1 /*
2 * MatchWare Screen Capture Codec decoder
3 *
4 * Copyright (c) 2018 Paul B Mahol
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <string.h>
26
27 #include "avcodec.h"
28 #include "bytestream.h"
29 #include "codec_internal.h"
30 #include "internal.h"
31 #include "zlib_wrapper.h"
32
33 #include <zlib.h>
34
35 typedef struct MWSCContext {
36 unsigned int decomp_size;
37 uint8_t *decomp_buf;
38 AVFrame *prev_frame;
39 FFZStream zstream;
40 } MWSCContext;
41
rle_uncompress(GetByteContext *gb, PutByteContext *pb, GetByteContext *gbp, int width, int height, int stride, int pb_linesize, int gbp_linesize)42 static int rle_uncompress(GetByteContext *gb, PutByteContext *pb, GetByteContext *gbp,
43 int width, int height, int stride, int pb_linesize, int gbp_linesize)
44 {
45 int intra = 1, w = 0;
46
47 bytestream2_seek_p(pb, (height - 1) * pb_linesize, SEEK_SET);
48
49 while (bytestream2_get_bytes_left(gb) > 0) {
50 uint32_t fill = bytestream2_get_le24(gb);
51 unsigned run = bytestream2_get_byte(gb);
52
53 if (run == 0) {
54 run = bytestream2_get_le32(gb);
55 for (int j = 0; j < run; j++, w++) {
56 if (w == width) {
57 w = 0;
58 bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
59 }
60 bytestream2_put_le24(pb, fill);
61 }
62 } else if (run == 255) {
63 int pos = bytestream2_tell_p(pb);
64
65 bytestream2_seek(gbp, pos, SEEK_SET);
66 for (int j = 0; j < fill; j++, w++) {
67 if (w == width) {
68 w = 0;
69 bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
70 bytestream2_seek(gbp, -(gbp_linesize + stride), SEEK_CUR);
71 }
72 bytestream2_put_le24(pb, bytestream2_get_le24(gbp));
73 }
74
75 intra = 0;
76 } else {
77 for (int j = 0; j < run; j++, w++) {
78 if (w == width) {
79 w = 0;
80 bytestream2_seek_p(pb, -(pb_linesize + stride), SEEK_CUR);
81 }
82 bytestream2_put_le24(pb, fill);
83 }
84 }
85 }
86
87 return intra;
88 }
89
decode_frame(AVCodecContext *avctx, AVFrame *frame, int *got_frame, AVPacket *avpkt)90 static int decode_frame(AVCodecContext *avctx, AVFrame *frame,
91 int *got_frame, AVPacket *avpkt)
92 {
93 MWSCContext *s = avctx->priv_data;
94 z_stream *const zstream = &s->zstream.zstream;
95 const uint8_t *buf = avpkt->data;
96 int buf_size = avpkt->size;
97 GetByteContext gb;
98 GetByteContext gbp;
99 PutByteContext pb;
100 int ret;
101
102 ret = inflateReset(zstream);
103 if (ret != Z_OK) {
104 av_log(avctx, AV_LOG_ERROR, "Inflate reset error: %d\n", ret);
105 return AVERROR_EXTERNAL;
106 }
107 zstream->next_in = buf;
108 zstream->avail_in = buf_size;
109 zstream->next_out = s->decomp_buf;
110 zstream->avail_out = s->decomp_size;
111 ret = inflate(zstream, Z_FINISH);
112 if (ret != Z_STREAM_END) {
113 av_log(avctx, AV_LOG_ERROR, "Inflate error: %d\n", ret);
114 return AVERROR_EXTERNAL;
115 }
116
117 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
118 return ret;
119
120 bytestream2_init(&gb, s->decomp_buf, zstream->total_out);
121 bytestream2_init(&gbp, s->prev_frame->data[0], avctx->height * s->prev_frame->linesize[0]);
122 bytestream2_init_writer(&pb, frame->data[0], avctx->height * frame->linesize[0]);
123
124 frame->key_frame = rle_uncompress(&gb, &pb, &gbp, avctx->width, avctx->height, avctx->width * 3,
125 frame->linesize[0], s->prev_frame->linesize[0]);
126
127 frame->pict_type = frame->key_frame ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
128
129 av_frame_unref(s->prev_frame);
130 if ((ret = av_frame_ref(s->prev_frame, frame)) < 0)
131 return ret;
132
133 *got_frame = 1;
134
135 return avpkt->size;
136 }
137
decode_init(AVCodecContext *avctx)138 static av_cold int decode_init(AVCodecContext *avctx)
139 {
140 MWSCContext *s = avctx->priv_data;
141 int64_t size;
142
143 avctx->pix_fmt = AV_PIX_FMT_BGR24;
144
145 size = 32LL * avctx->height * avctx->width;
146 if (size >= INT32_MAX)
147 return AVERROR_INVALIDDATA;
148 s->decomp_size = size;
149 if (!(s->decomp_buf = av_malloc(s->decomp_size)))
150 return AVERROR(ENOMEM);
151
152 s->prev_frame = av_frame_alloc();
153 if (!s->prev_frame)
154 return AVERROR(ENOMEM);
155
156 return ff_inflate_init(&s->zstream, avctx);
157 }
158
decode_close(AVCodecContext *avctx)159 static av_cold int decode_close(AVCodecContext *avctx)
160 {
161 MWSCContext *s = avctx->priv_data;
162
163 av_frame_free(&s->prev_frame);
164 av_freep(&s->decomp_buf);
165 s->decomp_size = 0;
166 ff_inflate_end(&s->zstream);
167
168 return 0;
169 }
170
171 const FFCodec ff_mwsc_decoder = {
172 .p.name = "mwsc",
173 .p.long_name = NULL_IF_CONFIG_SMALL("MatchWare Screen Capture Codec"),
174 .p.type = AVMEDIA_TYPE_VIDEO,
175 .p.id = AV_CODEC_ID_MWSC,
176 .priv_data_size = sizeof(MWSCContext),
177 .init = decode_init,
178 .close = decode_close,
179 FF_CODEC_DECODE_CB(decode_frame),
180 .p.capabilities = AV_CODEC_CAP_DR1,
181 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
182 FF_CODEC_CAP_INIT_CLEANUP,
183 };
184