blob: 6662979c52cf119811d08d9bd4404fbc962eeb4b
1 | /* |
2 | * RL2 Video Decoder |
3 | * Copyright (C) 2008 Sascha Sommer (saschasommer@freenet.de) |
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 | * RL2 Video Decoder |
25 | * @author Sascha Sommer (saschasommer@freenet.de) |
26 | * @see http://wiki.multimedia.cx/index.php?title=RL2 |
27 | */ |
28 | |
29 | #include <stdio.h> |
30 | #include <stdlib.h> |
31 | #include <string.h> |
32 | |
33 | #include "libavutil/internal.h" |
34 | #include "libavutil/intreadwrite.h" |
35 | #include "libavutil/mem.h" |
36 | #include "avcodec.h" |
37 | #include "internal.h" |
38 | |
39 | |
40 | #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette |
41 | |
42 | typedef struct Rl2Context { |
43 | AVCodecContext *avctx; |
44 | |
45 | uint16_t video_base; ///< initial drawing offset |
46 | uint32_t clr_count; ///< number of used colors (currently unused) |
47 | uint8_t *back_frame; ///< background frame |
48 | uint32_t palette[AVPALETTE_COUNT]; |
49 | } Rl2Context; |
50 | |
51 | /** |
52 | * Run Length Decode a single 320x200 frame |
53 | * @param s rl2 context |
54 | * @param in input buffer |
55 | * @param size input buffer size |
56 | * @param out output buffer |
57 | * @param stride stride of the output buffer |
58 | * @param video_base offset of the rle data inside the frame |
59 | */ |
60 | static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, |
61 | uint8_t *out, int stride, int video_base) |
62 | { |
63 | int base_x = video_base % s->avctx->width; |
64 | int base_y = video_base / s->avctx->width; |
65 | int stride_adj = stride - s->avctx->width; |
66 | int i; |
67 | const uint8_t *back_frame = s->back_frame; |
68 | const uint8_t *in_end = in + size; |
69 | const uint8_t *out_end = out + stride * s->avctx->height; |
70 | uint8_t *line_end; |
71 | |
72 | /** copy start of the background frame */ |
73 | for (i = 0; i <= base_y; i++) { |
74 | if (s->back_frame) |
75 | memcpy(out, back_frame, s->avctx->width); |
76 | out += stride; |
77 | back_frame += s->avctx->width; |
78 | } |
79 | back_frame += base_x - s->avctx->width; |
80 | line_end = out - stride_adj; |
81 | out += base_x - stride; |
82 | |
83 | /** decode the variable part of the frame */ |
84 | while (in < in_end) { |
85 | uint8_t val = *in++; |
86 | int len = 1; |
87 | if (val >= 0x80) { |
88 | if (in >= in_end) |
89 | break; |
90 | len = *in++; |
91 | if (!len) |
92 | break; |
93 | } |
94 | |
95 | if (len >= out_end - out) |
96 | break; |
97 | |
98 | if (s->back_frame) |
99 | val |= 0x80; |
100 | else |
101 | val &= ~0x80; |
102 | |
103 | while (len--) { |
104 | *out++ = (val == 0x80) ? *back_frame : val; |
105 | back_frame++; |
106 | if (out == line_end) { |
107 | out += stride_adj; |
108 | line_end += stride; |
109 | if (len >= out_end - out) |
110 | break; |
111 | } |
112 | } |
113 | } |
114 | |
115 | /** copy the rest from the background frame */ |
116 | if (s->back_frame) { |
117 | while (out < out_end) { |
118 | memcpy(out, back_frame, line_end - out); |
119 | back_frame += line_end - out; |
120 | out = line_end + stride_adj; |
121 | line_end += stride; |
122 | } |
123 | } |
124 | } |
125 | |
126 | |
127 | /** |
128 | * Initialize the decoder |
129 | * @param avctx decoder context |
130 | * @return 0 success, -1 on error |
131 | */ |
132 | static av_cold int rl2_decode_init(AVCodecContext *avctx) |
133 | { |
134 | Rl2Context *s = avctx->priv_data; |
135 | int back_size; |
136 | int i; |
137 | |
138 | s->avctx = avctx; |
139 | avctx->pix_fmt = AV_PIX_FMT_PAL8; |
140 | |
141 | /** parse extra data */ |
142 | if (!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE) { |
143 | av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n"); |
144 | return AVERROR(EINVAL); |
145 | } |
146 | |
147 | /** get frame_offset */ |
148 | s->video_base = AV_RL16(&avctx->extradata[0]); |
149 | s->clr_count = AV_RL32(&avctx->extradata[2]); |
150 | |
151 | if (s->video_base >= avctx->width * avctx->height) { |
152 | av_log(avctx, AV_LOG_ERROR, "invalid video_base\n"); |
153 | return AVERROR_INVALIDDATA; |
154 | } |
155 | |
156 | /** initialize palette */ |
157 | for (i = 0; i < AVPALETTE_COUNT; i++) |
158 | s->palette[i] = 0xFFU << 24 | AV_RB24(&avctx->extradata[6 + i * 3]); |
159 | |
160 | /** decode background frame if present */ |
161 | back_size = avctx->extradata_size - EXTRADATA1_SIZE; |
162 | |
163 | if (back_size > 0) { |
164 | uint8_t *back_frame = av_mallocz(avctx->width*avctx->height); |
165 | if (!back_frame) |
166 | return AVERROR(ENOMEM); |
167 | rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size, |
168 | back_frame, avctx->width, 0); |
169 | s->back_frame = back_frame; |
170 | } |
171 | return 0; |
172 | } |
173 | |
174 | |
175 | static int rl2_decode_frame(AVCodecContext *avctx, |
176 | void *data, int *got_frame, |
177 | AVPacket *avpkt) |
178 | { |
179 | AVFrame *frame = data; |
180 | const uint8_t *buf = avpkt->data; |
181 | int ret, buf_size = avpkt->size; |
182 | Rl2Context *s = avctx->priv_data; |
183 | |
184 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
185 | return ret; |
186 | |
187 | /** run length decode */ |
188 | rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0], |
189 | s->video_base); |
190 | |
191 | /** make the palette available on the way out */ |
192 | memcpy(frame->data[1], s->palette, AVPALETTE_SIZE); |
193 | |
194 | *got_frame = 1; |
195 | |
196 | /** report that the buffer was completely consumed */ |
197 | return buf_size; |
198 | } |
199 | |
200 | |
201 | /** |
202 | * Uninit decoder |
203 | * @param avctx decoder context |
204 | * @return 0 success, -1 on error |
205 | */ |
206 | static av_cold int rl2_decode_end(AVCodecContext *avctx) |
207 | { |
208 | Rl2Context *s = avctx->priv_data; |
209 | |
210 | av_freep(&s->back_frame); |
211 | |
212 | return 0; |
213 | } |
214 | |
215 | |
216 | AVCodec ff_rl2_decoder = { |
217 | .name = "rl2", |
218 | .long_name = NULL_IF_CONFIG_SMALL("RL2 video"), |
219 | .type = AVMEDIA_TYPE_VIDEO, |
220 | .id = AV_CODEC_ID_RL2, |
221 | .priv_data_size = sizeof(Rl2Context), |
222 | .init = rl2_decode_init, |
223 | .close = rl2_decode_end, |
224 | .decode = rl2_decode_frame, |
225 | .capabilities = AV_CODEC_CAP_DR1, |
226 | }; |
227 |