yading@10: /*
yading@10:  * PNG image format
yading@10:  * Copyright (c) 2003 Fabrice Bellard
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: //#define DEBUG
yading@10: 
yading@10: #include "libavutil/bprint.h"
yading@10: #include "libavutil/imgutils.h"
yading@10: #include "avcodec.h"
yading@10: #include "bytestream.h"
yading@10: #include "internal.h"
yading@10: #include "png.h"
yading@10: #include "pngdsp.h"
yading@10: 
yading@10: /* TODO:
yading@10:  * - add 16 bit depth support
yading@10:  */
yading@10: 
yading@10: #include <zlib.h>
yading@10: 
yading@10: //#define DEBUG
yading@10: 
yading@10: typedef struct PNGDecContext {
yading@10:     PNGDSPContext dsp;
yading@10:     AVCodecContext *avctx;
yading@10: 
yading@10:     GetByteContext gb;
yading@10:     AVFrame *prev;
yading@10: 
yading@10:     int state;
yading@10:     int width, height;
yading@10:     int bit_depth;
yading@10:     int color_type;
yading@10:     int compression_type;
yading@10:     int interlace_type;
yading@10:     int filter_type;
yading@10:     int channels;
yading@10:     int bits_per_pixel;
yading@10:     int bpp;
yading@10: 
yading@10:     uint8_t *image_buf;
yading@10:     int image_linesize;
yading@10:     uint32_t palette[256];
yading@10:     uint8_t *crow_buf;
yading@10:     uint8_t *last_row;
yading@10:     uint8_t *tmp_row;
yading@10:     int pass;
yading@10:     int crow_size; /* compressed row size (include filter type) */
yading@10:     int row_size; /* decompressed row size */
yading@10:     int pass_row_size; /* decompress row size of the current pass */
yading@10:     int y;
yading@10:     z_stream zstream;
yading@10: } PNGDecContext;
yading@10: 
yading@10: /* Mask to determine which pixels are valid in a pass */
yading@10: static const uint8_t png_pass_mask[NB_PASSES] = {
yading@10:     0x01, 0x01, 0x11, 0x11, 0x55, 0x55, 0xff,
yading@10: };
yading@10: 
yading@10: /* Mask to determine which y pixels can be written in a pass */
yading@10: static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
yading@10:     0xff, 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
yading@10: };
yading@10: 
yading@10: /* Mask to determine which pixels to overwrite while displaying */
yading@10: static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
yading@10:     0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
yading@10: };
yading@10: 
yading@10: /* NOTE: we try to construct a good looking image at each pass. width
yading@10:    is the original image width. We also do pixel format conversion at
yading@10:    this stage */
yading@10: static void png_put_interlaced_row(uint8_t *dst, int width,
yading@10:                                    int bits_per_pixel, int pass,
yading@10:                                    int color_type, const uint8_t *src)
yading@10: {
yading@10:     int x, mask, dsp_mask, j, src_x, b, bpp;
yading@10:     uint8_t *d;
yading@10:     const uint8_t *s;
yading@10: 
yading@10:     mask     = png_pass_mask[pass];
yading@10:     dsp_mask = png_pass_dsp_mask[pass];
yading@10: 
yading@10:     switch (bits_per_pixel) {
yading@10:     case 1:
yading@10:         src_x = 0;
yading@10:         for (x = 0; x < width; x++) {
yading@10:             j = (x & 7);
yading@10:             if ((dsp_mask << j) & 0x80) {
yading@10:                 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
yading@10:                 dst[x >> 3] &= 0xFF7F>>j;
yading@10:                 dst[x >> 3] |= b << (7 - j);
yading@10:             }
yading@10:             if ((mask << j) & 0x80)
yading@10:                 src_x++;
yading@10:         }
yading@10:         break;
yading@10:     case 2:
yading@10:         src_x = 0;
yading@10:         for (x = 0; x < width; x++) {
yading@10:             int j2 = 2 * (x & 3);
yading@10:             j = (x & 7);
yading@10:             if ((dsp_mask << j) & 0x80) {
yading@10:                 b = (src[src_x >> 2] >> (6 - 2*(src_x & 3))) & 3;
yading@10:                 dst[x >> 2] &= 0xFF3F>>j2;
yading@10:                 dst[x >> 2] |= b << (6 - j2);
yading@10:             }
yading@10:             if ((mask << j) & 0x80)
yading@10:                 src_x++;
yading@10:         }
yading@10:         break;
yading@10:     case 4:
yading@10:         src_x = 0;
yading@10:         for (x = 0; x < width; x++) {
yading@10:             int j2 = 4*(x&1);
yading@10:             j = (x & 7);
yading@10:             if ((dsp_mask << j) & 0x80) {
yading@10:                 b = (src[src_x >> 1] >> (4 - 4*(src_x & 1))) & 15;
yading@10:                 dst[x >> 1] &= 0xFF0F>>j2;
yading@10:                 dst[x >> 1] |= b << (4 - j2);
yading@10:             }
yading@10:             if ((mask << j) & 0x80)
yading@10:                 src_x++;
yading@10:         }
yading@10:         break;
yading@10:     default:
yading@10:         bpp = bits_per_pixel >> 3;
yading@10:         d   = dst;
yading@10:         s   = src;
yading@10:             for (x = 0; x < width; x++) {
yading@10:                 j = x & 7;
yading@10:                 if ((dsp_mask << j) & 0x80) {
yading@10:                     memcpy(d, s, bpp);
yading@10:                 }
yading@10:                 d += bpp;
yading@10:                 if ((mask << j) & 0x80)
yading@10:                     s += bpp;
yading@10:             }
yading@10:         break;
yading@10:     }
yading@10: }
yading@10: 
yading@10: void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
yading@10: {
yading@10:     int i;
yading@10:     for (i = 0; i < w; i++) {
yading@10:         int a, b, c, p, pa, pb, pc;
yading@10: 
yading@10:         a = dst[i - bpp];
yading@10:         b = top[i];
yading@10:         c = top[i - bpp];
yading@10: 
yading@10:         p  = b - c;
yading@10:         pc = a - c;
yading@10: 
yading@10:         pa = abs(p);
yading@10:         pb = abs(pc);
yading@10:         pc = abs(p + pc);
yading@10: 
yading@10:         if (pa <= pb && pa <= pc)
yading@10:             p = a;
yading@10:         else if (pb <= pc)
yading@10:             p = b;
yading@10:         else
yading@10:             p = c;
yading@10:         dst[i] = p + src[i];
yading@10:     }
yading@10: }
yading@10: 
yading@10: #define UNROLL1(bpp, op) {\
yading@10:                  r = dst[0];\
yading@10:     if(bpp >= 2) g = dst[1];\
yading@10:     if(bpp >= 3) b = dst[2];\
yading@10:     if(bpp >= 4) a = dst[3];\
yading@10:     for(; i <= size - bpp; i+=bpp) {\
yading@10:         dst[i+0] = r = op(r, src[i+0], last[i+0]);\
yading@10:         if(bpp == 1) continue;\
yading@10:         dst[i+1] = g = op(g, src[i+1], last[i+1]);\
yading@10:         if(bpp == 2) continue;\
yading@10:         dst[i+2] = b = op(b, src[i+2], last[i+2]);\
yading@10:         if(bpp == 3) continue;\
yading@10:         dst[i+3] = a = op(a, src[i+3], last[i+3]);\
yading@10:     }\
yading@10: }
yading@10: 
yading@10: #define UNROLL_FILTER(op)\
yading@10:          if(bpp == 1) UNROLL1(1, op)\
yading@10:     else if(bpp == 2) UNROLL1(2, op)\
yading@10:     else if(bpp == 3) UNROLL1(3, op)\
yading@10:     else if(bpp == 4) UNROLL1(4, op)\
yading@10:     for (; i < size; i++) {\
yading@10:         dst[i] = op(dst[i-bpp], src[i], last[i]);\
yading@10:     }\
yading@10: 
yading@10: /* NOTE: 'dst' can be equal to 'last' */
yading@10: static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
yading@10:                            uint8_t *src, uint8_t *last, int size, int bpp)
yading@10: {
yading@10:     int i, p, r, g, b, a;
yading@10: 
yading@10:     switch (filter_type) {
yading@10:     case PNG_FILTER_VALUE_NONE:
yading@10:         memcpy(dst, src, size);
yading@10:         break;
yading@10:     case PNG_FILTER_VALUE_SUB:
yading@10:         for (i = 0; i < bpp; i++) {
yading@10:             dst[i] = src[i];
yading@10:         }
yading@10:         if (bpp == 4) {
yading@10:             p = *(int*)dst;
yading@10:             for (; i < size; i += bpp) {
yading@10:                 int s = *(int*)(src + i);
yading@10:                 p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
yading@10:                 *(int*)(dst + i) = p;
yading@10:             }
yading@10:         } else {
yading@10: #define OP_SUB(x,s,l) x+s
yading@10:             UNROLL_FILTER(OP_SUB);
yading@10:         }
yading@10:         break;
yading@10:     case PNG_FILTER_VALUE_UP:
yading@10:         dsp->add_bytes_l2(dst, src, last, size);
yading@10:         break;
yading@10:     case PNG_FILTER_VALUE_AVG:
yading@10:         for (i = 0; i < bpp; i++) {
yading@10:             p = (last[i] >> 1);
yading@10:             dst[i] = p + src[i];
yading@10:         }
yading@10: #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
yading@10:         UNROLL_FILTER(OP_AVG);
yading@10:         break;
yading@10:     case PNG_FILTER_VALUE_PAETH:
yading@10:         for (i = 0; i < bpp; i++) {
yading@10:             p = last[i];
yading@10:             dst[i] = p + src[i];
yading@10:         }
yading@10:         if (bpp > 2 && size > 4) {
yading@10:             // would write off the end of the array if we let it process the last pixel with bpp=3
yading@10:             int w = bpp == 4 ? size : size - 3;
yading@10:             dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
yading@10:             i = w;
yading@10:         }
yading@10:         ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
yading@10:         break;
yading@10:     }
yading@10: }
yading@10: 
yading@10: /* This used to be called "deloco" in FFmpeg
yading@10:  * and is actually an inverse reversible colorspace transformation */
yading@10: #define YUV2RGB(NAME, TYPE) \
yading@10: static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
yading@10: { \
yading@10:     int i; \
yading@10:     for (i = 0; i < size; i += 3 + alpha) { \
yading@10:         int g = dst [i+1]; \
yading@10:         dst[i+0] += g; \
yading@10:         dst[i+2] += g; \
yading@10:     } \
yading@10: }
yading@10: 
yading@10: YUV2RGB(rgb8, uint8_t)
yading@10: YUV2RGB(rgb16, uint16_t)
yading@10: 
yading@10: /* process exactly one decompressed row */
yading@10: static void png_handle_row(PNGDecContext *s)
yading@10: {
yading@10:     uint8_t *ptr, *last_row;
yading@10:     int got_line;
yading@10: 
yading@10:     if (!s->interlace_type) {
yading@10:         ptr = s->image_buf + s->image_linesize * s->y;
yading@10:             if (s->y == 0)
yading@10:                 last_row = s->last_row;
yading@10:             else
yading@10:                 last_row = ptr - s->image_linesize;
yading@10: 
yading@10:             png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
yading@10:                            last_row, s->row_size, s->bpp);
yading@10:         /* loco lags by 1 row so that it doesn't interfere with top prediction */
yading@10:         if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
yading@10:             if (s->bit_depth == 16) {
yading@10:                 deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
yading@10:                              s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
yading@10:             } else {
yading@10:                 deloco_rgb8(ptr - s->image_linesize, s->row_size,
yading@10:                             s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
yading@10:             }
yading@10:         }
yading@10:         s->y++;
yading@10:         if (s->y == s->height) {
yading@10:             s->state |= PNG_ALLIMAGE;
yading@10:             if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
yading@10:                 if (s->bit_depth == 16) {
yading@10:                     deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
yading@10:                                  s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
yading@10:                 } else {
yading@10:                     deloco_rgb8(ptr, s->row_size,
yading@10:                                 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
yading@10:                 }
yading@10:             }
yading@10:         }
yading@10:     } else {
yading@10:         got_line = 0;
yading@10:         for (;;) {
yading@10:             ptr = s->image_buf + s->image_linesize * s->y;
yading@10:             if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
yading@10:                 /* if we already read one row, it is time to stop to
yading@10:                    wait for the next one */
yading@10:                 if (got_line)
yading@10:                     break;
yading@10:                 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
yading@10:                                s->last_row, s->pass_row_size, s->bpp);
yading@10:                 FFSWAP(uint8_t*, s->last_row, s->tmp_row);
yading@10:                 got_line = 1;
yading@10:             }
yading@10:             if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
yading@10:                 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
yading@10:                                        s->color_type, s->last_row);
yading@10:             }
yading@10:             s->y++;
yading@10:             if (s->y == s->height) {
yading@10:                 memset(s->last_row, 0, s->row_size);
yading@10:                 for (;;) {
yading@10:                     if (s->pass == NB_PASSES - 1) {
yading@10:                         s->state |= PNG_ALLIMAGE;
yading@10:                         goto the_end;
yading@10:                     } else {
yading@10:                         s->pass++;
yading@10:                         s->y = 0;
yading@10:                         s->pass_row_size = ff_png_pass_row_size(s->pass,
yading@10:                                                              s->bits_per_pixel,
yading@10:                                                              s->width);
yading@10:                         s->crow_size = s->pass_row_size + 1;
yading@10:                         if (s->pass_row_size != 0)
yading@10:                             break;
yading@10:                         /* skip pass if empty row */
yading@10:                     }
yading@10:                 }
yading@10:             }
yading@10:         }
yading@10:     the_end: ;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static int png_decode_idat(PNGDecContext *s, int length)
yading@10: {
yading@10:     int ret;
yading@10:     s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
yading@10:     s->zstream.next_in  = (unsigned char *)s->gb.buffer;
yading@10:     bytestream2_skip(&s->gb, length);
yading@10: 
yading@10:     /* decode one line if possible */
yading@10:     while (s->zstream.avail_in > 0) {
yading@10:         ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
yading@10:         if (ret != Z_OK && ret != Z_STREAM_END) {
yading@10:             av_log(s->avctx, AV_LOG_ERROR, "inflate returned %d\n", ret);
yading@10:             return -1;
yading@10:         }
yading@10:         if (s->zstream.avail_out == 0) {
yading@10:             if (!(s->state & PNG_ALLIMAGE)) {
yading@10:                 png_handle_row(s);
yading@10:             }
yading@10:             s->zstream.avail_out = s->crow_size;
yading@10:             s->zstream.next_out  = s->crow_buf;
yading@10:         }
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
yading@10:                        const uint8_t *data_end)
yading@10: {
yading@10:     z_stream zstream;
yading@10:     unsigned char *buf;
yading@10:     unsigned buf_size;
yading@10:     int ret;
yading@10: 
yading@10:     zstream.zalloc = ff_png_zalloc;
yading@10:     zstream.zfree  = ff_png_zfree;
yading@10:     zstream.opaque = NULL;
yading@10:     if (inflateInit(&zstream) != Z_OK)
yading@10:         return AVERROR_EXTERNAL;
yading@10:     zstream.next_in  = (unsigned char *)data;
yading@10:     zstream.avail_in = data_end - data;
yading@10:     av_bprint_init(bp, 0, -1);
yading@10: 
yading@10:     while (zstream.avail_in > 0) {
yading@10:         av_bprint_get_buffer(bp, 1, &buf, &buf_size);
yading@10:         if (!buf_size) {
yading@10:             ret = AVERROR(ENOMEM);
yading@10:             goto fail;
yading@10:         }
yading@10:         zstream.next_out  = buf;
yading@10:         zstream.avail_out = buf_size;
yading@10:         ret = inflate(&zstream, Z_PARTIAL_FLUSH);
yading@10:         if (ret != Z_OK && ret != Z_STREAM_END) {
yading@10:             ret = AVERROR_EXTERNAL;
yading@10:             goto fail;
yading@10:         }
yading@10:         bp->len += zstream.next_out - buf;
yading@10:         if (ret == Z_STREAM_END)
yading@10:             break;
yading@10:     }
yading@10:     inflateEnd(&zstream);
yading@10:     bp->str[bp->len] = 0;
yading@10:     return 0;
yading@10: 
yading@10: fail:
yading@10:     inflateEnd(&zstream);
yading@10:     av_bprint_finalize(bp, NULL);
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
yading@10: {
yading@10:     size_t extra = 0, i;
yading@10:     uint8_t *out, *q;
yading@10: 
yading@10:     for (i = 0; i < size_in; i++)
yading@10:         extra += in[i] >= 0x80;
yading@10:     if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
yading@10:         return NULL;
yading@10:     q = out = av_malloc(size_in + extra + 1);
yading@10:     if (!out)
yading@10:         return NULL;
yading@10:     for (i = 0; i < size_in; i++) {
yading@10:         if (in[i] >= 0x80) {
yading@10:             *(q++) = 0xC0 | (in[i] >> 6);
yading@10:             *(q++) = 0x80 | (in[i] & 0x3F);
yading@10:         } else {
yading@10:             *(q++) = in[i];
yading@10:         }
yading@10:     }
yading@10:     *(q++) = 0;
yading@10:     return out;
yading@10: }
yading@10: 
yading@10: static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
yading@10:                              AVDictionary **dict)
yading@10: {
yading@10:     int ret, method;
yading@10:     const uint8_t *data        = s->gb.buffer;
yading@10:     const uint8_t *data_end    = data + length;
yading@10:     const uint8_t *keyword     = data;
yading@10:     const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
yading@10:     uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
yading@10:     unsigned text_len;
yading@10:     AVBPrint bp;
yading@10: 
yading@10:     if (!keyword_end)
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     data = keyword_end + 1;
yading@10: 
yading@10:     if (compressed) {
yading@10:         if (data == data_end)
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         method = *(data++);
yading@10:         if (method)
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
yading@10:             return ret;
yading@10:         text_len = bp.len;
yading@10:         av_bprint_finalize(&bp, (char **)&text);
yading@10:         if (!text)
yading@10:             return AVERROR(ENOMEM);
yading@10:     } else {
yading@10:         text = (uint8_t *)data;
yading@10:         text_len = data_end - text;
yading@10:     }
yading@10: 
yading@10:     kw_utf8  = iso88591_to_utf8(keyword, keyword_end - keyword);
yading@10:     txt_utf8 = iso88591_to_utf8(text, text_len);
yading@10:     if (text != data)
yading@10:         av_free(text);
yading@10:     if (!(kw_utf8 && txt_utf8)) {
yading@10:         av_free(kw_utf8);
yading@10:         av_free(txt_utf8);
yading@10:         return AVERROR(ENOMEM);
yading@10:     }
yading@10: 
yading@10:     av_dict_set(dict, kw_utf8, txt_utf8,
yading@10:                 AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int decode_frame(AVCodecContext *avctx,
yading@10:                         void *data, int *got_frame,
yading@10:                         AVPacket *avpkt)
yading@10: {
yading@10:     PNGDecContext * const s = avctx->priv_data;
yading@10:     const uint8_t *buf      = avpkt->data;
yading@10:     int buf_size            = avpkt->size;
yading@10:     AVFrame *p              = data;
yading@10:     AVDictionary *metadata  = NULL;
yading@10:     uint8_t *crow_buf_base  = NULL;
yading@10:     uint32_t tag, length;
yading@10:     int64_t sig;
yading@10:     int ret;
yading@10: 
yading@10:     bytestream2_init(&s->gb, buf, buf_size);
yading@10: 
yading@10:     /* check signature */
yading@10:     sig = bytestream2_get_be64(&s->gb);
yading@10:     if (sig != PNGSIG &&
yading@10:         sig != MNGSIG) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
yading@10:         return -1;
yading@10:     }
yading@10: 
yading@10:     s->y = s->state = 0;
yading@10: 
yading@10:     /* init the zlib */
yading@10:     s->zstream.zalloc = ff_png_zalloc;
yading@10:     s->zstream.zfree  = ff_png_zfree;
yading@10:     s->zstream.opaque = NULL;
yading@10:     ret = inflateInit(&s->zstream);
yading@10:     if (ret != Z_OK) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "inflateInit returned %d\n", ret);
yading@10:         return -1;
yading@10:     }
yading@10:     for (;;) {
yading@10:         if (bytestream2_get_bytes_left(&s->gb) <= 0) {
yading@10:             av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
yading@10:             goto fail;
yading@10:         }
yading@10: 
yading@10:         length = bytestream2_get_be32(&s->gb);
yading@10:         if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb))  {
yading@10:             av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
yading@10:             goto fail;
yading@10:         }
yading@10:         tag = bytestream2_get_le32(&s->gb);
yading@10:         if (avctx->debug & FF_DEBUG_STARTCODE)
yading@10:             av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
yading@10:                 (tag & 0xff),
yading@10:                 ((tag >> 8) & 0xff),
yading@10:                 ((tag >> 16) & 0xff),
yading@10:                 ((tag >> 24) & 0xff), length);
yading@10:         switch (tag) {
yading@10:         case MKTAG('I', 'H', 'D', 'R'):
yading@10:             if (length != 13)
yading@10:                 goto fail;
yading@10:             s->width  = bytestream2_get_be32(&s->gb);
yading@10:             s->height = bytestream2_get_be32(&s->gb);
yading@10:             if (av_image_check_size(s->width, s->height, 0, avctx)) {
yading@10:                 s->width = s->height = 0;
yading@10:                 av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
yading@10:                 goto fail;
yading@10:             }
yading@10:             s->bit_depth        = bytestream2_get_byte(&s->gb);
yading@10:             s->color_type       = bytestream2_get_byte(&s->gb);
yading@10:             s->compression_type = bytestream2_get_byte(&s->gb);
yading@10:             s->filter_type      = bytestream2_get_byte(&s->gb);
yading@10:             s->interlace_type   = bytestream2_get_byte(&s->gb);
yading@10:             bytestream2_skip(&s->gb, 4); /* crc */
yading@10:             s->state |= PNG_IHDR;
yading@10:             if (avctx->debug & FF_DEBUG_PICT_INFO)
yading@10:                 av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
yading@10:                     "compression_type=%d filter_type=%d interlace_type=%d\n",
yading@10:                     s->width, s->height, s->bit_depth, s->color_type,
yading@10:                     s->compression_type, s->filter_type, s->interlace_type);
yading@10:             break;
yading@10:         case MKTAG('p', 'H', 'Y', 's'):
yading@10:             if (s->state & PNG_IDAT) {
yading@10:                 av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
yading@10:                 goto fail;
yading@10:             }
yading@10:             avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
yading@10:             avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
yading@10:             if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
yading@10:                 avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
yading@10:             bytestream2_skip(&s->gb, 1); /* unit specifier */
yading@10:             bytestream2_skip(&s->gb, 4); /* crc */
yading@10:             break;
yading@10:         case MKTAG('I', 'D', 'A', 'T'):
yading@10:             if (!(s->state & PNG_IHDR)) {
yading@10:                 av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
yading@10:                 goto fail;
yading@10:             }
yading@10:             if (!(s->state & PNG_IDAT)) {
yading@10:                 /* init image info */
yading@10:                 avctx->width  = s->width;
yading@10:                 avctx->height = s->height;
yading@10: 
yading@10:                 s->channels       = ff_png_get_nb_channels(s->color_type);
yading@10:                 s->bits_per_pixel = s->bit_depth * s->channels;
yading@10:                 s->bpp            = (s->bits_per_pixel + 7) >> 3;
yading@10:                 s->row_size       = (avctx->width * s->bits_per_pixel + 7) >> 3;
yading@10: 
yading@10:                 if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
yading@10:                     s->color_type == PNG_COLOR_TYPE_RGB) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_RGB24;
yading@10:                 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
yading@10:                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_RGBA;
yading@10:                 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
yading@10:                            s->color_type == PNG_COLOR_TYPE_GRAY) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_GRAY8;
yading@10:                 } else if (s->bit_depth == 16 &&
yading@10:                            s->color_type == PNG_COLOR_TYPE_GRAY) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
yading@10:                 } else if (s->bit_depth == 16 &&
yading@10:                            s->color_type == PNG_COLOR_TYPE_RGB) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
yading@10:                 } else if (s->bit_depth == 16 &&
yading@10:                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
yading@10:                 } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
yading@10:                            s->color_type == PNG_COLOR_TYPE_PALETTE) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_PAL8;
yading@10:                 } else if (s->bit_depth == 1) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
yading@10:                 } else if (s->bit_depth == 8 &&
yading@10:                            s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
yading@10:                     avctx->pix_fmt = AV_PIX_FMT_Y400A;
yading@10:                 } else {
yading@10:                     av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
yading@10:                                                 "and color type %d\n",
yading@10:                                                  s->bit_depth, s->color_type);
yading@10:                     goto fail;
yading@10:                 }
yading@10: 
yading@10:                 if (ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF) < 0)
yading@10:                     goto fail;
yading@10:                 p->pict_type        = AV_PICTURE_TYPE_I;
yading@10:                 p->key_frame        = 1;
yading@10:                 p->interlaced_frame = !!s->interlace_type;
yading@10: 
yading@10:                 /* compute the compressed row size */
yading@10:                 if (!s->interlace_type) {
yading@10:                     s->crow_size = s->row_size + 1;
yading@10:                 } else {
yading@10:                     s->pass = 0;
yading@10:                     s->pass_row_size = ff_png_pass_row_size(s->pass,
yading@10:                                                          s->bits_per_pixel,
yading@10:                                                          s->width);
yading@10:                     s->crow_size = s->pass_row_size + 1;
yading@10:                 }
yading@10:                 av_dlog(avctx, "row_size=%d crow_size =%d\n",
yading@10:                         s->row_size, s->crow_size);
yading@10:                 s->image_buf      = p->data[0];
yading@10:                 s->image_linesize = p->linesize[0];
yading@10:                 /* copy the palette if needed */
yading@10:                 if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
yading@10:                     memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
yading@10:                 /* empty row is used if differencing to the first row */
yading@10:                 s->last_row = av_mallocz(s->row_size);
yading@10:                 if (!s->last_row)
yading@10:                     goto fail;
yading@10:                 if (s->interlace_type ||
yading@10:                     s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
yading@10:                     s->tmp_row = av_malloc(s->row_size);
yading@10:                     if (!s->tmp_row)
yading@10:                         goto fail;
yading@10:                 }
yading@10:                 /* compressed row */
yading@10:                 crow_buf_base = av_malloc(s->row_size + 16);
yading@10:                 if (!crow_buf_base)
yading@10:                     goto fail;
yading@10: 
yading@10:                 /* we want crow_buf+1 to be 16-byte aligned */
yading@10:                 s->crow_buf          = crow_buf_base + 15;
yading@10:                 s->zstream.avail_out = s->crow_size;
yading@10:                 s->zstream.next_out  = s->crow_buf;
yading@10:             }
yading@10:             s->state |= PNG_IDAT;
yading@10:             if (png_decode_idat(s, length) < 0)
yading@10:                 goto fail;
yading@10:             bytestream2_skip(&s->gb, 4); /* crc */
yading@10:             break;
yading@10:         case MKTAG('P', 'L', 'T', 'E'):
yading@10:             {
yading@10:                 int n, i, r, g, b;
yading@10: 
yading@10:                 if ((length % 3) != 0 || length > 256 * 3)
yading@10:                     goto skip_tag;
yading@10:                 /* read the palette */
yading@10:                 n = length / 3;
yading@10:                 for (i = 0; i < n; i++) {
yading@10:                     r = bytestream2_get_byte(&s->gb);
yading@10:                     g = bytestream2_get_byte(&s->gb);
yading@10:                     b = bytestream2_get_byte(&s->gb);
yading@10:                     s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
yading@10:                 }
yading@10:                 for (; i < 256; i++) {
yading@10:                     s->palette[i] = (0xFFU << 24);
yading@10:                 }
yading@10:                 s->state |= PNG_PLTE;
yading@10:                 bytestream2_skip(&s->gb, 4); /* crc */
yading@10:             }
yading@10:             break;
yading@10:         case MKTAG('t', 'R', 'N', 'S'):
yading@10:             {
yading@10:                 int v, i;
yading@10: 
yading@10:                 /* read the transparency. XXX: Only palette mode supported */
yading@10:                 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
yading@10:                     length > 256 ||
yading@10:                     !(s->state & PNG_PLTE))
yading@10:                     goto skip_tag;
yading@10:                 for (i = 0; i < length; i++) {
yading@10:                     v = bytestream2_get_byte(&s->gb);
yading@10:                     s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
yading@10:                 }
yading@10:                 bytestream2_skip(&s->gb, 4); /* crc */
yading@10:             }
yading@10:             break;
yading@10:         case MKTAG('t', 'E', 'X', 't'):
yading@10:             if (decode_text_chunk(s, length, 0, &metadata) < 0)
yading@10:                 av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
yading@10:             bytestream2_skip(&s->gb, length + 4);
yading@10:             break;
yading@10:         case MKTAG('z', 'T', 'X', 't'):
yading@10:             if (decode_text_chunk(s, length, 1, &metadata) < 0)
yading@10:                 av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
yading@10:             bytestream2_skip(&s->gb, length + 4);
yading@10:             break;
yading@10:         case MKTAG('I', 'E', 'N', 'D'):
yading@10:             if (!(s->state & PNG_ALLIMAGE))
yading@10:                 av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
yading@10:             if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
yading@10:                 goto fail;
yading@10:             }
yading@10:             bytestream2_skip(&s->gb, 4); /* crc */
yading@10:             goto exit_loop;
yading@10:         default:
yading@10:             /* skip tag */
yading@10:         skip_tag:
yading@10:             bytestream2_skip(&s->gb, length + 4);
yading@10:             break;
yading@10:         }
yading@10:     }
yading@10:  exit_loop:
yading@10: 
yading@10:     if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
yading@10:         int i, j, k;
yading@10:         uint8_t *pd = p->data[0];
yading@10:         for (j = 0; j < s->height; j++) {
yading@10:             i = s->width / 8;
yading@10:             for (k = 7; k >= 1; k--)
yading@10:                 if ((s->width&7) >= k)
yading@10:                     pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
yading@10:             for (i--; i >= 0; i--) {
yading@10:                 pd[8*i + 7]=  pd[i]     & 1;
yading@10:                 pd[8*i + 6]= (pd[i]>>1) & 1;
yading@10:                 pd[8*i + 5]= (pd[i]>>2) & 1;
yading@10:                 pd[8*i + 4]= (pd[i]>>3) & 1;
yading@10:                 pd[8*i + 3]= (pd[i]>>4) & 1;
yading@10:                 pd[8*i + 2]= (pd[i]>>5) & 1;
yading@10:                 pd[8*i + 1]= (pd[i]>>6) & 1;
yading@10:                 pd[8*i + 0]=  pd[i]>>7;
yading@10:             }
yading@10:             pd += s->image_linesize;
yading@10:         }
yading@10:     }
yading@10:     if (s->bits_per_pixel == 2){
yading@10:         int i, j;
yading@10:         uint8_t *pd = p->data[0];
yading@10:         for (j = 0; j < s->height; j++) {
yading@10:             i = s->width / 4;
yading@10:             if (s->color_type == PNG_COLOR_TYPE_PALETTE){
yading@10:                 if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
yading@10:                 if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
yading@10:                 if ((s->width&3) >= 1) pd[4*i + 0]=  pd[i] >> 6;
yading@10:                 for (i--; i >= 0; i--) {
yading@10:                     pd[4*i + 3]=  pd[i]     & 3;
yading@10:                     pd[4*i + 2]= (pd[i]>>2) & 3;
yading@10:                     pd[4*i + 1]= (pd[i]>>4) & 3;
yading@10:                     pd[4*i + 0]=  pd[i]>>6;
yading@10:                 }
yading@10:             } else {
yading@10:                 if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
yading@10:                 if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
yading@10:                 if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6     )*0x55;
yading@10:                 for (i--; i >= 0; i--) {
yading@10:                     pd[4*i + 3]= ( pd[i]     & 3)*0x55;
yading@10:                     pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
yading@10:                     pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
yading@10:                     pd[4*i + 0]= ( pd[i]>>6     )*0x55;
yading@10:                 }
yading@10:             }
yading@10:             pd += s->image_linesize;
yading@10:         }
yading@10:     }
yading@10:     if (s->bits_per_pixel == 4){
yading@10:         int i, j;
yading@10:         uint8_t *pd = p->data[0];
yading@10:         for (j = 0; j < s->height; j++) {
yading@10:             i = s->width/2;
yading@10:             if (s->color_type == PNG_COLOR_TYPE_PALETTE){
yading@10:                 if (s->width&1) pd[2*i+0]= pd[i]>>4;
yading@10:                 for (i--; i >= 0; i--) {
yading@10:                 pd[2*i + 1] = pd[i] & 15;
yading@10:                 pd[2*i + 0] = pd[i] >> 4;
yading@10:             }
yading@10:             } else {
yading@10:                 if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
yading@10:                 for (i--; i >= 0; i--) {
yading@10:                     pd[2*i + 1] = (pd[i] & 15) * 0x11;
yading@10:                     pd[2*i + 0] = (pd[i] >> 4) * 0x11;
yading@10:                 }
yading@10:             }
yading@10:             pd += s->image_linesize;
yading@10:         }
yading@10:     }
yading@10: 
yading@10:      /* handle p-frames only if a predecessor frame is available */
yading@10:      if (s->prev->data[0]) {
yading@10:          if (   !(avpkt->flags & AV_PKT_FLAG_KEY)
yading@10:             && s->prev->width == p->width
yading@10:             && s->prev->height== p->height
yading@10:             && s->prev->format== p->format
yading@10:          ) {
yading@10:             int i, j;
yading@10:             uint8_t *pd      = p->data[0];
yading@10:             uint8_t *pd_last = s->prev->data[0];
yading@10: 
yading@10:             for (j = 0; j < s->height; j++) {
yading@10:                 for (i = 0; i < s->width * s->bpp; i++) {
yading@10:                     pd[i] += pd_last[i];
yading@10:                 }
yading@10:                 pd      += s->image_linesize;
yading@10:                 pd_last += s->image_linesize;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     av_frame_set_metadata(p, metadata);
yading@10:     metadata   = NULL;
yading@10: 
yading@10:     av_frame_unref(s->prev);
yading@10:      if ((ret = av_frame_ref(s->prev, p)) < 0)
yading@10:          goto fail;
yading@10: 
yading@10:     *got_frame = 1;
yading@10: 
yading@10:     ret = bytestream2_tell(&s->gb);
yading@10:  the_end:
yading@10:     inflateEnd(&s->zstream);
yading@10:     av_free(crow_buf_base);
yading@10:     s->crow_buf = NULL;
yading@10:     av_freep(&s->last_row);
yading@10:     av_freep(&s->tmp_row);
yading@10:     return ret;
yading@10:  fail:
yading@10:     av_dict_free(&metadata);
yading@10:     ret = -1;
yading@10:     goto the_end;
yading@10: }
yading@10: 
yading@10: static av_cold int png_dec_init(AVCodecContext *avctx)
yading@10: {
yading@10:     PNGDecContext *s = avctx->priv_data;
yading@10: 
yading@10:     s->prev = av_frame_alloc();
yading@10:     if (!s->prev)
yading@10:         return AVERROR(ENOMEM);
yading@10: 
yading@10:     ff_pngdsp_init(&s->dsp);
yading@10: 
yading@10:     s->avctx = avctx;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static av_cold int png_dec_end(AVCodecContext *avctx)
yading@10: {
yading@10:     PNGDecContext *s = avctx->priv_data;
yading@10: 
yading@10:     av_frame_free(&s->prev);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_png_decoder = {
yading@10:     .name           = "png",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_PNG,
yading@10:     .priv_data_size = sizeof(PNGDecContext),
yading@10:     .init           = png_dec_init,
yading@10:     .close          = png_dec_end,
yading@10:     .decode         = decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
yading@10: };