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;
60 uint32_t palette[256];
65 int crow_size; /* compressed row size (include filter type) */
66 int row_size; /* decompressed row size */
67 int pass_row_size; /* decompress row size of the current pass */
72 /* Mask to determine which pixels are valid in a pass */
73 static const uint8_t png_pass_mask[NB_PASSES] = {
74 0x01, 0x01, 0x11, 0x11, 0x55, 0x55, 0xff,
77 /* Mask to determine which y pixels can be written in a pass */
78 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
79 0xff, 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
82 /* Mask to determine which pixels to overwrite while displaying */
83 static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
84 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
87 /* NOTE: we try to construct a good looking image at each pass. width
88 is the original image width. We also do pixel format conversion at
90 static void png_put_interlaced_row(uint8_t *dst, int width,
91 int bits_per_pixel, int pass,
92 int color_type, const uint8_t *src)
94 int x, mask, dsp_mask, j, src_x, b, bpp;
98 mask = png_pass_mask[pass];
99 dsp_mask = png_pass_dsp_mask[pass];
101 switch (bits_per_pixel) {
104 for (x = 0; x < width; x++) {
106 if ((dsp_mask << j) & 0x80) {
107 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
108 dst[x >> 3] &= 0xFF7F>>j;
109 dst[x >> 3] |= b << (7 - j);
111 if ((mask << j) & 0x80)
117 for (x = 0; x < width; x++) {
118 int j2 = 2 * (x & 3);
120 if ((dsp_mask << j) & 0x80) {
121 b = (src[src_x >> 2] >> (6 - 2*(src_x & 3))) & 3;
122 dst[x >> 2] &= 0xFF3F>>j2;
123 dst[x >> 2] |= b << (6 - j2);
125 if ((mask << j) & 0x80)
131 for (x = 0; x < width; x++) {
134 if ((dsp_mask << j) & 0x80) {
135 b = (src[src_x >> 1] >> (4 - 4*(src_x & 1))) & 15;
136 dst[x >> 1] &= 0xFF0F>>j2;
137 dst[x >> 1] |= b << (4 - j2);
139 if ((mask << j) & 0x80)
144 bpp = bits_per_pixel >> 3;
147 for (x = 0; x < width; x++) {
149 if ((dsp_mask << j) & 0x80) {
153 if ((mask << j) & 0x80)
160 void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
163 for (i = 0; i < w; i++) {
164 int a, b, c, p, pa, pb, pc;
177 if (pa <= pb && pa <= pc)
187 #define UNROLL1(bpp, op) {\
189 if(bpp >= 2) g = dst[1];\
190 if(bpp >= 3) b = dst[2];\
191 if(bpp >= 4) a = dst[3];\
192 for(; i <= size - bpp; i+=bpp) {\
193 dst[i+0] = r = op(r, src[i+0], last[i+0]);\
194 if(bpp == 1) continue;\
195 dst[i+1] = g = op(g, src[i+1], last[i+1]);\
196 if(bpp == 2) continue;\
197 dst[i+2] = b = op(b, src[i+2], last[i+2]);\
198 if(bpp == 3) continue;\
199 dst[i+3] = a = op(a, src[i+3], last[i+3]);\
203 #define UNROLL_FILTER(op)\
204 if(bpp == 1) UNROLL1(1, op)\
205 else if(bpp == 2) UNROLL1(2, op)\
206 else if(bpp == 3) UNROLL1(3, op)\
207 else if(bpp == 4) UNROLL1(4, op)\
208 for (; i < size; i++) {\
209 dst[i] = op(dst[i-bpp], src[i], last[i]);\
212 /* NOTE: 'dst' can be equal to 'last' */
213 static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
214 uint8_t *src, uint8_t *last, int size, int bpp)
216 int i, p, r, g, b, a;
218 switch (filter_type) {
219 case PNG_FILTER_VALUE_NONE:
220 memcpy(dst, src, size);
222 case PNG_FILTER_VALUE_SUB:
223 for (i = 0; i < bpp; i++) {
228 for (; i < size; i += bpp) {
229 int s = *(int*)(src + i);
230 p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
231 *(int*)(dst + i) = p;
234 #define OP_SUB(x,s,l) x+s
235 UNROLL_FILTER(OP_SUB);
238 case PNG_FILTER_VALUE_UP:
239 dsp->add_bytes_l2(dst, src, last, size);
241 case PNG_FILTER_VALUE_AVG:
242 for (i = 0; i < bpp; i++) {
246 #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
247 UNROLL_FILTER(OP_AVG);
249 case PNG_FILTER_VALUE_PAETH:
250 for (i = 0; i < bpp; i++) {
254 if (bpp > 2 && size > 4) {
255 // would write off the end of the array if we let it process the last pixel with bpp=3
256 int w = bpp == 4 ? size : size - 3;
257 dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
260 ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
265 /* This used to be called "deloco" in FFmpeg
266 * and is actually an inverse reversible colorspace transformation */
267 #define YUV2RGB(NAME, TYPE) \
268 static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
271 for (i = 0; i < size; i += 3 + alpha) { \
278 YUV2RGB(rgb8, uint8_t)
279 YUV2RGB(rgb16, uint16_t)
281 /* process exactly one decompressed row */
282 static void png_handle_row(PNGDecContext *s)
284 uint8_t *ptr, *last_row;
287 if (!s->interlace_type) {
288 ptr = s->image_buf + s->image_linesize * s->y;
290 last_row = s->last_row;
292 last_row = ptr - s->image_linesize;
294 png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
295 last_row, s->row_size, s->bpp);
296 /* loco lags by 1 row so that it doesn't interfere with top prediction */
297 if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
298 if (s->bit_depth == 16) {
299 deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
300 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
302 deloco_rgb8(ptr - s->image_linesize, s->row_size,
303 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
307 if (s->y == s->height) {
308 s->state |= PNG_ALLIMAGE;
309 if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
310 if (s->bit_depth == 16) {
311 deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
312 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
314 deloco_rgb8(ptr, s->row_size,
315 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
322 ptr = s->image_buf + s->image_linesize * s->y;
323 if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
324 /* if we already read one row, it is time to stop to
325 wait for the next one */
328 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
329 s->last_row, s->pass_row_size, s->bpp);
330 FFSWAP(uint8_t*, s->last_row, s->tmp_row);
333 if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
334 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
335 s->color_type, s->last_row);
338 if (s->y == s->height) {
339 memset(s->last_row, 0, s->row_size);
341 if (s->pass == NB_PASSES - 1) {
342 s->state |= PNG_ALLIMAGE;
347 s->pass_row_size = ff_png_pass_row_size(s->pass,
350 s->crow_size = s->pass_row_size + 1;
351 if (s->pass_row_size != 0)
353 /* skip pass if empty row */
362 static int png_decode_idat(PNGDecContext *s, int length)
365 s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
366 s->zstream.next_in = (unsigned char *)s->gb.buffer;
367 bytestream2_skip(&s->gb, length);
369 /* decode one line if possible */
370 while (s->zstream.avail_in > 0) {
371 ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
372 if (ret != Z_OK && ret != Z_STREAM_END) {
373 av_log(s->avctx, AV_LOG_ERROR, "inflate returned %d\n", ret);
376 if (s->zstream.avail_out == 0) {
377 if (!(s->state & PNG_ALLIMAGE)) {
380 s->zstream.avail_out = s->crow_size;
381 s->zstream.next_out = s->crow_buf;
387 static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
388 const uint8_t *data_end)
395 zstream.zalloc = ff_png_zalloc;
396 zstream.zfree = ff_png_zfree;
397 zstream.opaque = NULL;
398 if (inflateInit(&zstream) != Z_OK)
399 return AVERROR_EXTERNAL;
400 zstream.next_in = (unsigned char *)data;
401 zstream.avail_in = data_end - data;
402 av_bprint_init(bp, 0, -1);
404 while (zstream.avail_in > 0) {
405 av_bprint_get_buffer(bp, 1, &buf, &buf_size);
407 ret = AVERROR(ENOMEM);
410 zstream.next_out = buf;
411 zstream.avail_out = buf_size;
412 ret = inflate(&zstream, Z_PARTIAL_FLUSH);
413 if (ret != Z_OK && ret != Z_STREAM_END) {
414 ret = AVERROR_EXTERNAL;
417 bp->len += zstream.next_out - buf;
418 if (ret == Z_STREAM_END)
421 inflateEnd(&zstream);
422 bp->str[bp->len] = 0;
426 inflateEnd(&zstream);
427 av_bprint_finalize(bp, NULL);
431 static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
436 for (i = 0; i < size_in; i++)
437 extra += in[i] >= 0x80;
438 if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
440 q = out = av_malloc(size_in + extra + 1);
443 for (i = 0; i < size_in; i++) {
445 *(q++) = 0xC0 | (in[i] >> 6);
446 *(q++) = 0x80 | (in[i] & 0x3F);
455 static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
459 const uint8_t *data = s->gb.buffer;
460 const uint8_t *data_end = data + length;
461 const uint8_t *keyword = data;
462 const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
463 uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
468 return AVERROR_INVALIDDATA;
469 data = keyword_end + 1;
472 if (data == data_end)
473 return AVERROR_INVALIDDATA;
476 return AVERROR_INVALIDDATA;
477 if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
480 av_bprint_finalize(&bp, (char **)&text);
482 return AVERROR(ENOMEM);
484 text = (uint8_t *)data;
485 text_len = data_end - text;
488 kw_utf8 = iso88591_to_utf8(keyword, keyword_end - keyword);
489 txt_utf8 = iso88591_to_utf8(text, text_len);
492 if (!(kw_utf8 && txt_utf8)) {
495 return AVERROR(ENOMEM);
498 av_dict_set(dict, kw_utf8, txt_utf8,
499 AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
503 static int decode_frame(AVCodecContext *avctx,
504 void *data, int *got_frame,
507 PNGDecContext * const s = avctx->priv_data;
508 const uint8_t *buf = avpkt->data;
509 int buf_size = avpkt->size;
511 AVDictionary *metadata = NULL;
512 uint8_t *crow_buf_base = NULL;
513 uint32_t tag, length;
517 bytestream2_init(&s->gb, buf, buf_size);
519 /* check signature */
520 sig = bytestream2_get_be64(&s->gb);
523 av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
530 s->zstream.zalloc = ff_png_zalloc;
531 s->zstream.zfree = ff_png_zfree;
532 s->zstream.opaque = NULL;
533 ret = inflateInit(&s->zstream);
535 av_log(avctx, AV_LOG_ERROR, "inflateInit returned %d\n", ret);
539 if (bytestream2_get_bytes_left(&s->gb) <= 0) {
540 av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
544 length = bytestream2_get_be32(&s->gb);
545 if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
546 av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
549 tag = bytestream2_get_le32(&s->gb);
550 if (avctx->debug & FF_DEBUG_STARTCODE)
551 av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
554 ((tag >> 16) & 0xff),
555 ((tag >> 24) & 0xff), length);
557 case MKTAG('I', 'H', 'D', 'R'):
560 s->width = bytestream2_get_be32(&s->gb);
561 s->height = bytestream2_get_be32(&s->gb);
562 if (av_image_check_size(s->width, s->height, 0, avctx)) {
563 s->width = s->height = 0;
564 av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
567 s->bit_depth = bytestream2_get_byte(&s->gb);
568 s->color_type = bytestream2_get_byte(&s->gb);
569 s->compression_type = bytestream2_get_byte(&s->gb);
570 s->filter_type = bytestream2_get_byte(&s->gb);
571 s->interlace_type = bytestream2_get_byte(&s->gb);
572 bytestream2_skip(&s->gb, 4); /* crc */
573 s->state |= PNG_IHDR;
574 if (avctx->debug & FF_DEBUG_PICT_INFO)
575 av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
576 "compression_type=%d filter_type=%d interlace_type=%d\n",
577 s->width, s->height, s->bit_depth, s->color_type,
578 s->compression_type, s->filter_type, s->interlace_type);
580 case MKTAG('p', 'H', 'Y', 's'):
581 if (s->state & PNG_IDAT) {
582 av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
585 avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
586 avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
587 if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
588 avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
589 bytestream2_skip(&s->gb, 1); /* unit specifier */
590 bytestream2_skip(&s->gb, 4); /* crc */
592 case MKTAG('I', 'D', 'A', 'T'):
593 if (!(s->state & PNG_IHDR)) {
594 av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
597 if (!(s->state & PNG_IDAT)) {
598 /* init image info */
599 avctx->width = s->width;
600 avctx->height = s->height;
602 s->channels = ff_png_get_nb_channels(s->color_type);
603 s->bits_per_pixel = s->bit_depth * s->channels;
604 s->bpp = (s->bits_per_pixel + 7) >> 3;
605 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
607 if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
608 s->color_type == PNG_COLOR_TYPE_RGB) {
609 avctx->pix_fmt = AV_PIX_FMT_RGB24;
610 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
611 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
612 avctx->pix_fmt = AV_PIX_FMT_RGBA;
613 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
614 s->color_type == PNG_COLOR_TYPE_GRAY) {
615 avctx->pix_fmt = AV_PIX_FMT_GRAY8;
616 } else if (s->bit_depth == 16 &&
617 s->color_type == PNG_COLOR_TYPE_GRAY) {
618 avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
619 } else if (s->bit_depth == 16 &&
620 s->color_type == PNG_COLOR_TYPE_RGB) {
621 avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
622 } else if (s->bit_depth == 16 &&
623 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
624 avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
625 } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
626 s->color_type == PNG_COLOR_TYPE_PALETTE) {
627 avctx->pix_fmt = AV_PIX_FMT_PAL8;
628 } else if (s->bit_depth == 1) {
629 avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
630 } else if (s->bit_depth == 8 &&
631 s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
632 avctx->pix_fmt = AV_PIX_FMT_Y400A;
634 av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
635 "and color type %d\n",
636 s->bit_depth, s->color_type);
640 if (ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF) < 0)
642 p->pict_type = AV_PICTURE_TYPE_I;
644 p->interlaced_frame = !!s->interlace_type;
646 /* compute the compressed row size */
647 if (!s->interlace_type) {
648 s->crow_size = s->row_size + 1;
651 s->pass_row_size = ff_png_pass_row_size(s->pass,
654 s->crow_size = s->pass_row_size + 1;
656 av_dlog(avctx, "row_size=%d crow_size =%d\n",
657 s->row_size, s->crow_size);
658 s->image_buf = p->data[0];
659 s->image_linesize = p->linesize[0];
660 /* copy the palette if needed */
661 if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
662 memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
663 /* empty row is used if differencing to the first row */
664 s->last_row = av_mallocz(s->row_size);
667 if (s->interlace_type ||
668 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
669 s->tmp_row = av_malloc(s->row_size);
674 crow_buf_base = av_malloc(s->row_size + 16);
678 /* we want crow_buf+1 to be 16-byte aligned */
679 s->crow_buf = crow_buf_base + 15;
680 s->zstream.avail_out = s->crow_size;
681 s->zstream.next_out = s->crow_buf;
683 s->state |= PNG_IDAT;
684 if (png_decode_idat(s, length) < 0)
686 bytestream2_skip(&s->gb, 4); /* crc */
688 case MKTAG('P', 'L', 'T', 'E'):
692 if ((length % 3) != 0 || length > 256 * 3)
694 /* read the palette */
696 for (i = 0; i < n; i++) {
697 r = bytestream2_get_byte(&s->gb);
698 g = bytestream2_get_byte(&s->gb);
699 b = bytestream2_get_byte(&s->gb);
700 s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
702 for (; i < 256; i++) {
703 s->palette[i] = (0xFFU << 24);
705 s->state |= PNG_PLTE;
706 bytestream2_skip(&s->gb, 4); /* crc */
709 case MKTAG('t', 'R', 'N', 'S'):
713 /* read the transparency. XXX: Only palette mode supported */
714 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
716 !(s->state & PNG_PLTE))
718 for (i = 0; i < length; i++) {
719 v = bytestream2_get_byte(&s->gb);
720 s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
722 bytestream2_skip(&s->gb, 4); /* crc */
725 case MKTAG('t', 'E', 'X', 't'):
726 if (decode_text_chunk(s, length, 0, &metadata) < 0)
727 av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
728 bytestream2_skip(&s->gb, length + 4);
730 case MKTAG('z', 'T', 'X', 't'):
731 if (decode_text_chunk(s, length, 1, &metadata) < 0)
732 av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
733 bytestream2_skip(&s->gb, length + 4);
735 case MKTAG('I', 'E', 'N', 'D'):
736 if (!(s->state & PNG_ALLIMAGE))
737 av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
738 if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
741 bytestream2_skip(&s->gb, 4); /* crc */
746 bytestream2_skip(&s->gb, length + 4);
752 if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
754 uint8_t *pd = p->data[0];
755 for (j = 0; j < s->height; j++) {
757 for (k = 7; k >= 1; k--)
758 if ((s->width&7) >= k)
759 pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
760 for (i--; i >= 0; i--) {
761 pd[8*i + 7]= pd[i] & 1;
762 pd[8*i + 6]= (pd[i]>>1) & 1;
763 pd[8*i + 5]= (pd[i]>>2) & 1;
764 pd[8*i + 4]= (pd[i]>>3) & 1;
765 pd[8*i + 3]= (pd[i]>>4) & 1;
766 pd[8*i + 2]= (pd[i]>>5) & 1;
767 pd[8*i + 1]= (pd[i]>>6) & 1;
768 pd[8*i + 0]= pd[i]>>7;
770 pd += s->image_linesize;
773 if (s->bits_per_pixel == 2){
775 uint8_t *pd = p->data[0];
776 for (j = 0; j < s->height; j++) {
778 if (s->color_type == PNG_COLOR_TYPE_PALETTE){
779 if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
780 if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
781 if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
782 for (i--; i >= 0; i--) {
783 pd[4*i + 3]= pd[i] & 3;
784 pd[4*i + 2]= (pd[i]>>2) & 3;
785 pd[4*i + 1]= (pd[i]>>4) & 3;
786 pd[4*i + 0]= pd[i]>>6;
789 if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
790 if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
791 if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
792 for (i--; i >= 0; i--) {
793 pd[4*i + 3]= ( pd[i] & 3)*0x55;
794 pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
795 pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
796 pd[4*i + 0]= ( pd[i]>>6 )*0x55;
799 pd += s->image_linesize;
802 if (s->bits_per_pixel == 4){
804 uint8_t *pd = p->data[0];
805 for (j = 0; j < s->height; j++) {
807 if (s->color_type == PNG_COLOR_TYPE_PALETTE){
808 if (s->width&1) pd[2*i+0]= pd[i]>>4;
809 for (i--; i >= 0; i--) {
810 pd[2*i + 1] = pd[i] & 15;
811 pd[2*i + 0] = pd[i] >> 4;
814 if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
815 for (i--; i >= 0; i--) {
816 pd[2*i + 1] = (pd[i] & 15) * 0x11;
817 pd[2*i + 0] = (pd[i] >> 4) * 0x11;
820 pd += s->image_linesize;
824 /* handle p-frames only if a predecessor frame is available */
825 if (s->prev->data[0]) {
826 if ( !(avpkt->flags & AV_PKT_FLAG_KEY)
827 && s->prev->width == p->width
828 && s->prev->height== p->height
829 && s->prev->format== p->format
832 uint8_t *pd = p->data[0];
833 uint8_t *pd_last = s->prev->data[0];
835 for (j = 0; j < s->height; j++) {
836 for (i = 0; i < s->width * s->bpp; i++) {
839 pd += s->image_linesize;
840 pd_last += s->image_linesize;
845 av_frame_set_metadata(p, metadata);
848 av_frame_unref(s->prev);
849 if ((ret = av_frame_ref(s->prev, p)) < 0)
854 ret = bytestream2_tell(&s->gb);
856 inflateEnd(&s->zstream);
857 av_free(crow_buf_base);
859 av_freep(&s->last_row);
860 av_freep(&s->tmp_row);
863 av_dict_free(&metadata);
868 static av_cold int png_dec_init(AVCodecContext *avctx)
870 PNGDecContext *s = avctx->priv_data;
872 s->prev = av_frame_alloc();
874 return AVERROR(ENOMEM);
876 ff_pngdsp_init(&s->dsp);
883 static av_cold int png_dec_end(AVCodecContext *avctx)
885 PNGDecContext *s = avctx->priv_data;
887 av_frame_free(&s->prev);
892 AVCodec ff_png_decoder = {
894 .type = AVMEDIA_TYPE_VIDEO,
895 .id = AV_CODEC_ID_PNG,
896 .priv_data_size = sizeof(PNGDecContext),
897 .init = png_dec_init,
898 .close = png_dec_end,
899 .decode = decode_frame,
900 .capabilities = CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
901 .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),