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 "dsputil.h" 24#include "png.h" 25 26/* TODO: 27 * - add 2, 4 and 16 bit depth support 28 */ 29 30#include <zlib.h> 31 32//#define DEBUG 33 34#define IOBUF_SIZE 4096 35 36typedef struct PNGEncContext { 37 DSPContext dsp; 38 39 uint8_t *bytestream; 40 uint8_t *bytestream_start; 41 uint8_t *bytestream_end; 42 AVFrame picture; 43 44 int filter_type; 45 46 z_stream zstream; 47 uint8_t buf[IOBUF_SIZE]; 48} PNGEncContext; 49 50static void png_get_interlaced_row(uint8_t *dst, int row_size, 51 int bits_per_pixel, int pass, 52 const uint8_t *src, int width) 53{ 54 int x, mask, dst_x, j, b, bpp; 55 uint8_t *d; 56 const uint8_t *s; 57 58 mask = ff_png_pass_mask[pass]; 59 switch(bits_per_pixel) { 60 case 1: 61 memset(dst, 0, row_size); 62 dst_x = 0; 63 for(x = 0; x < width; x++) { 64 j = (x & 7); 65 if ((mask << j) & 0x80) { 66 b = (src[x >> 3] >> (7 - j)) & 1; 67 dst[dst_x >> 3] |= b << (7 - (dst_x & 7)); 68 dst_x++; 69 } 70 } 71 break; 72 default: 73 bpp = bits_per_pixel >> 3; 74 d = dst; 75 s = src; 76 for(x = 0; x < width; x++) { 77 j = x & 7; 78 if ((mask << j) & 0x80) { 79 memcpy(d, s, bpp); 80 d += bpp; 81 } 82 s += bpp; 83 } 84 break; 85 } 86} 87 88static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp) 89{ 90 int i; 91 for(i = 0; i < w; i++) { 92 int a, b, c, p, pa, pb, pc; 93 94 a = src[i - bpp]; 95 b = top[i]; 96 c = top[i - bpp]; 97 98 p = b - c; 99 pc = a - c; 100 101 pa = abs(p); 102 pb = abs(pc); 103 pc = abs(p + pc); 104 105 if (pa <= pb && pa <= pc) 106 p = a; 107 else if (pb <= pc) 108 p = b; 109 else 110 p = c; 111 dst[i] = src[i] - p; 112 } 113} 114 115static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type, 116 uint8_t *src, uint8_t *top, int size, int bpp) 117{ 118 int i; 119 120 switch(filter_type) { 121 case PNG_FILTER_VALUE_NONE: 122 memcpy(dst, src, size); 123 break; 124 case PNG_FILTER_VALUE_SUB: 125 dsp->diff_bytes(dst, src, src-bpp, size); 126 memcpy(dst, src, bpp); 127 break; 128 case PNG_FILTER_VALUE_UP: 129 dsp->diff_bytes(dst, src, top, size); 130 break; 131 case PNG_FILTER_VALUE_AVG: 132 for(i = 0; i < bpp; i++) 133 dst[i] = src[i] - (top[i] >> 1); 134 for(; i < size; i++) 135 dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1); 136 break; 137 case PNG_FILTER_VALUE_PAETH: 138 for(i = 0; i < bpp; i++) 139 dst[i] = src[i] - top[i]; 140 sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp); 141 break; 142 } 143} 144 145static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst, 146 uint8_t *src, uint8_t *top, int size, int bpp) 147{ 148 int pred = s->filter_type; 149 assert(bpp || !pred); 150 if(!top && pred) 151 pred = PNG_FILTER_VALUE_SUB; 152 if(pred == PNG_FILTER_VALUE_MIXED) { 153 int i; 154 int cost, bcost = INT_MAX; 155 uint8_t *buf1 = dst, *buf2 = dst + size + 16; 156 for(pred=0; pred<5; pred++) { 157 png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp); 158 buf1[0] = pred; 159 cost = 0; 160 for(i=0; i<=size; i++) 161 cost += abs((int8_t)buf1[i]); 162 if(cost < bcost) { 163 bcost = cost; 164 FFSWAP(uint8_t*, buf1, buf2); 165 } 166 } 167 return buf2; 168 } else { 169 png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp); 170 dst[0] = pred; 171 return dst; 172 } 173} 174 175static void convert_from_rgb32(uint8_t *dst, const uint8_t *src, int width) 176{ 177 uint8_t *d; 178 int j; 179 unsigned int v; 180 181 d = dst; 182 for(j = 0; j < width; j++) { 183 v = ((const uint32_t *)src)[j]; 184 d[0] = v >> 16; 185 d[1] = v >> 8; 186 d[2] = v; 187 d[3] = v >> 24; 188 d += 4; 189 } 190} 191 192static void png_write_chunk(uint8_t **f, uint32_t tag, 193 const uint8_t *buf, int length) 194{ 195 uint32_t crc; 196 uint8_t tagbuf[4]; 197 198 bytestream_put_be32(f, length); 199 crc = crc32(0, Z_NULL, 0); 200 AV_WL32(tagbuf, tag); 201 crc = crc32(crc, tagbuf, 4); 202 bytestream_put_be32(f, bswap_32(tag)); 203 if (length > 0) { 204 crc = crc32(crc, buf, length); 205 memcpy(*f, buf, length); 206 *f += length; 207 } 208 bytestream_put_be32(f, crc); 209} 210 211/* XXX: do filtering */ 212static int png_write_row(PNGEncContext *s, const uint8_t *data, int size) 213{ 214 int ret; 215 216 s->zstream.avail_in = size; 217 s->zstream.next_in = (uint8_t *)data; 218 while (s->zstream.avail_in > 0) { 219 ret = deflate(&s->zstream, Z_NO_FLUSH); 220 if (ret != Z_OK) 221 return -1; 222 if (s->zstream.avail_out == 0) { 223 if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100) 224 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE); 225 s->zstream.avail_out = IOBUF_SIZE; 226 s->zstream.next_out = s->buf; 227 } 228 } 229 return 0; 230} 231 232static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){ 233 PNGEncContext *s = avctx->priv_data; 234 AVFrame *pict = data; 235 AVFrame * const p= &s->picture; 236 int bit_depth, color_type, y, len, row_size, ret, is_progressive; 237 int bits_per_pixel, pass_row_size; 238 int compression_level; 239 uint8_t *ptr, *top; 240 uint8_t *crow_base = NULL, *crow_buf, *crow; 241 uint8_t *progressive_buf = NULL; 242 uint8_t *rgba_buf = NULL; 243 uint8_t *top_buf = NULL; 244 245 *p = *pict; 246 p->pict_type= FF_I_TYPE; 247 p->key_frame= 1; 248 249 s->bytestream_start= 250 s->bytestream= buf; 251 s->bytestream_end= buf+buf_size; 252 253 is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT); 254 switch(avctx->pix_fmt) { 255 case PIX_FMT_RGB32: 256 bit_depth = 8; 257 color_type = PNG_COLOR_TYPE_RGB_ALPHA; 258 break; 259 case PIX_FMT_RGB24: 260 bit_depth = 8; 261 color_type = PNG_COLOR_TYPE_RGB; 262 break; 263 case PIX_FMT_GRAY8: 264 bit_depth = 8; 265 color_type = PNG_COLOR_TYPE_GRAY; 266 break; 267 case PIX_FMT_MONOBLACK: 268 bit_depth = 1; 269 color_type = PNG_COLOR_TYPE_GRAY; 270 break; 271 case PIX_FMT_PAL8: 272 bit_depth = 8; 273 color_type = PNG_COLOR_TYPE_PALETTE; 274 break; 275 default: 276 return -1; 277 } 278 bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth; 279 row_size = (avctx->width * bits_per_pixel + 7) >> 3; 280 281 s->zstream.zalloc = ff_png_zalloc; 282 s->zstream.zfree = ff_png_zfree; 283 s->zstream.opaque = NULL; 284 compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ? 285 Z_DEFAULT_COMPRESSION : 286 av_clip(avctx->compression_level, 0, 9); 287 ret = deflateInit2(&s->zstream, compression_level, 288 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY); 289 if (ret != Z_OK) 290 return -1; 291 crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED)); 292 if (!crow_base) 293 goto fail; 294 crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it 295 if (is_progressive) { 296 progressive_buf = av_malloc(row_size + 1); 297 if (!progressive_buf) 298 goto fail; 299 } 300 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 301 rgba_buf = av_malloc(row_size + 1); 302 if (!rgba_buf) 303 goto fail; 304 } 305 if (is_progressive || color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 306 top_buf = av_malloc(row_size + 1); 307 if (!top_buf) 308 goto fail; 309 } 310 311 /* write png header */ 312 memcpy(s->bytestream, ff_pngsig, 8); 313 s->bytestream += 8; 314 315 AV_WB32(s->buf, avctx->width); 316 AV_WB32(s->buf + 4, avctx->height); 317 s->buf[8] = bit_depth; 318 s->buf[9] = color_type; 319 s->buf[10] = 0; /* compression type */ 320 s->buf[11] = 0; /* filter type */ 321 s->buf[12] = is_progressive; /* interlace type */ 322 323 png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13); 324 325 /* put the palette if needed */ 326 if (color_type == PNG_COLOR_TYPE_PALETTE) { 327 int has_alpha, alpha, i; 328 unsigned int v; 329 uint32_t *palette; 330 uint8_t *alpha_ptr; 331 332 palette = (uint32_t *)p->data[1]; 333 ptr = s->buf; 334 alpha_ptr = s->buf + 256 * 3; 335 has_alpha = 0; 336 for(i = 0; i < 256; i++) { 337 v = palette[i]; 338 alpha = v >> 24; 339 if (alpha && alpha != 0xff) 340 has_alpha = 1; 341 *alpha_ptr++ = alpha; 342 bytestream_put_be24(&ptr, v); 343 } 344 png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3); 345 if (has_alpha) { 346 png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256); 347 } 348 } 349 350 /* now put each row */ 351 s->zstream.avail_out = IOBUF_SIZE; 352 s->zstream.next_out = s->buf; 353 if (is_progressive) { 354 int pass; 355 356 for(pass = 0; pass < NB_PASSES; pass++) { 357 /* NOTE: a pass is completely omited if no pixels would be 358 output */ 359 pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width); 360 if (pass_row_size > 0) { 361 top = NULL; 362 for(y = 0; y < avctx->height; y++) { 363 if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) { 364 ptr = p->data[0] + y * p->linesize[0]; 365 FFSWAP(uint8_t*, progressive_buf, top_buf); 366 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 367 convert_from_rgb32(rgba_buf, ptr, avctx->width); 368 ptr = rgba_buf; 369 } 370 png_get_interlaced_row(progressive_buf, pass_row_size, 371 bits_per_pixel, pass, 372 ptr, avctx->width); 373 crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3); 374 png_write_row(s, crow, pass_row_size + 1); 375 top = progressive_buf; 376 } 377 } 378 } 379 } 380 } else { 381 top = NULL; 382 for(y = 0; y < avctx->height; y++) { 383 ptr = p->data[0] + y * p->linesize[0]; 384 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 385 FFSWAP(uint8_t*, rgba_buf, top_buf); 386 convert_from_rgb32(rgba_buf, ptr, avctx->width); 387 ptr = rgba_buf; 388 } 389 crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3); 390 png_write_row(s, crow, row_size + 1); 391 top = ptr; 392 } 393 } 394 /* compress last bytes */ 395 for(;;) { 396 ret = deflate(&s->zstream, Z_FINISH); 397 if (ret == Z_OK || ret == Z_STREAM_END) { 398 len = IOBUF_SIZE - s->zstream.avail_out; 399 if (len > 0 && s->bytestream_end - s->bytestream > len + 100) { 400 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len); 401 } 402 s->zstream.avail_out = IOBUF_SIZE; 403 s->zstream.next_out = s->buf; 404 if (ret == Z_STREAM_END) 405 break; 406 } else { 407 goto fail; 408 } 409 } 410 png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0); 411 412 ret = s->bytestream - s->bytestream_start; 413 the_end: 414 av_free(crow_base); 415 av_free(progressive_buf); 416 av_free(rgba_buf); 417 av_free(top_buf); 418 deflateEnd(&s->zstream); 419 return ret; 420 fail: 421 ret = -1; 422 goto the_end; 423} 424 425static av_cold int png_enc_init(AVCodecContext *avctx){ 426 PNGEncContext *s = avctx->priv_data; 427 428 avcodec_get_frame_defaults(&s->picture); 429 avctx->coded_frame= &s->picture; 430 dsputil_init(&s->dsp, avctx); 431 432 s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED); 433 if(avctx->pix_fmt == PIX_FMT_MONOBLACK) 434 s->filter_type = PNG_FILTER_VALUE_NONE; 435 436 return 0; 437} 438 439AVCodec png_encoder = { 440 "png", 441 AVMEDIA_TYPE_VIDEO, 442 CODEC_ID_PNG, 443 sizeof(PNGEncContext), 444 png_enc_init, 445 encode_frame, 446 NULL, //encode_end, 447 .pix_fmts= (const enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGB32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, PIX_FMT_NONE}, 448 .long_name= NULL_IF_CONFIG_SMALL("PNG image"), 449}; 450