3 * Copyright (c) 2009 Peter Holik
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
30 typedef struct PNGParseContext
34 uint32_t chunk_length;
35 uint32_t remaining_size;
38 static int png_parse(AVCodecParserContext *s, AVCodecContext *avctx,
39 const uint8_t **poutbuf, int *poutbuf_size,
40 const uint8_t *buf, int buf_size)
42 PNGParseContext *ppc = s->priv_data;
43 int next = END_NOT_FOUND;
46 s->pict_type = AV_PICTURE_TYPE_NONE;
52 if (!ppc->pc.frame_start_found) {
53 uint64_t state64 = ppc->pc.state64;
54 for (; i < buf_size; i++) {
55 state64 = (state64 << 8) | buf[i];
56 if (state64 == PNGSIG || state64 == MNGSIG) {
58 ppc->pc.frame_start_found = 1;
62 ppc->pc.state64 = state64;
64 if (ppc->remaining_size) {
65 i = FFMIN(ppc->remaining_size, buf_size);
66 ppc->remaining_size -= i;
67 if (ppc->remaining_size)
69 if (ppc->index == -1) {
75 for (;ppc->pc.frame_start_found && i < buf_size; i++) {
76 ppc->pc.state = (ppc->pc.state<<8) | buf[i];
77 if (ppc->index == 3) {
78 ppc->chunk_length = ppc->pc.state;
79 if (ppc->chunk_length > 0x7fffffff) {
80 ppc->index = ppc->pc.frame_start_found = 0;
83 ppc->chunk_length += 4;
84 } else if (ppc->index == 7) {
85 if (ppc->chunk_length >= buf_size - i)
86 ppc->remaining_size = ppc->chunk_length - buf_size + i + 1;
87 if (ppc->pc.state == MKBETAG('I', 'E', 'N', 'D')) {
88 if (ppc->remaining_size)
91 next = ppc->chunk_length + i + 1;
95 if (ppc->remaining_size)
98 i += ppc->chunk_length;
105 if (ff_combine_frame(&ppc->pc, next, &buf, &buf_size) < 0)
108 ppc->index = ppc->pc.frame_start_found = 0;
111 *poutbuf_size = buf_size;
115 AVCodecParser ff_png_parser = {
116 .codec_ids = { AV_CODEC_ID_PNG },
117 .priv_data_size = sizeof(PNGParseContext),
118 .parser_parse = png_parse,
119 .parser_close = ff_parse_close,