rl2.c
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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 Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 
33 #include "libavutil/intreadwrite.h"
34 #include "avcodec.h"
35 
36 
37 #define EXTRADATA1_SIZE (6 + 256 * 3)
38 
39 typedef struct Rl2Context {
42 
43  unsigned short video_base;
44  unsigned int clr_count;
45  unsigned char* back_frame;
46  unsigned int palette[AVPALETTE_COUNT];
47 } Rl2Context;
48 
58 static void rl2_rle_decode(Rl2Context *s,const unsigned char* in,int size,
59  unsigned char* out,int stride,int video_base){
60  int base_x = video_base % s->avctx->width;
61  int base_y = video_base / s->avctx->width;
62  int stride_adj = stride - s->avctx->width;
63  int i;
64  const unsigned char* back_frame = s->back_frame;
65  const unsigned char* in_end = in + size;
66  const unsigned char* out_end = out + stride * s->avctx->height;
67  unsigned char* line_end = out + s->avctx->width;
68 
70  for(i=0;i<=base_y;i++){
71  if(s->back_frame)
72  memcpy(out,back_frame,s->avctx->width);
73  out += stride;
74  back_frame += s->avctx->width;
75  }
76  back_frame += base_x - s->avctx->width;
77  line_end = out - stride_adj;
78  out += base_x - stride;
79 
81  while(in < in_end){
82  unsigned char val = *in++;
83  int len = 1;
84  if(val >= 0x80){
85  if(in >= in_end)
86  break;
87  len = *in++;
88  if(!len)
89  break;
90  }
91 
92  if(len >= out_end - out)
93  break;
94 
95  if(s->back_frame)
96  val |= 0x80;
97  else
98  val &= ~0x80;
99 
100  while(len--){
101  *out++ = (val == 0x80)? *back_frame:val;
102  back_frame++;
103  if(out == line_end){
104  out += stride_adj;
105  line_end += stride;
106  if(len >= out_end - out)
107  break;
108  }
109  }
110  }
111 
113  if(s->back_frame){
114  while(out < out_end){
115  memcpy(out, back_frame, line_end - out);
116  back_frame += line_end - out;
117  out = line_end + stride_adj;
118  line_end += stride;
119  }
120  }
121 }
122 
123 
130 {
131  Rl2Context *s = avctx->priv_data;
132  int back_size;
133  int i;
134  s->avctx = avctx;
135  avctx->pix_fmt = PIX_FMT_PAL8;
136 
138  if(!avctx->extradata || avctx->extradata_size < EXTRADATA1_SIZE){
139  av_log(avctx, AV_LOG_ERROR, "invalid extradata size\n");
140  return -1;
141  }
142 
144  s->video_base = AV_RL16(&avctx->extradata[0]);
145  s->clr_count = AV_RL32(&avctx->extradata[2]);
146 
147  if(s->video_base >= avctx->width * avctx->height){
148  av_log(avctx, AV_LOG_ERROR, "invalid video_base\n");
149  return -1;
150  }
151 
153  for(i=0;i<AVPALETTE_COUNT;i++)
154  s->palette[i] = AV_RB24(&avctx->extradata[6 + i * 3]);
155 
157  back_size = avctx->extradata_size - EXTRADATA1_SIZE;
158 
159  if(back_size > 0){
160  unsigned char* back_frame = av_mallocz(avctx->width*avctx->height);
161  if(!back_frame)
162  return -1;
163  rl2_rle_decode(s,avctx->extradata + EXTRADATA1_SIZE,back_size,
164  back_frame,avctx->width,0);
165  s->back_frame = back_frame;
166  }
167  return 0;
168 }
169 
170 
172  void *data, int *data_size,
173  AVPacket *avpkt)
174 {
175  const uint8_t *buf = avpkt->data;
176  int buf_size = avpkt->size;
177  Rl2Context *s = avctx->priv_data;
178 
179  if(s->frame.data[0])
180  avctx->release_buffer(avctx, &s->frame);
181 
183  s->frame.reference= 0;
184  if(avctx->get_buffer(avctx, &s->frame)) {
185  av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
186  return -1;
187  }
188 
190  rl2_rle_decode(s,buf,buf_size,s->frame.data[0],s->frame.linesize[0],s->video_base);
191 
193  memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
194 
195  *data_size = sizeof(AVFrame);
196  *(AVFrame*)data = s->frame;
197 
199  return buf_size;
200 }
201 
202 
209 {
210  Rl2Context *s = avctx->priv_data;
211 
212  if(s->frame.data[0])
213  avctx->release_buffer(avctx, &s->frame);
214 
215  av_free(s->back_frame);
216 
217  return 0;
218 }
219 
220 
222  .name = "rl2",
223  .type = AVMEDIA_TYPE_VIDEO,
224  .id = CODEC_ID_RL2,
225  .priv_data_size = sizeof(Rl2Context),
229  .capabilities = CODEC_CAP_DR1,
230  .long_name = NULL_IF_CONFIG_SMALL("RL2 video"),
231 };
232