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"
35 typedef struct PNGDecContext {
37 AVCodecContext *avctx;
40 ThreadFrame last_picture;
56 uint32_t palette[256];
59 unsigned int last_row_size;
61 unsigned int tmp_row_size;
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,
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) \
197 for (; i <= size - bpp; i += bpp) { \
198 dst[i + 0] = r = op(r, src[i + 0], last[i + 0]); \
201 dst[i + 1] = g = op(g, src[i + 1], last[i + 1]); \
204 dst[i + 2] = b = op(b, src[i + 2], last[i + 2]); \
207 dst[i + 3] = a = op(a, src[i + 3], last[i + 3]); \
211 #define UNROLL_FILTER(op) \
214 } else if (bpp == 2) { \
216 } else if (bpp == 3) { \
218 } else if (bpp == 4) { \
221 for (; i < size; i++) { \
222 dst[i] = op(dst[i - bpp], src[i], last[i]); \
225 /* NOTE: 'dst' can be equal to 'last' */
226 static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
227 uint8_t *src, uint8_t *last, int size, int bpp)
229 int i, p, r, g, b, a;
231 switch (filter_type) {
232 case PNG_FILTER_VALUE_NONE:
233 memcpy(dst, src, size);
235 case PNG_FILTER_VALUE_SUB:
236 for (i = 0; i < bpp; i++)
240 for (; i < size; i += bpp) {
241 unsigned s = *(int *)(src + i);
242 p = ((s & 0x7f7f7f7f) + (p & 0x7f7f7f7f)) ^ ((s ^ p) & 0x80808080);
243 *(int *)(dst + i) = p;
246 #define OP_SUB(x, s, l) ((x) + (s))
247 UNROLL_FILTER(OP_SUB);
250 case PNG_FILTER_VALUE_UP:
251 dsp->add_bytes_l2(dst, src, last, size);
253 case PNG_FILTER_VALUE_AVG:
254 for (i = 0; i < bpp; i++) {
258 #define OP_AVG(x, s, l) (((((x) + (l)) >> 1) + (s)) & 0xff)
259 UNROLL_FILTER(OP_AVG);
261 case PNG_FILTER_VALUE_PAETH:
262 for (i = 0; i < bpp; i++) {
266 if (bpp > 2 && size > 4) {
267 /* would write off the end of the array if we let it process
268 * the last pixel with bpp=3 */
269 int w = bpp == 4 ? size : size - 3;
270 dsp->add_paeth_prediction(dst + i, src + i, last + i, w - i, bpp);
273 ff_add_png_paeth_prediction(dst + i, src + i, last + i, size - i, bpp);
278 /* This used to be called "deloco" in FFmpeg
279 * and is actually an inverse reversible colorspace transformation */
280 #define YUV2RGB(NAME, TYPE) \
281 static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
284 for (i = 0; i < size; i += 3 + alpha) { \
285 int g = dst [i + 1]; \
291 YUV2RGB(rgb8, uint8_t)
292 YUV2RGB(rgb16, uint16_t)
294 /* process exactly one decompressed row */
295 static void png_handle_row(PNGDecContext *s)
297 uint8_t *ptr, *last_row;
300 if (!s->interlace_type) {
301 ptr = s->image_buf + s->image_linesize * s->y;
303 last_row = s->last_row;
305 last_row = ptr - s->image_linesize;
307 png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
308 last_row, s->row_size, s->bpp);
309 /* loco lags by 1 row so that it doesn't interfere with top prediction */
310 if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
311 if (s->bit_depth == 16) {
312 deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
313 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
315 deloco_rgb8(ptr - s->image_linesize, s->row_size,
316 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
320 if (s->y == s->height) {
321 s->state |= PNG_ALLIMAGE;
322 if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
323 if (s->bit_depth == 16) {
324 deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
325 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
327 deloco_rgb8(ptr, s->row_size,
328 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
335 ptr = s->image_buf + s->image_linesize * s->y;
336 if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
337 /* if we already read one row, it is time to stop to
338 * wait for the next one */
341 png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
342 s->last_row, s->pass_row_size, s->bpp);
343 FFSWAP(uint8_t *, s->last_row, s->tmp_row);
344 FFSWAP(unsigned int, s->last_row_size, s->tmp_row_size);
347 if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
348 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
349 s->color_type, s->last_row);
352 if (s->y == s->height) {
353 memset(s->last_row, 0, s->row_size);
355 if (s->pass == NB_PASSES - 1) {
356 s->state |= PNG_ALLIMAGE;
361 s->pass_row_size = ff_png_pass_row_size(s->pass,
364 s->crow_size = s->pass_row_size + 1;
365 if (s->pass_row_size != 0)
367 /* skip pass if empty row */
376 static int png_decode_idat(PNGDecContext *s, int length)
379 s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
380 s->zstream.next_in = (unsigned char *)s->gb.buffer;
381 bytestream2_skip(&s->gb, length);
383 /* decode one line if possible */
384 while (s->zstream.avail_in > 0) {
385 ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
386 if (ret != Z_OK && ret != Z_STREAM_END) {
387 av_log(s->avctx, AV_LOG_ERROR, "inflate returned error %d\n", ret);
388 return AVERROR_EXTERNAL;
390 if (s->zstream.avail_out == 0) {
391 if (!(s->state & PNG_ALLIMAGE)) {
394 s->zstream.avail_out = s->crow_size;
395 s->zstream.next_out = s->crow_buf;
397 if (ret == Z_STREAM_END && s->zstream.avail_in > 0) {
398 av_log(NULL, AV_LOG_WARNING,
399 "%d undecompressed bytes left in buffer\n", s->zstream.avail_in);
406 static int decode_zbuf(AVBPrint *bp, const uint8_t *data,
407 const uint8_t *data_end)
414 zstream.zalloc = ff_png_zalloc;
415 zstream.zfree = ff_png_zfree;
416 zstream.opaque = NULL;
417 if (inflateInit(&zstream) != Z_OK)
418 return AVERROR_EXTERNAL;
419 zstream.next_in = (unsigned char *)data;
420 zstream.avail_in = data_end - data;
421 av_bprint_init(bp, 0, -1);
423 while (zstream.avail_in > 0) {
424 av_bprint_get_buffer(bp, 1, &buf, &buf_size);
426 ret = AVERROR(ENOMEM);
429 zstream.next_out = buf;
430 zstream.avail_out = buf_size;
431 ret = inflate(&zstream, Z_PARTIAL_FLUSH);
432 if (ret != Z_OK && ret != Z_STREAM_END) {
433 ret = AVERROR_EXTERNAL;
436 bp->len += zstream.next_out - buf;
437 if (ret == Z_STREAM_END)
440 inflateEnd(&zstream);
441 bp->str[bp->len] = 0;
445 inflateEnd(&zstream);
446 av_bprint_finalize(bp, NULL);
450 static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
455 for (i = 0; i < size_in; i++)
456 extra += in[i] >= 0x80;
457 if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
459 q = out = av_malloc(size_in + extra + 1);
462 for (i = 0; i < size_in; i++) {
464 *(q++) = 0xC0 | (in[i] >> 6);
465 *(q++) = 0x80 | (in[i] & 0x3F);
474 static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
478 const uint8_t *data = s->gb.buffer;
479 const uint8_t *data_end = data + length;
480 const uint8_t *keyword = data;
481 const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
482 uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
487 return AVERROR_INVALIDDATA;
488 data = keyword_end + 1;
491 if (data == data_end)
492 return AVERROR_INVALIDDATA;
495 return AVERROR_INVALIDDATA;
496 if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
499 av_bprint_finalize(&bp, (char **)&text);
501 return AVERROR(ENOMEM);
503 text = (uint8_t *)data;
504 text_len = data_end - text;
507 kw_utf8 = iso88591_to_utf8(keyword, keyword_end - keyword);
508 txt_utf8 = iso88591_to_utf8(text, text_len);
511 if (!(kw_utf8 && txt_utf8)) {
514 return AVERROR(ENOMEM);
517 av_dict_set(dict, kw_utf8, txt_utf8,
518 AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
522 static int decode_frame(AVCodecContext *avctx,
523 void *data, int *got_frame,
526 PNGDecContext *const s = avctx->priv_data;
527 const uint8_t *buf = avpkt->data;
528 int buf_size = avpkt->size;
530 AVDictionary *metadata = NULL;
531 uint32_t tag, length;
535 ff_thread_release_buffer(avctx, &s->last_picture);
536 FFSWAP(ThreadFrame, s->picture, s->last_picture);
539 bytestream2_init(&s->gb, buf, buf_size);
541 /* check signature */
542 sig = bytestream2_get_be64(&s->gb);
545 av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
546 return AVERROR_INVALIDDATA;
552 s->zstream.zalloc = ff_png_zalloc;
553 s->zstream.zfree = ff_png_zfree;
554 s->zstream.opaque = NULL;
555 ret = inflateInit(&s->zstream);
557 av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
558 return AVERROR_EXTERNAL;
561 if (bytestream2_get_bytes_left(&s->gb) <= 0) {
562 av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
563 if ( s->state & PNG_ALLIMAGE
564 && avctx->strict_std_compliance <= FF_COMPLIANCE_NORMAL)
569 length = bytestream2_get_be32(&s->gb);
570 if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb)) {
571 av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
574 tag = bytestream2_get_le32(&s->gb);
575 if (avctx->debug & FF_DEBUG_STARTCODE)
576 av_log(avctx, AV_LOG_DEBUG, "png: tag=%c%c%c%c length=%u\n",
579 ((tag >> 16) & 0xff),
580 ((tag >> 24) & 0xff), length);
582 case MKTAG('I', 'H', 'D', 'R'):
585 s->width = bytestream2_get_be32(&s->gb);
586 s->height = bytestream2_get_be32(&s->gb);
587 if (av_image_check_size(s->width, s->height, 0, avctx)) {
588 s->width = s->height = 0;
589 av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
592 s->bit_depth = bytestream2_get_byte(&s->gb);
593 s->color_type = bytestream2_get_byte(&s->gb);
594 s->compression_type = bytestream2_get_byte(&s->gb);
595 s->filter_type = bytestream2_get_byte(&s->gb);
596 s->interlace_type = bytestream2_get_byte(&s->gb);
597 bytestream2_skip(&s->gb, 4); /* crc */
598 s->state |= PNG_IHDR;
599 if (avctx->debug & FF_DEBUG_PICT_INFO)
600 av_log(avctx, AV_LOG_DEBUG, "width=%d height=%d depth=%d color_type=%d "
601 "compression_type=%d filter_type=%d interlace_type=%d\n",
602 s->width, s->height, s->bit_depth, s->color_type,
603 s->compression_type, s->filter_type, s->interlace_type);
605 case MKTAG('p', 'H', 'Y', 's'):
606 if (s->state & PNG_IDAT) {
607 av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
610 avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
611 avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
612 if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
613 avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
614 bytestream2_skip(&s->gb, 1); /* unit specifier */
615 bytestream2_skip(&s->gb, 4); /* crc */
617 case MKTAG('I', 'D', 'A', 'T'):
618 if (!(s->state & PNG_IHDR)) {
619 av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
622 if (!(s->state & PNG_IDAT)) {
623 /* init image info */
624 avctx->width = s->width;
625 avctx->height = s->height;
627 s->channels = ff_png_get_nb_channels(s->color_type);
628 s->bits_per_pixel = s->bit_depth * s->channels;
629 s->bpp = (s->bits_per_pixel + 7) >> 3;
630 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
632 if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
633 s->color_type == PNG_COLOR_TYPE_RGB) {
634 avctx->pix_fmt = AV_PIX_FMT_RGB24;
635 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
636 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
637 avctx->pix_fmt = AV_PIX_FMT_RGBA;
638 } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
639 s->color_type == PNG_COLOR_TYPE_GRAY) {
640 avctx->pix_fmt = AV_PIX_FMT_GRAY8;
641 } else if (s->bit_depth == 16 &&
642 s->color_type == PNG_COLOR_TYPE_GRAY) {
643 avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
644 } else if (s->bit_depth == 16 &&
645 s->color_type == PNG_COLOR_TYPE_RGB) {
646 avctx->pix_fmt = AV_PIX_FMT_RGB48BE;
647 } else if (s->bit_depth == 16 &&
648 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
649 avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
650 } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
651 s->color_type == PNG_COLOR_TYPE_PALETTE) {
652 avctx->pix_fmt = AV_PIX_FMT_PAL8;
653 } else if (s->bit_depth == 1) {
654 avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
655 } else if (s->bit_depth == 8 &&
656 s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
657 avctx->pix_fmt = AV_PIX_FMT_Y400A;
659 av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
660 "and color type %d\n",
661 s->bit_depth, s->color_type);
665 if (ff_thread_get_buffer(avctx, &s->picture, AV_GET_BUFFER_FLAG_REF) < 0)
667 ff_thread_finish_setup(avctx);
669 p->pict_type = AV_PICTURE_TYPE_I;
671 p->interlaced_frame = !!s->interlace_type;
673 /* compute the compressed row size */
674 if (!s->interlace_type) {
675 s->crow_size = s->row_size + 1;
678 s->pass_row_size = ff_png_pass_row_size(s->pass,
681 s->crow_size = s->pass_row_size + 1;
683 av_dlog(avctx, "row_size=%d crow_size =%d\n",
684 s->row_size, s->crow_size);
685 s->image_buf = p->data[0];
686 s->image_linesize = p->linesize[0];
687 /* copy the palette if needed */
688 if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
689 memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
690 /* empty row is used if differencing to the first row */
691 av_fast_padded_mallocz(&s->last_row, &s->last_row_size, s->row_size);
694 if (s->interlace_type ||
695 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
696 av_fast_padded_malloc(&s->tmp_row, &s->tmp_row_size, s->row_size);
701 av_fast_padded_malloc(&s->buffer, &s->buffer_size, s->row_size + 16);
705 /* we want crow_buf+1 to be 16-byte aligned */
706 s->crow_buf = s->buffer + 15;
707 s->zstream.avail_out = s->crow_size;
708 s->zstream.next_out = s->crow_buf;
710 s->state |= PNG_IDAT;
711 if (png_decode_idat(s, length) < 0)
713 bytestream2_skip(&s->gb, 4); /* crc */
715 case MKTAG('P', 'L', 'T', 'E'):
719 if ((length % 3) != 0 || length > 256 * 3)
721 /* read the palette */
723 for (i = 0; i < n; i++) {
724 r = bytestream2_get_byte(&s->gb);
725 g = bytestream2_get_byte(&s->gb);
726 b = bytestream2_get_byte(&s->gb);
727 s->palette[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
730 s->palette[i] = (0xFFU << 24);
731 s->state |= PNG_PLTE;
732 bytestream2_skip(&s->gb, 4); /* crc */
735 case MKTAG('t', 'R', 'N', 'S'):
739 /* read the transparency. XXX: Only palette mode supported */
740 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
742 !(s->state & PNG_PLTE))
744 for (i = 0; i < length; i++) {
745 v = bytestream2_get_byte(&s->gb);
746 s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
748 bytestream2_skip(&s->gb, 4); /* crc */
751 case MKTAG('t', 'E', 'X', 't'):
752 if (decode_text_chunk(s, length, 0, &metadata) < 0)
753 av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
754 bytestream2_skip(&s->gb, length + 4);
756 case MKTAG('z', 'T', 'X', 't'):
757 if (decode_text_chunk(s, length, 1, &metadata) < 0)
758 av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
759 bytestream2_skip(&s->gb, length + 4);
761 case MKTAG('I', 'E', 'N', 'D'):
762 if (!(s->state & PNG_ALLIMAGE))
763 av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
764 if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
767 bytestream2_skip(&s->gb, 4); /* crc */
772 bytestream2_skip(&s->gb, length + 4);
778 if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
780 uint8_t *pd = p->data[0];
781 for (j = 0; j < s->height; j++) {
783 for (k = 7; k >= 1; k--)
784 if ((s->width&7) >= k)
785 pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
786 for (i--; i >= 0; i--) {
787 pd[8*i + 7]= pd[i] & 1;
788 pd[8*i + 6]= (pd[i]>>1) & 1;
789 pd[8*i + 5]= (pd[i]>>2) & 1;
790 pd[8*i + 4]= (pd[i]>>3) & 1;
791 pd[8*i + 3]= (pd[i]>>4) & 1;
792 pd[8*i + 2]= (pd[i]>>5) & 1;
793 pd[8*i + 1]= (pd[i]>>6) & 1;
794 pd[8*i + 0]= pd[i]>>7;
796 pd += s->image_linesize;
799 if (s->bits_per_pixel == 2){
801 uint8_t *pd = p->data[0];
802 for (j = 0; j < s->height; j++) {
804 if (s->color_type == PNG_COLOR_TYPE_PALETTE){
805 if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
806 if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
807 if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
808 for (i--; i >= 0; i--) {
809 pd[4*i + 3]= pd[i] & 3;
810 pd[4*i + 2]= (pd[i]>>2) & 3;
811 pd[4*i + 1]= (pd[i]>>4) & 3;
812 pd[4*i + 0]= pd[i]>>6;
815 if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
816 if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
817 if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
818 for (i--; i >= 0; i--) {
819 pd[4*i + 3]= ( pd[i] & 3)*0x55;
820 pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
821 pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
822 pd[4*i + 0]= ( pd[i]>>6 )*0x55;
825 pd += s->image_linesize;
828 if (s->bits_per_pixel == 4){
830 uint8_t *pd = p->data[0];
831 for (j = 0; j < s->height; j++) {
833 if (s->color_type == PNG_COLOR_TYPE_PALETTE){
834 if (s->width&1) pd[2*i+0]= pd[i]>>4;
835 for (i--; i >= 0; i--) {
836 pd[2*i + 1] = pd[i] & 15;
837 pd[2*i + 0] = pd[i] >> 4;
840 if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
841 for (i--; i >= 0; i--) {
842 pd[2*i + 1] = (pd[i] & 15) * 0x11;
843 pd[2*i + 0] = (pd[i] >> 4) * 0x11;
846 pd += s->image_linesize;
850 /* handle p-frames only if a predecessor frame is available */
851 if (s->last_picture.f->data[0]) {
852 if ( !(avpkt->flags & AV_PKT_FLAG_KEY) && avctx->codec_tag != AV_RL32("MPNG")
853 && s->last_picture.f->width == p->width
854 && s->last_picture.f->height== p->height
855 && s->last_picture.f->format== p->format
858 uint8_t *pd = p->data[0];
859 uint8_t *pd_last = s->last_picture.f->data[0];
861 ff_thread_await_progress(&s->last_picture, INT_MAX, 0);
862 for (j = 0; j < s->height; j++) {
863 for (i = 0; i < s->width * s->bpp; i++)
865 pd += s->image_linesize;
866 pd_last += s->image_linesize;
870 ff_thread_report_progress(&s->picture, INT_MAX, 0);
872 av_frame_set_metadata(p, metadata);
875 if ((ret = av_frame_ref(data, s->picture.f)) < 0)
880 ret = bytestream2_tell(&s->gb);
882 inflateEnd(&s->zstream);
886 av_dict_free(&metadata);
887 ff_thread_report_progress(&s->picture, INT_MAX, 0);
888 ret = AVERROR_INVALIDDATA;
892 static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
894 PNGDecContext *psrc = src->priv_data;
895 PNGDecContext *pdst = dst->priv_data;
900 ff_thread_release_buffer(dst, &pdst->picture);
901 if (psrc->picture.f->data[0])
902 return ff_thread_ref_frame(&pdst->picture, &psrc->picture);
907 static av_cold int png_dec_init(AVCodecContext *avctx)
909 PNGDecContext *s = avctx->priv_data;
912 s->last_picture.f = av_frame_alloc();
913 s->picture.f = av_frame_alloc();
914 if (!s->last_picture.f || !s->picture.f)
915 return AVERROR(ENOMEM);
917 if (!avctx->internal->is_copy) {
918 avctx->internal->allocate_progress = 1;
919 ff_pngdsp_init(&s->dsp);
925 static av_cold int png_dec_end(AVCodecContext *avctx)
927 PNGDecContext *s = avctx->priv_data;
929 ff_thread_release_buffer(avctx, &s->last_picture);
930 av_frame_free(&s->last_picture.f);
931 ff_thread_release_buffer(avctx, &s->picture);
932 av_frame_free(&s->picture.f);
933 av_freep(&s->buffer);
935 av_freep(&s->last_row);
936 s->last_row_size = 0;
937 av_freep(&s->tmp_row);
943 AVCodec ff_png_decoder = {
945 .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
946 .type = AVMEDIA_TYPE_VIDEO,
947 .id = AV_CODEC_ID_PNG,
948 .priv_data_size = sizeof(PNGDecContext),
949 .init = png_dec_init,
950 .close = png_dec_end,
951 .decode = decode_frame,
952 .init_thread_copy = ONLY_IF_THREADS_ENABLED(png_dec_init),
953 .update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
954 .capabilities = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS /*| CODEC_CAP_DRAW_HORIZ_BAND*/,