quicktime/ffmpeg/libavcodec/png.c

   1 /*
   2  * PNG image format
   3  * Copyright (c) 2003 Fabrice Bellard.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 #include "avcodec.h"
  20
  21 /* TODO:
  22  * - add 2, 4 and 16 bit depth support
  23  * - use filters when generating a png (better compression)
  24  */
  25
  26 #ifdef CONFIG_ZLIB
  27 #include <zlib.h>
  28
  29 //#define DEBUG
  30
  31 #define PNG_COLOR_MASK_PALETTE    1
  32 #define PNG_COLOR_MASK_COLOR      2
  33 #define PNG_COLOR_MASK_ALPHA      4
  34
  35 #define PNG_COLOR_TYPE_GRAY 0
  36 #define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
  37 #define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
  38 #define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
  39 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
  40
  41 #define PNG_FILTER_VALUE_NONE  0
  42 #define PNG_FILTER_VALUE_SUB   1
  43 #define PNG_FILTER_VALUE_UP    2
  44 #define PNG_FILTER_VALUE_AVG   3
  45 #define PNG_FILTER_VALUE_PAETH 4
  46
  47 #define PNG_IHDR      0x0001
  48 #define PNG_IDAT      0x0002
  49 #define PNG_ALLIMAGE  0x0004
  50 #define PNG_PLTE      0x0008
  51
  52 #define NB_PASSES 7
  53
  54 #define IOBUF_SIZE 4096
  55
  56 typedef struct PNGContext {
  57     uint8_t *bytestream;
  58     uint8_t *bytestream_start;
  59     uint8_t *bytestream_end;
  60     AVFrame picture;
  61
  62     int state;
  63     int width, height;
  64     int bit_depth;
  65     int color_type;
  66     int compression_type;
  67     int interlace_type;
  68     int filter_type;
  69     int channels;
  70     int bits_per_pixel;
  71     int bpp;
  72
  73     uint8_t *image_buf;
  74     int image_linesize;
  75     uint32_t palette[256];
  76     uint8_t *crow_buf;
  77     uint8_t *last_row;
  78     uint8_t *tmp_row;
  79     int pass;
  80     int crow_size; /* compressed row size (include filter type) */
  81     int row_size; /* decompressed row size */
  82     int pass_row_size; /* decompress row size of the current pass */
  83     int y;
  84     z_stream zstream;
  85     uint8_t buf[IOBUF_SIZE];
  86 } PNGContext;
  87
  88 static unsigned int get32(uint8_t **b){
  89     (*b) += 4;
  90     return ((*b)[-4]<<24) + ((*b)[-3]<<16) + ((*b)[-2]<<8) + (*b)[-1];
  91 }
  92
  93 static void put32(uint8_t **b, unsigned int v){
  94     *(*b)++= v>>24;
  95     *(*b)++= v>>16;
  96     *(*b)++= v>>8;
  97     *(*b)++= v;
  98 }
  99
 100 static const uint8_t pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
 101
 102 /* Mask to determine which y pixels are valid in a pass */
 103 static const uint8_t png_pass_ymask[NB_PASSES] = {
 104     0x80, 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55,
 105 };
 106
 107 /* Mask to determine which y pixels can be written in a pass */
 108 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
 109     0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
 110 };
 111
 112 /* minimum x value */
 113 static const uint8_t png_pass_xmin[NB_PASSES] = {
 114     0, 4, 0, 2, 0, 1, 0
 115 };
 116
 117 /* x shift to get row width */
 118 static const uint8_t png_pass_xshift[NB_PASSES] = {
 119     3, 3, 2, 2, 1, 1, 0
 120 };
 121
 122 /* Mask to determine which pixels are valid in a pass */
 123 static const uint8_t png_pass_mask[NB_PASSES] = {
 124     0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff
 125 };
 126
 127 /* Mask to determine which pixels to overwrite while displaying */
 128 static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
 129     0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
 130 };
 131 #if 0
 132 static int png_probe(AVProbeData *pd)
 133 {
 134     if (pd->buf_size >= 8 &&
 135         memcmp(pd->buf, pngsig, 8) == 0)
 136         return AVPROBE_SCORE_MAX;
 137     else
 138         return 0;
 139 }
 140 #endif
 141 static void *png_zalloc(void *opaque, unsigned int items, unsigned int size)
 142 {
 143     if(items >= UINT_MAX / size)
 144         return NULL;
 145     return av_malloc(items * size);
 146 }
 147
 148 static void png_zfree(void *opaque, void *ptr)
 149 {
 150     av_free(ptr);
 151 }
 152
 153 static int png_get_nb_channels(int color_type)
 154 {
 155     int channels;
 156     channels = 1;
 157     if ((color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
 158         PNG_COLOR_MASK_COLOR)
 159         channels = 3;
 160     if (color_type & PNG_COLOR_MASK_ALPHA)
 161         channels++;
 162     return channels;
 163 }
 164
 165 /* compute the row size of an interleaved pass */
 166 static int png_pass_row_size(int pass, int bits_per_pixel, int width)
 167 {
 168     int shift, xmin, pass_width;
 169
 170     xmin = png_pass_xmin[pass];
 171     if (width <= xmin)
 172         return 0;
 173     shift = png_pass_xshift[pass];
 174     pass_width = (width - xmin + (1 << shift) - 1) >> shift;
 175     return (pass_width * bits_per_pixel + 7) >> 3;
 176 }
 177
 178 /* NOTE: we try to construct a good looking image at each pass. width
 179    is the original image width. We also do pixel format convertion at
 180    this stage */
 181 static void png_put_interlaced_row(uint8_t *dst, int width,
 182                                    int bits_per_pixel, int pass,
 183                                    int color_type, const uint8_t *src)
 184 {
 185     int x, mask, dsp_mask, j, src_x, b, bpp;
 186     uint8_t *d;
 187     const uint8_t *s;
 188
 189     mask = png_pass_mask[pass];
 190     dsp_mask = png_pass_dsp_mask[pass];
 191     switch(bits_per_pixel) {
 192     case 1:
 193         /* we must intialize the line to zero before writing to it */
 194         if (pass == 0)
 195             memset(dst, 0, (width + 7) >> 3);
 196         src_x = 0;
 197         for(x = 0; x < width; x++) {
 198             j = (x & 7);
 199             if ((dsp_mask << j) & 0x80) {
 200                 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
 201                 dst[x >> 3] |= b << (7 - j);
 202             }
 203             if ((mask << j) & 0x80)
 204                 src_x++;
 205         }
 206         break;
 207     default:
 208         bpp = bits_per_pixel >> 3;
 209         d = dst;
 210         s = src;
 211         if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 212             for(x = 0; x < width; x++) {
 213                 j = x & 7;
 214                 if ((dsp_mask << j) & 0x80) {
 215                     *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
 216                 }
 217                 d += bpp;
 218                 if ((mask << j) & 0x80)
 219                     s += bpp;
 220             }
 221         } else {
 222             for(x = 0; x < width; x++) {
 223                 j = x & 7;
 224                 if ((dsp_mask << j) & 0x80) {
 225                     memcpy(d, s, bpp);
 226                 }
 227                 d += bpp;
 228                 if ((mask << j) & 0x80)
 229                     s += bpp;
 230             }
 231         }
 232         break;
 233     }
 234 }
 235
 236 static void png_get_interlaced_row(uint8_t *dst, int row_size,
 237                                    int bits_per_pixel, int pass,
 238                                    const uint8_t *src, int width)
 239 {
 240     int x, mask, dst_x, j, b, bpp;
 241     uint8_t *d;
 242     const uint8_t *s;
 243
 244     mask = png_pass_mask[pass];
 245     switch(bits_per_pixel) {
 246     case 1:
 247         memset(dst, 0, row_size);
 248         dst_x = 0;
 249         for(x = 0; x < width; x++) {
 250             j = (x & 7);
 251             if ((mask << j) & 0x80) {
 252                 b = (src[x >> 3] >> (7 - j)) & 1;
 253                 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
 254                 dst_x++;
 255             }
 256         }
 257         break;
 258     default:
 259         bpp = bits_per_pixel >> 3;
 260         d = dst;
 261         s = src;
 262         for(x = 0; x < width; x++) {
 263             j = x & 7;
 264             if ((mask << j) & 0x80) {
 265                 memcpy(d, s, bpp);
 266                 d += bpp;
 267             }
 268             s += bpp;
 269         }
 270         break;
 271     }
 272 }
 273
 274 /* XXX: optimize */
 275 /* NOTE: 'dst' can be equal to 'last' */
 276 static void png_filter_row(uint8_t *dst, int filter_type,
 277                            uint8_t *src, uint8_t *last, int size, int bpp)
 278 {
 279     int i, p;
 280
 281     switch(filter_type) {
 282     case PNG_FILTER_VALUE_NONE:
 283         memcpy(dst, src, size);
 284         break;
 285     case PNG_FILTER_VALUE_SUB:
 286         for(i = 0; i < bpp; i++) {
 287             dst[i] = src[i];
 288         }
 289         for(i = bpp; i < size; i++) {
 290             p = dst[i - bpp];
 291             dst[i] = p + src[i];
 292         }
 293         break;
 294     case PNG_FILTER_VALUE_UP:
 295         for(i = 0; i < size; i++) {
 296             p = last[i];
 297             dst[i] = p + src[i];
 298         }
 299         break;
 300     case PNG_FILTER_VALUE_AVG:
 301         for(i = 0; i < bpp; i++) {
 302             p = (last[i] >> 1);
 303             dst[i] = p + src[i];
 304         }
 305         for(i = bpp; i < size; i++) {
 306             p = ((dst[i - bpp] + last[i]) >> 1);
 307             dst[i] = p + src[i];
 308         }
 309         break;
 310     case PNG_FILTER_VALUE_PAETH:
 311         for(i = 0; i < bpp; i++) {
 312             p = last[i];
 313             dst[i] = p + src[i];
 314         }
 315         for(i = bpp; i < size; i++) {
 316             int a, b, c, pa, pb, pc;
 317
 318             a = dst[i - bpp];
 319             b = last[i];
 320             c = last[i - bpp];
 321
 322             p = b - c;
 323             pc = a - c;
 324
 325             pa = abs(p);
 326             pb = abs(pc);
 327             pc = abs(p + pc);
 328
 329             if (pa <= pb && pa <= pc)
 330                 p = a;
 331             else if (pb <= pc)
 332                 p = b;
 333             else
 334                 p = c;
 335             dst[i] = p + src[i];
 336         }
 337         break;
 338     }
 339 }
 340
 341 static void convert_from_rgba32(uint8_t *dst, const uint8_t *src, int width)
 342 {
 343     uint8_t *d;
 344     int j;
 345     unsigned int v;
 346
 347     d = dst;
 348     for(j = 0; j < width; j++) {
 349         v = ((uint32_t *)src)[j];
 350         d[0] = v >> 16;
 351         d[1] = v >> 8;
 352         d[2] = v;
 353         d[3] = v >> 24;
 354         d += 4;
 355     }
 356 }
 357
 358 static void convert_to_rgba32(uint8_t *dst, const uint8_t *src, int width)
 359 {
 360     int j;
 361     unsigned int r, g, b, a;
 362
 363     for(j = 0;j < width; j++) {
 364         r = src[0];
 365         g = src[1];
 366         b = src[2];
 367         a = src[3];
 368         *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
 369         dst += 4;
 370         src += 4;
 371     }
 372 }
 373
 374 /* process exactly one decompressed row */
 375 static void png_handle_row(PNGContext *s)
 376 {
 377     uint8_t *ptr, *last_row;
 378     int got_line;
 379
 380     if (!s->interlace_type) {
 381         ptr = s->image_buf + s->image_linesize * s->y;
 382         /* need to swap bytes correctly for RGB_ALPHA */
 383         if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 384             png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
 385                            s->last_row, s->row_size, s->bpp);
 386             memcpy(s->last_row, s->tmp_row, s->row_size);
 387             convert_to_rgba32(ptr, s->tmp_row, s->width);
 388         } else {
 389             /* in normal case, we avoid one copy */
 390             if (s->y == 0)
 391                 last_row = s->last_row;
 392             else
 393                 last_row = ptr - s->image_linesize;
 394
 395             png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1,
 396                            last_row, s->row_size, s->bpp);
 397         }
 398         s->y++;
 399         if (s->y == s->height) {
 400             s->state |= PNG_ALLIMAGE;
 401         }
 402     } else {
 403         got_line = 0;
 404         for(;;) {
 405             ptr = s->image_buf + s->image_linesize * s->y;
 406             if ((png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
 407                 /* if we already read one row, it is time to stop to
 408                    wait for the next one */
 409                 if (got_line)
 410                     break;
 411                 png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
 412                                s->last_row, s->pass_row_size, s->bpp);
 413                 memcpy(s->last_row, s->tmp_row, s->pass_row_size);
 414                 got_line = 1;
 415             }
 416             if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
 417                 /* NOTE: rgba32 is handled directly in png_put_interlaced_row */
 418                 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
 419                                        s->color_type, s->last_row);
 420             }
 421             s->y++;
 422             if (s->y == s->height) {
 423                 for(;;) {
 424                     if (s->pass == NB_PASSES - 1) {
 425                         s->state |= PNG_ALLIMAGE;
 426                         goto the_end;
 427                     } else {
 428                         s->pass++;
 429                         s->y = 0;
 430                         s->pass_row_size = png_pass_row_size(s->pass,
 431                                                              s->bits_per_pixel,
 432                                                              s->width);
 433                         s->crow_size = s->pass_row_size + 1;
 434                         if (s->pass_row_size != 0)
 435                             break;
 436                         /* skip pass if empty row */
 437                     }
 438                 }
 439             }
 440         }
 441     the_end: ;
 442     }
 443 }
 444
 445 static int png_decode_idat(PNGContext *s, int length)
 446 {
 447     int ret;
 448     s->zstream.avail_in = length;
 449     s->zstream.next_in = s->bytestream;
 450     s->bytestream += length;
 451
 452     if(s->bytestream > s->bytestream_end)
 453         return -1;
 454
 455     /* decode one line if possible */
 456     while (s->zstream.avail_in > 0) {
 457         ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
 458         if (ret != Z_OK && ret != Z_STREAM_END) {
 459             return -1;
 460         }
 461         if (s->zstream.avail_out == 0) {
 462             if (!(s->state & PNG_ALLIMAGE)) {
 463                 png_handle_row(s);
 464             }
 465             s->zstream.avail_out = s->crow_size;
 466             s->zstream.next_out = s->crow_buf;
 467         }
 468     }
 469     return 0;
 470 }
 471
 472 static int decode_frame(AVCodecContext *avctx,
 473                         void *data, int *data_size,
 474                         uint8_t *buf, int buf_size)
 475 {
 476     PNGContext * const s = avctx->priv_data;
 477     AVFrame *picture = data;
 478     AVFrame * const p= (AVFrame*)&s->picture;
 479     uint32_t tag, length;
 480     int ret, crc;
 481
 482     s->bytestream_start=
 483     s->bytestream= buf;
 484     s->bytestream_end= buf + buf_size;
 485
 486     /* check signature */
 487     if (memcmp(s->bytestream, pngsig, 8) != 0)
 488         return -1;
 489     s->bytestream+= 8;
 490     s->y=
 491     s->state=0;
 492 //    memset(s, 0, sizeof(PNGContext));
 493     /* init the zlib */
 494     s->zstream.zalloc = png_zalloc;
 495     s->zstream.zfree = png_zfree;
 496     s->zstream.opaque = NULL;
 497     ret = inflateInit(&s->zstream);
 498     if (ret != Z_OK)
 499         return -1;
 500     for(;;) {
 501         int tag32;
 502         if (s->bytestream >= s->bytestream_end)
 503             goto fail;
 504         length = get32(&s->bytestream);
 505         if (length > 0x7fffffff)
 506             goto fail;
 507         tag32 = get32(&s->bytestream);
 508         tag = bswap_32(tag32);
 509 #ifdef DEBUG
 510         printf("png: tag=%c%c%c%c length=%u\n",
 511                (tag & 0xff),
 512                ((tag >> 8) & 0xff),
 513                ((tag >> 16) & 0xff),
 514                ((tag >> 24) & 0xff), length);
 515 #endif
 516         switch(tag) {
 517         case MKTAG('I', 'H', 'D', 'R'):
 518             if (length != 13)
 519                 goto fail;
 520             s->width = get32(&s->bytestream);
 521             s->height = get32(&s->bytestream);
 522             if(avcodec_check_dimensions(avctx, s->width, s->height)){
 523                 s->width= s->height= 0;
 524                 goto fail;
 525             }
 526             s->bit_depth = *s->bytestream++;
 527             s->color_type = *s->bytestream++;
 528             s->compression_type = *s->bytestream++;
 529             s->filter_type = *s->bytestream++;
 530             s->interlace_type = *s->bytestream++;
 531             crc = get32(&s->bytestream);
 532             s->state |= PNG_IHDR;
 533 #ifdef DEBUG
 534             printf("width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
 535                    s->width, s->height, s->bit_depth, s->color_type,
 536                    s->compression_type, s->filter_type, s->interlace_type);
 537 #endif
 538             break;
 539         case MKTAG('I', 'D', 'A', 'T'):
 540             if (!(s->state & PNG_IHDR))
 541                 goto fail;
 542             if (!(s->state & PNG_IDAT)) {
 543                 /* init image info */
 544                 avctx->width = s->width;
 545                 avctx->height = s->height;
 546
 547                 s->channels = png_get_nb_channels(s->color_type);
 548                 s->bits_per_pixel = s->bit_depth * s->channels;
 549                 s->bpp = (s->bits_per_pixel + 7) >> 3;
 550                 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
 551
 552                 if (s->bit_depth == 8 &&
 553                     s->color_type == PNG_COLOR_TYPE_RGB) {
 554                     avctx->pix_fmt = PIX_FMT_RGB24;
 555                 } else if (s->bit_depth == 8 &&
 556                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 557                     avctx->pix_fmt = PIX_FMT_RGBA32;
 558                 } else if (s->bit_depth == 8 &&
 559                            s->color_type == PNG_COLOR_TYPE_GRAY) {
 560                     avctx->pix_fmt = PIX_FMT_GRAY8;
 561                 } else if (s->bit_depth == 1 &&
 562                            s->color_type == PNG_COLOR_TYPE_GRAY) {
 563                     avctx->pix_fmt = PIX_FMT_MONOBLACK;
 564                 } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
 565                     avctx->pix_fmt = PIX_FMT_PAL8;
 566                 } else {
 567                     goto fail;
 568                 }
 569                 if(p->data[0])
 570                     avctx->release_buffer(avctx, p);
 571
 572                 p->reference= 0;
 573                 if(avctx->get_buffer(avctx, p) < 0){
 574                     av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 575                     goto fail;
 576                 }
 577                 p->pict_type= FF_I_TYPE;
 578                 p->key_frame= 1;
 579                 p->interlaced_frame = !!s->interlace_type;
 580
 581                 /* compute the compressed row size */
 582                 if (!s->interlace_type) {
 583                     s->crow_size = s->row_size + 1;
 584                 } else {
 585                     s->pass = 0;
 586                     s->pass_row_size = png_pass_row_size(s->pass,
 587                                                          s->bits_per_pixel,
 588                                                          s->width);
 589                     s->crow_size = s->pass_row_size + 1;
 590                 }
 591 #ifdef DEBUG
 592                 printf("row_size=%d crow_size =%d\n",
 593                        s->row_size, s->crow_size);
 594 #endif
 595                 s->image_buf = p->data[0];
 596                 s->image_linesize = p->linesize[0];
 597                 /* copy the palette if needed */
 598                 if (s->color_type == PNG_COLOR_TYPE_PALETTE)
 599                     memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
 600                 /* empty row is used if differencing to the first row */
 601                 s->last_row = av_mallocz(s->row_size);
 602                 if (!s->last_row)
 603                     goto fail;
 604                 if (s->interlace_type ||
 605                     s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 606                     s->tmp_row = av_malloc(s->row_size);
 607                     if (!s->tmp_row)
 608                         goto fail;
 609                 }
 610                 /* compressed row */
 611                 s->crow_buf = av_malloc(s->row_size + 1);
 612                 if (!s->crow_buf)
 613                     goto fail;
 614                 s->zstream.avail_out = s->crow_size;
 615                 s->zstream.next_out = s->crow_buf;
 616             }
 617             s->state |= PNG_IDAT;
 618             if (png_decode_idat(s, length) < 0)
 619                 goto fail;
 620             /* skip crc */
 621             crc = get32(&s->bytestream);
 622             break;
 623         case MKTAG('P', 'L', 'T', 'E'):
 624             {
 625                 int n, i, r, g, b;
 626
 627                 if ((length % 3) != 0 || length > 256 * 3)
 628                     goto skip_tag;
 629                 /* read the palette */
 630                 n = length / 3;
 631                 for(i=0;i<n;i++) {
 632                     r = *s->bytestream++;
 633                     g = *s->bytestream++;
 634                     b = *s->bytestream++;
 635                     s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
 636                 }
 637                 for(;i<256;i++) {
 638                     s->palette[i] = (0xff << 24);
 639                 }
 640                 s->state |= PNG_PLTE;
 641                 crc = get32(&s->bytestream);
 642             }
 643             break;
 644         case MKTAG('t', 'R', 'N', 'S'):
 645             {
 646                 int v, i;
 647
 648                 /* read the transparency. XXX: Only palette mode supported */
 649                 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
 650                     length > 256 ||
 651                     !(s->state & PNG_PLTE))
 652                     goto skip_tag;
 653                 for(i=0;i<length;i++) {
 654                     v = *s->bytestream++;
 655                     s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
 656                 }
 657                 crc = get32(&s->bytestream);
 658             }
 659             break;
 660         case MKTAG('I', 'E', 'N', 'D'):
 661             if (!(s->state & PNG_ALLIMAGE))
 662                 goto fail;
 663             crc = get32(&s->bytestream);
 664             goto exit_loop;
 665         default:
 666             /* skip tag */
 667         skip_tag:
 668             s->bytestream += length + 4;
 669             break;
 670         }
 671     }
 672  exit_loop:
 673     *picture= *(AVFrame*)&s->picture;
 674     *data_size = sizeof(AVPicture);
 675
 676     ret = s->bytestream - s->bytestream_start;
 677  the_end:
 678     inflateEnd(&s->zstream);
 679     av_freep(&s->crow_buf);
 680     av_freep(&s->last_row);
 681     av_freep(&s->tmp_row);
 682     return ret;
 683  fail:
 684     ret = -1;
 685     goto the_end;
 686 }
 687
 688 static void png_write_chunk(uint8_t **f, uint32_t tag,
 689                             const uint8_t *buf, int length)
 690 {
 691     uint32_t crc;
 692     uint8_t tagbuf[4];
 693
 694     put32(f, length);
 695     crc = crc32(0, Z_NULL, 0);
 696     tagbuf[0] = tag;
 697     tagbuf[1] = tag >> 8;
 698     tagbuf[2] = tag >> 16;
 699     tagbuf[3] = tag >> 24;
 700     crc = crc32(crc, tagbuf, 4);
 701     put32(f, bswap_32(tag));
 702     if (length > 0) {
 703         crc = crc32(crc, buf, length);
 704         memcpy(*f, buf, length);
 705         *f += length;
 706     }
 707     put32(f, crc);
 708 }
 709
 710 /* XXX: use avcodec generic function ? */
 711 static void to_be32(uint8_t *p, uint32_t v)
 712 {
 713     p[0] = v >> 24;
 714     p[1] = v >> 16;
 715     p[2] = v >> 8;
 716     p[3] = v;
 717 }
 718
 719 /* XXX: do filtering */
 720 static int png_write_row(PNGContext *s, const uint8_t *data, int size)
 721 {
 722     int ret;
 723
 724     s->zstream.avail_in = size;
 725     s->zstream.next_in = (uint8_t *)data;
 726     while (s->zstream.avail_in > 0) {
 727         ret = deflate(&s->zstream, Z_NO_FLUSH);
 728         if (ret != Z_OK)
 729             return -1;
 730         if (s->zstream.avail_out == 0) {
 731             if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
 732                 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
 733             s->zstream.avail_out = IOBUF_SIZE;
 734             s->zstream.next_out = s->buf;
 735         }
 736     }
 737     return 0;
 738 }
 739
 740 static int common_init(AVCodecContext *avctx){
 741     PNGContext *s = avctx->priv_data;
 742
 743     avcodec_get_frame_defaults((AVFrame*)&s->picture);
 744     avctx->coded_frame= (AVFrame*)&s->picture;
 745 //    s->avctx= avctx;
 746
 747     return 0;
 748 }
 749
 750 static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
 751     PNGContext *s = avctx->priv_data;
 752     AVFrame *pict = data;
 753     AVFrame * const p= (AVFrame*)&s->picture;
 754     int bit_depth, color_type, y, len, row_size, ret, is_progressive;
 755     int bits_per_pixel, pass_row_size;
 756     uint8_t *ptr;
 757     uint8_t *crow_buf = NULL;
 758     uint8_t *tmp_buf = NULL;
 759
 760     *p = *pict;
 761     p->pict_type= FF_I_TYPE;
 762     p->key_frame= 1;
 763
 764     s->bytestream_start=
 765     s->bytestream= buf;
 766     s->bytestream_end= buf+buf_size;
 767
 768     is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
 769     switch(avctx->pix_fmt) {
 770     case PIX_FMT_RGBA32:
 771         bit_depth = 8;
 772         color_type = PNG_COLOR_TYPE_RGB_ALPHA;
 773         break;
 774     case PIX_FMT_RGB24:
 775         bit_depth = 8;
 776         color_type = PNG_COLOR_TYPE_RGB;
 777         break;
 778     case PIX_FMT_GRAY8:
 779         bit_depth = 8;
 780         color_type = PNG_COLOR_TYPE_GRAY;
 781         break;
 782     case PIX_FMT_MONOBLACK:
 783         bit_depth = 1;
 784         color_type = PNG_COLOR_TYPE_GRAY;
 785         break;
 786     case PIX_FMT_PAL8:
 787         bit_depth = 8;
 788         color_type = PNG_COLOR_TYPE_PALETTE;
 789         break;
 790     default:
 791         return -1;
 792     }
 793     bits_per_pixel = png_get_nb_channels(color_type) * bit_depth;
 794     row_size = (avctx->width * bits_per_pixel + 7) >> 3;
 795
 796     s->zstream.zalloc = png_zalloc;
 797     s->zstream.zfree = png_zfree;
 798     s->zstream.opaque = NULL;
 799     ret = deflateInit2(&s->zstream, Z_DEFAULT_COMPRESSION,
 800                        Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
 801     if (ret != Z_OK)
 802         return -1;
 803     crow_buf = av_malloc(row_size + 1);
 804     if (!crow_buf)
 805         goto fail;
 806     if (is_progressive) {
 807         tmp_buf = av_malloc(row_size + 1);
 808         if (!tmp_buf)
 809             goto fail;
 810     }
 811
 812     /* write png header */
 813     memcpy(s->bytestream, pngsig, 8);
 814     s->bytestream += 8;
 815
 816     to_be32(s->buf, avctx->width);
 817     to_be32(s->buf + 4, avctx->height);
 818     s->buf[8] = bit_depth;
 819     s->buf[9] = color_type;
 820     s->buf[10] = 0; /* compression type */
 821     s->buf[11] = 0; /* filter type */
 822     s->buf[12] = is_progressive; /* interlace type */
 823
 824     png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
 825
 826     /* put the palette if needed */
 827     if (color_type == PNG_COLOR_TYPE_PALETTE) {
 828         int has_alpha, alpha, i;
 829         unsigned int v;
 830         uint32_t *palette;
 831         uint8_t *alpha_ptr;
 832
 833         palette = (uint32_t *)p->data[1];
 834         ptr = s->buf;
 835         alpha_ptr = s->buf + 256 * 3;
 836         has_alpha = 0;
 837         for(i = 0; i < 256; i++) {
 838             v = palette[i];
 839             alpha = v >> 24;
 840             if (alpha != 0xff)
 841                 has_alpha = 1;
 842             *alpha_ptr++ = alpha;
 843             ptr[0] = v >> 16;
 844             ptr[1] = v >> 8;
 845             ptr[2] = v;
 846             ptr += 3;
 847         }
 848         png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
 849         if (has_alpha) {
 850             png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
 851         }
 852     }
 853
 854     /* now put each row */
 855     s->zstream.avail_out = IOBUF_SIZE;
 856     s->zstream.next_out = s->buf;
 857     if (is_progressive) {
 858         uint8_t *ptr1;
 859         int pass;
 860
 861         for(pass = 0; pass < NB_PASSES; pass++) {
 862             /* NOTE: a pass is completely omited if no pixels would be
 863                output */
 864             pass_row_size = png_pass_row_size(pass, bits_per_pixel, avctx->width);
 865             if (pass_row_size > 0) {
 866                 for(y = 0; y < avctx->height; y++) {
 867                     if ((png_pass_ymask[pass] << (y & 7)) & 0x80) {
 868                         ptr = p->data[0] + y * p->linesize[0];
 869                         if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
 870                             convert_from_rgba32(tmp_buf, ptr, avctx->width);
 871                             ptr1 = tmp_buf;
 872                         } else {
 873                             ptr1 = ptr;
 874                         }
 875                         png_get_interlaced_row(crow_buf + 1, pass_row_size,
 876                                                bits_per_pixel, pass,
 877                                                ptr1, avctx->width);
 878                         crow_buf[0] = PNG_FILTER_VALUE_NONE;
 879                         png_write_row(s, crow_buf, pass_row_size + 1);
 880                     }
 881                 }
 882             }
 883         }
 884     } else {
 885         for(y = 0; y < avctx->height; y++) {
 886             ptr = p->data[0] + y * p->linesize[0];
 887             if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
 888                 convert_from_rgba32(crow_buf + 1, ptr, avctx->width);
 889             else
 890                 memcpy(crow_buf + 1, ptr, row_size);
 891             crow_buf[0] = PNG_FILTER_VALUE_NONE;
 892             png_write_row(s, crow_buf, row_size + 1);
 893         }
 894     }
 895     /* compress last bytes */
 896     for(;;) {
 897         ret = deflate(&s->zstream, Z_FINISH);
 898         if (ret == Z_OK || ret == Z_STREAM_END) {
 899             len = IOBUF_SIZE - s->zstream.avail_out;
 900             if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
 901                 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
 902             }
 903             s->zstream.avail_out = IOBUF_SIZE;
 904             s->zstream.next_out = s->buf;
 905             if (ret == Z_STREAM_END)
 906                 break;
 907         } else {
 908             goto fail;
 909         }
 910     }
 911     png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
 912
 913     ret = s->bytestream - s->bytestream_start;
 914  the_end:
 915     av_free(crow_buf);
 916     av_free(tmp_buf);
 917     deflateEnd(&s->zstream);
 918     return ret;
 919  fail:
 920     ret = -1;
 921     goto the_end;
 922 }
 923
 924 AVCodec png_decoder = {
 925     "png",
 926     CODEC_TYPE_VIDEO,
 927     CODEC_ID_PNG,
 928     sizeof(PNGContext),
 929     common_init,
 930     NULL,
 931     NULL, //decode_end,
 932     decode_frame,
 933     0 /*CODEC_CAP_DR1*/ /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
 934     NULL
 935 };
 936
 937 #ifdef CONFIG_PNG_ENCODER
 938 AVCodec png_encoder = {
 939     "png",
 940     CODEC_TYPE_VIDEO,
 941     CODEC_ID_PNG,
 942     sizeof(PNGContext),
 943     common_init,
 944     encode_frame,
 945     NULL, //encode_end,
 946     .pix_fmts= (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGBA32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, -1},
 947 };
 948 #endif // CONFIG_PNG_ENCODER
 949 #endif