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