mirror of https://git.ffmpeg.org/ffmpeg.git
660 lines
21 KiB
C
660 lines
21 KiB
C
/*
|
|
* PNG image format
|
|
* Copyright (c) 2003 Fabrice Bellard
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg 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 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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 FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
//#define DEBUG
|
|
|
|
#include "libavutil/imgutils.h"
|
|
#include "avcodec.h"
|
|
#include "bytestream.h"
|
|
#include "png.h"
|
|
|
|
/* TODO:
|
|
* - add 2, 4 and 16 bit depth support
|
|
*/
|
|
|
|
#include <zlib.h>
|
|
|
|
/* 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,
|
|
};
|
|
|
|
/* 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
|
|
};
|
|
|
|
/* NOTE: we try to construct a good looking image at each pass. width
|
|
is the original image width. We also do pixel format conversion 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 = ff_png_pass_mask[pass];
|
|
dsp_mask = png_pass_dsp_mask[pass];
|
|
switch(bits_per_pixel) {
|
|
case 1:
|
|
/* we must initialize 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;
|
|
}
|
|
}
|
|
|
|
// 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
|
|
#define pb_7f (~0UL/255 * 0x7f)
|
|
#define pb_80 (~0UL/255 * 0x80)
|
|
|
|
static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
|
|
{
|
|
long i;
|
|
for(i=0; i<=w-sizeof(long); i+=sizeof(long)){
|
|
long a = *(long*)(src1+i);
|
|
long b = *(long*)(src2+i);
|
|
*(long*)(dst+i) = ((a&pb_7f) + (b&pb_7f)) ^ ((a^b)&pb_80);
|
|
}
|
|
for(; i<w; i++)
|
|
dst[i] = src1[i]+src2[i];
|
|
}
|
|
|
|
static void add_paeth_prediction_c(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
|
|
{
|
|
int i;
|
|
for(i = 0; i < w; i++) {
|
|
int a, b, c, p, pa, pb, pc;
|
|
|
|
a = dst[i - bpp];
|
|
b = top[i];
|
|
c = top[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];
|
|
}
|
|
}
|
|
|
|
#define UNROLL1(bpp, op) {\
|
|
r = dst[0];\
|
|
if(bpp >= 2) g = dst[1];\
|
|
if(bpp >= 3) b = dst[2];\
|
|
if(bpp >= 4) a = dst[3];\
|
|
for(; i < size; i+=bpp) {\
|
|
dst[i+0] = r = op(r, src[i+0], last[i+0]);\
|
|
if(bpp == 1) continue;\
|
|
dst[i+1] = g = op(g, src[i+1], last[i+1]);\
|
|
if(bpp == 2) continue;\
|
|
dst[i+2] = b = op(b, src[i+2], last[i+2]);\
|
|
if(bpp == 3) continue;\
|
|
dst[i+3] = a = op(a, src[i+3], last[i+3]);\
|
|
}\
|
|
}
|
|
|
|
#define UNROLL_FILTER(op)\
|
|
if(bpp == 1) UNROLL1(1, op)\
|
|
else if(bpp == 2) UNROLL1(2, op)\
|
|
else if(bpp == 3) UNROLL1(3, op)\
|
|
else if(bpp == 4) UNROLL1(4, op)\
|
|
else {\
|
|
for (; i < size; i += bpp) {\
|
|
int j;\
|
|
for (j = 0; j < bpp; j++)\
|
|
dst[i+j] = op(dst[i+j-bpp], src[i+j], last[i+j]);\
|
|
}\
|
|
}
|
|
|
|
/* NOTE: 'dst' can be equal to 'last' */
|
|
static void png_filter_row(PNGDecContext *s, uint8_t *dst, int filter_type,
|
|
uint8_t *src, uint8_t *last, int size, int bpp)
|
|
{
|
|
int i, p, r, g, b, a;
|
|
|
|
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];
|
|
}
|
|
if(bpp == 4) {
|
|
p = *(int*)dst;
|
|
for(; i < size; i+=bpp) {
|
|
int s = *(int*)(src+i);
|
|
p = ((s&0x7f7f7f7f) + (p&0x7f7f7f7f)) ^ ((s^p)&0x80808080);
|
|
*(int*)(dst+i) = p;
|
|
}
|
|
} else {
|
|
#define OP_SUB(x,s,l) x+s
|
|
UNROLL_FILTER(OP_SUB);
|
|
}
|
|
break;
|
|
case PNG_FILTER_VALUE_UP:
|
|
s->add_bytes_l2(dst, src, last, size);
|
|
break;
|
|
case PNG_FILTER_VALUE_AVG:
|
|
for(i = 0; i < bpp; i++) {
|
|
p = (last[i] >> 1);
|
|
dst[i] = p + src[i];
|
|
}
|
|
#define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
|
|
UNROLL_FILTER(OP_AVG);
|
|
break;
|
|
case PNG_FILTER_VALUE_PAETH:
|
|
for(i = 0; i < bpp; i++) {
|
|
p = last[i];
|
|
dst[i] = p + src[i];
|
|
}
|
|
if(bpp > 1 && size > 4) {
|
|
// would write off the end of the array if we let it process the last pixel with bpp=3
|
|
int w = bpp==4 ? size : size-3;
|
|
s->add_paeth_prediction(dst+i, src+i, last+i, w-i, bpp);
|
|
i = w;
|
|
}
|
|
add_paeth_prediction_c(dst+i, src+i, last+i, size-i, bpp);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static av_always_inline void convert_to_rgb32_loco(uint8_t *dst, const uint8_t *src, int width, int loco)
|
|
{
|
|
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];
|
|
if(loco) {
|
|
r = (r+g)&0xff;
|
|
b = (b+g)&0xff;
|
|
}
|
|
*(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
|
|
dst += 4;
|
|
src += 4;
|
|
}
|
|
}
|
|
|
|
static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width, int loco)
|
|
{
|
|
if(loco)
|
|
convert_to_rgb32_loco(dst, src, width, 1);
|
|
else
|
|
convert_to_rgb32_loco(dst, src, width, 0);
|
|
}
|
|
|
|
static void deloco_rgb24(uint8_t *dst, int size)
|
|
{
|
|
int i;
|
|
for(i=0; i<size; i+=3) {
|
|
int g = dst[i+1];
|
|
dst[i+0] += g;
|
|
dst[i+2] += g;
|
|
}
|
|
}
|
|
|
|
/* process exactly one decompressed row */
|
|
static void png_handle_row(PNGDecContext *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, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
|
|
s->last_row, s->row_size, s->bpp);
|
|
convert_to_rgb32(ptr, s->tmp_row, s->width, s->filter_type == PNG_FILTER_TYPE_LOCO);
|
|
FFSWAP(uint8_t*, s->last_row, s->tmp_row);
|
|
} 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(s, ptr, s->crow_buf[0], s->crow_buf + 1,
|
|
last_row, s->row_size, s->bpp);
|
|
}
|
|
/* loco lags by 1 row so that it doesn't interfere with top prediction */
|
|
if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
|
|
s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0)
|
|
deloco_rgb24(ptr - s->image_linesize, s->row_size);
|
|
s->y++;
|
|
if (s->y == s->height) {
|
|
s->state |= PNG_ALLIMAGE;
|
|
if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
|
|
s->color_type == PNG_COLOR_TYPE_RGB)
|
|
deloco_rgb24(ptr, s->row_size);
|
|
}
|
|
} else {
|
|
got_line = 0;
|
|
for(;;) {
|
|
ptr = s->image_buf + s->image_linesize * s->y;
|
|
if ((ff_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, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
|
|
s->last_row, s->pass_row_size, s->bpp);
|
|
FFSWAP(uint8_t*, s->last_row, s->tmp_row);
|
|
got_line = 1;
|
|
}
|
|
if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
|
|
/* NOTE: RGB32 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 = ff_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(PNGDecContext *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,
|
|
AVPacket *avpkt)
|
|
{
|
|
const uint8_t *buf = avpkt->data;
|
|
int buf_size = avpkt->size;
|
|
PNGDecContext * const s = avctx->priv_data;
|
|
AVFrame *picture = data;
|
|
AVFrame *p;
|
|
uint8_t *crow_buf_base = NULL;
|
|
uint32_t tag, length;
|
|
int ret;
|
|
|
|
FFSWAP(AVFrame *, s->current_picture, s->last_picture);
|
|
avctx->coded_frame= s->current_picture;
|
|
p = s->current_picture;
|
|
|
|
s->bytestream_start=
|
|
s->bytestream= buf;
|
|
s->bytestream_end= buf + buf_size;
|
|
|
|
/* check signature */
|
|
if (memcmp(s->bytestream, ff_pngsig, 8) != 0 &&
|
|
memcmp(s->bytestream, ff_mngsig, 8) != 0)
|
|
return -1;
|
|
s->bytestream+= 8;
|
|
s->y=
|
|
s->state=0;
|
|
// memset(s, 0, sizeof(PNGDecContext));
|
|
/* init the zlib */
|
|
s->zstream.zalloc = ff_png_zalloc;
|
|
s->zstream.zfree = ff_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 = bytestream_get_be32(&s->bytestream);
|
|
if (length > 0x7fffffff)
|
|
goto fail;
|
|
tag32 = bytestream_get_be32(&s->bytestream);
|
|
tag = av_bswap32(tag32);
|
|
av_dlog(avctx, "png: tag=%c%c%c%c length=%u\n",
|
|
(tag & 0xff),
|
|
((tag >> 8) & 0xff),
|
|
((tag >> 16) & 0xff),
|
|
((tag >> 24) & 0xff), length);
|
|
switch(tag) {
|
|
case MKTAG('I', 'H', 'D', 'R'):
|
|
if (length != 13)
|
|
goto fail;
|
|
s->width = bytestream_get_be32(&s->bytestream);
|
|
s->height = bytestream_get_be32(&s->bytestream);
|
|
if(av_image_check_size(s->width, s->height, 0, avctx)){
|
|
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++;
|
|
s->bytestream += 4; /* crc */
|
|
s->state |= PNG_IHDR;
|
|
av_dlog(avctx, "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);
|
|
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 = ff_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_RGB32;
|
|
} else if (s->bit_depth == 8 &&
|
|
s->color_type == PNG_COLOR_TYPE_GRAY) {
|
|
avctx->pix_fmt = PIX_FMT_GRAY8;
|
|
} else if (s->bit_depth == 16 &&
|
|
s->color_type == PNG_COLOR_TYPE_GRAY) {
|
|
avctx->pix_fmt = PIX_FMT_GRAY16BE;
|
|
} else if (s->bit_depth == 16 &&
|
|
s->color_type == PNG_COLOR_TYPE_RGB) {
|
|
avctx->pix_fmt = PIX_FMT_RGB48BE;
|
|
} else if (s->bit_depth == 1) {
|
|
avctx->pix_fmt = PIX_FMT_MONOBLACK;
|
|
} else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
|
|
avctx->pix_fmt = PIX_FMT_PAL8;
|
|
} else if (s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
|
|
avctx->pix_fmt = PIX_FMT_GRAY8A;
|
|
} 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= AV_PICTURE_TYPE_I;
|
|
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 = ff_png_pass_row_size(s->pass,
|
|
s->bits_per_pixel,
|
|
s->width);
|
|
s->crow_size = s->pass_row_size + 1;
|
|
}
|
|
av_dlog(avctx, "row_size=%d crow_size =%d\n",
|
|
s->row_size, s->crow_size);
|
|
s->image_buf = p->data[0];
|
|
s->image_linesize = p->linesize[0];
|
|
/* copy the palette if needed */
|
|
if (avctx->pix_fmt == PIX_FMT_PAL8)
|
|
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 */
|
|
crow_buf_base = av_malloc(s->row_size + 16);
|
|
if (!crow_buf_base)
|
|
goto fail;
|
|
|
|
/* we want crow_buf+1 to be 16-byte aligned */
|
|
s->crow_buf = crow_buf_base + 15;
|
|
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;
|
|
s->bytestream += 4; /* crc */
|
|
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;
|
|
s->bytestream += 4; /* crc */
|
|
}
|
|
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);
|
|
}
|
|
s->bytestream += 4; /* crc */
|
|
}
|
|
break;
|
|
case MKTAG('I', 'E', 'N', 'D'):
|
|
if (!(s->state & PNG_ALLIMAGE))
|
|
goto fail;
|
|
s->bytestream += 4; /* crc */
|
|
goto exit_loop;
|
|
default:
|
|
/* skip tag */
|
|
skip_tag:
|
|
s->bytestream += length + 4;
|
|
break;
|
|
}
|
|
}
|
|
exit_loop:
|
|
/* handle p-frames only if a predecessor frame is available */
|
|
if(s->last_picture->data[0] != NULL) {
|
|
if(!(avpkt->flags & AV_PKT_FLAG_KEY)) {
|
|
int i, j;
|
|
uint8_t *pd = s->current_picture->data[0];
|
|
uint8_t *pd_last = s->last_picture->data[0];
|
|
|
|
for(j=0; j < s->height; j++) {
|
|
for(i=0; i < s->width * s->bpp; i++) {
|
|
pd[i] += pd_last[i];
|
|
}
|
|
pd += s->image_linesize;
|
|
pd_last += s->image_linesize;
|
|
}
|
|
}
|
|
}
|
|
|
|
*picture= *s->current_picture;
|
|
*data_size = sizeof(AVFrame);
|
|
|
|
ret = s->bytestream - s->bytestream_start;
|
|
the_end:
|
|
inflateEnd(&s->zstream);
|
|
av_free(crow_buf_base);
|
|
s->crow_buf = NULL;
|
|
av_freep(&s->last_row);
|
|
av_freep(&s->tmp_row);
|
|
return ret;
|
|
fail:
|
|
ret = -1;
|
|
goto the_end;
|
|
}
|
|
|
|
static av_cold int png_dec_init(AVCodecContext *avctx)
|
|
{
|
|
PNGDecContext *s = avctx->priv_data;
|
|
|
|
s->current_picture = &s->picture1;
|
|
s->last_picture = &s->picture2;
|
|
avcodec_get_frame_defaults(&s->picture1);
|
|
avcodec_get_frame_defaults(&s->picture2);
|
|
|
|
#if HAVE_MMX
|
|
ff_png_init_mmx(s);
|
|
#endif
|
|
|
|
if (!s->add_paeth_prediction)
|
|
s->add_paeth_prediction = add_paeth_prediction_c;
|
|
if (!s->add_bytes_l2)
|
|
s->add_bytes_l2 = add_bytes_l2_c;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static av_cold int png_dec_end(AVCodecContext *avctx)
|
|
{
|
|
PNGDecContext *s = avctx->priv_data;
|
|
|
|
if (s->picture1.data[0])
|
|
avctx->release_buffer(avctx, &s->picture1);
|
|
if (s->picture2.data[0])
|
|
avctx->release_buffer(avctx, &s->picture2);
|
|
|
|
return 0;
|
|
}
|
|
|
|
AVCodec ff_png_decoder = {
|
|
.name = "png",
|
|
.type = AVMEDIA_TYPE_VIDEO,
|
|
.id = CODEC_ID_PNG,
|
|
.priv_data_size = sizeof(PNGDecContext),
|
|
.init = png_dec_init,
|
|
.close = png_dec_end,
|
|
.decode = decode_frame,
|
|
.capabilities = CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
|
|
.long_name = NULL_IF_CONFIG_SMALL("PNG image"),
|
|
};
|