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
34 #define IOBUF_SIZE 4096
36 typedef struct PNGEncContext {
40 uint8_t *bytestream_start;
41 uint8_t *bytestream_end;
47 uint8_t buf[IOBUF_SIZE];
50 static 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)
54 int x, mask, dst_x, j, b, bpp;
58 mask = ff_png_pass_mask[pass];
59 switch(bits_per_pixel) {
61 memset(dst, 0, row_size);
63 for(x = 0; x < width; x++) {
65 if ((mask << j) & 0x80) {
66 b = (src[x >> 3] >> (7 - j)) & 1;
67 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
73 bpp = bits_per_pixel >> 3;
76 for(x = 0; x < width; x++) {
78 if ((mask << j) & 0x80) {
88 static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
91 for(i = 0; i < w; i++) {
92 int a, b, c, p, pa, pb, pc;
105 if (pa <= pb && pa <= pc)
115 static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type,
116 uint8_t *src, uint8_t *top, int size, int bpp)
120 switch(filter_type) {
121 case PNG_FILTER_VALUE_NONE:
122 memcpy(dst, src, size);
124 case PNG_FILTER_VALUE_SUB:
125 dsp->diff_bytes(dst, src, src-bpp, size);
126 memcpy(dst, src, bpp);
128 case PNG_FILTER_VALUE_UP:
129 dsp->diff_bytes(dst, src, top, size);
131 case PNG_FILTER_VALUE_AVG:
132 for(i = 0; i < bpp; i++)
133 dst[i] = src[i] - (top[i] >> 1);
135 dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1);
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);
145 static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,
146 uint8_t *src, uint8_t *top, int size, int bpp)
148 int pred = s->filter_type;
149 assert(bpp || !pred);
151 pred = PNG_FILTER_VALUE_SUB;
152 if(pred == PNG_FILTER_VALUE_MIXED) {
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);
160 for(i=0; i<=size; i++)
161 cost += abs((int8_t)buf1[i]);
164 FFSWAP(uint8_t*, buf1, buf2);
169 png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp);
175 static void convert_from_rgb32(uint8_t *dst, const uint8_t *src, int width)
182 for(j = 0; j < width; j++) {
183 v = ((const uint32_t *)src)[j];
192 static void png_write_chunk(uint8_t **f, uint32_t tag,
193 const uint8_t *buf, int length)
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, av_bswap32(tag));
204 crc = crc32(crc, buf, length);
205 memcpy(*f, buf, length);
208 bytestream_put_be32(f, crc);
211 /* XXX: do filtering */
212 static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
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);
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;
232 static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
233 const AVFrame *pict, int *got_packet)
235 PNGEncContext *s = avctx->priv_data;
236 AVFrame * const p= &s->picture;
237 int bit_depth, color_type, y, len, row_size, ret, is_progressive;
238 int bits_per_pixel, pass_row_size, max_packet_size;
239 int compression_level;
241 uint8_t *crow_base = NULL, *crow_buf, *crow;
242 uint8_t *progressive_buf = NULL;
243 uint8_t *rgba_buf = NULL;
244 uint8_t *top_buf = NULL;
247 p->pict_type= AV_PICTURE_TYPE_I;
250 max_packet_size = IOBUF_SIZE*avctx->height + FF_MIN_BUFFER_SIZE;
252 (ret = av_new_packet(pkt, max_packet_size)) < 0) {
253 av_log(avctx, AV_LOG_ERROR, "Could not allocate output packet of size %d.\n",
258 s->bytestream_start =
259 s->bytestream = pkt->data;
260 s->bytestream_end = pkt->data + pkt->size;
262 is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
263 switch(avctx->pix_fmt) {
266 color_type = PNG_COLOR_TYPE_RGB_ALPHA;
270 color_type = PNG_COLOR_TYPE_RGB;
274 color_type = PNG_COLOR_TYPE_GRAY;
276 case PIX_FMT_MONOBLACK:
278 color_type = PNG_COLOR_TYPE_GRAY;
282 color_type = PNG_COLOR_TYPE_PALETTE;
287 bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;
288 row_size = (avctx->width * bits_per_pixel + 7) >> 3;
290 s->zstream.zalloc = ff_png_zalloc;
291 s->zstream.zfree = ff_png_zfree;
292 s->zstream.opaque = NULL;
293 compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ?
294 Z_DEFAULT_COMPRESSION :
295 av_clip(avctx->compression_level, 0, 9);
296 ret = deflateInit2(&s->zstream, compression_level,
297 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
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 (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
310 rgba_buf = av_malloc(row_size + 1);
314 if (is_progressive || color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
315 top_buf = av_malloc(row_size + 1);
320 /* write png header */
321 memcpy(s->bytestream, ff_pngsig, 8);
324 AV_WB32(s->buf, avctx->width);
325 AV_WB32(s->buf + 4, avctx->height);
326 s->buf[8] = bit_depth;
327 s->buf[9] = color_type;
328 s->buf[10] = 0; /* compression type */
329 s->buf[11] = 0; /* filter type */
330 s->buf[12] = is_progressive; /* interlace type */
332 png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
334 /* put the palette if needed */
335 if (color_type == PNG_COLOR_TYPE_PALETTE) {
336 int has_alpha, alpha, i;
341 palette = (uint32_t *)p->data[1];
343 alpha_ptr = s->buf + 256 * 3;
345 for(i = 0; i < 256; i++) {
348 if (alpha && alpha != 0xff)
350 *alpha_ptr++ = alpha;
351 bytestream_put_be24(&ptr, v);
353 png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
355 png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
359 /* now put each row */
360 s->zstream.avail_out = IOBUF_SIZE;
361 s->zstream.next_out = s->buf;
362 if (is_progressive) {
365 for(pass = 0; pass < NB_PASSES; pass++) {
366 /* NOTE: a pass is completely omited if no pixels would be
368 pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);
369 if (pass_row_size > 0) {
371 for(y = 0; y < avctx->height; y++) {
372 if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
373 ptr = p->data[0] + y * p->linesize[0];
374 FFSWAP(uint8_t*, progressive_buf, top_buf);
375 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
376 convert_from_rgb32(rgba_buf, ptr, avctx->width);
379 png_get_interlaced_row(progressive_buf, pass_row_size,
380 bits_per_pixel, pass,
382 crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3);
383 png_write_row(s, crow, pass_row_size + 1);
384 top = progressive_buf;
391 for(y = 0; y < avctx->height; y++) {
392 ptr = p->data[0] + y * p->linesize[0];
393 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
394 FFSWAP(uint8_t*, rgba_buf, top_buf);
395 convert_from_rgb32(rgba_buf, ptr, avctx->width);
398 crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3);
399 png_write_row(s, crow, row_size + 1);
403 /* compress last bytes */
405 ret = deflate(&s->zstream, Z_FINISH);
406 if (ret == Z_OK || ret == Z_STREAM_END) {
407 len = IOBUF_SIZE - s->zstream.avail_out;
408 if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
409 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
411 s->zstream.avail_out = IOBUF_SIZE;
412 s->zstream.next_out = s->buf;
413 if (ret == Z_STREAM_END)
419 png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
421 pkt->size = s->bytestream - s->bytestream_start;
422 pkt->flags |= AV_PKT_FLAG_KEY;
428 av_free(progressive_buf);
431 deflateEnd(&s->zstream);
438 static av_cold int png_enc_init(AVCodecContext *avctx){
439 PNGEncContext *s = avctx->priv_data;
441 avcodec_get_frame_defaults(&s->picture);
442 avctx->coded_frame= &s->picture;
443 ff_dsputil_init(&s->dsp, avctx);
445 s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED);
446 if(avctx->pix_fmt == PIX_FMT_MONOBLACK)
447 s->filter_type = PNG_FILTER_VALUE_NONE;
452 AVCodec ff_png_encoder = {
454 .type = AVMEDIA_TYPE_VIDEO,
456 .priv_data_size = sizeof(PNGEncContext),
457 .init = png_enc_init,
458 .encode2 = encode_frame,
459 .pix_fmts= (const enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGB32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, PIX_FMT_NONE},
460 .long_name= NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),