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 - bpp; 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)\
209 for (; i < size; i++) {\
210 dst[i] = op(dst[i-bpp], src[i], last[i]);\
213 /* NOTE: 'dst' can be equal to 'last' */
214 static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
215 uint8_t *src, uint8_t *last, int size, int bpp)
217 int i, p, r, g, b, a;
219 switch (filter_type) {
220 case PNG_FILTER_VALUE_NONE:
221 memcpy(dst, src, size);
223 case PNG_FILTER_VALUE_SUB:
224 for (i = 0; i < bpp; i++) {
229 for (; i < size; i += bpp) {
230 int s = *(int*)(src + i);
231 p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
232 *(int*)(dst + i) = p;
235 #define OP_SUB(x,s,l) x+s
236 UNROLL_FILTER(OP_SUB);
239 case PNG_FILTER_VALUE_UP:
240 dsp->add_bytes_l2(dst, src, last, size);
242 case PNG_FILTER_VALUE_AVG:
243 for (i = 0; i < bpp; i++) {
247 #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
248 UNROLL_FILTER(OP_AVG);
250 case PNG_FILTER_VALUE_PAETH:
251 for (i = 0; i < bpp; i++) {
255 if (bpp > 2 && size > 4) {
256 // would write off the end of the array if we let it process the last pixel with bpp=3
257 int w = bpp == 4 ? size : size - 3;
258 dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
261 ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
266 /* This used to be called "deloco" in FFmpeg
267 * and is actually an inverse reversible colorspace transformation */
268 #define YUV2RGB(NAME, TYPE) \
269 static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
272 for (i = 0; i < size; i += 3 + alpha) { \
279 YUV2RGB(rgb8, uint8_t)
280 YUV2RGB(rgb16, uint16_t)
282 /* process exactly one decompressed row */
283 static void png_handle_row(PNGDecContext *s)
285 uint8_t *ptr, *last_row;
288 if (!s->interlace_type) {
289 ptr = s->image_buf + s->image_linesize * s->y;
291 last_row = s->last_row;
293 last_row = ptr - s->image_linesize;
295 png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
296 last_row, s->row_size, s->bpp);
297 /* loco lags by 1 row so that it doesn't interfere with top prediction */
298 if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
299 if (s->bit_depth == 16) {
300 deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
301 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
303 deloco_rgb8(ptr - s->image_linesize, s->row_size,
304 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
308 if (s->y == s->height) {
309 s->state |= PNG_ALLIMAGE;
310 if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
311 if (s->bit_depth == 16) {
312 deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
313 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
315 deloco_rgb8(ptr, s->row_size,
316 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
323 ptr = s->image_buf + s->image_linesize * s->y;
324 if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
325 /* if we already read one row, it is time to stop to
326 wait for the next one */
329 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
330 s->last_row, s->pass_row_size, s->bpp);
331 FFSWAP(uint8_t*, s->last_row, s->tmp_row);
334 if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
335 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
336 s->color_type, s->last_row);
339 if (s->y == s->height) {
340 memset(s->last_row, 0, s->row_size);
342 if (s->pass == NB_PASSES - 1) {
343 s->state |= PNG_ALLIMAGE;
348 s->pass_row_size = ff_png_pass_row_size(s->pass,
351 s->crow_size = s->pass_row_size + 1;
352 if (s->pass_row_size != 0)
354 /* skip pass if empty row */
363 static int png_decode_idat(PNGDecContext *s, int length)
366 s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
367 s->zstream.next_in = (unsigned char *)s->gb.buffer;
368 bytestream2_skip(&s->gb, length);
370 /* decode one line if possible */
371 while (s->zstream.avail_in > 0) {
372 ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
373 if (ret != Z_OK && ret != Z_STREAM_END) {
374 av_log(s->avctx, AV_LOG_ERROR, "inflate returned %d\n", ret);
377 if (s->zstream.avail_out == 0) {
378 if (!(s->state & PNG_ALLIMAGE)) {
381 s->zstream.avail_out = s->crow_size;
382 s->zstream.next_out = s->crow_buf;
388 static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
389 const uint8_t *data_end)
396 zstream.zalloc = ff_png_zalloc;
397 zstream.zfree = ff_png_zfree;
398 zstream.opaque = NULL;
399 if (inflateInit(&zstream) != Z_OK)
400 return AVERROR_EXTERNAL;
401 zstream.next_in = (unsigned char *)data;
402 zstream.avail_in = data_end - data;
403 av_bprint_init(bp, 0, -1);
405 while (zstream.avail_in > 0) {
406 av_bprint_get_buffer(bp, 1, &buf, &buf_size);
408 ret = AVERROR(ENOMEM);
411 zstream.next_out = buf;
412 zstream.avail_out = buf_size;
413 ret = inflate(&zstream, Z_PARTIAL_FLUSH);
414 if (ret != Z_OK && ret != Z_STREAM_END) {
415 ret = AVERROR_EXTERNAL;
418 bp->len += zstream.next_out - buf;
419 if (ret == Z_STREAM_END)
422 inflateEnd(&zstream);
423 bp->str[bp->len] = 0;
427 inflateEnd(&zstream);
428 av_bprint_finalize(bp, NULL);
432 static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
437 for (i = 0; i < size_in; i++)
438 extra += in[i] >= 0x80;
439 if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
441 q = out = av_malloc(size_in + extra + 1);
444 for (i = 0; i < size_in; i++) {
446 *(q++) = 0xC0 | (in[i] >> 6);
447 *(q++) = 0x80 | (in[i] & 0x3F);
456 static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
460 const uint8_t *data = s->gb.buffer;
461 const uint8_t *data_end = data + length;
462 const uint8_t *keyword = data;
463 const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
464 uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
469 return AVERROR_INVALIDDATA;
470 data = keyword_end + 1;
473 if (data == data_end)
474 return AVERROR_INVALIDDATA;
477 return AVERROR_INVALIDDATA;
478 if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
481 av_bprint_finalize(&bp, (char **)&text);
483 return AVERROR(ENOMEM);
485 text = (uint8_t *)data;
486 text_len = data_end - text;
489 kw_utf8 = iso88591_to_utf8(keyword, keyword_end - keyword);
490 txt_utf8 = iso88591_to_utf8(text, text_len);
493 if (!(kw_utf8 && txt_utf8)) {
496 return AVERROR(ENOMEM);
499 av_dict_set(dict, kw_utf8, txt_utf8,
500 AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
504 static int decode_frame(AVCodecContext *avctx,
505 void *data, int *got_frame,
508 PNGDecContext * const s = avctx->priv_data;
509 const uint8_t *buf = avpkt->data;
510 int buf_size = avpkt->size;
511 AVFrame *picture = data;
512 AVDictionary *metadata = NULL;
513 uint8_t *crow_buf_base = NULL;
515 uint32_t tag, length;
519 FFSWAP(AVFrame *, s->current_picture, s->last_picture);
520 avctx->coded_frame = s->current_picture;
521 p = s->current_picture;
523 bytestream2_init(&s->gb, buf, buf_size);
525 /* check signature */
526 sig = bytestream2_get_be64(&s->gb);
529 av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
536 s->zstream.zalloc = ff_png_zalloc;
537 s->zstream.zfree = ff_png_zfree;
538 s->zstream.opaque = NULL;
539 ret = inflateInit(&s->zstream);
541 av_log(avctx, AV_LOG_ERROR, "inflateInit returned %d\n", ret);
545 if (bytestream2_get_bytes_left(&s->gb) <= 0) {
546 av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
550 length = bytestream2_get_be32(&s->gb);
551 if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
552 av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
555 tag = bytestream2_get_le32(&s->gb);
556 if (avctx->debug & FF_DEBUG_STARTCODE)
557 av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
560 ((tag >> 16) & 0xff),
561 ((tag >> 24) & 0xff), length);
563 case MKTAG('I', 'H', 'D', 'R'):
566 s->width = bytestream2_get_be32(&s->gb);
567 s->height = bytestream2_get_be32(&s->gb);
568 if (av_image_check_size(s->width, s->height, 0, avctx)) {
569 s->width = s->height = 0;
570 av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
573 s->bit_depth = bytestream2_get_byte(&s->gb);
574 s->color_type = bytestream2_get_byte(&s->gb);
575 s->compression_type = bytestream2_get_byte(&s->gb);
576 s->filter_type = bytestream2_get_byte(&s->gb);
577 s->interlace_type = bytestream2_get_byte(&s->gb);
578 bytestream2_skip(&s->gb, 4); /* crc */
579 s->state |= PNG_IHDR;
580 if (avctx->debug & FF_DEBUG_PICT_INFO)
581 av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
582 "compression_type=%d filter_type=%d interlace_type=%d\n",
583 s->width, s->height, s->bit_depth, s->color_type,
584 s->compression_type, s->filter_type, s->interlace_type);
586 case MKTAG('p', 'H', 'Y', 's'):
587 if (s->state & PNG_IDAT) {
588 av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
591 avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
592 avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
593 if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
594 avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
595 bytestream2_skip(&s->gb, 1); /* unit specifier */
596 bytestream2_skip(&s->gb, 4); /* crc */
598 case MKTAG('I', 'D', 'A', 'T'):
599 if (!(s->state & PNG_IHDR)) {
600 av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
603 if (!(s->state & PNG_IDAT)) {
604 /* init image info */
605 avctx->width = s->width;
606 avctx->height = s->height;
608 s->channels = ff_png_get_nb_channels(s->color_type);
609 s->bits_per_pixel = s->bit_depth * s->channels;
610 s->bpp = (s->bits_per_pixel + 7) >> 3;
611 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
613 if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
614 s->color_type == PNG_COLOR_TYPE_RGB) {
615 avctx->pix_fmt = AV_PIX_FMT_RGB24;
616 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
617 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
618 avctx->pix_fmt = AV_PIX_FMT_RGBA;
619 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
620 s->color_type == PNG_COLOR_TYPE_GRAY) {
621 avctx->pix_fmt = AV_PIX_FMT_GRAY8;
622 } else if (s->bit_depth == 16 &&
623 s->color_type == PNG_COLOR_TYPE_GRAY) {
624 avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
625 } else if (s->bit_depth == 16 &&
626 s->color_type == PNG_COLOR_TYPE_RGB) {
627 avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
628 } else if (s->bit_depth == 16 &&
629 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
630 avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
631 } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
632 s->color_type == PNG_COLOR_TYPE_PALETTE) {
633 avctx->pix_fmt = AV_PIX_FMT_PAL8;
634 } else if (s->bit_depth == 1) {
635 avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
636 } else if (s->bit_depth == 8 &&
637 s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
638 avctx->pix_fmt = AV_PIX_FMT_Y400A;
640 av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
641 "and color type %d\n",
642 s->bit_depth, s->color_type);
646 avctx->release_buffer(avctx, p);
649 if (ff_get_buffer(avctx, p) < 0) {
650 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
653 p->pict_type = AV_PICTURE_TYPE_I;
655 p->interlaced_frame = !!s->interlace_type;
657 /* compute the compressed row size */
658 if (!s->interlace_type) {
659 s->crow_size = s->row_size + 1;
662 s->pass_row_size = ff_png_pass_row_size(s->pass,
665 s->crow_size = s->pass_row_size + 1;
667 av_dlog(avctx, "row_size=%d crow_size =%d\n",
668 s->row_size, s->crow_size);
669 s->image_buf = p->data[0];
670 s->image_linesize = p->linesize[0];
671 /* copy the palette if needed */
672 if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
673 memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
674 /* empty row is used if differencing to the first row */
675 s->last_row = av_mallocz(s->row_size);
678 if (s->interlace_type ||
679 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
680 s->tmp_row = av_malloc(s->row_size);
685 crow_buf_base = av_malloc(s->row_size + 16);
689 /* we want crow_buf+1 to be 16-byte aligned */
690 s->crow_buf = crow_buf_base + 15;
691 s->zstream.avail_out = s->crow_size;
692 s->zstream.next_out = s->crow_buf;
694 s->state |= PNG_IDAT;
695 if (png_decode_idat(s, length) < 0)
697 bytestream2_skip(&s->gb, 4); /* crc */
699 case MKTAG('P', 'L', 'T', 'E'):
703 if ((length % 3) != 0 || length > 256 * 3)
705 /* read the palette */
707 for (i = 0; i < n; i++) {
708 r = bytestream2_get_byte(&s->gb);
709 g = bytestream2_get_byte(&s->gb);
710 b = bytestream2_get_byte(&s->gb);
711 s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
713 for (; i < 256; i++) {
714 s->palette[i] = (0xFFU << 24);
716 s->state |= PNG_PLTE;
717 bytestream2_skip(&s->gb, 4); /* crc */
720 case MKTAG('t', 'R', 'N', 'S'):
724 /* read the transparency. XXX: Only palette mode supported */
725 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
727 !(s->state & PNG_PLTE))
729 for (i = 0; i < length; i++) {
730 v = bytestream2_get_byte(&s->gb);
731 s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
733 bytestream2_skip(&s->gb, 4); /* crc */
736 case MKTAG('t', 'E', 'X', 't'):
737 if (decode_text_chunk(s, length, 0, &metadata) < 0)
738 av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
739 bytestream2_skip(&s->gb, length + 4);
741 case MKTAG('z', 'T', 'X', 't'):
742 if (decode_text_chunk(s, length, 1, &metadata) < 0)
743 av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
744 bytestream2_skip(&s->gb, length + 4);
746 case MKTAG('I', 'E', 'N', 'D'):
747 if (!(s->state & PNG_ALLIMAGE))
748 av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
749 if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
752 bytestream2_skip(&s->gb, 4); /* crc */
757 bytestream2_skip(&s->gb, length + 4);
763 if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
765 uint8_t *pd = s->current_picture->data[0];
766 for (j = 0; j < s->height; j++) {
768 for (k = 7; k >= 1; k--)
769 if ((s->width&7) >= k)
770 pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
771 for (i--; i >= 0; i--) {
772 pd[8*i + 7]= pd[i] & 1;
773 pd[8*i + 6]= (pd[i]>>1) & 1;
774 pd[8*i + 5]= (pd[i]>>2) & 1;
775 pd[8*i + 4]= (pd[i]>>3) & 1;
776 pd[8*i + 3]= (pd[i]>>4) & 1;
777 pd[8*i + 2]= (pd[i]>>5) & 1;
778 pd[8*i + 1]= (pd[i]>>6) & 1;
779 pd[8*i + 0]= pd[i]>>7;
781 pd += s->image_linesize;
784 if (s->bits_per_pixel == 2){
786 uint8_t *pd = s->current_picture->data[0];
787 for (j = 0; j < s->height; j++) {
789 if (s->color_type == PNG_COLOR_TYPE_PALETTE){
790 if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
791 if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
792 if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
793 for (i--; i >= 0; i--) {
794 pd[4*i + 3]= pd[i] & 3;
795 pd[4*i + 2]= (pd[i]>>2) & 3;
796 pd[4*i + 1]= (pd[i]>>4) & 3;
797 pd[4*i + 0]= pd[i]>>6;
800 if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
801 if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
802 if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
803 for (i--; i >= 0; i--) {
804 pd[4*i + 3]= ( pd[i] & 3)*0x55;
805 pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
806 pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
807 pd[4*i + 0]= ( pd[i]>>6 )*0x55;
810 pd += s->image_linesize;
813 if (s->bits_per_pixel == 4){
815 uint8_t *pd = s->current_picture->data[0];
816 for (j = 0; j < s->height; j++) {
818 if (s->color_type == PNG_COLOR_TYPE_PALETTE){
819 if (s->width&1) pd[2*i+0]= pd[i]>>4;
820 for (i--; i >= 0; i--) {
821 pd[2*i + 1] = pd[i] & 15;
822 pd[2*i + 0] = pd[i] >> 4;
825 if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
826 for (i--; i >= 0; i--) {
827 pd[2*i + 1] = (pd[i] & 15) * 0x11;
828 pd[2*i + 0] = (pd[i] >> 4) * 0x11;
831 pd += s->image_linesize;
835 /* handle p-frames only if a predecessor frame is available */
836 if (s->last_picture->data[0] != NULL) {
837 if ( !(avpkt->flags & AV_PKT_FLAG_KEY)
838 && s->last_picture->width == s->current_picture->width
839 && s->last_picture->height== s->current_picture->height
840 && s->last_picture->format== s->current_picture->format
843 uint8_t *pd = s->current_picture->data[0];
844 uint8_t *pd_last = s->last_picture->data[0];
846 for (j = 0; j < s->height; j++) {
847 for (i = 0; i < s->width * s->bpp; i++) {
850 pd += s->image_linesize;
851 pd_last += s->image_linesize;
856 s->current_picture->metadata = metadata;
858 *picture = *s->current_picture;
861 ret = bytestream2_tell(&s->gb);
863 inflateEnd(&s->zstream);
864 av_free(crow_buf_base);
866 av_freep(&s->last_row);
867 av_freep(&s->tmp_row);
870 av_dict_free(&metadata);
875 static av_cold int png_dec_init(AVCodecContext *avctx)
877 PNGDecContext *s = avctx->priv_data;
879 s->current_picture = &s->picture1;
880 s->last_picture = &s->picture2;
881 avcodec_get_frame_defaults(&s->picture1);
882 avcodec_get_frame_defaults(&s->picture2);
884 ff_pngdsp_init(&s->dsp);
891 static av_cold int png_dec_end(AVCodecContext *avctx)
893 PNGDecContext *s = avctx->priv_data;
895 if (s->picture1.data[0])
896 avctx->release_buffer(avctx, &s->picture1);
897 if (s->picture2.data[0])
898 avctx->release_buffer(avctx, &s->picture2);
903 AVCodec ff_png_decoder = {
905 .type = AVMEDIA_TYPE_VIDEO,
906 .id = AV_CODEC_ID_PNG,
907 .priv_data_size = sizeof(PNGDecContext),
908 .init = png_dec_init,
909 .close = png_dec_end,
910 .decode = decode_frame,
911 .capabilities = CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
912 .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),