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 PNGContext {
58 uint8_t *bytestream_start;
59 uint8_t *bytestream_end;
75 uint32_t palette[256];
80 int crow_size; /* compressed row size (include filter type) */
81 int row_size; /* decompressed row size */
82 int pass_row_size; /* decompress row size of the current pass */
85 uint8_t buf[IOBUF_SIZE];
88 static unsigned int get32(uint8_t **b){
90 return ((*b)[-4]<<24) + ((*b)[-3]<<16) + ((*b)[-2]<<8) + (*b)[-1];
93 static void put32(uint8_t **b, unsigned int v){
100 static const uint8_t pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
102 /* Mask to determine which y pixels are valid in a pass */
103 static const uint8_t png_pass_ymask[NB_PASSES] = {
104 0x80, 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55,
107 /* Mask to determine which y pixels can be written in a pass */
108 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
109 0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
112 /* minimum x value */
113 static const uint8_t png_pass_xmin[NB_PASSES] = {
117 /* x shift to get row width */
118 static const uint8_t png_pass_xshift[NB_PASSES] = {
122 /* Mask to determine which pixels are valid in a pass */
123 static const uint8_t png_pass_mask[NB_PASSES] = {
124 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff
127 /* Mask to determine which pixels to overwrite while displaying */
128 static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
129 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
132 static int png_probe(AVProbeData *pd)
134 if (pd->buf_size >= 8 &&
135 memcmp(pd->buf, pngsig, 8) == 0)
136 return AVPROBE_SCORE_MAX;
141 static void *png_zalloc(void *opaque, unsigned int items, unsigned int size)
143 if(items >= UINT_MAX / size)
145 return av_malloc(items * size);
148 static void png_zfree(void *opaque, void *ptr)
153 static int png_get_nb_channels(int color_type)
157 if ((color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
158 PNG_COLOR_MASK_COLOR)
160 if (color_type & PNG_COLOR_MASK_ALPHA)
165 /* compute the row size of an interleaved pass */
166 static int png_pass_row_size(int pass, int bits_per_pixel, int width)
168 int shift, xmin, pass_width;
170 xmin = png_pass_xmin[pass];
173 shift = png_pass_xshift[pass];
174 pass_width = (width - xmin + (1 << shift) - 1) >> shift;
175 return (pass_width * bits_per_pixel + 7) >> 3;
178 /* NOTE: we try to construct a good looking image at each pass. width
179 is the original image width. We also do pixel format convertion at
181 static void png_put_interlaced_row(uint8_t *dst, int width,
182 int bits_per_pixel, int pass,
183 int color_type, const uint8_t *src)
185 int x, mask, dsp_mask, j, src_x, b, bpp;
189 mask = png_pass_mask[pass];
190 dsp_mask = png_pass_dsp_mask[pass];
191 switch(bits_per_pixel) {
193 /* we must intialize the line to zero before writing to it */
195 memset(dst, 0, (width + 7) >> 3);
197 for(x = 0; x < width; x++) {
199 if ((dsp_mask << j) & 0x80) {
200 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
201 dst[x >> 3] |= b << (7 - j);
203 if ((mask << j) & 0x80)
208 bpp = bits_per_pixel >> 3;
211 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
212 for(x = 0; x < width; x++) {
214 if ((dsp_mask << j) & 0x80) {
215 *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
218 if ((mask << j) & 0x80)
222 for(x = 0; x < width; x++) {
224 if ((dsp_mask << j) & 0x80) {
228 if ((mask << j) & 0x80)
236 static void png_get_interlaced_row(uint8_t *dst, int row_size,
237 int bits_per_pixel, int pass,
238 const uint8_t *src, int width)
240 int x, mask, dst_x, j, b, bpp;
244 mask = png_pass_mask[pass];
245 switch(bits_per_pixel) {
247 memset(dst, 0, row_size);
249 for(x = 0; x < width; x++) {
251 if ((mask << j) & 0x80) {
252 b = (src[x >> 3] >> (7 - j)) & 1;
253 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
259 bpp = bits_per_pixel >> 3;
262 for(x = 0; x < width; x++) {
264 if ((mask << j) & 0x80) {
275 /* NOTE: 'dst' can be equal to 'last' */
276 static void png_filter_row(uint8_t *dst, int filter_type,
277 uint8_t *src, uint8_t *last, int size, int bpp)
281 switch(filter_type) {
282 case PNG_FILTER_VALUE_NONE:
283 memcpy(dst, src, size);
285 case PNG_FILTER_VALUE_SUB:
286 for(i = 0; i < bpp; i++) {
289 for(i = bpp; i < size; i++) {
294 case PNG_FILTER_VALUE_UP:
295 for(i = 0; i < size; i++) {
300 case PNG_FILTER_VALUE_AVG:
301 for(i = 0; i < bpp; i++) {
305 for(i = bpp; i < size; i++) {
306 p = ((dst[i - bpp] + last[i]) >> 1);
310 case PNG_FILTER_VALUE_PAETH:
311 for(i = 0; i < bpp; i++) {
315 for(i = bpp; i < size; i++) {
316 int a, b, c, pa, pb, pc;
329 if (pa <= pb && pa <= pc)
341 static void convert_from_rgba32(uint8_t *dst, const uint8_t *src, int width)
348 for(j = 0; j < width; j++) {
349 v = ((uint32_t *)src)[j];
358 static void convert_to_rgba32(uint8_t *dst, const uint8_t *src, int width)
361 unsigned int r, g, b, a;
363 for(j = 0;j < width; j++) {
368 *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
374 /* process exactly one decompressed row */
375 static void png_handle_row(PNGContext *s)
377 uint8_t *ptr, *last_row;
380 if (!s->interlace_type) {
381 ptr = s->image_buf + s->image_linesize * s->y;
382 /* need to swap bytes correctly for RGB_ALPHA */
383 if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
384 png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
385 s->last_row, s->row_size, s->bpp);
386 memcpy(s->last_row, s->tmp_row, s->row_size);
387 convert_to_rgba32(ptr, s->tmp_row, s->width);
389 /* in normal case, we avoid one copy */
391 last_row = s->last_row;
393 last_row = ptr - s->image_linesize;
395 png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1,
396 last_row, s->row_size, s->bpp);
399 if (s->y == s->height) {
400 s->state |= PNG_ALLIMAGE;
405 ptr = s->image_buf + s->image_linesize * s->y;
406 if ((png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
407 /* if we already read one row, it is time to stop to
408 wait for the next one */
411 png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
412 s->last_row, s->pass_row_size, s->bpp);
413 memcpy(s->last_row, s->tmp_row, s->pass_row_size);
416 if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
417 /* NOTE: rgba32 is handled directly in png_put_interlaced_row */
418 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
419 s->color_type, s->last_row);
422 if (s->y == s->height) {
424 if (s->pass == NB_PASSES - 1) {
425 s->state |= PNG_ALLIMAGE;
430 s->pass_row_size = png_pass_row_size(s->pass,
433 s->crow_size = s->pass_row_size + 1;
434 if (s->pass_row_size != 0)
436 /* skip pass if empty row */
445 static int png_decode_idat(PNGContext *s, int length)
448 s->zstream.avail_in = length;
449 s->zstream.next_in = s->bytestream;
450 s->bytestream += length;
452 if(s->bytestream > s->bytestream_end)
455 /* decode one line if possible */
456 while (s->zstream.avail_in > 0) {
457 ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
458 if (ret != Z_OK && ret != Z_STREAM_END) {
461 if (s->zstream.avail_out == 0) {
462 if (!(s->state & PNG_ALLIMAGE)) {
465 s->zstream.avail_out = s->crow_size;
466 s->zstream.next_out = s->crow_buf;
472 static int decode_frame(AVCodecContext *avctx,
473 void *data, int *data_size,
474 uint8_t *buf, int buf_size)
476 PNGContext * const s = avctx->priv_data;
477 AVFrame *picture = data;
478 AVFrame * const p= (AVFrame*)&s->picture;
479 uint32_t tag, length;
484 s->bytestream_end= buf + buf_size;
486 /* check signature */
487 if (memcmp(s->bytestream, pngsig, 8) != 0)
492 // memset(s, 0, sizeof(PNGContext));
494 s->zstream.zalloc = png_zalloc;
495 s->zstream.zfree = png_zfree;
496 s->zstream.opaque = NULL;
497 ret = inflateInit(&s->zstream);
502 if (s->bytestream >= s->bytestream_end)
504 length = get32(&s->bytestream);
505 if (length > 0x7fffffff)
507 tag32 = get32(&s->bytestream);
508 tag = bswap_32(tag32);
510 printf("png: tag=%c%c%c%c length=%u\n",
513 ((tag >> 16) & 0xff),
514 ((tag >> 24) & 0xff), length);
517 case MKTAG('I', 'H', 'D', 'R'):
520 s->width = get32(&s->bytestream);
521 s->height = get32(&s->bytestream);
522 if(avcodec_check_dimensions(avctx, s->width, s->height)){
523 s->width= s->height= 0;
526 s->bit_depth = *s->bytestream++;
527 s->color_type = *s->bytestream++;
528 s->compression_type = *s->bytestream++;
529 s->filter_type = *s->bytestream++;
530 s->interlace_type = *s->bytestream++;
531 crc = get32(&s->bytestream);
532 s->state |= PNG_IHDR;
534 printf("width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
535 s->width, s->height, s->bit_depth, s->color_type,
536 s->compression_type, s->filter_type, s->interlace_type);
539 case MKTAG('I', 'D', 'A', 'T'):
540 if (!(s->state & PNG_IHDR))
542 if (!(s->state & PNG_IDAT)) {
543 /* init image info */
544 avctx->width = s->width;
545 avctx->height = s->height;
547 s->channels = png_get_nb_channels(s->color_type);
548 s->bits_per_pixel = s->bit_depth * s->channels;
549 s->bpp = (s->bits_per_pixel + 7) >> 3;
550 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
552 if (s->bit_depth == 8 &&
553 s->color_type == PNG_COLOR_TYPE_RGB) {
554 avctx->pix_fmt = PIX_FMT_RGB24;
555 } else if (s->bit_depth == 8 &&
556 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
557 avctx->pix_fmt = PIX_FMT_RGBA32;
558 } else if (s->bit_depth == 8 &&
559 s->color_type == PNG_COLOR_TYPE_GRAY) {
560 avctx->pix_fmt = PIX_FMT_GRAY8;
561 } else if (s->bit_depth == 1 &&
562 s->color_type == PNG_COLOR_TYPE_GRAY) {
563 avctx->pix_fmt = PIX_FMT_MONOBLACK;
564 } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
565 avctx->pix_fmt = PIX_FMT_PAL8;
570 avctx->release_buffer(avctx, p);
573 if(avctx->get_buffer(avctx, p) < 0){
574 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
577 p->pict_type= FF_I_TYPE;
579 p->interlaced_frame = !!s->interlace_type;
581 /* compute the compressed row size */
582 if (!s->interlace_type) {
583 s->crow_size = s->row_size + 1;
586 s->pass_row_size = png_pass_row_size(s->pass,
589 s->crow_size = s->pass_row_size + 1;
592 printf("row_size=%d crow_size =%d\n",
593 s->row_size, s->crow_size);
595 s->image_buf = p->data[0];
596 s->image_linesize = p->linesize[0];
597 /* copy the palette if needed */
598 if (s->color_type == PNG_COLOR_TYPE_PALETTE)
599 memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
600 /* empty row is used if differencing to the first row */
601 s->last_row = av_mallocz(s->row_size);
604 if (s->interlace_type ||
605 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
606 s->tmp_row = av_malloc(s->row_size);
611 s->crow_buf = av_malloc(s->row_size + 1);
614 s->zstream.avail_out = s->crow_size;
615 s->zstream.next_out = s->crow_buf;
617 s->state |= PNG_IDAT;
618 if (png_decode_idat(s, length) < 0)
621 crc = get32(&s->bytestream);
623 case MKTAG('P', 'L', 'T', 'E'):
627 if ((length % 3) != 0 || length > 256 * 3)
629 /* read the palette */
632 r = *s->bytestream++;
633 g = *s->bytestream++;
634 b = *s->bytestream++;
635 s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
638 s->palette[i] = (0xff << 24);
640 s->state |= PNG_PLTE;
641 crc = get32(&s->bytestream);
644 case MKTAG('t', 'R', 'N', 'S'):
648 /* read the transparency. XXX: Only palette mode supported */
649 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
651 !(s->state & PNG_PLTE))
653 for(i=0;i<length;i++) {
654 v = *s->bytestream++;
655 s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
657 crc = get32(&s->bytestream);
660 case MKTAG('I', 'E', 'N', 'D'):
661 if (!(s->state & PNG_ALLIMAGE))
663 crc = get32(&s->bytestream);
668 s->bytestream += length + 4;
673 *picture= *(AVFrame*)&s->picture;
674 *data_size = sizeof(AVPicture);
676 ret = s->bytestream - s->bytestream_start;
678 inflateEnd(&s->zstream);
679 av_freep(&s->crow_buf);
680 av_freep(&s->last_row);
681 av_freep(&s->tmp_row);
688 static void png_write_chunk(uint8_t **f, uint32_t tag,
689 const uint8_t *buf, int length)
695 crc = crc32(0, Z_NULL, 0);
697 tagbuf[1] = tag >> 8;
698 tagbuf[2] = tag >> 16;
699 tagbuf[3] = tag >> 24;
700 crc = crc32(crc, tagbuf, 4);
701 put32(f, bswap_32(tag));
703 crc = crc32(crc, buf, length);
704 memcpy(*f, buf, length);
710 /* XXX: use avcodec generic function ? */
711 static void to_be32(uint8_t *p, uint32_t v)
719 /* XXX: do filtering */
720 static int png_write_row(PNGContext *s, const uint8_t *data, int size)
724 s->zstream.avail_in = size;
725 s->zstream.next_in = (uint8_t *)data;
726 while (s->zstream.avail_in > 0) {
727 ret = deflate(&s->zstream, Z_NO_FLUSH);
730 if (s->zstream.avail_out == 0) {
731 if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
732 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
733 s->zstream.avail_out = IOBUF_SIZE;
734 s->zstream.next_out = s->buf;
740 static int common_init(AVCodecContext *avctx){
741 PNGContext *s = avctx->priv_data;
743 avcodec_get_frame_defaults((AVFrame*)&s->picture);
744 avctx->coded_frame= (AVFrame*)&s->picture;
750 static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
751 PNGContext *s = avctx->priv_data;
752 AVFrame *pict = data;
753 AVFrame * const p= (AVFrame*)&s->picture;
754 int bit_depth, color_type, y, len, row_size, ret, is_progressive;
755 int bits_per_pixel, pass_row_size;
757 uint8_t *crow_buf = NULL;
758 uint8_t *tmp_buf = NULL;
761 p->pict_type= FF_I_TYPE;
766 s->bytestream_end= buf+buf_size;
768 is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
769 switch(avctx->pix_fmt) {
772 color_type = PNG_COLOR_TYPE_RGB_ALPHA;
776 color_type = PNG_COLOR_TYPE_RGB;
780 color_type = PNG_COLOR_TYPE_GRAY;
782 case PIX_FMT_MONOBLACK:
784 color_type = PNG_COLOR_TYPE_GRAY;
788 color_type = PNG_COLOR_TYPE_PALETTE;
793 bits_per_pixel = png_get_nb_channels(color_type) * bit_depth;
794 row_size = (avctx->width * bits_per_pixel + 7) >> 3;
796 s->zstream.zalloc = png_zalloc;
797 s->zstream.zfree = png_zfree;
798 s->zstream.opaque = NULL;
799 ret = deflateInit2(&s->zstream, Z_DEFAULT_COMPRESSION,
800 Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
803 crow_buf = av_malloc(row_size + 1);
806 if (is_progressive) {
807 tmp_buf = av_malloc(row_size + 1);
812 /* write png header */
813 memcpy(s->bytestream, pngsig, 8);
816 to_be32(s->buf, avctx->width);
817 to_be32(s->buf + 4, avctx->height);
818 s->buf[8] = bit_depth;
819 s->buf[9] = color_type;
820 s->buf[10] = 0; /* compression type */
821 s->buf[11] = 0; /* filter type */
822 s->buf[12] = is_progressive; /* interlace type */
824 png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
826 /* put the palette if needed */
827 if (color_type == PNG_COLOR_TYPE_PALETTE) {
828 int has_alpha, alpha, i;
833 palette = (uint32_t *)p->data[1];
835 alpha_ptr = s->buf + 256 * 3;
837 for(i = 0; i < 256; i++) {
842 *alpha_ptr++ = alpha;
848 png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
850 png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
854 /* now put each row */
855 s->zstream.avail_out = IOBUF_SIZE;
856 s->zstream.next_out = s->buf;
857 if (is_progressive) {
861 for(pass = 0; pass < NB_PASSES; pass++) {
862 /* NOTE: a pass is completely omited if no pixels would be
864 pass_row_size = png_pass_row_size(pass, bits_per_pixel, avctx->width);
865 if (pass_row_size > 0) {
866 for(y = 0; y < avctx->height; y++) {
867 if ((png_pass_ymask[pass] << (y & 7)) & 0x80) {
868 ptr = p->data[0] + y * p->linesize[0];
869 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
870 convert_from_rgba32(tmp_buf, ptr, avctx->width);
875 png_get_interlaced_row(crow_buf + 1, pass_row_size,
876 bits_per_pixel, pass,
878 crow_buf[0] = PNG_FILTER_VALUE_NONE;
879 png_write_row(s, crow_buf, pass_row_size + 1);
885 for(y = 0; y < avctx->height; y++) {
886 ptr = p->data[0] + y * p->linesize[0];
887 if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
888 convert_from_rgba32(crow_buf + 1, ptr, avctx->width);
890 memcpy(crow_buf + 1, ptr, row_size);
891 crow_buf[0] = PNG_FILTER_VALUE_NONE;
892 png_write_row(s, crow_buf, row_size + 1);
895 /* compress last bytes */
897 ret = deflate(&s->zstream, Z_FINISH);
898 if (ret == Z_OK || ret == Z_STREAM_END) {
899 len = IOBUF_SIZE - s->zstream.avail_out;
900 if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
901 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
903 s->zstream.avail_out = IOBUF_SIZE;
904 s->zstream.next_out = s->buf;
905 if (ret == Z_STREAM_END)
911 png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
913 ret = s->bytestream - s->bytestream_start;
917 deflateEnd(&s->zstream);
924 AVCodec png_decoder = {
933 0 /*CODEC_CAP_DR1*/ /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
937 #ifdef CONFIG_PNG_ENCODER
938 AVCodec png_encoder = {
946 .pix_fmts= (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGBA32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, -1},
948 #endif // CONFIG_PNG_ENCODER