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),
added
removed
ffmpeg/libavformat/png.c
