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 "dsputil.h" 00024 #include "png.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 #define IOBUF_SIZE 4096 00035 00036 typedef struct PNGEncContext { 00037 DSPContext dsp; 00038 00039 uint8_t *bytestream; 00040 uint8_t *bytestream_start; 00041 uint8_t *bytestream_end; 00042 AVFrame picture; 00043 00044 int filter_type; 00045 00046 z_stream zstream; 00047 uint8_t buf[IOBUF_SIZE]; 00048 } PNGEncContext; 00049 00050 static void png_get_interlaced_row(uint8_t *dst, int row_size, 00051 int bits_per_pixel, int pass, 00052 const uint8_t *src, int width) 00053 { 00054 int x, mask, dst_x, j, b, bpp; 00055 uint8_t *d; 00056 const uint8_t *s; 00057 00058 mask = ff_png_pass_mask[pass]; 00059 switch(bits_per_pixel) { 00060 case 1: 00061 memset(dst, 0, row_size); 00062 dst_x = 0; 00063 for(x = 0; x < width; x++) { 00064 j = (x & 7); 00065 if ((mask << j) & 0x80) { 00066 b = (src[x >> 3] >> (7 - j)) & 1; 00067 dst[dst_x >> 3] |= b << (7 - (dst_x & 7)); 00068 dst_x++; 00069 } 00070 } 00071 break; 00072 default: 00073 bpp = bits_per_pixel >> 3; 00074 d = dst; 00075 s = src; 00076 for(x = 0; x < width; x++) { 00077 j = x & 7; 00078 if ((mask << j) & 0x80) { 00079 memcpy(d, s, bpp); 00080 d += bpp; 00081 } 00082 s += bpp; 00083 } 00084 break; 00085 } 00086 } 00087 00088 static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp) 00089 { 00090 int i; 00091 for(i = 0; i < w; i++) { 00092 int a, b, c, p, pa, pb, pc; 00093 00094 a = src[i - bpp]; 00095 b = top[i]; 00096 c = top[i - bpp]; 00097 00098 p = b - c; 00099 pc = a - c; 00100 00101 pa = abs(p); 00102 pb = abs(pc); 00103 pc = abs(p + pc); 00104 00105 if (pa <= pb && pa <= pc) 00106 p = a; 00107 else if (pb <= pc) 00108 p = b; 00109 else 00110 p = c; 00111 dst[i] = src[i] - p; 00112 } 00113 } 00114 00115 static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type, 00116 uint8_t *src, uint8_t *top, int size, int bpp) 00117 { 00118 int i; 00119 00120 switch(filter_type) { 00121 case PNG_FILTER_VALUE_NONE: 00122 memcpy(dst, src, size); 00123 break; 00124 case PNG_FILTER_VALUE_SUB: 00125 dsp->diff_bytes(dst, src, src-bpp, size); 00126 memcpy(dst, src, bpp); 00127 break; 00128 case PNG_FILTER_VALUE_UP: 00129 dsp->diff_bytes(dst, src, top, size); 00130 break; 00131 case PNG_FILTER_VALUE_AVG: 00132 for(i = 0; i < bpp; i++) 00133 dst[i] = src[i] - (top[i] >> 1); 00134 for(; i < size; i++) 00135 dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1); 00136 break; 00137 case PNG_FILTER_VALUE_PAETH: 00138 for(i = 0; i < bpp; i++) 00139 dst[i] = src[i] - top[i]; 00140 sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp); 00141 break; 00142 } 00143 } 00144 00145 static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst, 00146 uint8_t *src, uint8_t *top, int size, int bpp) 00147 { 00148 int pred = s->filter_type; 00149 assert(bpp || !pred); 00150 if(!top && pred) 00151 pred = PNG_FILTER_VALUE_SUB; 00152 if(pred == PNG_FILTER_VALUE_MIXED) { 00153 int i; 00154 int cost, bcost = INT_MAX; 00155 uint8_t *buf1 = dst, *buf2 = dst + size + 16; 00156 for(pred=0; pred<5; pred++) { 00157 png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp); 00158 buf1[0] = pred; 00159 cost = 0; 00160 for(i=0; i<=size; i++) 00161 cost += abs((int8_t)buf1[i]); 00162 if(cost < bcost) { 00163 bcost = cost; 00164 FFSWAP(uint8_t*, buf1, buf2); 00165 } 00166 } 00167 return buf2; 00168 } else { 00169 png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp); 00170 dst[0] = pred; 00171 return dst; 00172 } 00173 } 00174 00175 static void convert_from_rgb32(uint8_t *dst, const uint8_t *src, int width) 00176 { 00177 uint8_t *d; 00178 int j; 00179 unsigned int v; 00180 00181 d = dst; 00182 for(j = 0; j < width; j++) { 00183 v = ((const uint32_t *)src)[j]; 00184 d[0] = v >> 16; 00185 d[1] = v >> 8; 00186 d[2] = v; 00187 d[3] = v >> 24; 00188 d += 4; 00189 } 00190 } 00191 00192 static void png_write_chunk(uint8_t **f, uint32_t tag, 00193 const uint8_t *buf, int length) 00194 { 00195 uint32_t crc; 00196 uint8_t tagbuf[4]; 00197 00198 bytestream_put_be32(f, length); 00199 crc = crc32(0, Z_NULL, 0); 00200 AV_WL32(tagbuf, tag); 00201 crc = crc32(crc, tagbuf, 4); 00202 bytestream_put_be32(f, bswap_32(tag)); 00203 if (length > 0) { 00204 crc = crc32(crc, buf, length); 00205 memcpy(*f, buf, length); 00206 *f += length; 00207 } 00208 bytestream_put_be32(f, crc); 00209 } 00210 00211 /* XXX: do filtering */ 00212 static int png_write_row(PNGEncContext *s, const uint8_t *data, int size) 00213 { 00214 int ret; 00215 00216 s->zstream.avail_in = size; 00217 s->zstream.next_in = (uint8_t *)data; 00218 while (s->zstream.avail_in > 0) { 00219 ret = deflate(&s->zstream, Z_NO_FLUSH); 00220 if (ret != Z_OK) 00221 return -1; 00222 if (s->zstream.avail_out == 0) { 00223 if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100) 00224 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE); 00225 s->zstream.avail_out = IOBUF_SIZE; 00226 s->zstream.next_out = s->buf; 00227 } 00228 } 00229 return 0; 00230 } 00231 00232 static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){ 00233 PNGEncContext *s = avctx->priv_data; 00234 AVFrame *pict = data; 00235 AVFrame * const p= &s->picture; 00236 int bit_depth, color_type, y, len, row_size, ret, is_progressive; 00237 int bits_per_pixel, pass_row_size; 00238 int compression_level; 00239 uint8_t *ptr, *top; 00240 uint8_t *crow_base = NULL, *crow_buf, *crow; 00241 uint8_t *progressive_buf = NULL; 00242 uint8_t *rgba_buf = NULL; 00243 uint8_t *top_buf = NULL; 00244 00245 *p = *pict; 00246 p->pict_type= FF_I_TYPE; 00247 p->key_frame= 1; 00248 00249 s->bytestream_start= 00250 s->bytestream= buf; 00251 s->bytestream_end= buf+buf_size; 00252 00253 is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT); 00254 switch(avctx->pix_fmt) { 00255 case PIX_FMT_RGB32: 00256 bit_depth = 8; 00257 color_type = PNG_COLOR_TYPE_RGB_ALPHA; 00258 break; 00259 case PIX_FMT_RGB24: 00260 bit_depth = 8; 00261 color_type = PNG_COLOR_TYPE_RGB; 00262 break; 00263 case PIX_FMT_GRAY8: 00264 bit_depth = 8; 00265 color_type = PNG_COLOR_TYPE_GRAY; 00266 break; 00267 case PIX_FMT_MONOBLACK: 00268 bit_depth = 1; 00269 color_type = PNG_COLOR_TYPE_GRAY; 00270 break; 00271 case PIX_FMT_PAL8: 00272 bit_depth = 8; 00273 color_type = PNG_COLOR_TYPE_PALETTE; 00274 break; 00275 default: 00276 return -1; 00277 } 00278 bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth; 00279 row_size = (avctx->width * bits_per_pixel + 7) >> 3; 00280 00281 s->zstream.zalloc = ff_png_zalloc; 00282 s->zstream.zfree = ff_png_zfree; 00283 s->zstream.opaque = NULL; 00284 compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ? 00285 Z_DEFAULT_COMPRESSION : 00286 av_clip(avctx->compression_level, 0, 9); 00287 ret = deflateInit2(&s->zstream, compression_level, 00288 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY); 00289 if (ret != Z_OK) 00290 return -1; 00291 crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED)); 00292 if (!crow_base) 00293 goto fail; 00294 crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it 00295 if (is_progressive) { 00296 progressive_buf = av_malloc(row_size + 1); 00297 if (!progressive_buf) 00298 goto fail; 00299 } 00300 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 00301 rgba_buf = av_malloc(row_size + 1); 00302 if (!rgba_buf) 00303 goto fail; 00304 } 00305 if (is_progressive || color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 00306 top_buf = av_malloc(row_size + 1); 00307 if (!top_buf) 00308 goto fail; 00309 } 00310 00311 /* write png header */ 00312 memcpy(s->bytestream, ff_pngsig, 8); 00313 s->bytestream += 8; 00314 00315 AV_WB32(s->buf, avctx->width); 00316 AV_WB32(s->buf + 4, avctx->height); 00317 s->buf[8] = bit_depth; 00318 s->buf[9] = color_type; 00319 s->buf[10] = 0; /* compression type */ 00320 s->buf[11] = 0; /* filter type */ 00321 s->buf[12] = is_progressive; /* interlace type */ 00322 00323 png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13); 00324 00325 /* put the palette if needed */ 00326 if (color_type == PNG_COLOR_TYPE_PALETTE) { 00327 int has_alpha, alpha, i; 00328 unsigned int v; 00329 uint32_t *palette; 00330 uint8_t *alpha_ptr; 00331 00332 palette = (uint32_t *)p->data[1]; 00333 ptr = s->buf; 00334 alpha_ptr = s->buf + 256 * 3; 00335 has_alpha = 0; 00336 for(i = 0; i < 256; i++) { 00337 v = palette[i]; 00338 alpha = v >> 24; 00339 if (alpha && alpha != 0xff) 00340 has_alpha = 1; 00341 *alpha_ptr++ = alpha; 00342 bytestream_put_be24(&ptr, v); 00343 } 00344 png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3); 00345 if (has_alpha) { 00346 png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256); 00347 } 00348 } 00349 00350 /* now put each row */ 00351 s->zstream.avail_out = IOBUF_SIZE; 00352 s->zstream.next_out = s->buf; 00353 if (is_progressive) { 00354 int pass; 00355 00356 for(pass = 0; pass < NB_PASSES; pass++) { 00357 /* NOTE: a pass is completely omited if no pixels would be 00358 output */ 00359 pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width); 00360 if (pass_row_size > 0) { 00361 top = NULL; 00362 for(y = 0; y < avctx->height; y++) { 00363 if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) { 00364 ptr = p->data[0] + y * p->linesize[0]; 00365 FFSWAP(uint8_t*, progressive_buf, top_buf); 00366 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 00367 convert_from_rgb32(rgba_buf, ptr, avctx->width); 00368 ptr = rgba_buf; 00369 } 00370 png_get_interlaced_row(progressive_buf, pass_row_size, 00371 bits_per_pixel, pass, 00372 ptr, avctx->width); 00373 crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3); 00374 png_write_row(s, crow, pass_row_size + 1); 00375 top = progressive_buf; 00376 } 00377 } 00378 } 00379 } 00380 } else { 00381 top = NULL; 00382 for(y = 0; y < avctx->height; y++) { 00383 ptr = p->data[0] + y * p->linesize[0]; 00384 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { 00385 FFSWAP(uint8_t*, rgba_buf, top_buf); 00386 convert_from_rgb32(rgba_buf, ptr, avctx->width); 00387 ptr = rgba_buf; 00388 } 00389 crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3); 00390 png_write_row(s, crow, row_size + 1); 00391 top = ptr; 00392 } 00393 } 00394 /* compress last bytes */ 00395 for(;;) { 00396 ret = deflate(&s->zstream, Z_FINISH); 00397 if (ret == Z_OK || ret == Z_STREAM_END) { 00398 len = IOBUF_SIZE - s->zstream.avail_out; 00399 if (len > 0 && s->bytestream_end - s->bytestream > len + 100) { 00400 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len); 00401 } 00402 s->zstream.avail_out = IOBUF_SIZE; 00403 s->zstream.next_out = s->buf; 00404 if (ret == Z_STREAM_END) 00405 break; 00406 } else { 00407 goto fail; 00408 } 00409 } 00410 png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0); 00411 00412 ret = s->bytestream - s->bytestream_start; 00413 the_end: 00414 av_free(crow_base); 00415 av_free(progressive_buf); 00416 av_free(rgba_buf); 00417 av_free(top_buf); 00418 deflateEnd(&s->zstream); 00419 return ret; 00420 fail: 00421 ret = -1; 00422 goto the_end; 00423 } 00424 00425 static av_cold int png_enc_init(AVCodecContext *avctx){ 00426 PNGEncContext *s = avctx->priv_data; 00427 00428 avcodec_get_frame_defaults(&s->picture); 00429 avctx->coded_frame= &s->picture; 00430 dsputil_init(&s->dsp, avctx); 00431 00432 s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED); 00433 if(avctx->pix_fmt == PIX_FMT_MONOBLACK) 00434 s->filter_type = PNG_FILTER_VALUE_NONE; 00435 00436 return 0; 00437 } 00438 00439 AVCodec png_encoder = { 00440 "png", 00441 AVMEDIA_TYPE_VIDEO, 00442 CODEC_ID_PNG, 00443 sizeof(PNGEncContext), 00444 png_enc_init, 00445 encode_frame, 00446 NULL, //encode_end, 00447 .pix_fmts= (const enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGB32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, PIX_FMT_NONE}, 00448 .long_name= NULL_IF_CONFIG_SMALL("PNG image"), 00449 };