3 * Copyright (c) 2003 Fabrice Bellard
5 * This file is part of FFmpeg.
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "libavutil/bprint.h"
25 #include "libavutil/imgutils.h"
27 #include "bytestream.h"
33 * - add 16 bit depth support
40 typedef struct PNGDecContext {
42 AVCodecContext *avctx;
45 AVFrame picture1, picture2;
46 AVFrame *current_picture, *last_picture;
61 uint32_t palette[256];
66 int crow_size; /* compressed row size (include filter type) */
67 int row_size; /* decompressed row size */
68 int pass_row_size; /* decompress row size of the current pass */
73 /* Mask to determine which pixels are valid in a pass */
74 static const uint8_t png_pass_mask[NB_PASSES] = {
75 0x01, 0x01, 0x11, 0x11, 0x55, 0x55, 0xff,
78 /* Mask to determine which y pixels can be written in a pass */
79 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
80 0xff, 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
83 /* Mask to determine which pixels to overwrite while displaying */
84 static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
85 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
88 /* NOTE: we try to construct a good looking image at each pass. width
89 is the original image width. We also do pixel format conversion at
91 static void png_put_interlaced_row(uint8_t *dst, int width,
92 int bits_per_pixel, int pass,
93 int color_type, const uint8_t *src)
95 int x, mask, dsp_mask, j, src_x, b, bpp;
99 mask = png_pass_mask[pass];
100 dsp_mask = png_pass_dsp_mask[pass];
102 switch (bits_per_pixel) {
105 for (x = 0; x < width; x++) {
107 if ((dsp_mask << j) & 0x80) {
108 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
109 dst[x >> 3] &= 0xFF7F>>j;
110 dst[x >> 3] |= b << (7 - j);
112 if ((mask << j) & 0x80)
118 for (x = 0; x < width; x++) {
119 int j2 = 2 * (x & 3);
121 if ((dsp_mask << j) & 0x80) {
122 b = (src[src_x >> 2] >> (6 - 2*(src_x & 3))) & 3;
123 dst[x >> 2] &= 0xFF3F>>j2;
124 dst[x >> 2] |= b << (6 - j2);
126 if ((mask << j) & 0x80)
132 for (x = 0; x < width; x++) {
135 if ((dsp_mask << j) & 0x80) {
136 b = (src[src_x >> 1] >> (4 - 4*(src_x & 1))) & 15;
137 dst[x >> 1] &= 0xFF0F>>j2;
138 dst[x >> 1] |= b << (4 - j2);
140 if ((mask << j) & 0x80)
145 bpp = bits_per_pixel >> 3;
148 for (x = 0; x < width; x++) {
150 if ((dsp_mask << j) & 0x80) {
154 if ((mask << j) & 0x80)
161 void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
164 for (i = 0; i < w; i++) {
165 int a, b, c, p, pa, pb, pc;
178 if (pa <= pb && pa <= pc)
188 #define UNROLL1(bpp, op) {\
190 if(bpp >= 2) g = dst[1];\
191 if(bpp >= 3) b = dst[2];\
192 if(bpp >= 4) a = dst[3];\
193 for(; i < size; i+=bpp) {\
194 dst[i+0] = r = op(r, src[i+0], last[i+0]);\
195 if(bpp == 1) continue;\
196 dst[i+1] = g = op(g, src[i+1], last[i+1]);\
197 if(bpp == 2) continue;\
198 dst[i+2] = b = op(b, src[i+2], last[i+2]);\
199 if(bpp == 3) continue;\
200 dst[i+3] = a = op(a, src[i+3], last[i+3]);\
204 #define UNROLL_FILTER(op)\
205 if(bpp == 1) UNROLL1(1, op)\
206 else if(bpp == 2) UNROLL1(2, op)\
207 else if(bpp == 3) UNROLL1(3, op)\
208 else if(bpp == 4) UNROLL1(4, op)\
210 for (; i < size; i += bpp) {\
212 for (j = 0; j < bpp; j++)\
213 dst[i+j] = op(dst[i+j-bpp], src[i+j], last[i+j]);\
217 /* NOTE: 'dst' can be equal to 'last' */
218 static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
219 uint8_t *src, uint8_t *last, int size, int bpp)
221 int i, p, r, g, b, a;
223 switch (filter_type) {
224 case PNG_FILTER_VALUE_NONE:
225 memcpy(dst, src, size);
227 case PNG_FILTER_VALUE_SUB:
228 for (i = 0; i < bpp; i++) {
233 for (; i < size; i += bpp) {
234 int s = *(int*)(src + i);
235 p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
236 *(int*)(dst + i) = p;
239 #define OP_SUB(x,s,l) x+s
240 UNROLL_FILTER(OP_SUB);
243 case PNG_FILTER_VALUE_UP:
244 dsp->add_bytes_l2(dst, src, last, size);
246 case PNG_FILTER_VALUE_AVG:
247 for (i = 0; i < bpp; i++) {
251 #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
252 UNROLL_FILTER(OP_AVG);
254 case PNG_FILTER_VALUE_PAETH:
255 for (i = 0; i < bpp; i++) {
259 if (bpp > 2 && size > 4) {
260 // would write off the end of the array if we let it process the last pixel with bpp=3
261 int w = bpp == 4 ? size : size - 3;
262 dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
265 ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
270 /* This used to be called "deloco" in FFmpeg
271 * and is actually an inverse reversible colorspace transformation */
272 #define YUV2RGB(NAME, TYPE) \
273 static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
276 for (i = 0; i < size; i += 3 + alpha) { \
283 YUV2RGB(rgb8, uint8_t)
284 YUV2RGB(rgb16, uint16_t)
286 /* process exactly one decompressed row */
287 static void png_handle_row(PNGDecContext *s)
289 uint8_t *ptr, *last_row;
292 if (!s->interlace_type) {
293 ptr = s->image_buf + s->image_linesize * s->y;
295 last_row = s->last_row;
297 last_row = ptr - s->image_linesize;
299 png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
300 last_row, s->row_size, s->bpp);
301 /* loco lags by 1 row so that it doesn't interfere with top prediction */
302 if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
303 if (s->bit_depth == 16) {
304 deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
305 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
307 deloco_rgb8(ptr - s->image_linesize, s->row_size,
308 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
312 if (s->y == s->height) {
313 s->state |= PNG_ALLIMAGE;
314 if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
315 if (s->bit_depth == 16) {
316 deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
317 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
319 deloco_rgb8(ptr, s->row_size,
320 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
327 ptr = s->image_buf + s->image_linesize * s->y;
328 if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
329 /* if we already read one row, it is time to stop to
330 wait for the next one */
333 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
334 s->last_row, s->pass_row_size, s->bpp);
335 FFSWAP(uint8_t*, s->last_row, s->tmp_row);
338 if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
339 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
340 s->color_type, s->last_row);
343 if (s->y == s->height) {
344 memset(s->last_row, 0, s->row_size);
346 if (s->pass == NB_PASSES - 1) {
347 s->state |= PNG_ALLIMAGE;
352 s->pass_row_size = ff_png_pass_row_size(s->pass,
355 s->crow_size = s->pass_row_size + 1;
356 if (s->pass_row_size != 0)
358 /* skip pass if empty row */
367 static int png_decode_idat(PNGDecContext *s, int length)
370 s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
371 s->zstream.next_in = (unsigned char *)s->gb.buffer;
372 bytestream2_skip(&s->gb, length);
374 /* decode one line if possible */
375 while (s->zstream.avail_in > 0) {
376 ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
377 if (ret != Z_OK && ret != Z_STREAM_END) {
378 av_log(s->avctx, AV_LOG_ERROR, "inflate returned %d\n", ret);
381 if (s->zstream.avail_out == 0) {
382 if (!(s->state & PNG_ALLIMAGE)) {
385 s->zstream.avail_out = s->crow_size;
386 s->zstream.next_out = s->crow_buf;
392 static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
393 const uint8_t *data_end)
400 zstream.zalloc = ff_png_zalloc;
401 zstream.zfree = ff_png_zfree;
402 zstream.opaque = NULL;
403 if (inflateInit(&zstream) != Z_OK)
404 return AVERROR_EXTERNAL;
405 zstream.next_in = (unsigned char *)data;
406 zstream.avail_in = data_end - data;
407 av_bprint_init(bp, 0, -1);
409 while (zstream.avail_in > 0) {
410 av_bprint_get_buffer(bp, 1, &buf, &buf_size);
412 ret = AVERROR(ENOMEM);
415 zstream.next_out = buf;
416 zstream.avail_out = buf_size;
417 ret = inflate(&zstream, Z_PARTIAL_FLUSH);
418 if (ret != Z_OK && ret != Z_STREAM_END) {
419 ret = AVERROR_EXTERNAL;
422 bp->len += zstream.next_out - buf;
423 if (ret == Z_STREAM_END)
426 inflateEnd(&zstream);
427 bp->str[bp->len] = 0;
431 inflateEnd(&zstream);
432 av_bprint_finalize(bp, NULL);
436 static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
441 for (i = 0; i < size_in; i++)
442 extra += in[i] >= 0x80;
443 if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
445 q = out = av_malloc(size_in + extra + 1);
448 for (i = 0; i < size_in; i++) {
450 *(q++) = 0xC0 | (in[i] >> 6);
451 *(q++) = 0x80 | (in[i] & 0x3F);
460 static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
464 const uint8_t *data = s->gb.buffer;
465 const uint8_t *data_end = data + length;
466 const uint8_t *keyword = data;
467 const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
468 uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
473 return AVERROR_INVALIDDATA;
474 data = keyword_end + 1;
477 if (data == data_end)
478 return AVERROR_INVALIDDATA;
481 return AVERROR_INVALIDDATA;
482 if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
485 av_bprint_finalize(&bp, (char **)&text);
487 return AVERROR(ENOMEM);
489 text = (uint8_t *)data;
490 text_len = data_end - text;
493 kw_utf8 = iso88591_to_utf8(keyword, keyword_end - keyword);
494 txt_utf8 = iso88591_to_utf8(text, text_len);
497 if (!(kw_utf8 && txt_utf8)) {
500 return AVERROR(ENOMEM);
503 av_dict_set(dict, kw_utf8, txt_utf8,
504 AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
508 static int decode_frame(AVCodecContext *avctx,
509 void *data, int *got_frame,
512 PNGDecContext * const s = avctx->priv_data;
513 const uint8_t *buf = avpkt->data;
514 int buf_size = avpkt->size;
515 AVFrame *picture = data;
516 AVDictionary *metadata = NULL;
517 uint8_t *crow_buf_base = NULL;
519 uint32_t tag, length;
523 FFSWAP(AVFrame *, s->current_picture, s->last_picture);
524 avctx->coded_frame = s->current_picture;
525 p = s->current_picture;
527 bytestream2_init(&s->gb, buf, buf_size);
529 /* check signature */
530 sig = bytestream2_get_be64(&s->gb);
533 av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
540 s->zstream.zalloc = ff_png_zalloc;
541 s->zstream.zfree = ff_png_zfree;
542 s->zstream.opaque = NULL;
543 ret = inflateInit(&s->zstream);
545 av_log(avctx, AV_LOG_ERROR, "inflateInit returned %d\n", ret);
549 if (bytestream2_get_bytes_left(&s->gb) <= 0) {
550 av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
554 length = bytestream2_get_be32(&s->gb);
555 if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
556 av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
559 tag = bytestream2_get_le32(&s->gb);
560 if (avctx->debug & FF_DEBUG_STARTCODE)
561 av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
564 ((tag >> 16) & 0xff),
565 ((tag >> 24) & 0xff), length);
567 case MKTAG('I', 'H', 'D', 'R'):
570 s->width = bytestream2_get_be32(&s->gb);
571 s->height = bytestream2_get_be32(&s->gb);
572 if (av_image_check_size(s->width, s->height, 0, avctx)) {
573 s->width = s->height = 0;
574 av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
577 s->bit_depth = bytestream2_get_byte(&s->gb);
578 s->color_type = bytestream2_get_byte(&s->gb);
579 s->compression_type = bytestream2_get_byte(&s->gb);
580 s->filter_type = bytestream2_get_byte(&s->gb);
581 s->interlace_type = bytestream2_get_byte(&s->gb);
582 bytestream2_skip(&s->gb, 4); /* crc */
583 s->state |= PNG_IHDR;
584 if (avctx->debug & FF_DEBUG_PICT_INFO)
585 av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
586 "compression_type=%d filter_type=%d interlace_type=%d\n",
587 s->width, s->height, s->bit_depth, s->color_type,
588 s->compression_type, s->filter_type, s->interlace_type);
590 case MKTAG('p', 'H', 'Y', 's'):
591 if (s->state & PNG_IDAT) {
592 av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
595 avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
596 avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
597 if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
598 avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
599 bytestream2_skip(&s->gb, 1); /* unit specifier */
600 bytestream2_skip(&s->gb, 4); /* crc */
602 case MKTAG('I', 'D', 'A', 'T'):
603 if (!(s->state & PNG_IHDR)) {
604 av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
607 if (!(s->state & PNG_IDAT)) {
608 /* init image info */
609 avctx->width = s->width;
610 avctx->height = s->height;
612 s->channels = ff_png_get_nb_channels(s->color_type);
613 s->bits_per_pixel = s->bit_depth * s->channels;
614 s->bpp = (s->bits_per_pixel + 7) >> 3;
615 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
617 if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
618 s->color_type == PNG_COLOR_TYPE_RGB) {
619 avctx->pix_fmt = AV_PIX_FMT_RGB24;
620 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
621 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
622 avctx->pix_fmt = AV_PIX_FMT_RGBA;
623 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
624 s->color_type == PNG_COLOR_TYPE_GRAY) {
625 avctx->pix_fmt = AV_PIX_FMT_GRAY8;
626 } else if (s->bit_depth == 16 &&
627 s->color_type == PNG_COLOR_TYPE_GRAY) {
628 avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
629 } else if (s->bit_depth == 16 &&
630 s->color_type == PNG_COLOR_TYPE_RGB) {
631 avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
632 } else if (s->bit_depth == 16 &&
633 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
634 avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
635 } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
636 s->color_type == PNG_COLOR_TYPE_PALETTE) {
637 avctx->pix_fmt = AV_PIX_FMT_PAL8;
638 } else if (s->bit_depth == 1) {
639 avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
640 } else if (s->bit_depth == 8 &&
641 s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
642 avctx->pix_fmt = AV_PIX_FMT_Y400A;
644 av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
645 "and color type %d\n",
646 s->bit_depth, s->color_type);
650 avctx->release_buffer(avctx, p);
653 if (ff_get_buffer(avctx, p) < 0) {
654 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
657 p->pict_type = AV_PICTURE_TYPE_I;
659 p->interlaced_frame = !!s->interlace_type;
661 /* compute the compressed row size */
662 if (!s->interlace_type) {
663 s->crow_size = s->row_size + 1;
666 s->pass_row_size = ff_png_pass_row_size(s->pass,
669 s->crow_size = s->pass_row_size + 1;
671 av_dlog(avctx, "row_size=%d crow_size =%d\n",
672 s->row_size, s->crow_size);
673 s->image_buf = p->data[0];
674 s->image_linesize = p->linesize[0];
675 /* copy the palette if needed */
676 if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
677 memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
678 /* empty row is used if differencing to the first row */
679 s->last_row = av_mallocz(s->row_size);
682 if (s->interlace_type ||
683 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
684 s->tmp_row = av_malloc(s->row_size);
689 crow_buf_base = av_malloc(s->row_size + 16);
693 /* we want crow_buf+1 to be 16-byte aligned */
694 s->crow_buf = crow_buf_base + 15;
695 s->zstream.avail_out = s->crow_size;
696 s->zstream.next_out = s->crow_buf;
698 s->state |= PNG_IDAT;
699 if (png_decode_idat(s, length) < 0)
701 bytestream2_skip(&s->gb, 4); /* crc */
703 case MKTAG('P', 'L', 'T', 'E'):
707 if ((length % 3) != 0 || length > 256 * 3)
709 /* read the palette */
711 for (i = 0; i < n; i++) {
712 r = bytestream2_get_byte(&s->gb);
713 g = bytestream2_get_byte(&s->gb);
714 b = bytestream2_get_byte(&s->gb);
715 s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
717 for (; i < 256; i++) {
718 s->palette[i] = (0xFFU << 24);
720 s->state |= PNG_PLTE;
721 bytestream2_skip(&s->gb, 4); /* crc */
724 case MKTAG('t', 'R', 'N', 'S'):
728 /* read the transparency. XXX: Only palette mode supported */
729 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
731 !(s->state & PNG_PLTE))
733 for (i = 0; i < length; i++) {
734 v = bytestream2_get_byte(&s->gb);
735 s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
737 bytestream2_skip(&s->gb, 4); /* crc */
740 case MKTAG('t', 'E', 'X', 't'):
741 if (decode_text_chunk(s, length, 0, &metadata) < 0)
742 av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
743 bytestream2_skip(&s->gb, length + 4);
745 case MKTAG('z', 'T', 'X', 't'):
746 if (decode_text_chunk(s, length, 1, &metadata) < 0)
747 av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
748 bytestream2_skip(&s->gb, length + 4);
750 case MKTAG('I', 'E', 'N', 'D'):
751 if (!(s->state & PNG_ALLIMAGE))
752 av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
753 if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
756 bytestream2_skip(&s->gb, 4); /* crc */
761 bytestream2_skip(&s->gb, length + 4);
767 if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
769 uint8_t *pd = s->current_picture->data[0];
770 for (j = 0; j < s->height; j++) {
772 for (k = 7; k >= 1; k--)
773 if ((s->width&7) >= k)
774 pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
775 for (i--; i >= 0; i--) {
776 pd[8*i + 7]= pd[i] & 1;
777 pd[8*i + 6]= (pd[i]>>1) & 1;
778 pd[8*i + 5]= (pd[i]>>2) & 1;
779 pd[8*i + 4]= (pd[i]>>3) & 1;
780 pd[8*i + 3]= (pd[i]>>4) & 1;
781 pd[8*i + 2]= (pd[i]>>5) & 1;
782 pd[8*i + 1]= (pd[i]>>6) & 1;
783 pd[8*i + 0]= pd[i]>>7;
785 pd += s->image_linesize;
788 if (s->bits_per_pixel == 2){
790 uint8_t *pd = s->current_picture->data[0];
791 for (j = 0; j < s->height; j++) {
793 if (s->color_type == PNG_COLOR_TYPE_PALETTE){
794 if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
795 if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
796 if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
797 for (i--; i >= 0; i--) {
798 pd[4*i + 3]= pd[i] & 3;
799 pd[4*i + 2]= (pd[i]>>2) & 3;
800 pd[4*i + 1]= (pd[i]>>4) & 3;
801 pd[4*i + 0]= pd[i]>>6;
804 if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
805 if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
806 if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
807 for (i--; i >= 0; i--) {
808 pd[4*i + 3]= ( pd[i] & 3)*0x55;
809 pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
810 pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
811 pd[4*i + 0]= ( pd[i]>>6 )*0x55;
814 pd += s->image_linesize;
817 if (s->bits_per_pixel == 4){
819 uint8_t *pd = s->current_picture->data[0];
820 for (j = 0; j < s->height; j++) {
822 if (s->color_type == PNG_COLOR_TYPE_PALETTE){
823 if (s->width&1) pd[2*i+0]= pd[i]>>4;
824 for (i--; i >= 0; i--) {
825 pd[2*i + 1] = pd[i] & 15;
826 pd[2*i + 0] = pd[i] >> 4;
829 if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
830 for (i--; i >= 0; i--) {
831 pd[2*i + 1] = (pd[i] & 15) * 0x11;
832 pd[2*i + 0] = (pd[i] >> 4) * 0x11;
835 pd += s->image_linesize;
839 /* handle p-frames only if a predecessor frame is available */
840 if (s->last_picture->data[0] != NULL) {
841 if ( !(avpkt->flags & AV_PKT_FLAG_KEY)
842 && s->last_picture->width == s->current_picture->width
843 && s->last_picture->height== s->current_picture->height
844 && s->last_picture->format== s->current_picture->format
847 uint8_t *pd = s->current_picture->data[0];
848 uint8_t *pd_last = s->last_picture->data[0];
850 for (j = 0; j < s->height; j++) {
851 for (i = 0; i < s->width * s->bpp; i++) {
854 pd += s->image_linesize;
855 pd_last += s->image_linesize;
860 s->current_picture->metadata = metadata;
862 *picture = *s->current_picture;
865 ret = bytestream2_tell(&s->gb);
867 inflateEnd(&s->zstream);
868 av_free(crow_buf_base);
870 av_freep(&s->last_row);
871 av_freep(&s->tmp_row);
874 av_dict_free(&metadata);
879 static av_cold int png_dec_init(AVCodecContext *avctx)
881 PNGDecContext *s = avctx->priv_data;
883 s->current_picture = &s->picture1;
884 s->last_picture = &s->picture2;
885 avcodec_get_frame_defaults(&s->picture1);
886 avcodec_get_frame_defaults(&s->picture2);
888 ff_pngdsp_init(&s->dsp);
895 static av_cold int png_dec_end(AVCodecContext *avctx)
897 PNGDecContext *s = avctx->priv_data;
899 if (s->picture1.data[0])
900 avctx->release_buffer(avctx, &s->picture1);
901 if (s->picture2.data[0])
902 avctx->release_buffer(avctx, &s->picture2);
907 AVCodec ff_png_decoder = {
909 .type = AVMEDIA_TYPE_VIDEO,
910 .id = AV_CODEC_ID_PNG,
911 .priv_data_size = sizeof(PNGDecContext),
912 .init = png_dec_init,
913 .close = png_dec_end,
914 .decode = decode_frame,
915 .capabilities = CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
916 .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),