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1720791e36
Use optional sTER chunk defining side-by-side stereo pair within "Extensions to the PNG 1.2 Specification", version 1.3.0. Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
712 lines
25 KiB
C
712 lines
25 KiB
C
/*
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* PNG image format
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* Copyright (c) 2003 Fabrice Bellard
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/avstring.h"
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#include "libavutil/imgutils.h"
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#include "libavutil/stereo3d.h"
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#include "avcodec.h"
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#include "bytestream.h"
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#include "internal.h"
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#include "png.h"
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#include "pngdsp.h"
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/* TODO:
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* - add 2, 4 and 16 bit depth support
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*/
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#include <zlib.h>
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typedef struct PNGDecContext {
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PNGDSPContext dsp;
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GetByteContext gb;
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AVFrame *prev;
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int state;
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int width, height;
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int bit_depth;
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int color_type;
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int compression_type;
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int interlace_type;
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int filter_type;
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int channels;
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int bits_per_pixel;
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int bpp;
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uint8_t *image_buf;
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int image_linesize;
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uint32_t palette[256];
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uint8_t *crow_buf;
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uint8_t *last_row;
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uint8_t *tmp_row;
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int pass;
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int crow_size; /* compressed row size (include filter type) */
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int row_size; /* decompressed row size */
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int pass_row_size; /* decompress row size of the current pass */
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int y;
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z_stream zstream;
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} PNGDecContext;
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/* Mask to determine which y pixels can be written in a pass */
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static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
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0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
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};
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/* Mask to determine which pixels to overwrite while displaying */
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static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
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0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
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};
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/* NOTE: we try to construct a good looking image at each pass. width
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* is the original image width. We also do pixel format conversion at
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* this stage */
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static void png_put_interlaced_row(uint8_t *dst, int width,
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int bits_per_pixel, int pass,
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int color_type, const uint8_t *src)
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{
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int x, mask, dsp_mask, j, src_x, b, bpp;
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uint8_t *d;
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const uint8_t *s;
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mask = ff_png_pass_mask[pass];
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dsp_mask = png_pass_dsp_mask[pass];
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switch (bits_per_pixel) {
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case 1:
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/* we must initialize the line to zero before writing to it */
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if (pass == 0)
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memset(dst, 0, (width + 7) >> 3);
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src_x = 0;
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for (x = 0; x < width; x++) {
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j = (x & 7);
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if ((dsp_mask << j) & 0x80) {
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b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
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dst[x >> 3] |= b << (7 - j);
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}
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if ((mask << j) & 0x80)
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src_x++;
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}
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break;
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default:
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bpp = bits_per_pixel >> 3;
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d = dst;
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s = src;
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if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
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for (x = 0; x < width; x++) {
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j = x & 7;
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if ((dsp_mask << j) & 0x80) {
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*(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
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}
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d += bpp;
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if ((mask << j) & 0x80)
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s += bpp;
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}
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} else {
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for (x = 0; x < width; x++) {
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j = x & 7;
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if ((dsp_mask << j) & 0x80) {
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memcpy(d, s, bpp);
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}
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d += bpp;
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if ((mask << j) & 0x80)
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s += bpp;
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}
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}
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break;
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}
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}
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void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top,
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int w, int bpp)
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{
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int i;
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for (i = 0; i < w; i++) {
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int a, b, c, p, pa, pb, pc;
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a = dst[i - bpp];
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b = top[i];
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c = top[i - bpp];
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p = b - c;
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pc = a - c;
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pa = abs(p);
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pb = abs(pc);
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pc = abs(p + pc);
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if (pa <= pb && pa <= pc)
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p = a;
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else if (pb <= pc)
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p = b;
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else
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p = c;
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dst[i] = p + src[i];
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}
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}
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#define UNROLL1(bpp, op) \
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{ \
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r = dst[0]; \
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if (bpp >= 2) \
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g = dst[1]; \
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if (bpp >= 3) \
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b = dst[2]; \
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if (bpp >= 4) \
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a = dst[3]; \
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for (; i < size; i += bpp) { \
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dst[i + 0] = r = op(r, src[i + 0], last[i + 0]); \
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if (bpp == 1) \
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continue; \
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dst[i + 1] = g = op(g, src[i + 1], last[i + 1]); \
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if (bpp == 2) \
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continue; \
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dst[i + 2] = b = op(b, src[i + 2], last[i + 2]); \
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if (bpp == 3) \
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continue; \
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dst[i + 3] = a = op(a, src[i + 3], last[i + 3]); \
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} \
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}
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#define UNROLL_FILTER(op) \
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if (bpp == 1) { \
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UNROLL1(1, op) \
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} else if (bpp == 2) { \
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UNROLL1(2, op) \
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} else if (bpp == 3) { \
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UNROLL1(3, op) \
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} else if (bpp == 4) { \
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UNROLL1(4, op) \
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} else { \
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for (; i < size; i += bpp) { \
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int j; \
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for (j = 0; j < bpp; j++) \
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dst[i + j] = op(dst[i + j - bpp], src[i + j], last[i + j]); \
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} \
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}
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/* NOTE: 'dst' can be equal to 'last' */
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static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
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uint8_t *src, uint8_t *last, int size, int bpp)
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{
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int i, p, r, g, b, a;
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switch (filter_type) {
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case PNG_FILTER_VALUE_NONE:
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memcpy(dst, src, size);
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break;
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case PNG_FILTER_VALUE_SUB:
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for (i = 0; i < bpp; i++)
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dst[i] = src[i];
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if (bpp == 4) {
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p = *(int *)dst;
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for (; i < size; i += bpp) {
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int s = *(int *)(src + i);
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p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
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*(int *)(dst + i) = p;
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}
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} else {
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#define OP_SUB(x, s, l) x + s
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UNROLL_FILTER(OP_SUB);
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}
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break;
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case PNG_FILTER_VALUE_UP:
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dsp->add_bytes_l2(dst, src, last, size);
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break;
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case PNG_FILTER_VALUE_AVG:
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for (i = 0; i < bpp; i++) {
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p = (last[i] >> 1);
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dst[i] = p + src[i];
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}
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#define OP_AVG(x, s, l) (((x + l) >> 1) + s) & 0xff
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UNROLL_FILTER(OP_AVG);
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break;
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case PNG_FILTER_VALUE_PAETH:
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for (i = 0; i < bpp; i++) {
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p = last[i];
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dst[i] = p + src[i];
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}
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if (bpp > 2 && size > 4) {
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/* would write off the end of the array if we let it process
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* the last pixel with bpp=3 */
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int w = bpp == 4 ? size : size - 3;
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dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
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i = w;
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}
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ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
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break;
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}
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}
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static av_always_inline void convert_to_rgb32_loco(uint8_t *dst,
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const uint8_t *src,
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int width, int loco)
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{
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int j;
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unsigned int r, g, b, a;
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for (j = 0; j < width; j++) {
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r = src[0];
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g = src[1];
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b = src[2];
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a = src[3];
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if (loco) {
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r = (r + g) & 0xff;
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b = (b + g) & 0xff;
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}
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*(uint32_t *) dst = (a << 24) | (r << 16) | (g << 8) | b;
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dst += 4;
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src += 4;
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}
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}
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static void convert_to_rgb32(uint8_t *dst, const uint8_t *src,
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int width, int loco)
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{
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if (loco)
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convert_to_rgb32_loco(dst, src, width, 1);
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else
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convert_to_rgb32_loco(dst, src, width, 0);
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}
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static void deloco_rgb24(uint8_t *dst, int size)
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{
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int i;
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for (i = 0; i < size; i += 3) {
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int g = dst[i + 1];
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dst[i + 0] += g;
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dst[i + 2] += g;
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}
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}
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/* process exactly one decompressed row */
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static void png_handle_row(PNGDecContext *s)
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{
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uint8_t *ptr, *last_row;
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int got_line;
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if (!s->interlace_type) {
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ptr = s->image_buf + s->image_linesize * s->y;
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/* need to swap bytes correctly for RGB_ALPHA */
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if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
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png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
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s->last_row, s->row_size, s->bpp);
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convert_to_rgb32(ptr, s->tmp_row, s->width,
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s->filter_type == PNG_FILTER_TYPE_LOCO);
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FFSWAP(uint8_t *, s->last_row, s->tmp_row);
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} else {
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/* in normal case, we avoid one copy */
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if (s->y == 0)
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last_row = s->last_row;
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else
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last_row = ptr - s->image_linesize;
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png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
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last_row, s->row_size, s->bpp);
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}
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/* loco lags by 1 row so that it doesn't interfere with top prediction */
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if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
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s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0)
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deloco_rgb24(ptr - s->image_linesize, s->row_size);
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s->y++;
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if (s->y == s->height) {
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s->state |= PNG_ALLIMAGE;
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if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
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s->color_type == PNG_COLOR_TYPE_RGB)
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deloco_rgb24(ptr, s->row_size);
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}
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} else {
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got_line = 0;
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for (;;) {
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ptr = s->image_buf + s->image_linesize * s->y;
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if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
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/* if we already read one row, it is time to stop to
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* wait for the next one */
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if (got_line)
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break;
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png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
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s->last_row, s->pass_row_size, s->bpp);
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FFSWAP(uint8_t *, s->last_row, s->tmp_row);
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got_line = 1;
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}
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if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
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/* NOTE: RGB32 is handled directly in png_put_interlaced_row */
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png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
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s->color_type, s->last_row);
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}
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s->y++;
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if (s->y == s->height) {
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for (;;) {
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if (s->pass == NB_PASSES - 1) {
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s->state |= PNG_ALLIMAGE;
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goto the_end;
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} else {
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s->pass++;
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s->y = 0;
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s->pass_row_size = ff_png_pass_row_size(s->pass,
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s->bits_per_pixel,
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s->width);
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s->crow_size = s->pass_row_size + 1;
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if (s->pass_row_size != 0)
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break;
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/* skip pass if empty row */
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}
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}
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}
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}
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the_end:;
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}
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}
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static int png_decode_idat(PNGDecContext *s, int length)
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{
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int ret;
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s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
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s->zstream.next_in = s->gb.buffer;
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bytestream2_skip(&s->gb, length);
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/* decode one line if possible */
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while (s->zstream.avail_in > 0) {
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ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
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if (ret != Z_OK && ret != Z_STREAM_END) {
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return -1;
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}
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if (s->zstream.avail_out == 0) {
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if (!(s->state & PNG_ALLIMAGE)) {
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png_handle_row(s);
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}
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s->zstream.avail_out = s->crow_size;
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s->zstream.next_out = s->crow_buf;
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}
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if (ret == Z_STREAM_END && s->zstream.avail_in > 0) {
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av_log(NULL, AV_LOG_WARNING,
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"%d undecompressed bytes left in buffer\n", s->zstream.avail_in);
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return 0;
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}
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}
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return 0;
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}
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static int decode_frame(AVCodecContext *avctx,
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void *data, int *got_frame,
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AVPacket *avpkt)
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{
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PNGDecContext *const s = avctx->priv_data;
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const uint8_t *buf = avpkt->data;
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int buf_size = avpkt->size;
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AVFrame *p = data;
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uint8_t *crow_buf_base = NULL;
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uint32_t tag, length;
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int ret;
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/* check signature */
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if (buf_size < 8) {
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av_log(avctx, AV_LOG_ERROR, "Not enough data %d\n",
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buf_size);
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return AVERROR_INVALIDDATA;
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}
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if (memcmp(buf, ff_pngsig, 8) != 0 &&
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memcmp(buf, ff_mngsig, 8) != 0) {
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char signature[5 * 8 + 1] = { 0 };
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int i;
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for (i = 0; i < 8; i++) {
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av_strlcatf(signature + i * 5, sizeof(signature) - i * 5,
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" 0x%02x", buf[i]);
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}
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av_log(avctx, AV_LOG_ERROR, "Invalid PNG signature %s\n",
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signature);
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return AVERROR_INVALIDDATA;
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}
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bytestream2_init(&s->gb, buf + 8, buf_size - 8);
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s->y = s->state = 0;
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/* init the zlib */
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s->zstream.zalloc = ff_png_zalloc;
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s->zstream.zfree = ff_png_zfree;
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s->zstream.opaque = NULL;
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ret = inflateInit(&s->zstream);
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if (ret != Z_OK)
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return -1;
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for (;;) {
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if (bytestream2_get_bytes_left(&s->gb) <= 0)
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goto fail;
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length = bytestream2_get_be32(&s->gb);
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if (length > 0x7fffffff)
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goto fail;
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tag = bytestream2_get_le32(&s->gb);
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ff_dlog(avctx, "png: tag=%c%c%c%c length=%u\n",
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(tag & 0xff),
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((tag >> 8) & 0xff),
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((tag >> 16) & 0xff),
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((tag >> 24) & 0xff), length);
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switch (tag) {
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case MKTAG('I', 'H', 'D', 'R'):
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if (length != 13)
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goto fail;
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s->width = bytestream2_get_be32(&s->gb);
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s->height = bytestream2_get_be32(&s->gb);
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if (av_image_check_size(s->width, s->height, 0, avctx)) {
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s->width = s->height = 0;
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goto fail;
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}
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s->bit_depth = bytestream2_get_byte(&s->gb);
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s->color_type = bytestream2_get_byte(&s->gb);
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s->compression_type = bytestream2_get_byte(&s->gb);
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s->filter_type = bytestream2_get_byte(&s->gb);
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s->interlace_type = bytestream2_get_byte(&s->gb);
|
|
bytestream2_skip(&s->gb, 4); /* crc */
|
|
s->state |= PNG_IHDR;
|
|
ff_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 = AV_PIX_FMT_RGB24;
|
|
} else if (s->bit_depth == 8 &&
|
|
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
|
|
avctx->pix_fmt = AV_PIX_FMT_RGB32;
|
|
} else if (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 == 1 &&
|
|
s->color_type == PNG_COLOR_TYPE_GRAY) {
|
|
avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
|
|
} else if (s->bit_depth == 8 &&
|
|
s->color_type == PNG_COLOR_TYPE_PALETTE) {
|
|
avctx->pix_fmt = AV_PIX_FMT_PAL8;
|
|
} 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 {
|
|
goto fail;
|
|
}
|
|
|
|
if (ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF) < 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;
|
|
}
|
|
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 (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 */
|
|
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;
|
|
bytestream2_skip(&s->gb, 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 = bytestream2_get_byte(&s->gb);
|
|
g = bytestream2_get_byte(&s->gb);
|
|
b = bytestream2_get_byte(&s->gb);
|
|
s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
|
|
}
|
|
for (; i < 256; i++)
|
|
s->palette[i] = (0xff << 24);
|
|
s->state |= PNG_PLTE;
|
|
bytestream2_skip(&s->gb, 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 = bytestream2_get_byte(&s->gb);
|
|
s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
|
|
}
|
|
bytestream2_skip(&s->gb, 4); /* crc */
|
|
}
|
|
break;
|
|
case MKTAG('s', 'T', 'E', 'R'): {
|
|
int mode = bytestream2_get_byte(&s->gb);
|
|
AVStereo3D *stereo3d = av_stereo3d_create_side_data(p);
|
|
if (!stereo3d)
|
|
goto the_end;
|
|
|
|
if (mode == 0 || mode == 1) {
|
|
stereo3d->type = AV_STEREO3D_SIDEBYSIDE;
|
|
stereo3d->flags = mode ? 0 : AV_STEREO3D_FLAG_INVERT;
|
|
} else {
|
|
av_log(avctx, AV_LOG_WARNING,
|
|
"Unknown value in sTER chunk (%d)\n", mode);
|
|
}
|
|
bytestream2_skip(&s->gb, 4); /* crc */
|
|
break;
|
|
}
|
|
case MKTAG('I', 'E', 'N', 'D'):
|
|
if (!(s->state & PNG_ALLIMAGE))
|
|
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:
|
|
/* handle p-frames only if a predecessor frame is available */
|
|
if (s->prev->data[0]) {
|
|
if (!(avpkt->flags & AV_PKT_FLAG_KEY)) {
|
|
int i, j;
|
|
uint8_t *pd = p->data[0];
|
|
uint8_t *pd_last = s->prev->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;
|
|
}
|
|
}
|
|
}
|
|
|
|
av_frame_unref(s->prev);
|
|
if ((ret = av_frame_ref(s->prev, p)) < 0)
|
|
goto fail;
|
|
|
|
*got_frame = 1;
|
|
|
|
ret = bytestream2_tell(&s->gb);
|
|
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;
|
|
|
|
avctx->color_range = AVCOL_RANGE_JPEG;
|
|
|
|
s->prev = av_frame_alloc();
|
|
if (!s->prev)
|
|
return AVERROR(ENOMEM);
|
|
|
|
ff_pngdsp_init(&s->dsp);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static av_cold int png_dec_end(AVCodecContext *avctx)
|
|
{
|
|
PNGDecContext *s = avctx->priv_data;
|
|
|
|
av_frame_free(&s->prev);
|
|
|
|
return 0;
|
|
}
|
|
|
|
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,
|
|
.capabilities = AV_CODEC_CAP_DR1 /*| AV_CODEC_CAP_DRAW_HORIZ_BAND*/,
|
|
};
|