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ffmpeg/libavcodec/png.c

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/*
* PNG image format
* Copyright (c) 2003 Fabrice Bellard.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avcodec.h"
/* TODO:
* - add 2, 4 and 16 bit depth support
* - use filters when generating a png (better compression)
*/
#ifdef CONFIG_ZLIB
#include <zlib.h>
//#define DEBUG
#define PNG_COLOR_MASK_PALETTE 1
#define PNG_COLOR_MASK_COLOR 2
#define PNG_COLOR_MASK_ALPHA 4
#define PNG_COLOR_TYPE_GRAY 0
#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
#define PNG_FILTER_VALUE_NONE 0
#define PNG_FILTER_VALUE_SUB 1
#define PNG_FILTER_VALUE_UP 2
#define PNG_FILTER_VALUE_AVG 3
#define PNG_FILTER_VALUE_PAETH 4
#define PNG_IHDR 0x0001
#define PNG_IDAT 0x0002
#define PNG_ALLIMAGE 0x0004
#define PNG_PLTE 0x0008
#define NB_PASSES 7
#define IOBUF_SIZE 4096
typedef struct PNGContext {
uint8_t *bytestream;
uint8_t *bytestream_start;
uint8_t *bytestream_end;
AVFrame picture;
int state;
int width, height;
int bit_depth;
int color_type;
int compression_type;
int interlace_type;
int filter_type;
int channels;
int bits_per_pixel;
int bpp;
uint8_t *image_buf;
int image_linesize;
uint32_t palette[256];
uint8_t *crow_buf;
uint8_t *last_row;
uint8_t *tmp_row;
int pass;
int crow_size; /* compressed row size (include filter type) */
int row_size; /* decompressed row size */
int pass_row_size; /* decompress row size of the current pass */
int y;
z_stream zstream;
uint8_t buf[IOBUF_SIZE];
} PNGContext;
static unsigned int get32(uint8_t **b){
(*b) += 4;
return ((*b)[-4]<<24) + ((*b)[-3]<<16) + ((*b)[-2]<<8) + (*b)[-1];
}
static void put32(uint8_t **b, unsigned int v){
*(*b)++= v>>24;
*(*b)++= v>>16;
*(*b)++= v>>8;
*(*b)++= v;
}
static const uint8_t pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
/* Mask to determine which y pixels are valid in a pass */
static const uint8_t png_pass_ymask[NB_PASSES] = {
0x80, 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55,
};
/* Mask to determine which y pixels can be written in a pass */
static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
};
/* minimum x value */
static const uint8_t png_pass_xmin[NB_PASSES] = {
0, 4, 0, 2, 0, 1, 0
};
/* x shift to get row width */
static const uint8_t png_pass_xshift[NB_PASSES] = {
3, 3, 2, 2, 1, 1, 0
};
/* Mask to determine which pixels are valid in a pass */
static const uint8_t png_pass_mask[NB_PASSES] = {
0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff
};
/* Mask to determine which pixels to overwrite while displaying */
static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
};
#if 0
static int png_probe(AVProbeData *pd)
{
if (pd->buf_size >= 8 &&
memcmp(pd->buf, pngsig, 8) == 0)
return AVPROBE_SCORE_MAX;
else
return 0;
}
#endif
static void *png_zalloc(void *opaque, unsigned int items, unsigned int size)
{
if(items >= UINT_MAX / size)
return NULL;
return av_malloc(items * size);
}
static void png_zfree(void *opaque, void *ptr)
{
av_free(ptr);
}
static int png_get_nb_channels(int color_type)
{
int channels;
channels = 1;
if ((color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
PNG_COLOR_MASK_COLOR)
channels = 3;
if (color_type & PNG_COLOR_MASK_ALPHA)
channels++;
return channels;
}
/* compute the row size of an interleaved pass */
static int png_pass_row_size(int pass, int bits_per_pixel, int width)
{
int shift, xmin, pass_width;
xmin = png_pass_xmin[pass];
if (width <= xmin)
return 0;
shift = png_pass_xshift[pass];
pass_width = (width - xmin + (1 << shift) - 1) >> shift;
return (pass_width * bits_per_pixel + 7) >> 3;
}
/* NOTE: we try to construct a good looking image at each pass. width
is the original image width. We also do pixel format convertion at
this stage */
static void png_put_interlaced_row(uint8_t *dst, int width,
int bits_per_pixel, int pass,
int color_type, const uint8_t *src)
{
int x, mask, dsp_mask, j, src_x, b, bpp;
uint8_t *d;
const uint8_t *s;
mask = png_pass_mask[pass];
dsp_mask = png_pass_dsp_mask[pass];
switch(bits_per_pixel) {
case 1:
/* we must intialize the line to zero before writing to it */
if (pass == 0)
memset(dst, 0, (width + 7) >> 3);
src_x = 0;
for(x = 0; x < width; x++) {
j = (x & 7);
if ((dsp_mask << j) & 0x80) {
b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
dst[x >> 3] |= b << (7 - j);
}
if ((mask << j) & 0x80)
src_x++;
}
break;
default:
bpp = bits_per_pixel >> 3;
d = dst;
s = src;
if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
for(x = 0; x < width; x++) {
j = x & 7;
if ((dsp_mask << j) & 0x80) {
*(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
}
d += bpp;
if ((mask << j) & 0x80)
s += bpp;
}
} else {
for(x = 0; x < width; x++) {
j = x & 7;
if ((dsp_mask << j) & 0x80) {
memcpy(d, s, bpp);
}
d += bpp;
if ((mask << j) & 0x80)
s += bpp;
}
}
break;
}
}
static void png_get_interlaced_row(uint8_t *dst, int row_size,
int bits_per_pixel, int pass,
const uint8_t *src, int width)
{
int x, mask, dst_x, j, b, bpp;
uint8_t *d;
const uint8_t *s;
mask = png_pass_mask[pass];
switch(bits_per_pixel) {
case 1:
memset(dst, 0, row_size);
dst_x = 0;
for(x = 0; x < width; x++) {
j = (x & 7);
if ((mask << j) & 0x80) {
b = (src[x >> 3] >> (7 - j)) & 1;
dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
dst_x++;
}
}
break;
default:
bpp = bits_per_pixel >> 3;
d = dst;
s = src;
for(x = 0; x < width; x++) {
j = x & 7;
if ((mask << j) & 0x80) {
memcpy(d, s, bpp);
d += bpp;
}
s += bpp;
}
break;
}
}
/* XXX: optimize */
/* NOTE: 'dst' can be equal to 'last' */
static void png_filter_row(uint8_t *dst, int filter_type,
uint8_t *src, uint8_t *last, int size, int bpp)
{
int i, p;
switch(filter_type) {
case PNG_FILTER_VALUE_NONE:
memcpy(dst, src, size);
break;
case PNG_FILTER_VALUE_SUB:
for(i = 0; i < bpp; i++) {
dst[i] = src[i];
}
for(i = bpp; i < size; i++) {
p = dst[i - bpp];
dst[i] = p + src[i];
}
break;
case PNG_FILTER_VALUE_UP:
for(i = 0; i < size; i++) {
p = last[i];
dst[i] = p + src[i];
}
break;
case PNG_FILTER_VALUE_AVG:
for(i = 0; i < bpp; i++) {
p = (last[i] >> 1);
dst[i] = p + src[i];
}
for(i = bpp; i < size; i++) {
p = ((dst[i - bpp] + last[i]) >> 1);
dst[i] = p + src[i];
}
break;
case PNG_FILTER_VALUE_PAETH:
for(i = 0; i < bpp; i++) {
p = last[i];
dst[i] = p + src[i];
}
for(i = bpp; i < size; i++) {
int a, b, c, pa, pb, pc;
a = dst[i - bpp];
b = last[i];
c = last[i - bpp];
p = b - c;
pc = a - c;
pa = abs(p);
pb = abs(pc);
pc = abs(p + pc);
if (pa <= pb && pa <= pc)
p = a;
else if (pb <= pc)
p = b;
else
p = c;
dst[i] = p + src[i];
}
break;
}
}
static void convert_from_rgba32(uint8_t *dst, const uint8_t *src, int width)
{
uint8_t *d;
int j;
unsigned int v;
d = dst;
for(j = 0; j < width; j++) {
v = ((const uint32_t *)src)[j];
d[0] = v >> 16;
d[1] = v >> 8;
d[2] = v;
d[3] = v >> 24;
d += 4;
}
}
static void convert_to_rgba32(uint8_t *dst, const uint8_t *src, int width)
{
int j;
unsigned int r, g, b, a;
for(j = 0;j < width; j++) {
r = src[0];
g = src[1];
b = src[2];
a = src[3];
*(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
dst += 4;
src += 4;
}
}
/* process exactly one decompressed row */
static void png_handle_row(PNGContext *s)
{
uint8_t *ptr, *last_row;
int got_line;
if (!s->interlace_type) {
ptr = s->image_buf + s->image_linesize * s->y;
/* need to swap bytes correctly for RGB_ALPHA */
if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
s->last_row, s->row_size, s->bpp);
memcpy(s->last_row, s->tmp_row, s->row_size);
convert_to_rgba32(ptr, s->tmp_row, s->width);
} else {
/* in normal case, we avoid one copy */
if (s->y == 0)
last_row = s->last_row;
else
last_row = ptr - s->image_linesize;
png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1,
last_row, s->row_size, s->bpp);
}
s->y++;
if (s->y == s->height) {
s->state |= PNG_ALLIMAGE;
}
} else {
got_line = 0;
for(;;) {
ptr = s->image_buf + s->image_linesize * s->y;
if ((png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
/* if we already read one row, it is time to stop to
wait for the next one */
if (got_line)
break;
png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
s->last_row, s->pass_row_size, s->bpp);
memcpy(s->last_row, s->tmp_row, s->pass_row_size);
got_line = 1;
}
if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
/* NOTE: rgba32 is handled directly in png_put_interlaced_row */
png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
s->color_type, s->last_row);
}
s->y++;
if (s->y == s->height) {
for(;;) {
if (s->pass == NB_PASSES - 1) {
s->state |= PNG_ALLIMAGE;
goto the_end;
} else {
s->pass++;
s->y = 0;
s->pass_row_size = png_pass_row_size(s->pass,
s->bits_per_pixel,
s->width);
s->crow_size = s->pass_row_size + 1;
if (s->pass_row_size != 0)
break;
/* skip pass if empty row */
}
}
}
}
the_end: ;
}
}
static int png_decode_idat(PNGContext *s, int length)
{
int ret;
s->zstream.avail_in = length;
s->zstream.next_in = s->bytestream;
s->bytestream += length;
if(s->bytestream > s->bytestream_end)
return -1;
/* decode one line if possible */
while (s->zstream.avail_in > 0) {
ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END) {
return -1;
}
if (s->zstream.avail_out == 0) {
if (!(s->state & PNG_ALLIMAGE)) {
png_handle_row(s);
}
s->zstream.avail_out = s->crow_size;
s->zstream.next_out = s->crow_buf;
}
}
return 0;
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
uint8_t *buf, int buf_size)
{
PNGContext * const s = avctx->priv_data;
AVFrame *picture = data;
AVFrame * const p= (AVFrame*)&s->picture;
uint32_t tag, length;
int ret, crc;
s->bytestream_start=
s->bytestream= buf;
s->bytestream_end= buf + buf_size;
/* check signature */
if (memcmp(s->bytestream, pngsig, 8) != 0)
return -1;
s->bytestream+= 8;
s->y=
s->state=0;
// memset(s, 0, sizeof(PNGContext));
/* init the zlib */
s->zstream.zalloc = png_zalloc;
s->zstream.zfree = png_zfree;
s->zstream.opaque = NULL;
ret = inflateInit(&s->zstream);
if (ret != Z_OK)
return -1;
for(;;) {
int tag32;
if (s->bytestream >= s->bytestream_end)
goto fail;
length = get32(&s->bytestream);
if (length > 0x7fffffff)
goto fail;
tag32 = get32(&s->bytestream);
tag = bswap_32(tag32);
#ifdef DEBUG
av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
(tag & 0xff),
((tag >> 8) & 0xff),
((tag >> 16) & 0xff),
((tag >> 24) & 0xff), length);
#endif
switch(tag) {
case MKTAG('I', 'H', 'D', 'R'):
if (length != 13)
goto fail;
s->width = get32(&s->bytestream);
s->height = get32(&s->bytestream);
if(avcodec_check_dimensions(avctx, s->width, s->height)){
s->width= s->height= 0;
goto fail;
}
s->bit_depth = *s->bytestream++;
s->color_type = *s->bytestream++;
s->compression_type = *s->bytestream++;
s->filter_type = *s->bytestream++;
s->interlace_type = *s->bytestream++;
crc = get32(&s->bytestream);
s->state |= PNG_IHDR;
#ifdef DEBUG
av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
s->width, s->height, s->bit_depth, s->color_type,
s->compression_type, s->filter_type, s->interlace_type);
#endif
break;
case MKTAG('I', 'D', 'A', 'T'):
if (!(s->state & PNG_IHDR))
goto fail;
if (!(s->state & PNG_IDAT)) {
/* init image info */
avctx->width = s->width;
avctx->height = s->height;
s->channels = png_get_nb_channels(s->color_type);
s->bits_per_pixel = s->bit_depth * s->channels;
s->bpp = (s->bits_per_pixel + 7) >> 3;
s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
if (s->bit_depth == 8 &&
s->color_type == PNG_COLOR_TYPE_RGB) {
avctx->pix_fmt = PIX_FMT_RGB24;
} else if (s->bit_depth == 8 &&
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
avctx->pix_fmt = PIX_FMT_RGBA32;
} else if (s->bit_depth == 8 &&
s->color_type == PNG_COLOR_TYPE_GRAY) {
avctx->pix_fmt = PIX_FMT_GRAY8;
} else if (s->bit_depth == 1 &&
s->color_type == PNG_COLOR_TYPE_GRAY) {
avctx->pix_fmt = PIX_FMT_MONOBLACK;
} else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
avctx->pix_fmt = PIX_FMT_PAL8;
} else {
goto fail;
}
if(p->data[0])
avctx->release_buffer(avctx, p);
p->reference= 0;
if(avctx->get_buffer(avctx, p) < 0){
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
goto fail;
}
p->pict_type= FF_I_TYPE;
p->key_frame= 1;
p->interlaced_frame = !!s->interlace_type;
/* compute the compressed row size */
if (!s->interlace_type) {
s->crow_size = s->row_size + 1;
} else {
s->pass = 0;
s->pass_row_size = png_pass_row_size(s->pass,
s->bits_per_pixel,
s->width);
s->crow_size = s->pass_row_size + 1;
}
#ifdef DEBUG
av_log(avctx, AV_LOG_DEBUG, "row_size=%d crow_size =%d\n",
s->row_size, s->crow_size);
#endif
s->image_buf = p->data[0];
s->image_linesize = p->linesize[0];
/* copy the palette if needed */
if (s->color_type == PNG_COLOR_TYPE_PALETTE)
memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
/* empty row is used if differencing to the first row */
s->last_row = av_mallocz(s->row_size);
if (!s->last_row)
goto fail;
if (s->interlace_type ||
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
s->tmp_row = av_malloc(s->row_size);
if (!s->tmp_row)
goto fail;
}
/* compressed row */
s->crow_buf = av_malloc(s->row_size + 1);
if (!s->crow_buf)
goto fail;
s->zstream.avail_out = s->crow_size;
s->zstream.next_out = s->crow_buf;
}
s->state |= PNG_IDAT;
if (png_decode_idat(s, length) < 0)
goto fail;
/* skip crc */
crc = get32(&s->bytestream);
break;
case MKTAG('P', 'L', 'T', 'E'):
{
int n, i, r, g, b;
if ((length % 3) != 0 || length > 256 * 3)
goto skip_tag;
/* read the palette */
n = length / 3;
for(i=0;i<n;i++) {
r = *s->bytestream++;
g = *s->bytestream++;
b = *s->bytestream++;
s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
}
for(;i<256;i++) {
s->palette[i] = (0xff << 24);
}
s->state |= PNG_PLTE;
crc = get32(&s->bytestream);
}
break;
case MKTAG('t', 'R', 'N', 'S'):
{
int v, i;
/* read the transparency. XXX: Only palette mode supported */
if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
length > 256 ||
!(s->state & PNG_PLTE))
goto skip_tag;
for(i=0;i<length;i++) {
v = *s->bytestream++;
s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
}
crc = get32(&s->bytestream);
}
break;
case MKTAG('I', 'E', 'N', 'D'):
if (!(s->state & PNG_ALLIMAGE))
goto fail;
crc = get32(&s->bytestream);
goto exit_loop;
default:
/* skip tag */
skip_tag:
s->bytestream += length + 4;
break;
}
}
exit_loop:
*picture= *(AVFrame*)&s->picture;
*data_size = sizeof(AVPicture);
ret = s->bytestream - s->bytestream_start;
the_end:
inflateEnd(&s->zstream);
av_freep(&s->crow_buf);
av_freep(&s->last_row);
av_freep(&s->tmp_row);
return ret;
fail:
ret = -1;
goto the_end;
}
static void png_write_chunk(uint8_t **f, uint32_t tag,
const uint8_t *buf, int length)
{
uint32_t crc;
uint8_t tagbuf[4];
put32(f, length);
crc = crc32(0, Z_NULL, 0);
tagbuf[0] = tag;
tagbuf[1] = tag >> 8;
tagbuf[2] = tag >> 16;
tagbuf[3] = tag >> 24;
crc = crc32(crc, tagbuf, 4);
put32(f, bswap_32(tag));
if (length > 0) {
crc = crc32(crc, buf, length);
memcpy(*f, buf, length);
*f += length;
}
put32(f, crc);
}
/* XXX: use avcodec generic function ? */
static void to_be32(uint8_t *p, uint32_t v)
{
p[0] = v >> 24;
p[1] = v >> 16;
p[2] = v >> 8;
p[3] = v;
}
/* XXX: do filtering */
static int png_write_row(PNGContext *s, const uint8_t *data, int size)
{
int ret;
s->zstream.avail_in = size;
s->zstream.next_in = (uint8_t *)data;
while (s->zstream.avail_in > 0) {
ret = deflate(&s->zstream, Z_NO_FLUSH);
if (ret != Z_OK)
return -1;
if (s->zstream.avail_out == 0) {
if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
}
}
return 0;
}
static int common_init(AVCodecContext *avctx){
PNGContext *s = avctx->priv_data;
avcodec_get_frame_defaults((AVFrame*)&s->picture);
avctx->coded_frame= (AVFrame*)&s->picture;
// s->avctx= avctx;
return 0;
}
static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){
PNGContext *s = avctx->priv_data;
AVFrame *pict = data;
AVFrame * const p= (AVFrame*)&s->picture;
int bit_depth, color_type, y, len, row_size, ret, is_progressive;
int bits_per_pixel, pass_row_size;
uint8_t *ptr;
uint8_t *crow_buf = NULL;
uint8_t *tmp_buf = NULL;
*p = *pict;
p->pict_type= FF_I_TYPE;
p->key_frame= 1;
s->bytestream_start=
s->bytestream= buf;
s->bytestream_end= buf+buf_size;
is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
switch(avctx->pix_fmt) {
case PIX_FMT_RGBA32:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB_ALPHA;
break;
case PIX_FMT_RGB24:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_RGB;
break;
case PIX_FMT_GRAY8:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_GRAY;
break;
case PIX_FMT_MONOBLACK:
bit_depth = 1;
color_type = PNG_COLOR_TYPE_GRAY;
break;
case PIX_FMT_PAL8:
bit_depth = 8;
color_type = PNG_COLOR_TYPE_PALETTE;
break;
default:
return -1;
}
bits_per_pixel = png_get_nb_channels(color_type) * bit_depth;
row_size = (avctx->width * bits_per_pixel + 7) >> 3;
s->zstream.zalloc = png_zalloc;
s->zstream.zfree = png_zfree;
s->zstream.opaque = NULL;
ret = deflateInit2(&s->zstream, Z_DEFAULT_COMPRESSION,
Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
if (ret != Z_OK)
return -1;
crow_buf = av_malloc(row_size + 1);
if (!crow_buf)
goto fail;
if (is_progressive) {
tmp_buf = av_malloc(row_size + 1);
if (!tmp_buf)
goto fail;
}
/* write png header */
memcpy(s->bytestream, pngsig, 8);
s->bytestream += 8;
to_be32(s->buf, avctx->width);
to_be32(s->buf + 4, avctx->height);
s->buf[8] = bit_depth;
s->buf[9] = color_type;
s->buf[10] = 0; /* compression type */
s->buf[11] = 0; /* filter type */
s->buf[12] = is_progressive; /* interlace type */
png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
/* put the palette if needed */
if (color_type == PNG_COLOR_TYPE_PALETTE) {
int has_alpha, alpha, i;
unsigned int v;
uint32_t *palette;
uint8_t *alpha_ptr;
palette = (uint32_t *)p->data[1];
ptr = s->buf;
alpha_ptr = s->buf + 256 * 3;
has_alpha = 0;
for(i = 0; i < 256; i++) {
v = palette[i];
alpha = v >> 24;
if (alpha != 0xff)
has_alpha = 1;
*alpha_ptr++ = alpha;
ptr[0] = v >> 16;
ptr[1] = v >> 8;
ptr[2] = v;
ptr += 3;
}
png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
if (has_alpha) {
png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
}
}
/* now put each row */
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
if (is_progressive) {
uint8_t *ptr1;
int pass;
for(pass = 0; pass < NB_PASSES; pass++) {
/* NOTE: a pass is completely omited if no pixels would be
output */
pass_row_size = png_pass_row_size(pass, bits_per_pixel, avctx->width);
if (pass_row_size > 0) {
for(y = 0; y < avctx->height; y++) {
if ((png_pass_ymask[pass] << (y & 7)) & 0x80) {
ptr = p->data[0] + y * p->linesize[0];
if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
convert_from_rgba32(tmp_buf, ptr, avctx->width);
ptr1 = tmp_buf;
} else {
ptr1 = ptr;
}
png_get_interlaced_row(crow_buf + 1, pass_row_size,
bits_per_pixel, pass,
ptr1, avctx->width);
crow_buf[0] = PNG_FILTER_VALUE_NONE;
png_write_row(s, crow_buf, pass_row_size + 1);
}
}
}
}
} else {
for(y = 0; y < avctx->height; y++) {
ptr = p->data[0] + y * p->linesize[0];
if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
convert_from_rgba32(crow_buf + 1, ptr, avctx->width);
else
memcpy(crow_buf + 1, ptr, row_size);
crow_buf[0] = PNG_FILTER_VALUE_NONE;
png_write_row(s, crow_buf, row_size + 1);
}
}
/* compress last bytes */
for(;;) {
ret = deflate(&s->zstream, Z_FINISH);
if (ret == Z_OK || ret == Z_STREAM_END) {
len = IOBUF_SIZE - s->zstream.avail_out;
if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
}
s->zstream.avail_out = IOBUF_SIZE;
s->zstream.next_out = s->buf;
if (ret == Z_STREAM_END)
break;
} else {
goto fail;
}
}
png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
ret = s->bytestream - s->bytestream_start;
the_end:
av_free(crow_buf);
av_free(tmp_buf);
deflateEnd(&s->zstream);
return ret;
fail:
ret = -1;
goto the_end;
}
AVCodec png_decoder = {
"png",
CODEC_TYPE_VIDEO,
CODEC_ID_PNG,
sizeof(PNGContext),
common_init,
NULL,
NULL, //decode_end,
decode_frame,
0 /*CODEC_CAP_DR1*/ /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
NULL
};
#ifdef CONFIG_PNG_ENCODER
AVCodec png_encoder = {
"png",
CODEC_TYPE_VIDEO,
CODEC_ID_PNG,
sizeof(PNGContext),
common_init,
encode_frame,
NULL, //encode_end,
.pix_fmts= (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGBA32, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_MONOBLACK, -1},
};
#endif // CONFIG_PNG_ENCODER
#endif
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