3 * Copyright (c) 2003 Fabrice Bellard
5 * This file is part of Libav.
7 * Libav 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 * Libav 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 Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "bytestream.h"
27 * - add 2, 4 and 16 bit depth support
32 #define IOBUF_SIZE 4096
34 typedef struct PNGEncContext {
38 uint8_t *bytestream_start;
39 uint8_t *bytestream_end;
44 uint8_t buf[IOBUF_SIZE];
47 static void png_get_interlaced_row(uint8_t *dst, int row_size,
48 int bits_per_pixel, int pass,
49 const uint8_t *src, int width)
51 int x, mask, dst_x, j, b, bpp;
55 mask = ff_png_pass_mask[pass];
56 switch(bits_per_pixel) {
58 memset(dst, 0, row_size);
60 for(x = 0; x < width; x++) {
62 if ((mask << j) & 0x80) {
63 b = (src[x >> 3] >> (7 - j)) & 1;
64 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
70 bpp = bits_per_pixel >> 3;
73 for(x = 0; x < width; x++) {
75 if ((mask << j) & 0x80) {
85 static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
88 for(i = 0; i < w; i++) {
89 int a, b, c, p, pa, pb, pc;
102 if (pa <= pb && pa <= pc)
112 static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type,
113 uint8_t *src, uint8_t *top, int size, int bpp)
117 switch(filter_type) {
118 case PNG_FILTER_VALUE_NONE:
119 memcpy(dst, src, size);
121 case PNG_FILTER_VALUE_SUB:
122 dsp->diff_bytes(dst, src, src-bpp, size);
123 memcpy(dst, src, bpp);
125 case PNG_FILTER_VALUE_UP:
126 dsp->diff_bytes(dst, src, top, size);
128 case PNG_FILTER_VALUE_AVG:
129 for(i = 0; i < bpp; i++)
130 dst[i] = src[i] - (top[i] >> 1);
132 dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1);
134 case PNG_FILTER_VALUE_PAETH:
135 for(i = 0; i < bpp; i++)
136 dst[i] = src[i] - top[i];
137 sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp);
142 static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,
143 uint8_t *src, uint8_t *top, int size, int bpp)
145 int pred = s->filter_type;
146 assert(bpp || !pred);
148 pred = PNG_FILTER_VALUE_SUB;
149 if(pred == PNG_FILTER_VALUE_MIXED) {
151 int cost, bcost = INT_MAX;
152 uint8_t *buf1 = dst, *buf2 = dst + size + 16;
153 for(pred=0; pred<5; pred++) {
154 png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp);
157 for(i=0; i<=size; i++)
158 cost += abs((int8_t)buf1[i]);
161 FFSWAP(uint8_t*, buf1, buf2);
166 png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp);
172 static void convert_from_rgb32(uint8_t *dst, const uint8_t *src, int width)
179 for(j = 0; j < width; j++) {
180 v = ((const uint32_t *)src)[j];
189 static void png_write_chunk(uint8_t **f, uint32_t tag,
190 const uint8_t *buf, int length)
195 bytestream_put_be32(f, length);
196 crc = crc32(0, Z_NULL, 0);
197 AV_WL32(tagbuf, tag);
198 crc = crc32(crc, tagbuf, 4);
199 bytestream_put_be32(f, av_bswap32(tag));
201 crc = crc32(crc, buf, length);
202 memcpy(*f, buf, length);
205 bytestream_put_be32(f, crc);
208 /* XXX: do filtering */
209 static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
213 s->zstream.avail_in = size;
214 s->zstream.next_in = (uint8_t *)data;
215 while (s->zstream.avail_in > 0) {
216 ret = deflate(&s->zstream, Z_NO_FLUSH);
219 if (s->zstream.avail_out == 0) {
220 if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
221 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
222 s->zstream.avail_out = IOBUF_SIZE;
223 s->zstream.next_out = s->buf;
229 static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
230 const AVFrame *pict, int *got_packet)
232 PNGEncContext *s = avctx->priv_data;
233 const AVFrame * const p = pict;
234 int bit_depth, color_type, y, len, row_size, ret, is_progressive;
235 int bits_per_pixel, pass_row_size, enc_row_size, max_packet_size;
236 int compression_level;
238 uint8_t *crow_base = NULL, *crow_buf, *crow;
239 uint8_t *progressive_buf = NULL;
240 uint8_t *rgba_buf = NULL;
241 uint8_t *top_buf = NULL;
243 is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
244 switch(avctx->pix_fmt) {
245 case AV_PIX_FMT_RGB32:
247 color_type = PNG_COLOR_TYPE_RGB_ALPHA;
249 case AV_PIX_FMT_RGB24:
251 color_type = PNG_COLOR_TYPE_RGB;
253 case AV_PIX_FMT_GRAY16BE:
255 color_type = PNG_COLOR_TYPE_GRAY;
257 case AV_PIX_FMT_GRAY8:
259 color_type = PNG_COLOR_TYPE_GRAY;
261 case AV_PIX_FMT_MONOBLACK:
263 color_type = PNG_COLOR_TYPE_GRAY;
265 case AV_PIX_FMT_PAL8:
267 color_type = PNG_COLOR_TYPE_PALETTE;
272 bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;
273 row_size = (avctx->width * bits_per_pixel + 7) >> 3;
275 s->zstream.zalloc = ff_png_zalloc;
276 s->zstream.zfree = ff_png_zfree;
277 s->zstream.opaque = NULL;
278 compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ?
279 Z_DEFAULT_COMPRESSION :
280 av_clip(avctx->compression_level, 0, 9);
281 ret = deflateInit2(&s->zstream, compression_level,
282 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
286 enc_row_size = deflateBound(&s->zstream, row_size);
287 max_packet_size = avctx->height * (enc_row_size +
288 ((enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) * 12)
289 + FF_MIN_BUFFER_SIZE;
291 (ret = av_new_packet(pkt, max_packet_size)) < 0) {
292 av_log(avctx, AV_LOG_ERROR, "Could not allocate output packet of size %d.\n",
297 s->bytestream_start =
298 s->bytestream = pkt->data;
299 s->bytestream_end = pkt->data + pkt->size;
301 crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));
304 crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it
305 if (is_progressive) {
306 progressive_buf = av_malloc(row_size + 1);
307 if (!progressive_buf)
310 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
311 rgba_buf = av_malloc(row_size + 1);
315 if (is_progressive || color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
316 top_buf = av_malloc(row_size + 1);
321 /* write png header */
322 memcpy(s->bytestream, ff_pngsig, 8);
325 AV_WB32(s->buf, avctx->width);
326 AV_WB32(s->buf + 4, avctx->height);
327 s->buf[8] = bit_depth;
328 s->buf[9] = color_type;
329 s->buf[10] = 0; /* compression type */
330 s->buf[11] = 0; /* filter type */
331 s->buf[12] = is_progressive; /* interlace type */
333 png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
335 /* put the palette if needed */
336 if (color_type == PNG_COLOR_TYPE_PALETTE) {
337 int has_alpha, alpha, i;
342 palette = (uint32_t *)p->data[1];
344 alpha_ptr = s->buf + 256 * 3;
346 for(i = 0; i < 256; i++) {
349 if (alpha && alpha != 0xff)
351 *alpha_ptr++ = alpha;
352 bytestream_put_be24(&ptr, v);
354 png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
356 png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
360 /* now put each row */
361 s->zstream.avail_out = IOBUF_SIZE;
362 s->zstream.next_out = s->buf;
363 if (is_progressive) {
366 for(pass = 0; pass < NB_PASSES; pass++) {
367 /* NOTE: a pass is completely omitted if no pixels would be
369 pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);
370 if (pass_row_size > 0) {
372 for(y = 0; y < avctx->height; y++) {
373 if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
374 ptr = p->data[0] + y * p->linesize[0];
375 FFSWAP(uint8_t*, progressive_buf, top_buf);
376 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
377 convert_from_rgb32(rgba_buf, ptr, avctx->width);
380 png_get_interlaced_row(progressive_buf, pass_row_size,
381 bits_per_pixel, pass,
383 crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3);
384 png_write_row(s, crow, pass_row_size + 1);
385 top = progressive_buf;
392 for(y = 0; y < avctx->height; y++) {
393 ptr = p->data[0] + y * p->linesize[0];
394 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
395 FFSWAP(uint8_t*, rgba_buf, top_buf);
396 convert_from_rgb32(rgba_buf, ptr, avctx->width);
399 crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3);
400 png_write_row(s, crow, row_size + 1);
404 /* compress last bytes */
406 ret = deflate(&s->zstream, Z_FINISH);
407 if (ret == Z_OK || ret == Z_STREAM_END) {
408 len = IOBUF_SIZE - s->zstream.avail_out;
409 if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
410 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
412 s->zstream.avail_out = IOBUF_SIZE;
413 s->zstream.next_out = s->buf;
414 if (ret == Z_STREAM_END)
420 png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
422 pkt->size = s->bytestream - s->bytestream_start;
423 pkt->flags |= AV_PKT_FLAG_KEY;
429 av_free(progressive_buf);
432 deflateEnd(&s->zstream);
439 static av_cold int png_enc_init(AVCodecContext *avctx){
440 PNGEncContext *s = avctx->priv_data;
442 avctx->coded_frame = av_frame_alloc();
443 if (!avctx->coded_frame)
444 return AVERROR(ENOMEM);
446 avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
447 avctx->coded_frame->key_frame = 1;
449 ff_dsputil_init(&s->dsp, avctx);
451 s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED);
452 if(avctx->pix_fmt == AV_PIX_FMT_MONOBLACK)
453 s->filter_type = PNG_FILTER_VALUE_NONE;
458 static av_cold int png_enc_close(AVCodecContext *avctx)
460 av_frame_free(&avctx->coded_frame);
464 AVCodec ff_png_encoder = {
466 .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
467 .type = AVMEDIA_TYPE_VIDEO,
468 .id = AV_CODEC_ID_PNG,
469 .priv_data_size = sizeof(PNGEncContext),
470 .init = png_enc_init,
471 .close = png_enc_close,
472 .encode2 = encode_frame,
473 .pix_fmts = (const enum AVPixelFormat[]){
474 AV_PIX_FMT_RGB24, AV_PIX_FMT_RGB32, AV_PIX_FMT_PAL8, AV_PIX_FMT_GRAY8,
476 AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE