1 /*
2 * Microsoft Paint (MSP) version 2 decoder
3 * Copyright (c) 2020 Peter Ross (pross@xvid.org)
4 *
5 * This file is part of FFmpeg.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 /**
23 * @file
24 * Microsoft Paint (MSP) version 2 decoder
25 */
26
27 #include "avcodec.h"
28 #include "bytestream.h"
29 #include "internal.h"
30
msp2_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)31 static int msp2_decode_frame(AVCodecContext *avctx,
32 void *data, int *got_frame,
33 AVPacket *avpkt)
34 {
35 const uint8_t *buf = avpkt->data;
36 int buf_size = avpkt->size;
37 AVFrame *p = data;
38 int ret;
39 unsigned int x, y, width = (avctx->width + 7) / 8;
40 GetByteContext idx, gb;
41
42 if (buf_size <= 2 * avctx->height)
43 return AVERROR_INVALIDDATA;
44
45 avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
46
47 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
48 return ret;
49
50 p->pict_type = AV_PICTURE_TYPE_I;
51 p->key_frame = 1;
52
53 bytestream2_init(&idx, buf, 2 * avctx->height);
54 buf += 2 * avctx->height;
55 buf_size -= 2 * avctx->height;
56
57 for (y = 0; y < avctx->height; y++) {
58 unsigned int pkt_size = bytestream2_get_le16(&idx);
59 if (!pkt_size) {
60 memset(p->data[0] + y * p->linesize[0], 0xFF, width);
61 continue;
62 }
63
64 if (pkt_size > buf_size) {
65 av_log(avctx, AV_LOG_WARNING, "image probably corrupt\n");
66 pkt_size = buf_size;
67 }
68
69 bytestream2_init(&gb, buf, pkt_size);
70 x = 0;
71 while (bytestream2_get_bytes_left(&gb) && x < width) {
72 int size = bytestream2_get_byte(&gb);
73 if (size) {
74 size = FFMIN(size, bytestream2_get_bytes_left(&gb));
75 memcpy(p->data[0] + y * p->linesize[0] + x, gb.buffer, FFMIN(size, width - x));
76 bytestream2_skip(&gb, size);
77 } else {
78 int value;
79 size = bytestream2_get_byte(&gb);
80 if (!size)
81 avpriv_request_sample(avctx, "escape value");
82 value = bytestream2_get_byte(&gb);
83 memset(p->data[0] + y * p->linesize[0] + x, value, FFMIN(size, width - x));
84 }
85 x += size;
86 }
87
88 buf += pkt_size;
89 buf_size -= pkt_size;
90 }
91
92 *got_frame = 1;
93 return buf_size;
94 }
95
96 AVCodec ff_msp2_decoder = {
97 .name = "msp2",
98 .long_name = NULL_IF_CONFIG_SMALL("Microsoft Paint (MSP) version 2"),
99 .type = AVMEDIA_TYPE_VIDEO,
100 .id = AV_CODEC_ID_MSP2,
101 .decode = msp2_decode_frame,
102 .capabilities = AV_CODEC_CAP_DR1,
103 };
104