3 * Copyright (c) 2003 Fabrice Bellard
5 * This file is part of FFmpeg.
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.
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.
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
23 #include "bytestream.h"
28 * - add 2, 4 and 16 bit depth support
35 #define IOBUF_SIZE 4096
37 typedef struct PNGEncContext {
41 uint8_t *bytestream_start;
42 uint8_t *bytestream_end;
48 uint8_t buf[IOBUF_SIZE];
51 static void png_get_interlaced_row(uint8_t *dst, int row_size,
52 int bits_per_pixel, int pass,
53 const uint8_t *src, int width)
55 int x, mask, dst_x, j, b, bpp;
59 mask = (int[]){0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff}[pass];
60 switch(bits_per_pixel) {
62 memset(dst, 0, row_size);
64 for(x = 0; x < width; x++) {
66 if ((mask << j) & 0x80) {
67 b = (src[x >> 3] >> (7 - j)) & 1;
68 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
74 bpp = bits_per_pixel >> 3;
77 for(x = 0; x < width; x++) {
79 if ((mask << j) & 0x80) {
89 static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
92 for(i = 0; i < w; i++) {
93 int a, b, c, p, pa, pb, pc;
106 if (pa <= pb && pa <= pc)
116 static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type,
117 uint8_t *src, uint8_t *top, int size, int bpp)
121 switch(filter_type) {
122 case PNG_FILTER_VALUE_NONE:
123 memcpy(dst, src, size);
125 case PNG_FILTER_VALUE_SUB:
126 dsp->diff_bytes(dst, src, src-bpp, size);
127 memcpy(dst, src, bpp);
129 case PNG_FILTER_VALUE_UP:
130 dsp->diff_bytes(dst, src, top, size);
132 case PNG_FILTER_VALUE_AVG:
133 for(i = 0; i < bpp; i++)
134 dst[i] = src[i] - (top[i] >> 1);
136 dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1);
138 case PNG_FILTER_VALUE_PAETH:
139 for(i = 0; i < bpp; i++)
140 dst[i] = src[i] - top[i];
141 sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp);
146 static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,
147 uint8_t *src, uint8_t *top, int size, int bpp)
149 int pred = s->filter_type;
150 assert(bpp || !pred);
152 pred = PNG_FILTER_VALUE_SUB;
153 if(pred == PNG_FILTER_VALUE_MIXED) {
155 int cost, bcost = INT_MAX;
156 uint8_t *buf1 = dst, *buf2 = dst + size + 16;
157 for(pred=0; pred<5; pred++) {
158 png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp);
161 for(i=0; i<=size; i++)
162 cost += abs((int8_t)buf1[i]);
165 FFSWAP(uint8_t*, buf1, buf2);
170 png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp);
176 static void png_write_chunk(uint8_t **f, uint32_t tag,
177 const uint8_t *buf, int length)
182 bytestream_put_be32(f, length);
183 crc = crc32(0, Z_NULL, 0);
184 AV_WL32(tagbuf, tag);
185 crc = crc32(crc, tagbuf, 4);
186 bytestream_put_be32(f, av_bswap32(tag));
188 crc = crc32(crc, buf, length);
189 memcpy(*f, buf, length);
192 bytestream_put_be32(f, crc);
195 /* XXX: do filtering */
196 static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
200 s->zstream.avail_in = size;
201 s->zstream.next_in = (uint8_t *)data;
202 while (s->zstream.avail_in > 0) {
203 ret = deflate(&s->zstream, Z_NO_FLUSH);
206 if (s->zstream.avail_out == 0) {
207 if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
208 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
209 s->zstream.avail_out = IOBUF_SIZE;
210 s->zstream.next_out = s->buf;
216 static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
217 const AVFrame *pict, int *got_packet)
219 PNGEncContext *s = avctx->priv_data;
220 AVFrame * const p= &s->picture;
221 int bit_depth, color_type, y, len, row_size, ret, is_progressive;
222 int bits_per_pixel, pass_row_size, enc_row_size, max_packet_size;
223 int compression_level;
225 uint8_t *crow_base = NULL, *crow_buf, *crow;
226 uint8_t *progressive_buf = NULL;
227 uint8_t *top_buf = NULL;
230 p->pict_type= AV_PICTURE_TYPE_I;
233 is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
234 switch(avctx->pix_fmt) {
235 case PIX_FMT_RGBA64BE:
237 color_type = PNG_COLOR_TYPE_RGB_ALPHA;
239 case PIX_FMT_RGB48BE:
241 color_type = PNG_COLOR_TYPE_RGB;
245 color_type = PNG_COLOR_TYPE_RGB_ALPHA;
249 color_type = PNG_COLOR_TYPE_RGB;
251 case PIX_FMT_GRAY16BE:
253 color_type = PNG_COLOR_TYPE_GRAY;
257 color_type = PNG_COLOR_TYPE_GRAY;
261 color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
263 case PIX_FMT_MONOBLACK:
265 color_type = PNG_COLOR_TYPE_GRAY;
269 color_type = PNG_COLOR_TYPE_PALETTE;
274 bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;
275 row_size = (avctx->width * bits_per_pixel + 7) >> 3;
277 s->zstream.zalloc = ff_png_zalloc;
278 s->zstream.zfree = ff_png_zfree;
279 s->zstream.opaque = NULL;
280 compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ?
281 Z_DEFAULT_COMPRESSION :
282 av_clip(avctx->compression_level, 0, 9);
283 ret = deflateInit2(&s->zstream, compression_level,
284 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
288 enc_row_size = deflateBound(&s->zstream, row_size);
289 max_packet_size = avctx->height * (enc_row_size +
290 ((enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) * 12)
291 + FF_MIN_BUFFER_SIZE;
292 if ((ret = ff_alloc_packet2(avctx, pkt, max_packet_size)) < 0) {
296 s->bytestream_start =
297 s->bytestream = pkt->data;
298 s->bytestream_end = pkt->data + pkt->size;
300 crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));
303 crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it
304 if (is_progressive) {
305 progressive_buf = av_malloc(row_size + 1);
306 if (!progressive_buf)
309 if (is_progressive) {
310 top_buf = av_malloc(row_size + 1);
315 /* write png header */
316 memcpy(s->bytestream, ff_pngsig, 8);
319 AV_WB32(s->buf, avctx->width);
320 AV_WB32(s->buf + 4, avctx->height);
321 s->buf[8] = bit_depth;
322 s->buf[9] = color_type;
323 s->buf[10] = 0; /* compression type */
324 s->buf[11] = 0; /* filter type */
325 s->buf[12] = is_progressive; /* interlace type */
327 png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
329 /* put the palette if needed */
330 if (color_type == PNG_COLOR_TYPE_PALETTE) {
331 int has_alpha, alpha, i;
336 palette = (uint32_t *)p->data[1];
338 alpha_ptr = s->buf + 256 * 3;
340 for(i = 0; i < 256; i++) {
345 *alpha_ptr++ = alpha;
346 bytestream_put_be24(&ptr, v);
348 png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
350 png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
354 /* now put each row */
355 s->zstream.avail_out = IOBUF_SIZE;
356 s->zstream.next_out = s->buf;
357 if (is_progressive) {
360 for(pass = 0; pass < NB_PASSES; pass++) {
361 /* NOTE: a pass is completely omited if no pixels would be
363 pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);
364 if (pass_row_size > 0) {
366 for(y = 0; y < avctx->height; y++) {
367 if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
368 ptr = p->data[0] + y * p->linesize[0];
369 FFSWAP(uint8_t*, progressive_buf, top_buf);
370 png_get_interlaced_row(progressive_buf, pass_row_size,
371 bits_per_pixel, pass,
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;
382 for(y = 0; y < avctx->height; y++) {
383 ptr = p->data[0] + y * p->linesize[0];
384 crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3);
385 png_write_row(s, crow, row_size + 1);
389 /* compress last bytes */
391 ret = deflate(&s->zstream, Z_FINISH);
392 if (ret == Z_OK || ret == Z_STREAM_END) {
393 len = IOBUF_SIZE - s->zstream.avail_out;
394 if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
395 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
397 s->zstream.avail_out = IOBUF_SIZE;
398 s->zstream.next_out = s->buf;
399 if (ret == Z_STREAM_END)
405 png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
407 pkt->size = s->bytestream - s->bytestream_start;
408 pkt->flags |= AV_PKT_FLAG_KEY;
414 av_free(progressive_buf);
416 deflateEnd(&s->zstream);
423 static av_cold int png_enc_init(AVCodecContext *avctx){
424 PNGEncContext *s = avctx->priv_data;
426 avcodec_get_frame_defaults(&s->picture);
427 avctx->coded_frame= &s->picture;
428 ff_dsputil_init(&s->dsp, avctx);
430 s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED);
431 if(avctx->pix_fmt == PIX_FMT_MONOBLACK)
432 s->filter_type = PNG_FILTER_VALUE_NONE;
437 AVCodec ff_png_encoder = {
439 .type = AVMEDIA_TYPE_VIDEO,
441 .priv_data_size = sizeof(PNGEncContext),
442 .init = png_enc_init,
443 .encode2 = encode_frame,
444 .pix_fmts= (const enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGBA,
445 PIX_FMT_RGB48BE, PIX_FMT_RGBA64BE,
447 PIX_FMT_GRAY8, PIX_FMT_GRAY8A,
449 PIX_FMT_MONOBLACK, PIX_FMT_NONE},
450 .long_name= NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),