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#include "dsputil.h" 25 26/* TODO: 27 * - add 2, 4 and 16 bit depth support 28 */ 29 30#include <zlib.h> 31 32//#define DEBUG 33 34typedef struct PNGDecContext { 35 DSPContext dsp; 36 37 const uint8_t *bytestream; 38 const uint8_t *bytestream_start; 39 const uint8_t *bytestream_end; 40 AVFrame picture; 41 42 int state; 43 int width, height; 44 int bit_depth; 45 int color_type; 46 int compression_type; 47 int interlace_type; 48 int filter_type; 49 int channels; 50 int bits_per_pixel; 51 int bpp; 52 53 uint8_t *image_buf; 54 int image_linesize; 55 uint32_t palette[256]; 56 uint8_t *crow_buf; 57 uint8_t *last_row; 58 uint8_t *tmp_row; 59 int pass; 60 int crow_size; /* compressed row size (include filter type) */ 61 int row_size; /* decompressed row size */ 62 int pass_row_size; /* decompress row size of the current pass */ 63 int y; 64 z_stream zstream; 65} PNGDecContext; 66 67/* Mask to determine which y pixels can be written in a pass */ 68static const uint8_t png_pass_dsp_ymask[NB_PASSES] = { 69 0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55, 70}; 71 72/* Mask to determine which pixels to overwrite while displaying */ 73static const uint8_t png_pass_dsp_mask[NB_PASSES] = { 74 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff 75}; 76 77/* NOTE: we try to construct a good looking image at each pass. width 78 is the original image width. We also do pixel format conversion at 79 this stage */ 80static void png_put_interlaced_row(uint8_t *dst, int width, 81 int bits_per_pixel, int pass, 82 int color_type, const uint8_t *src) 83{ 84 int x, mask, dsp_mask, j, src_x, b, bpp; 85 uint8_t *d; 86 const uint8_t *s; 87 88 mask = ff_png_pass_mask[pass]; 89 dsp_mask = png_pass_dsp_mask[pass]; 90 switch(bits_per_pixel) { 91 case 1: 92 /* we must initialize the line to zero before writing to it */ 93 if (pass == 0) 94 memset(dst, 0, (width + 7) >> 3); 95 src_x = 0; 96 for(x = 0; x < width; x++) { 97 j = (x & 7); 98 if ((dsp_mask << j) & 0x80) { 99 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1; 100 dst[x >> 3] |= b << (7 - j); 101 } 102 if ((mask << j) & 0x80) 103 src_x++; 104 } 105 break; 106 default: 107 bpp = bits_per_pixel >> 3; 108 d = dst; 109 s = src; 110 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 111 for(x = 0; x < width; x++) { 112 j = x & 7; 113 if ((dsp_mask << j) & 0x80) { 114 *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2]; 115 } 116 d += bpp; 117 if ((mask << j) & 0x80) 118 s += bpp; 119 } 120 } else { 121 for(x = 0; x < width; x++) { 122 j = x & 7; 123 if ((dsp_mask << j) & 0x80) { 124 memcpy(d, s, bpp); 125 } 126 d += bpp; 127 if ((mask << j) & 0x80) 128 s += bpp; 129 } 130 } 131 break; 132 } 133} 134 135void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp) 136{ 137 int i; 138 for(i = 0; i < w; i++) { 139 int a, b, c, p, pa, pb, pc; 140 141 a = dst[i - bpp]; 142 b = top[i]; 143 c = top[i - bpp]; 144 145 p = b - c; 146 pc = a - c; 147 148 pa = abs(p); 149 pb = abs(pc); 150 pc = abs(p + pc); 151 152 if (pa <= pb && pa <= pc) 153 p = a; 154 else if (pb <= pc) 155 p = b; 156 else 157 p = c; 158 dst[i] = p + src[i]; 159 } 160} 161 162#define UNROLL1(bpp, op) {\ 163 r = dst[0];\ 164 if(bpp >= 2) g = dst[1];\ 165 if(bpp >= 3) b = dst[2];\ 166 if(bpp >= 4) a = dst[3];\ 167 for(; i < size; i+=bpp) {\ 168 dst[i+0] = r = op(r, src[i+0], last[i+0]);\ 169 if(bpp == 1) continue;\ 170 dst[i+1] = g = op(g, src[i+1], last[i+1]);\ 171 if(bpp == 2) continue;\ 172 dst[i+2] = b = op(b, src[i+2], last[i+2]);\ 173 if(bpp == 3) continue;\ 174 dst[i+3] = a = op(a, src[i+3], last[i+3]);\ 175 }\ 176} 177 178#define UNROLL_FILTER(op)\ 179 if(bpp == 1) UNROLL1(1, op)\ 180 else if(bpp == 2) UNROLL1(2, op)\ 181 else if(bpp == 3) UNROLL1(3, op)\ 182 else if(bpp == 4) UNROLL1(4, op)\ 183 184/* NOTE: 'dst' can be equal to 'last' */ 185static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type, 186 uint8_t *src, uint8_t *last, int size, int bpp) 187{ 188 int i, p, r, g, b, a; 189 190 switch(filter_type) { 191 case PNG_FILTER_VALUE_NONE: 192 memcpy(dst, src, size); 193 break; 194 case PNG_FILTER_VALUE_SUB: 195 for(i = 0; i < bpp; i++) { 196 dst[i] = src[i]; 197 } 198 if(bpp == 4) { 199 p = *(int*)dst; 200 for(; i < size; i+=bpp) { 201 int s = *(int*)(src+i); 202 p = ((s&0x7f7f7f7f) + (p&0x7f7f7f7f)) ^ ((s^p)&0x80808080); 203 *(int*)(dst+i) = p; 204 } 205 } else { 206#define OP_SUB(x,s,l) x+s 207 UNROLL_FILTER(OP_SUB); 208 } 209 break; 210 case PNG_FILTER_VALUE_UP: 211 dsp->add_bytes_l2(dst, src, last, size); 212 break; 213 case PNG_FILTER_VALUE_AVG: 214 for(i = 0; i < bpp; i++) { 215 p = (last[i] >> 1); 216 dst[i] = p + src[i]; 217 } 218#define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff 219 UNROLL_FILTER(OP_AVG); 220 break; 221 case PNG_FILTER_VALUE_PAETH: 222 for(i = 0; i < bpp; i++) { 223 p = last[i]; 224 dst[i] = p + src[i]; 225 } 226 if(bpp > 1 && size > 4) { 227 // would write off the end of the array if we let it process the last pixel with bpp=3 228 int w = bpp==4 ? size : size-3; 229 dsp->add_png_paeth_prediction(dst+i, src+i, last+i, w-i, bpp); 230 i = w; 231 } 232 ff_add_png_paeth_prediction(dst+i, src+i, last+i, size-i, bpp); 233 break; 234 } 235} 236 237static av_always_inline void convert_to_rgb32_loco(uint8_t *dst, const uint8_t *src, int width, int loco) 238{ 239 int j; 240 unsigned int r, g, b, a; 241 242 for(j = 0;j < width; j++) { 243 r = src[0]; 244 g = src[1]; 245 b = src[2]; 246 a = src[3]; 247 if(loco) { 248 r = (r+g)&0xff; 249 b = (b+g)&0xff; 250 } 251 *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b; 252 dst += 4; 253 src += 4; 254 } 255} 256 257static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width, int loco) 258{ 259 if(loco) 260 convert_to_rgb32_loco(dst, src, width, 1); 261 else 262 convert_to_rgb32_loco(dst, src, width, 0); 263} 264 265static void deloco_rgb24(uint8_t *dst, int size) 266{ 267 int i; 268 for(i=0; i<size; i+=3) { 269 int g = dst[i+1]; 270 dst[i+0] += g; 271 dst[i+2] += g; 272 } 273} 274 275/* process exactly one decompressed row */ 276static void png_handle_row(PNGDecContext *s) 277{ 278 uint8_t *ptr, *last_row; 279 int got_line; 280 281 if (!s->interlace_type) { 282 ptr = s->image_buf + s->image_linesize * s->y; 283 /* need to swap bytes correctly for RGB_ALPHA */ 284 if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 285 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1, 286 s->last_row, s->row_size, s->bpp); 287 convert_to_rgb32(ptr, s->tmp_row, s->width, s->filter_type == PNG_FILTER_TYPE_LOCO); 288 FFSWAP(uint8_t*, s->last_row, s->tmp_row); 289 } else { 290 /* in normal case, we avoid one copy */ 291 if (s->y == 0) 292 last_row = s->last_row; 293 else 294 last_row = ptr - s->image_linesize; 295 296 png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1, 297 last_row, s->row_size, s->bpp); 298 } 299 /* loco lags by 1 row so that it doesn't interfere with top prediction */ 300 if (s->filter_type == PNG_FILTER_TYPE_LOCO && 301 s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0) 302 deloco_rgb24(ptr - s->image_linesize, s->row_size); 303 s->y++; 304 if (s->y == s->height) { 305 s->state |= PNG_ALLIMAGE; 306 if (s->filter_type == PNG_FILTER_TYPE_LOCO && 307 s->color_type == PNG_COLOR_TYPE_RGB) 308 deloco_rgb24(ptr, s->row_size); 309 } 310 } else { 311 got_line = 0; 312 for(;;) { 313 ptr = s->image_buf + s->image_linesize * s->y; 314 if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) { 315 /* if we already read one row, it is time to stop to 316 wait for the next one */ 317 if (got_line) 318 break; 319 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1, 320 s->last_row, s->pass_row_size, s->bpp); 321 FFSWAP(uint8_t*, s->last_row, s->tmp_row); 322 got_line = 1; 323 } 324 if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) { 325 /* NOTE: RGB32 is handled directly in png_put_interlaced_row */ 326 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass, 327 s->color_type, s->last_row); 328 } 329 s->y++; 330 if (s->y == s->height) { 331 for(;;) { 332 if (s->pass == NB_PASSES - 1) { 333 s->state |= PNG_ALLIMAGE; 334 goto the_end; 335 } else { 336 s->pass++; 337 s->y = 0; 338 s->pass_row_size = ff_png_pass_row_size(s->pass, 339 s->bits_per_pixel, 340 s->width); 341 s->crow_size = s->pass_row_size + 1; 342 if (s->pass_row_size != 0) 343 break; 344 /* skip pass if empty row */ 345 } 346 } 347 } 348 } 349 the_end: ; 350 } 351} 352 353static int png_decode_idat(PNGDecContext *s, int length) 354{ 355 int ret; 356 s->zstream.avail_in = length; 357 s->zstream.next_in = s->bytestream; 358 s->bytestream += length; 359 360 if(s->bytestream > s->bytestream_end) 361 return -1; 362 363 /* decode one line if possible */ 364 while (s->zstream.avail_in > 0) { 365 ret = inflate(&s->zstream, Z_PARTIAL_FLUSH); 366 if (ret != Z_OK && ret != Z_STREAM_END) { 367 return -1; 368 } 369 if (s->zstream.avail_out == 0) { 370 if (!(s->state & PNG_ALLIMAGE)) { 371 png_handle_row(s); 372 } 373 s->zstream.avail_out = s->crow_size; 374 s->zstream.next_out = s->crow_buf; 375 } 376 } 377 return 0; 378} 379 380static int decode_frame(AVCodecContext *avctx, 381 void *data, int *data_size, 382 const uint8_t *buf, int buf_size) 383{ 384 PNGDecContext * const s = avctx->priv_data; 385 AVFrame *picture = data; 386 AVFrame * const p= &s->picture; 387 uint32_t tag, length; 388 int ret, crc; 389 390 s->bytestream_start= 391 s->bytestream= buf; 392 s->bytestream_end= buf + buf_size; 393 394 /* check signature */ 395 if (memcmp(s->bytestream, ff_pngsig, 8) != 0 && 396 memcmp(s->bytestream, ff_mngsig, 8) != 0) 397 return -1; 398 s->bytestream+= 8; 399 s->y= 400 s->state=0; 401// memset(s, 0, sizeof(PNGDecContext)); 402 /* init the zlib */ 403 s->zstream.zalloc = ff_png_zalloc; 404 s->zstream.zfree = ff_png_zfree; 405 s->zstream.opaque = NULL; 406 ret = inflateInit(&s->zstream); 407 if (ret != Z_OK) 408 return -1; 409 for(;;) { 410 int tag32; 411 if (s->bytestream >= s->bytestream_end) 412 goto fail; 413 length = bytestream_get_be32(&s->bytestream); 414 if (length > 0x7fffffff) 415 goto fail; 416 tag32 = bytestream_get_be32(&s->bytestream); 417 tag = bswap_32(tag32); 418#ifdef DEBUG 419 av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n", 420 (tag & 0xff), 421 ((tag >> 8) & 0xff), 422 ((tag >> 16) & 0xff), 423 ((tag >> 24) & 0xff), length); 424#endif 425 switch(tag) { 426 case MKTAG('I', 'H', 'D', 'R'): 427 if (length != 13) 428 goto fail; 429 s->width = bytestream_get_be32(&s->bytestream); 430 s->height = bytestream_get_be32(&s->bytestream); 431 if(avcodec_check_dimensions(avctx, s->width, s->height)){ 432 s->width= s->height= 0; 433 goto fail; 434 } 435 s->bit_depth = *s->bytestream++; 436 s->color_type = *s->bytestream++; 437 s->compression_type = *s->bytestream++; 438 s->filter_type = *s->bytestream++; 439 s->interlace_type = *s->bytestream++; 440 crc = bytestream_get_be32(&s->bytestream); 441 s->state |= PNG_IHDR; 442#ifdef DEBUG 443 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", 444 s->width, s->height, s->bit_depth, s->color_type, 445 s->compression_type, s->filter_type, s->interlace_type); 446#endif 447 break; 448 case MKTAG('I', 'D', 'A', 'T'): 449 if (!(s->state & PNG_IHDR)) 450 goto fail; 451 if (!(s->state & PNG_IDAT)) { 452 /* init image info */ 453 avctx->width = s->width; 454 avctx->height = s->height; 455 456 s->channels = ff_png_get_nb_channels(s->color_type); 457 s->bits_per_pixel = s->bit_depth * s->channels; 458 s->bpp = (s->bits_per_pixel + 7) >> 3; 459 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3; 460 461 if (s->bit_depth == 8 && 462 s->color_type == PNG_COLOR_TYPE_RGB) { 463 avctx->pix_fmt = PIX_FMT_RGB24; 464 } else if (s->bit_depth == 8 && 465 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 466 avctx->pix_fmt = PIX_FMT_RGB32; 467 } else if (s->bit_depth == 8 && 468 s->color_type == PNG_COLOR_TYPE_GRAY) { 469 avctx->pix_fmt = PIX_FMT_GRAY8; 470 } else if (s->bit_depth == 16 && 471 s->color_type == PNG_COLOR_TYPE_GRAY) { 472 avctx->pix_fmt = PIX_FMT_GRAY16BE; 473 } else if (s->bit_depth == 1 && 474 s->color_type == PNG_COLOR_TYPE_GRAY) { 475 avctx->pix_fmt = PIX_FMT_MONOBLACK; 476 } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) { 477 avctx->pix_fmt = PIX_FMT_PAL8; 478 } else { 479 goto fail; 480 } 481 if(p->data[0]) 482 avctx->release_buffer(avctx, p); 483 484 p->reference= 0; 485 if(avctx->get_buffer(avctx, p) < 0){ 486 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 487 goto fail; 488 } 489 p->pict_type= FF_I_TYPE; 490 p->key_frame= 1; 491 p->interlaced_frame = !!s->interlace_type; 492 493 /* compute the compressed row size */ 494 if (!s->interlace_type) { 495 s->crow_size = s->row_size + 1; 496 } else { 497 s->pass = 0; 498 s->pass_row_size = ff_png_pass_row_size(s->pass, 499 s->bits_per_pixel, 500 s->width); 501 s->crow_size = s->pass_row_size + 1; 502 } 503#ifdef DEBUG 504 av_log(avctx, AV_LOG_DEBUG, "row_size=%d crow_size =%d\n", 505 s->row_size, s->crow_size); 506#endif 507 s->image_buf = p->data[0]; 508 s->image_linesize = p->linesize[0]; 509 /* copy the palette if needed */ 510 if (s->color_type == PNG_COLOR_TYPE_PALETTE) 511 memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t)); 512 /* empty row is used if differencing to the first row */ 513 s->last_row = av_mallocz(s->row_size); 514 if (!s->last_row) 515 goto fail; 516 if (s->interlace_type || 517 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 518 s->tmp_row = av_malloc(s->row_size); 519 if (!s->tmp_row) 520 goto fail; 521 } 522 /* compressed row */ 523 s->crow_buf = av_malloc(s->row_size + 1); 524 if (!s->crow_buf) 525 goto fail; 526 s->zstream.avail_out = s->crow_size; 527 s->zstream.next_out = s->crow_buf; 528 } 529 s->state |= PNG_IDAT; 530 if (png_decode_idat(s, length) < 0) 531 goto fail; 532 /* skip crc */ 533 crc = bytestream_get_be32(&s->bytestream); 534 break; 535 case MKTAG('P', 'L', 'T', 'E'): 536 { 537 int n, i, r, g, b; 538 539 if ((length % 3) != 0 || length > 256 * 3) 540 goto skip_tag; 541 /* read the palette */ 542 n = length / 3; 543 for(i=0;i<n;i++) { 544 r = *s->bytestream++; 545 g = *s->bytestream++; 546 b = *s->bytestream++; 547 s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b; 548 } 549 for(;i<256;i++) { 550 s->palette[i] = (0xff << 24); 551 } 552 s->state |= PNG_PLTE; 553 crc = bytestream_get_be32(&s->bytestream); 554 } 555 break; 556 case MKTAG('t', 'R', 'N', 'S'): 557 { 558 int v, i; 559 560 /* read the transparency. XXX: Only palette mode supported */ 561 if (s->color_type != PNG_COLOR_TYPE_PALETTE || 562 length > 256 || 563 !(s->state & PNG_PLTE)) 564 goto skip_tag; 565 for(i=0;i<length;i++) { 566 v = *s->bytestream++; 567 s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24); 568 } 569 crc = bytestream_get_be32(&s->bytestream); 570 } 571 break; 572 case MKTAG('I', 'E', 'N', 'D'): 573 if (!(s->state & PNG_ALLIMAGE)) 574 goto fail; 575 crc = bytestream_get_be32(&s->bytestream); 576 goto exit_loop; 577 default: 578 /* skip tag */ 579 skip_tag: 580 s->bytestream += length + 4; 581 break; 582 } 583 } 584 exit_loop: 585 *picture= s->picture; 586 *data_size = sizeof(AVFrame); 587 588 ret = s->bytestream - s->bytestream_start; 589 the_end: 590 inflateEnd(&s->zstream); 591 av_freep(&s->crow_buf); 592 av_freep(&s->last_row); 593 av_freep(&s->tmp_row); 594 return ret; 595 fail: 596 ret = -1; 597 goto the_end; 598} 599 600static av_cold int png_dec_init(AVCodecContext *avctx){ 601 PNGDecContext *s = avctx->priv_data; 602 603 avcodec_get_frame_defaults(&s->picture); 604 avctx->coded_frame= &s->picture; 605 dsputil_init(&s->dsp, avctx); 606 607 return 0; 608} 609 610AVCodec png_decoder = { 611 "png", 612 CODEC_TYPE_VIDEO, 613 CODEC_ID_PNG, 614 sizeof(PNGDecContext), 615 png_dec_init, 616 NULL, 617 NULL, //decode_end, 618 decode_frame, 619 0 /*CODEC_CAP_DR1*/ /*| CODEC_CAP_DRAW_HORIZ_BAND*/, 620 NULL, 621 .long_name = NULL_IF_CONFIG_SMALL("PNG image"), 622}; 623