157         break;
 158     case PNG_FILTER_VALUE_AVG:
 159         for(i = 0; i < bpp; i++) {
 160             p = (last[i] >> 1);
 161             dst[i] = p + src[i];
 162         }
 163         for(i = bpp; i < size; i++) {
 164             p = ((dst[i - bpp] + last[i]) >> 1);
 165             dst[i] = p + src[i];
 166         }
 167         break;
 168     case PNG_FILTER_VALUE_PAETH:
 169         for(i = 0; i < bpp; i++) {
 170             p = last[i];
 171             dst[i] = p + src[i];
 172         }
 173         for(i = bpp; i < size; i++) {
 174             int a, b, c, pa, pb, pc;
 175
 176             a = dst[i - bpp];
 177             b = last[i];
 178             c = last[i - bpp];
 179
 180             p = b - c;
 181             pc = a - c;
 182
 183             pa = abs(p);
 184             pb = abs(pc);
 185             pc = abs(p + pc);
 186
 187             if (pa <= pb && pa <= pc)
 188                 p = a;
 189             else if (pb <= pc)
 190                 p = b;
 191             else
 192                 p = c;
 193             dst[i] = p + src[i];
 194         }
 195         break;
 196     }
 197 }
 198
 199 static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width)
 200 {
 201     int j;
 202     unsigned int r, g, b, a;
 203
 204     for(j = 0;j < width; j++) {
 205         r = src[0];
 206         g = src[1];
 207         b = src[2];
 208         a = src[3];
 209         *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
 210         dst += 4;
 211         src += 4;
 212     }
 213 }
 214
 215 /* process exactly one decompressed row */
 216 static void png_handle_row(PNGDecContext *s)
 217 {
 218     uint8_t *ptr, *last_row;
 219     int got_line;
 220
 221     if (!s->interlace_type) {
 222         ptr = s->image_buf + s->image_linesize * s->y;
 223         /* need to swap bytes correctly for RGB_ALPHA */
 224         if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 225             png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
 226                            s->last_row, s->row_size, s->bpp);
 227             memcpy(s->last_row, s->tmp_row, s->row_size);
 228             convert_to_rgb32(ptr, s->tmp_row, s->width);
 229         } else {
 230             /* in normal case, we avoid one copy */
 231             if (s->y == 0)
 232                 last_row = s->last_row;
 233             else
 234                 last_row = ptr - s->image_linesize;
 235
 236             png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1,
 237                            last_row, s->row_size, s->bpp);
 238         }
 239         s->y++;
 240         if (s->y == s->height) {
 241             s->state |= PNG_ALLIMAGE;
 242         }
 243     } else {
 244         got_line = 0;
 245         for(;;) {
 246             ptr = s->image_buf + s->image_linesize * s->y;
 247             if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
 248                 /* if we already read one row, it is time to stop to
 249                    wait for the next one */
 250                 if (got_line)
 251                     break;
 252                 png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
 253                                s->last_row, s->pass_row_size, s->bpp);
 254                 memcpy(s->last_row, s->tmp_row, s->pass_row_size);
 255                 got_line = 1;
 256             }
 257             if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
 258                 /* NOTE: RGB32 is handled directly in png_put_interlaced_row */
 259                 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
 260                                        s->color_type, s->last_row);
 261             }
 262             s->y++;
 263             if (s->y == s->height) {
 264                 for(;;) {
 265                     if (s->pass == NB_PASSES - 1) {
 266                         s->state |= PNG_ALLIMAGE;
 267                         goto the_end;
 268                     } else {
 269                         s->pass++;
 270                         s->y = 0;
 271                         s->pass_row_size = ff_png_pass_row_size(s->pass,
 272                                                              s->bits_per_pixel,
 273                                                              s->width);
 274                         s->crow_size = s->pass_row_size + 1;
 275                         if (s->pass_row_size != 0)
 276                             break;
 277                         /* skip pass if empty row */
 278                     }
 279                 }
 280             }
 281         }
 282     the_end: ;
 283     }
 284 }
 285
 286 static int png_decode_idat(PNGDecContext *s, int length)
 287 {
 288     int ret;
 289     s->zstream.avail_in = length;
 290     s->zstream.next_in = s->bytestream;
 291     s->bytestream += length;
 292
 293     if(s->bytestream > s->bytestream_end)
 294         return -1;
 295
 296     /* decode one line if possible */
 297     while (s->zstream.avail_in > 0) {
 298         ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
 299         if (ret != Z_OK && ret != Z_STREAM_END) {
 300             return -1;
 301         }
 302         if (s->zstream.avail_out == 0) {
 303             if (!(s->state & PNG_ALLIMAGE)) {
 304                 png_handle_row(s);
 305             }
 306             s->zstream.avail_out = s->crow_size;
 307             s->zstream.next_out = s->crow_buf;
 308         }
 309     }
 310     return 0;
 311 }
 312
 313 static int decode_frame(AVCodecContext *avctx,
 314                         void *data, int *data_size,
 315                         uint8_t *buf, int buf_size)
 316 {
 317     PNGDecContext * const s = avctx->priv_data;
 318     AVFrame *picture = data;
 319     AVFrame * const p= (AVFrame*)&s->picture;
 320     uint32_t tag, length;
 321     int ret, crc;
 322
 323     s->bytestream_start=
 324     s->bytestream= buf;
 325     s->bytestream_end= buf + buf_size;
 326
 327     /* check signature */
 328     if (memcmp(s->bytestream, ff_pngsig, 8) != 0)
 329         return -1;
 330     s->bytestream+= 8;
 331     s->y=
 332     s->state=0;
 333 //    memset(s, 0, sizeof(PNGDecContext));
 334     /* init the zlib */
 335     s->zstream.zalloc = ff_png_zalloc;
 336     s->zstream.zfree = ff_png_zfree;
 337     s->zstream.opaque = NULL;
 338     ret = inflateInit(&s->zstream);
 339     if (ret != Z_OK)
 340         return -1;
 341     for(;;) {
 342         int tag32;
 343         if (s->bytestream >= s->bytestream_end)
 344             goto fail;
 345         length = bytestream_get_be32(&s->bytestream);
 346         if (length > 0x7fffffff)
 347             goto fail;
 348         tag32 = bytestream_get_be32(&s->bytestream);
 349         tag = bswap_32(tag32);
 350 #ifdef DEBUG
 351         av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
 352                (tag & 0xff),
 353                ((tag >> 8) & 0xff),
 354                ((tag >> 16) & 0xff),
 355                ((tag >> 24) & 0xff), length);
 356 #endif
 357         switch(tag) {
 358         case MKTAG('I', 'H', 'D', 'R'):
 359             if (length != 13)
 360                 goto fail;
 361             s->width = bytestream_get_be32(&s->bytestream);
 362             s->height = bytestream_get_be32(&s->bytestream);
 363             if(avcodec_check_dimensions(avctx, s->width, s->height)){
 364                 s->width= s->height= 0;
 365                 goto fail;
 366             }
 367             s->bit_depth = *s->bytestream++;
 368             s->color_type = *s->bytestream++;
 369             s->compression_type = *s->bytestream++;
 370             s->filter_type = *s->bytestream++;
 371             s->interlace_type = *s->bytestream++;
 372             crc = bytestream_get_be32(&s->bytestream);
 373             s->state |= PNG_IHDR;
 374 #ifdef DEBUG
 375             av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
 376                    s->width, s->height, s->bit_depth, s->color_type,
 377                    s->compression_type, s->filter_type, s->interlace_type);
 378 #endif
 379             break;
 380         case MKTAG('I', 'D', 'A', 'T'):
 381             if (!(s->state & PNG_IHDR))
 382                 goto fail;
 383             if (!(s->state & PNG_IDAT)) {
 384                 /* init image info */
 385                 avctx->width = s->width;
 386                 avctx->height = s->height;
 387
 388                 s->channels = ff_png_get_nb_channels(s->color_type);
 389                 s->bits_per_pixel = s->bit_depth * s->channels;
 390                 s->bpp = (s->bits_per_pixel + 7) >> 3;
 391                 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
 392
 393                 if (s->bit_depth == 8 &&
 394                     s->color_type == PNG_COLOR_TYPE_RGB) {
 395                     avctx->pix_fmt = PIX_FMT_RGB24;
 396                 } else if (s->bit_depth == 8 &&
 397                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 398                     avctx->pix_fmt = PIX_FMT_RGB32;
 399                 } else if (s->bit_depth == 8 &&
 400                            s->color_type == PNG_COLOR_TYPE_GRAY) {
 401                     avctx->pix_fmt = PIX_FMT_GRAY8;
 402                 } else if (s->bit_depth == 16 &&
 403                            s->color_type == PNG_COLOR_TYPE_GRAY) {
 404                     avctx->pix_fmt = PIX_FMT_GRAY16BE;
 405                 } else if (s->bit_depth == 1 &&
 406                            s->color_type == PNG_COLOR_TYPE_GRAY) {
 407                     avctx->pix_fmt = PIX_FMT_MONOBLACK;
 408                 } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
 409                     avctx->pix_fmt = PIX_FMT_PAL8;
 410                 } else {
 411                     goto fail;
 412                 }
 413                 if(p->data[0])
 414                     avctx->release_buffer(avctx, p);
 415
 416                 p->reference= 0;
 417                 if(avctx->get_buffer(avctx, p) < 0){
 418                     av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 419                     goto fail;
 420                 }
 421                 p->pict_type= FF_I_TYPE;
 422                 p->key_frame= 1;
 423                 p->interlaced_frame = !!s->interlace_type;
 424
 425                 /* compute the compressed row size */
 426                 if (!s->interlace_type) {
 427                     s->crow_size = s->row_size + 1;
 428                 } else {
 429                     s->pass = 0;
 430                     s->pass_row_size = ff_png_pass_row_size(s->pass,
 431                                                          s->bits_per_pixel,
 432                                                          s->width);
 433                     s->crow_size = s->pass_row_size + 1;
 434                 }
 435 #ifdef DEBUG
 436                 av_log(avctx, AV_LOG_DEBUG, "row_size=%d crow_size =%d\n",
 437                        s->row_size, s->crow_size);
 438 #endif
 439                 s->image_buf = p->data[0];
 440                 s->image_linesize = p->linesize[0];
 441                 /* copy the palette if needed */
 442                 if (s->color_type == PNG_COLOR_TYPE_PALETTE)
 443                     memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
 444                 /* empty row is used if differencing to the first row */
 445                 s->last_row = av_mallocz(s->row_size);
 446                 if (!s->last_row)
 447                     goto fail;
 448                 if (s->interlace_type ||
 449                     s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 450                     s->tmp_row = av_malloc(s->row_size);
 451                     if (!s->tmp_row)
 452                         goto fail;
 453                 }
 454                 /* compressed row */
 455                 s->crow_buf = av_malloc(s->row_size + 1);
 456                 if (!s->crow_buf)
 457                     goto fail;
 458                 s->zstream.avail_out = s->crow_size;
 459                 s->zstream.next_out = s->crow_buf;
 460             }
 461             s->state |= PNG_IDAT;
 462             if (png_decode_idat(s, length) < 0)
 463                 goto fail;
 464             /* skip crc */
 465             crc = bytestream_get_be32(&s->bytestream);
 466             break;
 467         case MKTAG('P', 'L', 'T', 'E'):
 468             {
 469                 int n, i, r, g, b;
 470
 471                 if ((length % 3) != 0 || length > 256 * 3)
 472                     goto skip_tag;
 473                 /* read the palette */
 474                 n = length / 3;
 475                 for(i=0;i<n;i++) {
 476                     r = *s->bytestream++;
 477                     g = *s->bytestream++;
 478                     b = *s->bytestream++;
 479                     s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
 480                 }
 481                 for(;i<256;i++) {
 482                     s->palette[i] = (0xff << 24);
 483                 }
 484                 s->state |= PNG_PLTE;
 485                 crc = bytestream_get_be32(&s->bytestream);
 486             }
 487             break;
 488         case MKTAG('t', 'R', 'N', 'S'):
 489             {
 490                 int v, i;
 491
 492                 /* read the transparency. XXX: Only palette mode supported */
 493                 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
 494                     length > 256 ||
 495                     !(s->state & PNG_PLTE))
 496                     goto skip_tag;
 497                 for(i=0;i<length;i++) {
 498                     v = *s->bytestream++;
 499                     s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
 500                 }
 501                 crc = bytestream_get_be32(&s->bytestream);
 502             }
 503             break;
 504         case MKTAG('I', 'E', 'N', 'D'):
 505             if (!(s->state & PNG_ALLIMAGE))
 506                 goto fail;
 507             crc = bytestream_get_be32(&s->bytestream);
 508             goto exit_loop;
 509         default:
 510             /* skip tag */
 511         skip_tag:
 512             s->bytestream += length + 4;
 513             break;
 514         }
 515     }
 516  exit_loop:
 517     *picture= *(AVFrame*)&s->picture;
 518     *data_size = sizeof(AVPicture);
 519
 520     ret = s->bytestream - s->bytestream_start;
 521  the_end:
 522     inflateEnd(&s->zstream);
 523     av_freep(&s->crow_buf);
 524     av_freep(&s->last_row);
 525     av_freep(&s->tmp_row);
 526     return ret;
 527  fail:
 528     ret = -1;
 529     goto the_end;
 530 }
 531
 532 static int png_dec_init(AVCodecContext *avctx){
 533     PNGDecContext *s = avctx->priv_data;
 534
 535     avcodec_get_frame_defaults((AVFrame*)&s->picture);
 536     avctx->coded_frame= (AVFrame*)&s->picture;
 537
 538     return 0;
 539 }
 540
 541 AVCodec png_decoder = {
 542     "png",
 543     CODEC_TYPE_VIDEO,
 544     CODEC_ID_PNG,
 545     sizeof(PNGDecContext),
 546     png_dec_init,
 547     NULL,
 548     NULL, //decode_end,
 549     decode_frame,
 550     0 /*CODEC_CAP_DR1*/ /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
 551     NULL
 552 };