Libav
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00001 /* 00002 * PNG image format 00003 * Copyright (c) 2003 Fabrice Bellard 00004 * 00005 * This file is part of FFmpeg. 00006 * 00007 * FFmpeg is free software; you can redistribute it and/or 00008 * modify it under the terms of the GNU Lesser General Public 00009 * License as published by the Free Software Foundation; either 00010 * version 2.1 of the License, or (at your option) any later version. 00011 * 00012 * FFmpeg is distributed in the hope that it will be useful, 00013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00015 * Lesser General Public License for more details. 00016 * 00017 * You should have received a copy of the GNU Lesser General Public 00018 * License along with FFmpeg; if not, write to the Free Software 00019 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00020 */ 00021 #include "avcodec.h" 00022 #include "bytestream.h" 00023 #include "png.h" 00024 #include "dsputil.h" 00025 00026 /* TODO: 00027 * - add 2, 4 and 16 bit depth support 00028 */ 00029 00030 #include <zlib.h> 00031 00032 //#define DEBUG 00033 00034 typedef struct PNGDecContext { 00035 DSPContext dsp; 00036 00037 const uint8_t *bytestream; 00038 const uint8_t *bytestream_start; 00039 const uint8_t *bytestream_end; 00040 AVFrame picture1, picture2; 00041 AVFrame *current_picture, *last_picture; 00042 00043 int state; 00044 int width, height; 00045 int bit_depth; 00046 int color_type; 00047 int compression_type; 00048 int interlace_type; 00049 int filter_type; 00050 int channels; 00051 int bits_per_pixel; 00052 int bpp; 00053 00054 uint8_t *image_buf; 00055 int image_linesize; 00056 uint32_t palette[256]; 00057 uint8_t *crow_buf; 00058 uint8_t *last_row; 00059 uint8_t *tmp_row; 00060 int pass; 00061 int crow_size; /* compressed row size (include filter type) */ 00062 int row_size; /* decompressed row size */ 00063 int pass_row_size; /* decompress row size of the current pass */ 00064 int y; 00065 z_stream zstream; 00066 } PNGDecContext; 00067 00068 /* Mask to determine which y pixels can be written in a pass */ 00069 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = { 00070 0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55, 00071 }; 00072 00073 /* Mask to determine which pixels to overwrite while displaying */ 00074 static const uint8_t png_pass_dsp_mask[NB_PASSES] = { 00075 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff 00076 }; 00077 00078 /* NOTE: we try to construct a good looking image at each pass. width 00079 is the original image width. We also do pixel format conversion at 00080 this stage */ 00081 static void png_put_interlaced_row(uint8_t *dst, int width, 00082 int bits_per_pixel, int pass, 00083 int color_type, const uint8_t *src) 00084 { 00085 int x, mask, dsp_mask, j, src_x, b, bpp; 00086 uint8_t *d; 00087 const uint8_t *s; 00088 00089 mask = ff_png_pass_mask[pass]; 00090 dsp_mask = png_pass_dsp_mask[pass]; 00091 switch(bits_per_pixel) { 00092 case 1: 00093 /* we must initialize the line to zero before writing to it */ 00094 if (pass == 0) 00095 memset(dst, 0, (width + 7) >> 3); 00096 src_x = 0; 00097 for(x = 0; x < width; x++) { 00098 j = (x & 7); 00099 if ((dsp_mask << j) & 0x80) { 00100 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1; 00101 dst[x >> 3] |= b << (7 - j); 00102 } 00103 if ((mask << j) & 0x80) 00104 src_x++; 00105 } 00106 break; 00107 default: 00108 bpp = bits_per_pixel >> 3; 00109 d = dst; 00110 s = src; 00111 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 00112 for(x = 0; x < width; x++) { 00113 j = x & 7; 00114 if ((dsp_mask << j) & 0x80) { 00115 *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2]; 00116 } 00117 d += bpp; 00118 if ((mask << j) & 0x80) 00119 s += bpp; 00120 } 00121 } else { 00122 for(x = 0; x < width; x++) { 00123 j = x & 7; 00124 if ((dsp_mask << j) & 0x80) { 00125 memcpy(d, s, bpp); 00126 } 00127 d += bpp; 00128 if ((mask << j) & 0x80) 00129 s += bpp; 00130 } 00131 } 00132 break; 00133 } 00134 } 00135 00136 void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp) 00137 { 00138 int i; 00139 for(i = 0; i < w; i++) { 00140 int a, b, c, p, pa, pb, pc; 00141 00142 a = dst[i - bpp]; 00143 b = top[i]; 00144 c = top[i - bpp]; 00145 00146 p = b - c; 00147 pc = a - c; 00148 00149 pa = abs(p); 00150 pb = abs(pc); 00151 pc = abs(p + pc); 00152 00153 if (pa <= pb && pa <= pc) 00154 p = a; 00155 else if (pb <= pc) 00156 p = b; 00157 else 00158 p = c; 00159 dst[i] = p + src[i]; 00160 } 00161 } 00162 00163 #define UNROLL1(bpp, op) {\ 00164 r = dst[0];\ 00165 if(bpp >= 2) g = dst[1];\ 00166 if(bpp >= 3) b = dst[2];\ 00167 if(bpp >= 4) a = dst[3];\ 00168 for(; i < size; i+=bpp) {\ 00169 dst[i+0] = r = op(r, src[i+0], last[i+0]);\ 00170 if(bpp == 1) continue;\ 00171 dst[i+1] = g = op(g, src[i+1], last[i+1]);\ 00172 if(bpp == 2) continue;\ 00173 dst[i+2] = b = op(b, src[i+2], last[i+2]);\ 00174 if(bpp == 3) continue;\ 00175 dst[i+3] = a = op(a, src[i+3], last[i+3]);\ 00176 }\ 00177 } 00178 00179 #define UNROLL_FILTER(op)\ 00180 if(bpp == 1) UNROLL1(1, op)\ 00181 else if(bpp == 2) UNROLL1(2, op)\ 00182 else if(bpp == 3) UNROLL1(3, op)\ 00183 else if(bpp == 4) UNROLL1(4, op)\ 00184 else {\ 00185 for (; i < size; i += bpp) {\ 00186 int j;\ 00187 for (j = 0; j < bpp; j++)\ 00188 dst[i+j] = op(dst[i+j-bpp], src[i+j], last[i+j]);\ 00189 }\ 00190 } 00191 00192 /* NOTE: 'dst' can be equal to 'last' */ 00193 static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type, 00194 uint8_t *src, uint8_t *last, int size, int bpp) 00195 { 00196 int i, p, r, g, b, a; 00197 00198 switch(filter_type) { 00199 case PNG_FILTER_VALUE_NONE: 00200 memcpy(dst, src, size); 00201 break; 00202 case PNG_FILTER_VALUE_SUB: 00203 for(i = 0; i < bpp; i++) { 00204 dst[i] = src[i]; 00205 } 00206 if(bpp == 4) { 00207 p = *(int*)dst; 00208 for(; i < size; i+=bpp) { 00209 int s = *(int*)(src+i); 00210 p = ((s&0x7f7f7f7f) + (p&0x7f7f7f7f)) ^ ((s^p)&0x80808080); 00211 *(int*)(dst+i) = p; 00212 } 00213 } else { 00214 #define OP_SUB(x,s,l) x+s 00215 UNROLL_FILTER(OP_SUB); 00216 } 00217 break; 00218 case PNG_FILTER_VALUE_UP: 00219 dsp->add_bytes_l2(dst, src, last, size); 00220 break; 00221 case PNG_FILTER_VALUE_AVG: 00222 for(i = 0; i < bpp; i++) { 00223 p = (last[i] >> 1); 00224 dst[i] = p + src[i]; 00225 } 00226 #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff 00227 UNROLL_FILTER(OP_AVG); 00228 break; 00229 case PNG_FILTER_VALUE_PAETH: 00230 for(i = 0; i < bpp; i++) { 00231 p = last[i]; 00232 dst[i] = p + src[i]; 00233 } 00234 if(bpp > 1 && size > 4) { 00235 // would write off the end of the array if we let it process the last pixel with bpp=3 00236 int w = bpp==4 ? size : size-3; 00237 dsp->add_png_paeth_prediction(dst+i, src+i, last+i, w-i, bpp); 00238 i = w; 00239 } 00240 ff_add_png_paeth_prediction(dst+i, src+i, last+i, size-i, bpp); 00241 break; 00242 } 00243 } 00244 00245 static av_always_inline void convert_to_rgb32_loco(uint8_t *dst, const uint8_t *src, int width, int loco) 00246 { 00247 int j; 00248 unsigned int r, g, b, a; 00249 00250 for(j = 0;j < width; j++) { 00251 r = src[0]; 00252 g = src[1]; 00253 b = src[2]; 00254 a = src[3]; 00255 if(loco) { 00256 r = (r+g)&0xff; 00257 b = (b+g)&0xff; 00258 } 00259 *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b; 00260 dst += 4; 00261 src += 4; 00262 } 00263 } 00264 00265 static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width, int loco) 00266 { 00267 if(loco) 00268 convert_to_rgb32_loco(dst, src, width, 1); 00269 else 00270 convert_to_rgb32_loco(dst, src, width, 0); 00271 } 00272 00273 static void deloco_rgb24(uint8_t *dst, int size) 00274 { 00275 int i; 00276 for(i=0; i<size; i+=3) { 00277 int g = dst[i+1]; 00278 dst[i+0] += g; 00279 dst[i+2] += g; 00280 } 00281 } 00282 00283 /* process exactly one decompressed row */ 00284 static void png_handle_row(PNGDecContext *s) 00285 { 00286 uint8_t *ptr, *last_row; 00287 int got_line; 00288 00289 if (!s->interlace_type) { 00290 ptr = s->image_buf + s->image_linesize * s->y; 00291 /* need to swap bytes correctly for RGB_ALPHA */ 00292 if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 00293 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1, 00294 s->last_row, s->row_size, s->bpp); 00295 convert_to_rgb32(ptr, s->tmp_row, s->width, s->filter_type == PNG_FILTER_TYPE_LOCO); 00296 FFSWAP(uint8_t*, s->last_row, s->tmp_row); 00297 } else { 00298 /* in normal case, we avoid one copy */ 00299 if (s->y == 0) 00300 last_row = s->last_row; 00301 else 00302 last_row = ptr - s->image_linesize; 00303 00304 png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1, 00305 last_row, s->row_size, s->bpp); 00306 } 00307 /* loco lags by 1 row so that it doesn't interfere with top prediction */ 00308 if (s->filter_type == PNG_FILTER_TYPE_LOCO && 00309 s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0) 00310 deloco_rgb24(ptr - s->image_linesize, s->row_size); 00311 s->y++; 00312 if (s->y == s->height) { 00313 s->state |= PNG_ALLIMAGE; 00314 if (s->filter_type == PNG_FILTER_TYPE_LOCO && 00315 s->color_type == PNG_COLOR_TYPE_RGB) 00316 deloco_rgb24(ptr, s->row_size); 00317 } 00318 } else { 00319 got_line = 0; 00320 for(;;) { 00321 ptr = s->image_buf + s->image_linesize * s->y; 00322 if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) { 00323 /* if we already read one row, it is time to stop to 00324 wait for the next one */ 00325 if (got_line) 00326 break; 00327 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1, 00328 s->last_row, s->pass_row_size, s->bpp); 00329 FFSWAP(uint8_t*, s->last_row, s->tmp_row); 00330 got_line = 1; 00331 } 00332 if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) { 00333 /* NOTE: RGB32 is handled directly in png_put_interlaced_row */ 00334 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass, 00335 s->color_type, s->last_row); 00336 } 00337 s->y++; 00338 if (s->y == s->height) { 00339 for(;;) { 00340 if (s->pass == NB_PASSES - 1) { 00341 s->state |= PNG_ALLIMAGE; 00342 goto the_end; 00343 } else { 00344 s->pass++; 00345 s->y = 0; 00346 s->pass_row_size = ff_png_pass_row_size(s->pass, 00347 s->bits_per_pixel, 00348 s->width); 00349 s->crow_size = s->pass_row_size + 1; 00350 if (s->pass_row_size != 0) 00351 break; 00352 /* skip pass if empty row */ 00353 } 00354 } 00355 } 00356 } 00357 the_end: ; 00358 } 00359 } 00360 00361 static int png_decode_idat(PNGDecContext *s, int length) 00362 { 00363 int ret; 00364 s->zstream.avail_in = length; 00365 s->zstream.next_in = s->bytestream; 00366 s->bytestream += length; 00367 00368 if(s->bytestream > s->bytestream_end) 00369 return -1; 00370 00371 /* decode one line if possible */ 00372 while (s->zstream.avail_in > 0) { 00373 ret = inflate(&s->zstream, Z_PARTIAL_FLUSH); 00374 if (ret != Z_OK && ret != Z_STREAM_END) { 00375 return -1; 00376 } 00377 if (s->zstream.avail_out == 0) { 00378 if (!(s->state & PNG_ALLIMAGE)) { 00379 png_handle_row(s); 00380 } 00381 s->zstream.avail_out = s->crow_size; 00382 s->zstream.next_out = s->crow_buf; 00383 } 00384 } 00385 return 0; 00386 } 00387 00388 static int decode_frame(AVCodecContext *avctx, 00389 void *data, int *data_size, 00390 AVPacket *avpkt) 00391 { 00392 const uint8_t *buf = avpkt->data; 00393 int buf_size = avpkt->size; 00394 PNGDecContext * const s = avctx->priv_data; 00395 AVFrame *picture = data; 00396 AVFrame *p; 00397 uint8_t *crow_buf_base = NULL; 00398 uint32_t tag, length; 00399 int ret, crc; 00400 00401 FFSWAP(AVFrame *, s->current_picture, s->last_picture); 00402 avctx->coded_frame= s->current_picture; 00403 p = s->current_picture; 00404 00405 s->bytestream_start= 00406 s->bytestream= buf; 00407 s->bytestream_end= buf + buf_size; 00408 00409 /* check signature */ 00410 if (memcmp(s->bytestream, ff_pngsig, 8) != 0 && 00411 memcmp(s->bytestream, ff_mngsig, 8) != 0) 00412 return -1; 00413 s->bytestream+= 8; 00414 s->y= 00415 s->state=0; 00416 // memset(s, 0, sizeof(PNGDecContext)); 00417 /* init the zlib */ 00418 s->zstream.zalloc = ff_png_zalloc; 00419 s->zstream.zfree = ff_png_zfree; 00420 s->zstream.opaque = NULL; 00421 ret = inflateInit(&s->zstream); 00422 if (ret != Z_OK) 00423 return -1; 00424 for(;;) { 00425 int tag32; 00426 if (s->bytestream >= s->bytestream_end) 00427 goto fail; 00428 length = bytestream_get_be32(&s->bytestream); 00429 if (length > 0x7fffffff) 00430 goto fail; 00431 tag32 = bytestream_get_be32(&s->bytestream); 00432 tag = bswap_32(tag32); 00433 dprintf(avctx, "png: tag=%c%c%c%c length=%u\n", 00434 (tag & 0xff), 00435 ((tag >> 8) & 0xff), 00436 ((tag >> 16) & 0xff), 00437 ((tag >> 24) & 0xff), length); 00438 switch(tag) { 00439 case MKTAG('I', 'H', 'D', 'R'): 00440 if (length != 13) 00441 goto fail; 00442 s->width = bytestream_get_be32(&s->bytestream); 00443 s->height = bytestream_get_be32(&s->bytestream); 00444 if(avcodec_check_dimensions(avctx, s->width, s->height)){ 00445 s->width= s->height= 0; 00446 goto fail; 00447 } 00448 s->bit_depth = *s->bytestream++; 00449 s->color_type = *s->bytestream++; 00450 s->compression_type = *s->bytestream++; 00451 s->filter_type = *s->bytestream++; 00452 s->interlace_type = *s->bytestream++; 00453 crc = bytestream_get_be32(&s->bytestream); 00454 s->state |= PNG_IHDR; 00455 dprintf(avctx, "width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n", 00456 s->width, s->height, s->bit_depth, s->color_type, 00457 s->compression_type, s->filter_type, s->interlace_type); 00458 break; 00459 case MKTAG('I', 'D', 'A', 'T'): 00460 if (!(s->state & PNG_IHDR)) 00461 goto fail; 00462 if (!(s->state & PNG_IDAT)) { 00463 /* init image info */ 00464 avctx->width = s->width; 00465 avctx->height = s->height; 00466 00467 s->channels = ff_png_get_nb_channels(s->color_type); 00468 s->bits_per_pixel = s->bit_depth * s->channels; 00469 s->bpp = (s->bits_per_pixel + 7) >> 3; 00470 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3; 00471 00472 if (s->bit_depth == 8 && 00473 s->color_type == PNG_COLOR_TYPE_RGB) { 00474 avctx->pix_fmt = PIX_FMT_RGB24; 00475 } else if (s->bit_depth == 8 && 00476 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 00477 avctx->pix_fmt = PIX_FMT_RGB32; 00478 } else if (s->bit_depth == 8 && 00479 s->color_type == PNG_COLOR_TYPE_GRAY) { 00480 avctx->pix_fmt = PIX_FMT_GRAY8; 00481 } else if (s->bit_depth == 16 && 00482 s->color_type == PNG_COLOR_TYPE_GRAY) { 00483 avctx->pix_fmt = PIX_FMT_GRAY16BE; 00484 } else if (s->bit_depth == 16 && 00485 s->color_type == PNG_COLOR_TYPE_RGB) { 00486 avctx->pix_fmt = PIX_FMT_RGB48BE; 00487 } else if (s->bit_depth == 1 && 00488 s->color_type == PNG_COLOR_TYPE_GRAY) { 00489 avctx->pix_fmt = PIX_FMT_MONOBLACK; 00490 } else if (s->bit_depth == 8 && 00491 s->color_type == PNG_COLOR_TYPE_PALETTE) { 00492 avctx->pix_fmt = PIX_FMT_PAL8; 00493 } else if (s->bit_depth == 8 && 00494 s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { 00495 avctx->pix_fmt = PIX_FMT_Y400A; 00496 } else { 00497 goto fail; 00498 } 00499 if(p->data[0]) 00500 avctx->release_buffer(avctx, p); 00501 00502 p->reference= 0; 00503 if(avctx->get_buffer(avctx, p) < 0){ 00504 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 00505 goto fail; 00506 } 00507 p->pict_type= FF_I_TYPE; 00508 p->key_frame= 1; 00509 p->interlaced_frame = !!s->interlace_type; 00510 00511 /* compute the compressed row size */ 00512 if (!s->interlace_type) { 00513 s->crow_size = s->row_size + 1; 00514 } else { 00515 s->pass = 0; 00516 s->pass_row_size = ff_png_pass_row_size(s->pass, 00517 s->bits_per_pixel, 00518 s->width); 00519 s->crow_size = s->pass_row_size + 1; 00520 } 00521 dprintf(avctx, "row_size=%d crow_size =%d\n", 00522 s->row_size, s->crow_size); 00523 s->image_buf = p->data[0]; 00524 s->image_linesize = p->linesize[0]; 00525 /* copy the palette if needed */ 00526 if (s->color_type == PNG_COLOR_TYPE_PALETTE) 00527 memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t)); 00528 /* empty row is used if differencing to the first row */ 00529 s->last_row = av_mallocz(s->row_size); 00530 if (!s->last_row) 00531 goto fail; 00532 if (s->interlace_type || 00533 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 00534 s->tmp_row = av_malloc(s->row_size); 00535 if (!s->tmp_row) 00536 goto fail; 00537 } 00538 /* compressed row */ 00539 crow_buf_base = av_malloc(s->row_size + 16); 00540 if (!crow_buf_base) 00541 goto fail; 00542 00543 /* we want crow_buf+1 to be 16-byte aligned */ 00544 s->crow_buf = crow_buf_base + 15; 00545 s->zstream.avail_out = s->crow_size; 00546 s->zstream.next_out = s->crow_buf; 00547 } 00548 s->state |= PNG_IDAT; 00549 if (png_decode_idat(s, length) < 0) 00550 goto fail; 00551 /* skip crc */ 00552 crc = bytestream_get_be32(&s->bytestream); 00553 break; 00554 case MKTAG('P', 'L', 'T', 'E'): 00555 { 00556 int n, i, r, g, b; 00557 00558 if ((length % 3) != 0 || length > 256 * 3) 00559 goto skip_tag; 00560 /* read the palette */ 00561 n = length / 3; 00562 for(i=0;i<n;i++) { 00563 r = *s->bytestream++; 00564 g = *s->bytestream++; 00565 b = *s->bytestream++; 00566 s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b; 00567 } 00568 for(;i<256;i++) { 00569 s->palette[i] = (0xff << 24); 00570 } 00571 s->state |= PNG_PLTE; 00572 crc = bytestream_get_be32(&s->bytestream); 00573 } 00574 break; 00575 case MKTAG('t', 'R', 'N', 'S'): 00576 { 00577 int v, i; 00578 00579 /* read the transparency. XXX: Only palette mode supported */ 00580 if (s->color_type != PNG_COLOR_TYPE_PALETTE || 00581 length > 256 || 00582 !(s->state & PNG_PLTE)) 00583 goto skip_tag; 00584 for(i=0;i<length;i++) { 00585 v = *s->bytestream++; 00586 s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24); 00587 } 00588 crc = bytestream_get_be32(&s->bytestream); 00589 } 00590 break; 00591 case MKTAG('I', 'E', 'N', 'D'): 00592 if (!(s->state & PNG_ALLIMAGE)) 00593 goto fail; 00594 crc = bytestream_get_be32(&s->bytestream); 00595 goto exit_loop; 00596 default: 00597 /* skip tag */ 00598 skip_tag: 00599 s->bytestream += length + 4; 00600 break; 00601 } 00602 } 00603 exit_loop: 00604 /* handle p-frames only if a predecessor frame is available */ 00605 if(s->last_picture->data[0] != NULL) { 00606 if(!(avpkt->flags & AV_PKT_FLAG_KEY)) { 00607 int i, j; 00608 uint8_t *pd = s->current_picture->data[0]; 00609 uint8_t *pd_last = s->last_picture->data[0]; 00610 00611 for(j=0; j < s->height; j++) { 00612 for(i=0; i < s->width * s->bpp; i++) { 00613 pd[i] += pd_last[i]; 00614 } 00615 pd += s->image_linesize; 00616 pd_last += s->image_linesize; 00617 } 00618 } 00619 } 00620 00621 *picture= *s->current_picture; 00622 *data_size = sizeof(AVFrame); 00623 00624 ret = s->bytestream - s->bytestream_start; 00625 the_end: 00626 inflateEnd(&s->zstream); 00627 av_free(crow_buf_base); 00628 s->crow_buf = NULL; 00629 av_freep(&s->last_row); 00630 av_freep(&s->tmp_row); 00631 return ret; 00632 fail: 00633 ret = -1; 00634 goto the_end; 00635 } 00636 00637 static av_cold int png_dec_init(AVCodecContext *avctx){ 00638 PNGDecContext *s = avctx->priv_data; 00639 00640 s->current_picture = &s->picture1; 00641 s->last_picture = &s->picture2; 00642 avcodec_get_frame_defaults(&s->picture1); 00643 avcodec_get_frame_defaults(&s->picture2); 00644 dsputil_init(&s->dsp, avctx); 00645 00646 return 0; 00647 } 00648 00649 static av_cold int png_dec_end(AVCodecContext *avctx) 00650 { 00651 PNGDecContext *s = avctx->priv_data; 00652 00653 if (s->picture1.data[0]) 00654 avctx->release_buffer(avctx, &s->picture1); 00655 if (s->picture2.data[0]) 00656 avctx->release_buffer(avctx, &s->picture2); 00657 00658 return 0; 00659 } 00660 00661 AVCodec png_decoder = { 00662 "png", 00663 AVMEDIA_TYPE_VIDEO, 00664 CODEC_ID_PNG, 00665 sizeof(PNGDecContext), 00666 png_dec_init, 00667 NULL, 00668 png_dec_end, 00669 decode_frame, 00670 CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/, 00671 NULL, 00672 .long_name = NULL_IF_CONFIG_SMALL("PNG image"), 00673 };