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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 | ||
f6fa7814 | 210 | av_freep(&s->back_frame); |
2ba45a60 DM |
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 = CODEC_CAP_DR1, | |
226 | }; |