3 * Copyright (c) 2003 Fabrice Bellard.
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 * - add 2, 4 and 16 bit depth support
23 * - use filters when generating a png (better compression)
31 #define PNG_COLOR_MASK_PALETTE 1
32 #define PNG_COLOR_MASK_COLOR 2
33 #define PNG_COLOR_MASK_ALPHA 4
35 #define PNG_COLOR_TYPE_GRAY 0
36 #define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
37 #define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
38 #define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
39 #define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
41 #define PNG_FILTER_VALUE_NONE 0
42 #define PNG_FILTER_VALUE_SUB 1
43 #define PNG_FILTER_VALUE_UP 2
44 #define PNG_FILTER_VALUE_AVG 3
45 #define PNG_FILTER_VALUE_PAETH 4
47 #define PNG_IHDR 0x0001
48 #define PNG_IDAT 0x0002
49 #define PNG_ALLIMAGE 0x0004
50 #define PNG_PLTE 0x0008
54 #define IOBUF_SIZE 4096
56 typedef struct PNGDecodeState {
70 uint32_t palette[256];
75 int crow_size; /* compressed row size (include filter type) */
76 int row_size; /* decompressed row size */
77 int pass_row_size; /* decompress row size of the current pass */
82 static const uint8_t pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
84 /* Mask to determine which y pixels are valid in a pass */
85 static const uint8_t png_pass_ymask[NB_PASSES] = {
86 0x80, 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55,
89 /* Mask to determine which y pixels can be written in a pass */
90 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
91 0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
95 static const uint8_t png_pass_xmin[NB_PASSES] = {
99 /* x shift to get row width */
100 static const uint8_t png_pass_xshift[NB_PASSES] = {
104 /* Mask to determine which pixels are valid in a pass */
105 static const uint8_t png_pass_mask[NB_PASSES] = {
106 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff
109 /* Mask to determine which pixels to overwrite while displaying */
110 static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
111 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
114 static int png_probe(AVProbeData *pd)
116 if (pd->buf_size >= 8 &&
117 memcmp(pd->buf, pngsig, 8) == 0)
118 return AVPROBE_SCORE_MAX;
123 static void *png_zalloc(void *opaque, unsigned int items, unsigned int size)
125 return av_malloc(items * size);
128 static void png_zfree(void *opaque, void *ptr)
133 static int png_get_nb_channels(int color_type)
137 if ((color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
138 PNG_COLOR_MASK_COLOR)
140 if (color_type & PNG_COLOR_MASK_ALPHA)
145 /* compute the row size of an interleaved pass */
146 static int png_pass_row_size(int pass, int bits_per_pixel, int width)
148 int shift, xmin, pass_width;
150 xmin = png_pass_xmin[pass];
153 shift = png_pass_xshift[pass];
154 pass_width = (width - xmin + (1 << shift) - 1) >> shift;
155 return (pass_width * bits_per_pixel + 7) >> 3;
158 /* NOTE: we try to construct a good looking image at each pass. width
159 is the original image width. We also do pixel format convertion at
161 static void png_put_interlaced_row(uint8_t *dst, int width,
162 int bits_per_pixel, int pass,
163 int color_type, const uint8_t *src)
165 int x, mask, dsp_mask, j, src_x, b, bpp;
169 mask = png_pass_mask[pass];
170 dsp_mask = png_pass_dsp_mask[pass];
171 switch(bits_per_pixel) {
173 /* we must intialize the line to zero before writing to it */
175 memset(dst, 0, (width + 7) >> 3);
177 for(x = 0; x < width; x++) {
179 if ((dsp_mask << j) & 0x80) {
180 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
181 dst[x >> 3] |= b << (7 - j);
183 if ((mask << j) & 0x80)
188 bpp = bits_per_pixel >> 3;
191 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
192 for(x = 0; x < width; x++) {
194 if ((dsp_mask << j) & 0x80) {
195 *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
198 if ((mask << j) & 0x80)
202 for(x = 0; x < width; x++) {
204 if ((dsp_mask << j) & 0x80) {
208 if ((mask << j) & 0x80)
216 static void png_get_interlaced_row(uint8_t *dst, int row_size,
217 int bits_per_pixel, int pass,
218 const uint8_t *src, int width)
220 int x, mask, dst_x, j, b, bpp;
224 mask = png_pass_mask[pass];
225 switch(bits_per_pixel) {
227 memset(dst, 0, row_size);
229 for(x = 0; x < width; x++) {
231 if ((mask << j) & 0x80) {
232 b = (src[x >> 3] >> (7 - j)) & 1;
233 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
239 bpp = bits_per_pixel >> 3;
242 for(x = 0; x < width; x++) {
244 if ((mask << j) & 0x80) {
255 /* NOTE: 'dst' can be equal to 'last' */
256 static void png_filter_row(uint8_t *dst, int filter_type,
257 uint8_t *src, uint8_t *last, int size, int bpp)
261 switch(filter_type) {
262 case PNG_FILTER_VALUE_NONE:
263 memcpy(dst, src, size);
265 case PNG_FILTER_VALUE_SUB:
266 for(i = 0; i < bpp; i++) {
269 for(i = bpp; i < size; i++) {
274 case PNG_FILTER_VALUE_UP:
275 for(i = 0; i < size; i++) {
280 case PNG_FILTER_VALUE_AVG:
281 for(i = 0; i < bpp; i++) {
285 for(i = bpp; i < size; i++) {
286 p = ((dst[i - bpp] + last[i]) >> 1);
290 case PNG_FILTER_VALUE_PAETH:
291 for(i = 0; i < bpp; i++) {
295 for(i = bpp; i < size; i++) {
296 int a, b, c, pa, pb, pc;
309 if (pa <= pb && pa <= pc)
321 static void convert_from_rgba32(uint8_t *dst, const uint8_t *src, int width)
328 for(j = 0; j < width; j++) {
329 v = ((uint32_t *)src)[j];
338 static void convert_to_rgba32(uint8_t *dst, const uint8_t *src, int width)
341 unsigned int r, g, b, a;
343 for(j = 0;j < width; j++) {
348 *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
354 /* process exactly one decompressed row */
355 static void png_handle_row(PNGDecodeState *s)
357 uint8_t *ptr, *last_row;
360 if (!s->interlace_type) {
361 ptr = s->image_buf + s->image_linesize * s->y;
362 /* need to swap bytes correctly for RGB_ALPHA */
363 if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
364 png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
365 s->last_row, s->row_size, s->bpp);
366 memcpy(s->last_row, s->tmp_row, s->row_size);
367 convert_to_rgba32(ptr, s->tmp_row, s->width);
369 /* in normal case, we avoid one copy */
371 last_row = s->last_row;
373 last_row = ptr - s->image_linesize;
375 png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1,
376 last_row, s->row_size, s->bpp);
379 if (s->y == s->height) {
380 s->state |= PNG_ALLIMAGE;
385 ptr = s->image_buf + s->image_linesize * s->y;
386 if ((png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
387 /* if we already read one row, it is time to stop to
388 wait for the next one */
391 png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
392 s->last_row, s->pass_row_size, s->bpp);
393 memcpy(s->last_row, s->tmp_row, s->pass_row_size);
396 if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
397 /* NOTE: rgba32 is handled directly in png_put_interlaced_row */
398 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
399 s->color_type, s->last_row);
402 if (s->y == s->height) {
404 if (s->pass == NB_PASSES - 1) {
405 s->state |= PNG_ALLIMAGE;
410 s->pass_row_size = png_pass_row_size(s->pass,
413 s->crow_size = s->pass_row_size + 1;
414 if (s->pass_row_size != 0)
416 /* skip pass if empty row */
425 static int png_decode_idat(PNGDecodeState *s, ByteIOContext *f, int length)
427 uint8_t buf[IOBUF_SIZE];
431 /* read the buffer */
432 buf_size = IOBUF_SIZE;
433 if (buf_size > length)
435 ret = get_buffer(f, buf, buf_size);
438 s->zstream.avail_in = buf_size;
439 s->zstream.next_in = buf;
440 /* decode one line if possible */
441 while (s->zstream.avail_in > 0) {
442 ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
443 if (ret != Z_OK && ret != Z_STREAM_END) {
446 if (s->zstream.avail_out == 0) {
447 if (!(s->state & PNG_ALLIMAGE)) {
450 s->zstream.avail_out = s->crow_size;
451 s->zstream.next_out = s->crow_buf;
459 static int png_read(ByteIOContext *f,
460 int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
462 AVImageInfo info1, *info = &info1;
463 PNGDecodeState s1, *s = &s1;
464 uint32_t tag, length;
468 /* check signature */
469 ret = get_buffer(f, buf, 8);
472 if (memcmp(buf, pngsig, 8) != 0)
474 memset(s, 0, sizeof(PNGDecodeState));
476 s->zstream.zalloc = png_zalloc;
477 s->zstream.zfree = png_zfree;
478 s->zstream.opaque = NULL;
479 ret = inflateInit(&s->zstream);
485 length = get_be32(f);
486 if (length > 0x7fffffff)
490 printf("png: tag=%c%c%c%c length=%u\n",
493 ((tag >> 16) & 0xff),
494 ((tag >> 24) & 0xff), length);
497 case MKTAG('I', 'H', 'D', 'R'):
500 s->width = get_be32(f);
501 s->height = get_be32(f);
502 s->bit_depth = get_byte(f);
503 s->color_type = get_byte(f);
504 s->compression_type = get_byte(f);
505 s->filter_type = get_byte(f);
506 s->interlace_type = get_byte(f);
508 s->state |= PNG_IHDR;
510 printf("width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
511 s->width, s->height, s->bit_depth, s->color_type,
512 s->compression_type, s->filter_type, s->interlace_type);
515 case MKTAG('I', 'D', 'A', 'T'):
516 if (!(s->state & PNG_IHDR))
518 if (!(s->state & PNG_IDAT)) {
519 /* init image info */
520 info->width = s->width;
521 info->height = s->height;
522 info->interleaved = (s->interlace_type != 0);
524 s->channels = png_get_nb_channels(s->color_type);
525 s->bits_per_pixel = s->bit_depth * s->channels;
526 s->bpp = (s->bits_per_pixel + 7) >> 3;
527 s->row_size = (info->width * s->bits_per_pixel + 7) >> 3;
529 if (s->bit_depth == 8 &&
530 s->color_type == PNG_COLOR_TYPE_RGB) {
531 info->pix_fmt = PIX_FMT_RGB24;
532 } else if (s->bit_depth == 8 &&
533 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
534 info->pix_fmt = PIX_FMT_RGBA32;
535 } else if (s->bit_depth == 8 &&
536 s->color_type == PNG_COLOR_TYPE_GRAY) {
537 info->pix_fmt = PIX_FMT_GRAY8;
538 } else if (s->bit_depth == 1 &&
539 s->color_type == PNG_COLOR_TYPE_GRAY) {
540 info->pix_fmt = PIX_FMT_MONOBLACK;
541 } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
542 info->pix_fmt = PIX_FMT_PAL8;
546 ret = alloc_cb(opaque, info);
550 /* compute the compressed row size */
551 if (!s->interlace_type) {
552 s->crow_size = s->row_size + 1;
555 s->pass_row_size = png_pass_row_size(s->pass,
558 s->crow_size = s->pass_row_size + 1;
561 printf("row_size=%d crow_size =%d\n",
562 s->row_size, s->crow_size);
564 s->image_buf = info->pict.data[0];
565 s->image_linesize = info->pict.linesize[0];
566 /* copy the palette if needed */
567 if (s->color_type == PNG_COLOR_TYPE_PALETTE)
568 memcpy(info->pict.data[1], s->palette, 256 * sizeof(uint32_t));
569 /* empty row is used if differencing to the first row */
570 s->last_row = av_mallocz(s->row_size);
573 if (s->interlace_type ||
574 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
575 s->tmp_row = av_malloc(s->row_size);
580 s->crow_buf = av_malloc(s->row_size + 1);
583 s->zstream.avail_out = s->crow_size;
584 s->zstream.next_out = s->crow_buf;
586 s->state |= PNG_IDAT;
587 if (png_decode_idat(s, f, length) < 0)
592 case MKTAG('P', 'L', 'T', 'E'):
596 if ((length % 3) != 0 || length > 256 * 3)
598 /* read the palette */
604 s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
607 s->palette[i] = (0xff << 24);
609 s->state |= PNG_PLTE;
613 case MKTAG('t', 'R', 'N', 'S'):
617 /* read the transparency. XXX: Only palette mode supported */
618 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
620 !(s->state & PNG_PLTE))
622 for(i=0;i<length;i++) {
624 s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
629 case MKTAG('I', 'E', 'N', 'D'):
630 if (!(s->state & PNG_ALLIMAGE))
637 url_fskip(f, length + 4);
644 inflateEnd(&s->zstream);
645 av_free(s->crow_buf);
646 av_free(s->last_row);
654 static void png_write_chunk(ByteIOContext *f, uint32_t tag,
655 const uint8_t *buf, int length)
661 crc = crc32(0, Z_NULL, 0);
663 tagbuf[1] = tag >> 8;
664 tagbuf[2] = tag >> 16;
665 tagbuf[3] = tag >> 24;
666 crc = crc32(crc, tagbuf, 4);
669 crc = crc32(crc, buf, length);
670 put_buffer(f, buf, length);
675 /* XXX: use avcodec generic function ? */
676 static void to_be32(uint8_t *p, uint32_t v)
684 typedef struct PNGEncodeState {
687 uint8_t buf[IOBUF_SIZE];
691 /* XXX: do filtering */
692 static int png_write_row(PNGEncodeState *s, const uint8_t *data, int size)
696 s->zstream.avail_in = size;
697 s->zstream.next_in = (uint8_t *)data;
698 while (s->zstream.avail_in > 0) {
699 ret = deflate(&s->zstream, Z_NO_FLUSH);
702 if (s->zstream.avail_out == 0) {
703 png_write_chunk(s->f, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
704 s->zstream.avail_out = IOBUF_SIZE;
705 s->zstream.next_out = s->buf;
711 static int png_write(ByteIOContext *f, AVImageInfo *info)
713 PNGEncodeState s1, *s = &s1;
714 int bit_depth, color_type, y, len, row_size, ret, is_progressive;
715 int bits_per_pixel, pass_row_size;
717 uint8_t *crow_buf = NULL;
718 uint8_t *tmp_buf = NULL;
721 is_progressive = info->interleaved;
722 switch(info->pix_fmt) {
725 color_type = PNG_COLOR_TYPE_RGB_ALPHA;
729 color_type = PNG_COLOR_TYPE_RGB;
733 color_type = PNG_COLOR_TYPE_GRAY;
735 case PIX_FMT_MONOBLACK:
737 color_type = PNG_COLOR_TYPE_GRAY;
741 color_type = PNG_COLOR_TYPE_PALETTE;
746 bits_per_pixel = png_get_nb_channels(color_type) * bit_depth;
747 row_size = (info->width * bits_per_pixel + 7) >> 3;
749 s->zstream.zalloc = png_zalloc;
750 s->zstream.zfree = png_zfree;
751 s->zstream.opaque = NULL;
752 ret = deflateInit2(&s->zstream, Z_DEFAULT_COMPRESSION,
753 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
756 crow_buf = av_malloc(row_size + 1);
759 if (is_progressive) {
760 tmp_buf = av_malloc(row_size + 1);
765 /* write png header */
766 put_buffer(f, pngsig, 8);
768 to_be32(s->buf, info->width);
769 to_be32(s->buf + 4, info->height);
770 s->buf[8] = bit_depth;
771 s->buf[9] = color_type;
772 s->buf[10] = 0; /* compression type */
773 s->buf[11] = 0; /* filter type */
774 s->buf[12] = is_progressive; /* interlace type */
776 png_write_chunk(f, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
778 /* put the palette if needed */
779 if (color_type == PNG_COLOR_TYPE_PALETTE) {
780 int has_alpha, alpha, i;
785 palette = (uint32_t *)info->pict.data[1];
787 alpha_ptr = s->buf + 256 * 3;
789 for(i = 0; i < 256; i++) {
794 *alpha_ptr++ = alpha;
800 png_write_chunk(f, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
802 png_write_chunk(f, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
806 /* now put each row */
807 s->zstream.avail_out = IOBUF_SIZE;
808 s->zstream.next_out = s->buf;
809 if (is_progressive) {
813 for(pass = 0; pass < NB_PASSES; pass++) {
814 /* NOTE: a pass is completely omited if no pixels would be
816 pass_row_size = png_pass_row_size(pass, bits_per_pixel, info->width);
817 if (pass_row_size > 0) {
818 for(y = 0; y < info->height; y++) {
819 if ((png_pass_ymask[pass] << (y & 7)) & 0x80) {
820 ptr = info->pict.data[0] + y * info->pict.linesize[0];
821 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
822 convert_from_rgba32(tmp_buf, ptr, info->width);
827 png_get_interlaced_row(crow_buf + 1, pass_row_size,
828 bits_per_pixel, pass,
830 crow_buf[0] = PNG_FILTER_VALUE_NONE;
831 png_write_row(s, crow_buf, pass_row_size + 1);
837 for(y = 0; y < info->height; y++) {
838 ptr = info->pict.data[0] + y * info->pict.linesize[0];
839 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
840 convert_from_rgba32(crow_buf + 1, ptr, info->width);
842 memcpy(crow_buf + 1, ptr, row_size);
843 crow_buf[0] = PNG_FILTER_VALUE_NONE;
844 png_write_row(s, crow_buf, row_size + 1);
847 /* compress last bytes */
849 ret = deflate(&s->zstream, Z_FINISH);
850 if (ret == Z_OK || ret == Z_STREAM_END) {
851 len = IOBUF_SIZE - s->zstream.avail_out;
853 png_write_chunk(f, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
855 s->zstream.avail_out = IOBUF_SIZE;
856 s->zstream.next_out = s->buf;
857 if (ret == Z_STREAM_END)
863 png_write_chunk(f, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
870 deflateEnd(&s->zstream);
877 AVImageFormat png_image_format = {
882 (1 << PIX_FMT_RGBA32) | (1 << PIX_FMT_RGB24) | (1 << PIX_FMT_GRAY8) |
883 (1 << PIX_FMT_MONOBLACK) | (1 << PIX_FMT_PAL8),