FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/rl2.c
Date: 2026-01-23 19:11:46
Exec Total Coverage
Lines: 81 97 83.5%
Functions: 4 4 100.0%
Branches: 34 48 70.8%
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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 <string.h>
30
31 #include "libavutil/internal.h"
32 #include "libavutil/intreadwrite.h"
33 #include "libavutil/mem.h"
34 #include "avcodec.h"
35 #include "codec_internal.h"
36 #include "decode.h"
37
38
39 #define EXTRADATA1_SIZE (6 + 256 * 3) ///< video base, clr count, palette
40
41 typedef struct Rl2Context {
42 AVCodecContext *avctx;
43
44 uint16_t video_base; ///< initial drawing offset
45 uint32_t clr_count; ///< number of used colors (currently unused)
46 uint8_t *back_frame; ///< background frame
47 uint32_t palette[AVPALETTE_COUNT];
48 } Rl2Context;
49
50 /**
51 * Run Length Decode a single 320x200 frame
52 * @param s rl2 context
53 * @param in input buffer
54 * @param size input buffer size
55 * @param out output buffer
56 * @param stride stride of the output buffer
57 * @param video_base offset of the rle data inside the frame
58 */
59 110 static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size,
60 uint8_t *out, ptrdiff_t stride, int video_base)
61 {
62 110 int base_x = video_base % s->avctx->width;
63 110 int base_y = video_base / s->avctx->width;
64 110 ptrdiff_t stride_adj = stride - s->avctx->width;
65 110 const uint8_t *back_frame = s->back_frame;
66 110 const uint8_t *in_end = in + size;
67 110 const uint8_t *out_end = out + stride * s->avctx->height - stride_adj;
68 uint8_t *line_end;
69
70 /** copy start of the background frame */
71
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 110 if (s->back_frame) {
72
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 3996 for (int i = 0; i <= base_y; i++) {
73 3888 memcpy(out, back_frame, s->avctx->width);
74 3888 out += stride;
75 3888 back_frame += s->avctx->width;
76 }
77 108 back_frame += base_x - s->avctx->width;
78 } else {
79 2 out += stride * (base_y + 1);
80 }
81 110 line_end = out - stride_adj;
82 110 out += base_x - stride;
83
84 /** decode the variable part of the frame */
85
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 1296630 while (in < in_end) {
86 1296630 uint8_t val = *in++;
87 1296630 int len = 1;
88
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 1296630 if (val >= 0x80) {
89
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 130220 if (in >= in_end)
90 ✗ break;
91 130220 len = *in++;
92
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 130220 if (!len)
93 ✗ break;
94 130220 val &= 0x7F;
95 }
96
97
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 1296630 if (back_frame) {
98
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 1244636 if (!val) {
99 do {
100 42308 size_t copy = FFMIN(line_end - out, len);
101 42308 memcpy(out, back_frame, copy);
102 42308 out += copy;
103 42308 back_frame += copy;
104 42308 len -= copy;
105
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 42308 if (out == line_end) {
106
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 17820 if (out == out_end)
107 108 return;
108 17712 out += stride_adj;
109 17712 line_end += stride;
110 }
111
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 42200 } while (len > 0);
112 24488 continue;
113 }
114 1220040 back_frame += len;
115 1220040 val |= 0x80;
116 }
117
118
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119 1665646 *out++ = val;
120
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121
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 400 if (out == out_end)
122 2 return;
123 398 out += stride_adj;
124 398 line_end += stride;
125 }
126 }
127 }
128
129 /** copy the rest from the background frame */
130 ✗ if (s->back_frame) {
131 while (1) {
132 ✗ memcpy(out, back_frame, line_end - out);
133 ✗ if (line_end == out_end)
134 ✗ break;
135 ✗ back_frame += line_end - out;
136 ✗ out = line_end + stride_adj;
137 ✗ line_end += stride;
138 }
139 }
140 }
141
142
143 /**
144 * Initialize the decoder
145 * @param avctx decoder context
146 * @return 0 success, -1 on error
147 */
148 2 static av_cold int rl2_decode_init(AVCodecContext *avctx)
149 {
150 2 Rl2Context *s = avctx->priv_data;
151 int back_size;
152 int i;
153 int ret;
154
155 2 s->avctx = avctx;
156 2 avctx->pix_fmt = AV_PIX_FMT_PAL8;
157
158 2 ret = ff_set_dimensions(avctx, 320, 200);
159
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 2 if (ret < 0)
160 ✗ return ret;
161
162 /** parse extra data */
163
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 2 if (!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE) {
164 ✗ av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n");
165 ✗ return AVERROR(EINVAL);
166 }
167
168 /** get frame_offset */
169 2 s->video_base = AV_RL16(&avctx->extradata[0]);
170 2 s->clr_count = AV_RL32(&avctx->extradata[2]);
171
172
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 2 if (s->video_base >= avctx->width * avctx->height) {
173 ✗ av_log(avctx, AV_LOG_ERROR, "invalid video_base\n");
174 ✗ return AVERROR_INVALIDDATA;
175 }
176
177 /** initialize palette */
178
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 514 for (i = 0; i < AVPALETTE_COUNT; i++)
179 512 s->palette[i] = 0xFFU << 24 | AV_RB24(&avctx->extradata[6 + i * 3]);
180
181 /** decode background frame if present */
182 2 back_size = avctx->extradata_size - EXTRADATA1_SIZE;
183
184
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 2 if (back_size > 0) {
185 /* The 254 are padding to ensure that pointer arithmetic stays within
186 * the buffer. */
187 2 uint8_t *back_frame = av_mallocz(avctx->width * avctx->height + 254);
188
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 2 if (!back_frame)
189 ✗ return AVERROR(ENOMEM);
190 2 rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size,
191 2 back_frame, avctx->width, 0);
192 2 s->back_frame = back_frame;
193 }
194 2 return 0;
195 }
196
197
198 108 static int rl2_decode_frame(AVCodecContext *avctx, AVFrame *frame,
199 int *got_frame, AVPacket *avpkt)
200 {
201 108 const uint8_t *buf = avpkt->data;
202 108 int ret, buf_size = avpkt->size;
203 108 Rl2Context *s = avctx->priv_data;
204
205
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 108 if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
206 ✗ return ret;
207
208 /** run length decode */
209 108 rl2_rle_decode(s, buf, buf_size, frame->data[0], frame->linesize[0],
210 108 s->video_base);
211
212 /** make the palette available on the way out */
213 108 memcpy(frame->data[1], s->palette, AVPALETTE_SIZE);
214
215 108 *got_frame = 1;
216
217 /** report that the buffer was completely consumed */
218 108 return buf_size;
219 }
220
221
222 /**
223 * Uninit decoder
224 * @param avctx decoder context
225 * @return 0 success, -1 on error
226 */
227 2 static av_cold int rl2_decode_end(AVCodecContext *avctx)
228 {
229 2 Rl2Context *s = avctx->priv_data;
230
231 2 av_freep(&s->back_frame);
232
233 2 return 0;
234 }
235
236
237 const FFCodec ff_rl2_decoder = {
238 .p.name = "rl2",
239 CODEC_LONG_NAME("RL2 video"),
240 .p.type = AVMEDIA_TYPE_VIDEO,
241 .p.id = AV_CODEC_ID_RL2,
242 .priv_data_size = sizeof(Rl2Context),
243 .init = rl2_decode_init,
244 .close = rl2_decode_end,
245 FF_CODEC_DECODE_CB(rl2_decode_frame),
246 .p.capabilities = AV_CODEC_CAP_DR1,
247 };
248