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ed09bb3782
FFmpeg/libavcodec/pngdec.c
Donny Yang ed09bb3782 avcodec/apng: Dispose previous frame properly 
The spec specifies the dispose operation as how the current (i.e., currently
being rendered) frame should be disposed when the next frame is blended onto it

This is contrary to ffmpeg's current behaviour of interpreting the dispose
operation as how the previous (i.e., already rendered) frame should be disposed

This patch fixes ffmpeg's behaviour to match those of the spec, which involved
a rewrite of the blending function

Signed-off-by: Donny Yang <work@kota.moe>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2015-06-08 15:32:49 +02:00

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/*
* 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/bprint.h"
#include "libavutil/imgutils.h"
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
#include "apng.h"
#include "png.h"
#include "pngdsp.h"
#include "thread.h"
#include <zlib.h>
typedef struct PNGDecContext {
PNGDSPContext dsp;
AVCodecContext *avctx;
GetByteContext gb;
ThreadFrame previous_picture;
ThreadFrame last_picture;
ThreadFrame picture;
int state;
int width, height;
int cur_w, cur_h;
int last_w, last_h;
int x_offset, y_offset;
int last_x_offset, last_y_offset;
uint8_t dispose_op, blend_op;
uint8_t last_dispose_op;
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;
unsigned int last_row_size;
uint8_t *tmp_row;
unsigned int tmp_row_size;
uint8_t *buffer;
int buffer_size;
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;
} PNGDecContext;
/* Mask to determine which pixels are valid in a pass */
static const uint8_t png_pass_mask[NB_PASSES] = {
0x01, 0x01, 0x11, 0x11, 0x55, 0x55, 0xff,
};
/* 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, 0xff, 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 = png_pass_mask[pass];
dsp_mask = png_pass_dsp_mask[pass];
switch (bits_per_pixel) {
case 1:
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] &= 0xFF7F>>j;
dst[x >> 3] |= b << (7 - j);
}
if ((mask << j) & 0x80)
src_x++;
}
break;
case 2:
src_x = 0;
for (x = 0; x < width; x++) {
int j2 = 2 * (x & 3);
j = (x & 7);
if ((dsp_mask << j) & 0x80) {
b = (src[src_x >> 2] >> (6 - 2*(src_x & 3))) & 3;
dst[x >> 2] &= 0xFF3F>>j2;
dst[x >> 2] |= b << (6 - j2);
}
if ((mask << j) & 0x80)
src_x++;
}
break;
case 4:
src_x = 0;
for (x = 0; x < width; x++) {
int j2 = 4*(x&1);
j = (x & 7);
if ((dsp_mask << j) & 0x80) {
b = (src[src_x >> 1] >> (4 - 4*(src_x & 1))) & 15;
dst[x >> 1] &= 0xFF0F>>j2;
dst[x >> 1] |= b << (4 - j2);
}
if ((mask << j) & 0x80)
src_x++;
}
break;
default:
bpp = bits_per_pixel >> 3;
d = dst;
s = src;
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;
}
}
void ff_add_png_paeth_prediction(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 - bpp; 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) \
} \
for (; i < size; i++) { \
dst[i] = op(dst[i - bpp], src[i], last[i]); \
}
/* NOTE: 'dst' can be equal to 'last' */
static void png_filter_row(PNGDSPContext *dsp, 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) {
unsigned 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:
dsp->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 > 2 && size > 4) {
/* would write off the end of the array if we let it process
* the last pixel with bpp=3 */
int w = (bpp & 3) ? size - 3 : size;
if (w > i) {
dsp->add_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
i = w;
}
}
ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
break;
}
}
/* This used to be called "deloco" in FFmpeg
* and is actually an inverse reversible colorspace transformation */
#define YUV2RGB(NAME, TYPE) \
static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
{ \
int i; \
for (i = 0; i < size; i += 3 + alpha) { \
int g = dst [i + 1]; \
dst[i + 0] += g; \
dst[i + 2] += g; \
} \
}
YUV2RGB(rgb8, uint8_t)
YUV2RGB(rgb16, uint16_t)
/* 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 + s->y_offset) + s->x_offset * s->bpp;
if (s->y == 0)
last_row = s->last_row;
else
last_row = ptr - s->image_linesize;
png_filter_row(&s->dsp, 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->y > 0) {
if (s->bit_depth == 16) {
deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
} else {
deloco_rgb8(ptr - s->image_linesize, s->row_size,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
}
}
s->y++;
if (s->y == s->cur_h) {
s->state |= PNG_ALLIMAGE;
if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
if (s->bit_depth == 16) {
deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
} else {
deloco_rgb8(ptr, s->row_size,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
}
}
}
} else {
got_line = 0;
for (;;) {
ptr = s->image_buf + s->image_linesize * (s->y + s->y_offset) + s->x_offset * s->bpp;
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->dsp, 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);
FFSWAP(unsigned int, s->last_row_size, s->tmp_row_size);
got_line = 1;
}
if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
png_put_interlaced_row(ptr, s->cur_w, s->bits_per_pixel, s->pass,
s->color_type, s->last_row);
}
s->y++;
if (s->y == s->cur_h) {
memset(s->last_row, 0, s->row_size);
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->cur_w);
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 = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
s->zstream.next_in = (unsigned char *)s->gb.buffer;
bytestream2_skip(&s->gb, length);
/* 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) {
av_log(s->avctx, AV_LOG_ERROR, "inflate returned error %d\n", ret);
return AVERROR_EXTERNAL;
}
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;
}
if (ret == Z_STREAM_END && s->zstream.avail_in > 0) {
av_log(NULL, AV_LOG_WARNING,
"%d undecompressed bytes left in buffer\n", s->zstream.avail_in);
return 0;
}
}
return 0;
}
static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
const uint8_t *data_end)
{
z_stream zstream;
unsigned char *buf;
unsigned buf_size;
int ret;
zstream.zalloc = ff_png_zalloc;
zstream.zfree = ff_png_zfree;
zstream.opaque = NULL;
if (inflateInit(&zstream) != Z_OK)
return AVERROR_EXTERNAL;
zstream.next_in = (unsigned char *)data;
zstream.avail_in = data_end - data;
av_bprint_init(bp, 0, -1);
while (zstream.avail_in > 0) {
av_bprint_get_buffer(bp, 1, &buf, &buf_size);
if (!buf_size) {
ret = AVERROR(ENOMEM);
goto fail;
}
zstream.next_out = buf;
zstream.avail_out = buf_size;
ret = inflate(&zstream, Z_PARTIAL_FLUSH);
if (ret != Z_OK && ret != Z_STREAM_END) {
ret = AVERROR_EXTERNAL;
goto fail;
}
bp->len += zstream.next_out - buf;
if (ret == Z_STREAM_END)
break;
}
inflateEnd(&zstream);
bp->str[bp->len] = 0;
return 0;
fail:
inflateEnd(&zstream);
av_bprint_finalize(bp, NULL);
return ret;
}
static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
{
size_t extra = 0, i;
uint8_t *out, *q;
for (i = 0; i < size_in; i++)
extra += in[i] >= 0x80;
if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
return NULL;
q = out = av_malloc(size_in + extra + 1);
if (!out)
return NULL;
for (i = 0; i < size_in; i++) {
if (in[i] >= 0x80) {
*(q++) = 0xC0 | (in[i] >> 6);
*(q++) = 0x80 | (in[i] & 0x3F);
} else {
*(q++) = in[i];
}
}
*(q++) = 0;
return out;
}
static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
AVDictionary **dict)
{
int ret, method;
const uint8_t *data = s->gb.buffer;
const uint8_t *data_end = data + length;
const uint8_t *keyword = data;
const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
unsigned text_len;
AVBPrint bp;
if (!keyword_end)
return AVERROR_INVALIDDATA;
data = keyword_end + 1;
if (compressed) {
if (data == data_end)
return AVERROR_INVALIDDATA;
method = *(data++);
if (method)
return AVERROR_INVALIDDATA;
if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
return ret;
text_len = bp.len;
av_bprint_finalize(&bp, (char **)&text);
if (!text)
return AVERROR(ENOMEM);
} else {
text = (uint8_t *)data;
text_len = data_end - text;
}
kw_utf8 = iso88591_to_utf8(keyword, keyword_end - keyword);
txt_utf8 = iso88591_to_utf8(text, text_len);
if (text != data)
av_free(text);
if (!(kw_utf8 && txt_utf8)) {
av_free(kw_utf8);
av_free(txt_utf8);
return AVERROR(ENOMEM);
}
av_dict_set(dict, kw_utf8, txt_utf8,
AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
return 0;
}
static int decode_ihdr_chunk(AVCodecContext *avctx, PNGDecContext *s,
uint32_t length)
{
if (length != 13)
return AVERROR_INVALIDDATA;
if (s->state & PNG_IDAT) {
av_log(avctx, AV_LOG_ERROR, "IHDR after IDAT\n");
return AVERROR_INVALIDDATA;
}
s->width = bytestream2_get_be32(&s->gb);
s->height = bytestream2_get_be32(&s->gb);
if (av_image_check_size(s->width, s->height, 0, avctx)) {
s->width = s->height = 0;
av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
return AVERROR_INVALIDDATA;
}
if (s->cur_w == 0 && s->cur_h == 0) {
// Only set cur_w/h if update_thread_context() has not set it
s->cur_w = s->width;
s->cur_h = s->height;
}
s->bit_depth = bytestream2_get_byte(&s->gb);
s->color_type = bytestream2_get_byte(&s->gb);
s->compression_type = bytestream2_get_byte(&s->gb);
s->filter_type = bytestream2_get_byte(&s->gb);
s->interlace_type = bytestream2_get_byte(&s->gb);
bytestream2_skip(&s->gb, 4); /* crc */
s->state |= PNG_IHDR;
if (avctx->debug & FF_DEBUG_PICT_INFO)
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);
return 0;
}
static int decode_phys_chunk(AVCodecContext *avctx, PNGDecContext *s)
{
if (s->state & PNG_IDAT) {
av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
return AVERROR_INVALIDDATA;
}
avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
bytestream2_skip(&s->gb, 1); /* unit specifier */
bytestream2_skip(&s->gb, 4); /* crc */
return 0;
}
static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
uint32_t length, AVFrame *p)
{
int ret;
if (!(s->state & PNG_IHDR)) {
av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
return AVERROR_INVALIDDATA;
}
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 = (s->cur_w * s->bits_per_pixel + 7) >> 3;
if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
s->color_type == PNG_COLOR_TYPE_RGB) {
avctx->pix_fmt = AV_PIX_FMT_RGB24;
} else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
avctx->pix_fmt = AV_PIX_FMT_RGBA;
} else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
s->color_type == PNG_COLOR_TYPE_GRAY) {
avctx->pix_fmt = AV_PIX_FMT_GRAY8;
} else if (s->bit_depth == 16 &&
s->color_type == PNG_COLOR_TYPE_GRAY) {
avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
} else if (s->bit_depth == 16 &&
s->color_type == PNG_COLOR_TYPE_RGB) {
avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
} else if (s->bit_depth == 16 &&
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
} else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
s->color_type == PNG_COLOR_TYPE_PALETTE) {
avctx->pix_fmt = AV_PIX_FMT_PAL8;
} else if (s->bit_depth == 1 && s->bits_per_pixel == 1 && avctx->codec_id != AV_CODEC_ID_APNG) {
avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
} else if (s->bit_depth == 8 &&
s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
avctx->pix_fmt = AV_PIX_FMT_YA8;
} else if (s->bit_depth == 16 &&
s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
avctx->pix_fmt = AV_PIX_FMT_YA16BE;
} else {
av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
"and color type %d\n",
s->bit_depth, s->color_type);
return AVERROR_INVALIDDATA;
}
if ((ret = ff_thread_get_buffer(avctx, &s->picture, AV_GET_BUFFER_FLAG_REF)) < 0)
return ret;
ff_thread_finish_setup(avctx);
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->cur_w);
s->crow_size = s->pass_row_size + 1;
}
ff_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 == AV_PIX_FMT_PAL8)
memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
/* empty row is used if differencing to the first row */
av_fast_padded_mallocz(&s->last_row, &s->last_row_size, s->row_size);
if (!s->last_row)
return AVERROR_INVALIDDATA;
if (s->interlace_type ||
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
av_fast_padded_malloc(&s->tmp_row, &s->tmp_row_size, s->row_size);
if (!s->tmp_row)
return AVERROR_INVALIDDATA;
}
/* compressed row */
av_fast_padded_malloc(&s->buffer, &s->buffer_size, s->row_size + 16);
if (!s->buffer)
return AVERROR(ENOMEM);
/* we want crow_buf+1 to be 16-byte aligned */
s->crow_buf = s->buffer + 15;
s->zstream.avail_out = s->crow_size;
s->zstream.next_out = s->crow_buf;
}
s->state |= PNG_IDAT;
if ((ret = png_decode_idat(s, length)) < 0)
return ret;
bytestream2_skip(&s->gb, 4); /* crc */
return 0;
}
static int decode_plte_chunk(AVCodecContext *avctx, PNGDecContext *s,
uint32_t length)
{
int n, i, r, g, b;
if ((length % 3) != 0 || length > 256 * 3)
return AVERROR_INVALIDDATA;
/* read the palette */
n = length / 3;
for (i = 0; i < n; i++) {
r = bytestream2_get_byte(&s->gb);
g = bytestream2_get_byte(&s->gb);
b = bytestream2_get_byte(&s->gb);
s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
}
for (; i < 256; i++)
s->palette[i] = (0xFFU << 24);
s->state |= PNG_PLTE;
bytestream2_skip(&s->gb, 4); /* crc */
return 0;
}
static int decode_trns_chunk(AVCodecContext *avctx, PNGDecContext *s,
uint32_t length)
{
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))
return AVERROR_INVALIDDATA;
for (i = 0; i < length; i++) {
v = bytestream2_get_byte(&s->gb);
s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
}
bytestream2_skip(&s->gb, 4); /* crc */
return 0;
}
static void handle_small_bpp(PNGDecContext *s, AVFrame *p)
{
if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE) {
int i, j, k;
uint8_t *pd = p->data[0];
for (j = 0; j < s->height; j++) {
i = s->width / 8;
for (k = 7; k >= 1; k--)
if ((s->width&7) >= k)
pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
for (i--; i >= 0; i--) {
pd[8*i + 7]= pd[i] & 1;
pd[8*i + 6]= (pd[i]>>1) & 1;
pd[8*i + 5]= (pd[i]>>2) & 1;
pd[8*i + 4]= (pd[i]>>3) & 1;
pd[8*i + 3]= (pd[i]>>4) & 1;
pd[8*i + 2]= (pd[i]>>5) & 1;
pd[8*i + 1]= (pd[i]>>6) & 1;
pd[8*i + 0]= pd[i]>>7;
}
pd += s->image_linesize;
}
} else if (s->bits_per_pixel == 2) {
int i, j;
uint8_t *pd = p->data[0];
for (j = 0; j < s->height; j++) {
i = s->width / 4;
if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
for (i--; i >= 0; i--) {
pd[4*i + 3]= pd[i] & 3;
pd[4*i + 2]= (pd[i]>>2) & 3;
pd[4*i + 1]= (pd[i]>>4) & 3;
pd[4*i + 0]= pd[i]>>6;
}
} else {
if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
for (i--; i >= 0; i--) {
pd[4*i + 3]= ( pd[i] & 3)*0x55;
pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
pd[4*i + 0]= ( pd[i]>>6 )*0x55;
}
}
pd += s->image_linesize;
}
} else if (s->bits_per_pixel == 4) {
int i, j;
uint8_t *pd = p->data[0];
for (j = 0; j < s->height; j++) {
i = s->width/2;
if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
if (s->width&1) pd[2*i+0]= pd[i]>>4;
for (i--; i >= 0; i--) {
pd[2*i + 1] = pd[i] & 15;
pd[2*i + 0] = pd[i] >> 4;
}
} else {
if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
for (i--; i >= 0; i--) {
pd[2*i + 1] = (pd[i] & 15) * 0x11;
pd[2*i + 0] = (pd[i] >> 4) * 0x11;
}
}
pd += s->image_linesize;
}
}
}
static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
uint32_t length)
{
uint32_t sequence_number;
if (length != 26)
return AVERROR_INVALIDDATA;
s->last_w = s->cur_w;
s->last_h = s->cur_h;
s->last_x_offset = s->x_offset;
s->last_y_offset = s->y_offset;
s->last_dispose_op = s->dispose_op;
sequence_number = bytestream2_get_be32(&s->gb);
s->cur_w = bytestream2_get_be32(&s->gb);
s->cur_h = bytestream2_get_be32(&s->gb);
s->x_offset = bytestream2_get_be32(&s->gb);
s->y_offset = bytestream2_get_be32(&s->gb);
bytestream2_skip(&s->gb, 4); /* delay_num (2), delay_den (2) */
s->dispose_op = bytestream2_get_byte(&s->gb);
s->blend_op = bytestream2_get_byte(&s->gb);
bytestream2_skip(&s->gb, 4); /* crc */
if (sequence_number == 0 &&
(s->cur_w != s->width ||
s->cur_h != s->height ||
s->x_offset != 0 ||
s->y_offset != 0) ||
s->cur_w <= 0 || s->cur_h <= 0 ||
s->x_offset < 0 || s->y_offset < 0 ||
s->cur_w > s->width - s->x_offset|| s->cur_h > s->height - s->y_offset)
return AVERROR_INVALIDDATA;
if (sequence_number == 0 && s->dispose_op == APNG_DISPOSE_OP_PREVIOUS) {
// No previous frame to revert to for the first frame
// Spec says to just treat it as a APNG_DISPOSE_OP_BACKGROUND
s->dispose_op = APNG_DISPOSE_OP_BACKGROUND;
}
return 0;
}
static void handle_p_frame_png(PNGDecContext *s, AVFrame *p)
{
int i, j;
uint8_t *pd = p->data[0];
uint8_t *pd_last = s->last_picture.f->data[0];
int ls = FFMIN(av_image_get_linesize(p->format, s->width, 0), s->width * s->bpp);
ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
for (j = 0; j < s->height; j++) {
for (i = 0; i < ls; i++)
pd[i] += pd_last[i];
pd += s->image_linesize;
pd_last += s->image_linesize;
}
}
// divide by 255 and round to nearest
// apply a fast variant: (X+127)/255 = ((X+127)*257+257)>>16 = ((X+128)*257)>>16
#define FAST_DIV255(x) ((((x) + 128) * 257) >> 16)
static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
AVFrame *p)
{
size_t x, y;
uint8_t *buffer = av_malloc(s->image_linesize * s->height);
if (!buffer)
return AVERROR(ENOMEM);
if (s->blend_op == APNG_BLEND_OP_OVER &&
avctx->pix_fmt != AV_PIX_FMT_RGBA) {
avpriv_request_sample(avctx, "Blending with pixel format %s",
av_get_pix_fmt_name(avctx->pix_fmt));
return AVERROR_PATCHWELCOME;
}
// Copy the previous frame to the buffer
ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
memcpy(buffer, s->last_picture.f->data[0], s->image_linesize * s->height);
// Do the disposal operation specified by the last frame on the frame
if (s->last_dispose_op == APNG_DISPOSE_OP_BACKGROUND) {
for (y = s->last_y_offset; y < s->last_y_offset + s->last_h; ++y)
memset(buffer + s->image_linesize * y + s->bpp * s->last_x_offset, 0, s->bpp * s->last_w);
} else if (s->last_dispose_op == APNG_DISPOSE_OP_PREVIOUS) {
ff_thread_await_progress(&s->previous_picture, INT_MAX, 0);
for (y = s->last_y_offset; y < s->last_y_offset + s->last_h; ++y) {
size_t row_start = s->image_linesize * y + s->bpp * s->last_x_offset;
memcpy(buffer + row_start, s->previous_picture.f->data[0] + row_start, s->bpp * s->last_w);
}
}
// Perform blending
if (s->blend_op == APNG_BLEND_OP_SOURCE) {
for (y = s->y_offset; y < s->y_offset + s->cur_h; ++y) {
size_t row_start = s->image_linesize * y + s->bpp * s->x_offset;
memcpy(buffer + row_start, p->data[0] + row_start, s->bpp * s->cur_w);
}
} else { // APNG_BLEND_OP_OVER
for (y = s->y_offset; y < s->y_offset + s->cur_h; ++y) {
uint8_t *foreground = p->data[0] + s->image_linesize * y + s->bpp * s->x_offset;
uint8_t *background = buffer + s->image_linesize * y + s->bpp * s->x_offset;
for (x = s->x_offset; x < s->x_offset + s->cur_w; ++x, foreground += s->bpp, background += s->bpp) {
size_t b;
uint8_t foreground_alpha, background_alpha, output_alpha;
uint8_t output[4];
// Since we might be blending alpha onto alpha, we use the following equations:
// output_alpha = foreground_alpha + (1 - foreground_alpha) * background_alpha
// output = (foreground_alpha * foreground + (1 - foreground_alpha) * background_alpha * background) / output_alpha
switch (avctx->pix_fmt) {
case AV_PIX_FMT_RGBA:
foreground_alpha = foreground[3];
background_alpha = background[3];
break;
}
if (foreground_alpha == 0)
continue;
if (foreground_alpha == 255) {
memcpy(background, foreground, s->bpp);
continue;
}
output_alpha = foreground_alpha + FAST_DIV255((255 - foreground_alpha) * background_alpha);
for (b = 0; b < s->bpp - 1; ++b) {
if (output_alpha == 0) {
output[b] = 0;
} else if (background_alpha == 255) {
output[b] = FAST_DIV255(foreground_alpha * foreground[b] + (255 - foreground_alpha) * background[b]);
} else {
output[b] = (255 * foreground_alpha * foreground[b] + (255 - foreground_alpha) * background_alpha * background[b]) / (255 * output_alpha);
}
}
output[b] = output_alpha;
memcpy(background, output, s->bpp);
}
}
}
// Copy blended buffer into the frame and free
memcpy(p->data[0], buffer, s->image_linesize * s->height);
av_free(buffer);
return 0;
}
static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
AVFrame *p, AVPacket *avpkt)
{
AVDictionary *metadata = NULL;
uint32_t tag, length;
int decode_next_dat = 0;
int ret;
for (;;) {
length = bytestream2_get_bytes_left(&s->gb);
if (length <= 0) {
if (CONFIG_APNG_DECODER && avctx->codec_id == AV_CODEC_ID_APNG && length == 0) {
if (!(s->state & PNG_IDAT))
return 0;
else
goto exit_loop;
}
av_log(avctx, AV_LOG_ERROR, "%d bytes left\n", length);
if ( s->state & PNG_ALLIMAGE
&& avctx->strict_std_compliance <= FF_COMPLIANCE_NORMAL)
goto exit_loop;
ret = AVERROR_INVALIDDATA;
goto fail;
}
length = bytestream2_get_be32(&s->gb);
if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
ret = AVERROR_INVALIDDATA;
goto fail;
}
tag = bytestream2_get_le32(&s->gb);
if (avctx->debug & FF_DEBUG_STARTCODE)
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);
switch (tag) {
case MKTAG('I', 'H', 'D', 'R'):
if ((ret = decode_ihdr_chunk(avctx, s, length)) < 0)
goto fail;
break;
case MKTAG('p', 'H', 'Y', 's'):
if ((ret = decode_phys_chunk(avctx, s)) < 0)
goto fail;
break;
case MKTAG('f', 'c', 'T', 'L'):
if (!CONFIG_APNG_DECODER || avctx->codec_id != AV_CODEC_ID_APNG)
goto skip_tag;
if ((ret = decode_fctl_chunk(avctx, s, length)) < 0)
goto fail;
decode_next_dat = 1;
break;
case MKTAG('f', 'd', 'A', 'T'):
if (!CONFIG_APNG_DECODER || avctx->codec_id != AV_CODEC_ID_APNG)
goto skip_tag;
if (!decode_next_dat) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
bytestream2_get_be32(&s->gb);
length -= 4;
/* fallthrough */
case MKTAG('I', 'D', 'A', 'T'):
if (CONFIG_APNG_DECODER && avctx->codec_id == AV_CODEC_ID_APNG && !decode_next_dat)
goto skip_tag;
if ((ret = decode_idat_chunk(avctx, s, length, p)) < 0)
goto fail;
break;
case MKTAG('P', 'L', 'T', 'E'):
if (decode_plte_chunk(avctx, s, length) < 0)
goto skip_tag;
break;
case MKTAG('t', 'R', 'N', 'S'):
if (decode_trns_chunk(avctx, s, length) < 0)
goto skip_tag;
break;
case MKTAG('t', 'E', 'X', 't'):
if (decode_text_chunk(s, length, 0, &metadata) < 0)
av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
bytestream2_skip(&s->gb, length + 4);
break;
case MKTAG('z', 'T', 'X', 't'):
if (decode_text_chunk(s, length, 1, &metadata) < 0)
av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
bytestream2_skip(&s->gb, length + 4);
break;
case MKTAG('I', 'E', 'N', 'D'):
if (!(s->state & PNG_ALLIMAGE))
av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
bytestream2_skip(&s->gb, 4); /* crc */
goto exit_loop;
default:
/* skip tag */
skip_tag:
bytestream2_skip(&s->gb, length + 4);
break;
}
}
exit_loop:
if (s->bits_per_pixel <= 4)
handle_small_bpp(s, p);
/* handle p-frames only if a predecessor frame is available */
if (s->last_picture.f->data[0]) {
if ( !(avpkt->flags & AV_PKT_FLAG_KEY) && avctx->codec_tag != AV_RL32("MPNG")
&& s->last_picture.f->width == p->width
&& s->last_picture.f->height== p->height
&& s->last_picture.f->format== p->format
) {
if (CONFIG_PNG_DECODER && avctx->codec_id != AV_CODEC_ID_APNG)
handle_p_frame_png(s, p);
else if (CONFIG_APNG_DECODER &&
avctx->codec_id == AV_CODEC_ID_APNG &&
(ret = handle_p_frame_apng(avctx, s, p)) < 0)
goto fail;
}
}
ff_thread_report_progress(&s->picture, INT_MAX, 0);
av_frame_set_metadata(p, metadata);
metadata = NULL;
return 0;
fail:
av_dict_free(&metadata);
ff_thread_report_progress(&s->picture, INT_MAX, 0);
return ret;
}
#if CONFIG_PNG_DECODER
static int decode_frame_png(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
PNGDecContext *const s = avctx->priv_data;
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
AVFrame *p;
int64_t sig;
int ret;
ff_thread_release_buffer(avctx, &s->last_picture);
FFSWAP(ThreadFrame, s->picture, s->last_picture);
p = s->picture.f;
bytestream2_init(&s->gb, buf, buf_size);
/* check signature */
sig = bytestream2_get_be64(&s->gb);
if (sig != PNGSIG &&
sig != MNGSIG) {
av_log(avctx, AV_LOG_ERROR, "Invalid PNG signature (%d).\n", buf_size);
return AVERROR_INVALIDDATA;
}
s->y = s->state = 0;
/* 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) {
av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
return AVERROR_EXTERNAL;
}
if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
goto the_end;
if ((ret = av_frame_ref(data, s->picture.f)) < 0)
return ret;
*got_frame = 1;
ret = bytestream2_tell(&s->gb);
the_end:
inflateEnd(&s->zstream);
s->crow_buf = NULL;
return ret;
}
#endif
#if CONFIG_APNG_DECODER
static int decode_frame_apng(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
PNGDecContext *const s = avctx->priv_data;
int ret;
AVFrame *p;
ThreadFrame tmp;
ff_thread_release_buffer(avctx, &s->previous_picture);
tmp = s->previous_picture;
s->previous_picture = s->last_picture;
s->last_picture = s->picture;
s->picture = tmp;
p = s->picture.f;
if (!(s->state & PNG_IHDR)) {
if (!avctx->extradata_size)
return AVERROR_INVALIDDATA;
/* only init fields, there is no zlib use in extradata */
s->zstream.zalloc = ff_png_zalloc;
s->zstream.zfree = ff_png_zfree;
bytestream2_init(&s->gb, avctx->extradata, avctx->extradata_size);
if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
goto end;
}
/* reset state for a new frame */
if ((ret = inflateInit(&s->zstream)) != Z_OK) {
av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
ret = AVERROR_EXTERNAL;
goto end;
}
s->y = 0;
s->state &= ~(PNG_IDAT | PNG_ALLIMAGE);
bytestream2_init(&s->gb, avpkt->data, avpkt->size);
if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
goto end;
if (!(s->state & PNG_ALLIMAGE))
av_log(avctx, AV_LOG_WARNING, "Frame did not contain a complete image\n");
if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
ret = AVERROR_INVALIDDATA;
goto end;
}
if ((ret = av_frame_ref(data, s->picture.f)) < 0)
goto end;
*got_frame = 1;
ret = bytestream2_tell(&s->gb);
end:
inflateEnd(&s->zstream);
return ret;
}
#endif
static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
{
PNGDecContext *psrc = src->priv_data;
PNGDecContext *pdst = dst->priv_data;
int ret;
if (dst == src)
return 0;
ff_thread_release_buffer(dst, &pdst->picture);
if (psrc->picture.f->data[0] &&
(ret = ff_thread_ref_frame(&pdst->picture, &psrc->picture)) < 0)
return ret;
if (CONFIG_APNG_DECODER && dst->codec_id == AV_CODEC_ID_APNG) {
pdst->cur_w = psrc->cur_w;
pdst->cur_h = psrc->cur_h;
pdst->x_offset = psrc->x_offset;
pdst->y_offset = psrc->y_offset;
pdst->dispose_op = psrc->dispose_op;
ff_thread_release_buffer(dst, &pdst->last_picture);
if (psrc->last_picture.f->data[0])
return ff_thread_ref_frame(&pdst->last_picture, &psrc->last_picture);
}
return 0;
}
static av_cold int png_dec_init(AVCodecContext *avctx)
{
PNGDecContext *s = avctx->priv_data;
avctx->color_range = AVCOL_RANGE_JPEG;
s->avctx = avctx;
s->previous_picture.f = av_frame_alloc();
s->last_picture.f = av_frame_alloc();
s->picture.f = av_frame_alloc();
if (!s->previous_picture.f || !s->last_picture.f || !s->picture.f) {
av_frame_free(&s->previous_picture.f);
av_frame_free(&s->last_picture.f);
av_frame_free(&s->picture.f);
return AVERROR(ENOMEM);
}
if (!avctx->internal->is_copy) {
avctx->internal->allocate_progress = 1;
ff_pngdsp_init(&s->dsp);
}
return 0;
}
static av_cold int png_dec_end(AVCodecContext *avctx)
{
PNGDecContext *s = avctx->priv_data;
ff_thread_release_buffer(avctx, &s->previous_picture);
av_frame_free(&s->previous_picture.f);
ff_thread_release_buffer(avctx, &s->last_picture);
av_frame_free(&s->last_picture.f);
ff_thread_release_buffer(avctx, &s->picture);
av_frame_free(&s->picture.f);
av_freep(&s->buffer);
s->buffer_size = 0;
av_freep(&s->last_row);
s->last_row_size = 0;
av_freep(&s->tmp_row);
s->tmp_row_size = 0;
return 0;
}
#if CONFIG_APNG_DECODER
AVCodec ff_apng_decoder = {
.name = "apng",
.long_name = NULL_IF_CONFIG_SMALL("APNG (Animated Portable Network Graphics) image"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_APNG,
.priv_data_size = sizeof(PNGDecContext),
.init = png_dec_init,
.close = png_dec_end,
.decode = decode_frame_apng,
.init_thread_copy = ONLY_IF_THREADS_ENABLED(png_dec_init),
.update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
.capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
};
#endif
#if CONFIG_PNG_DECODER
AVCodec ff_png_decoder = {
.name = "png",
.long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_PNG,
.priv_data_size = sizeof(PNGDecContext),
.init = png_dec_init,
.close = png_dec_end,
.decode = decode_frame_png,
.init_thread_copy = ONLY_IF_THREADS_ENABLED(png_dec_init),
.update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
.capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
};
#endif
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