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msrle.c
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1 /*
2  * Microsoft RLE video decoder
3  * Copyright (C) 2003 the ffmpeg project
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  * MS RLE video decoder by Mike Melanson (melanson@pcisys.net)
25  * For more information about the MS RLE format, visit:
26  * http://www.pcisys.net/~melanson/codecs/
27  *
28  * The MS RLE decoder outputs PAL8 colorspace data.
29  */
30 
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <string.h>
34 
35 #include "avcodec.h"
36 #include "dsputil.h"
37 #include "msrledec.h"
38 
39 typedef struct MsrleContext {
42 
44  const unsigned char *buf;
45  int size;
46 
47  uint32_t pal[256];
48 } MsrleContext;
49 
51 {
52  MsrleContext *s = avctx->priv_data;
53  int i;
54 
55  s->avctx = avctx;
56 
57  switch (avctx->bits_per_coded_sample) {
58  case 1:
60  break;
61  case 4:
62  case 8:
63  avctx->pix_fmt = AV_PIX_FMT_PAL8;
64  break;
65  case 24:
66  avctx->pix_fmt = AV_PIX_FMT_BGR24;
67  break;
68  default:
69  av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
70  return -1;
71  }
72 
74  s->frame.data[0] = NULL;
75 
76  if (avctx->extradata_size >= 4)
77  for (i = 0; i < FFMIN(avctx->extradata_size, AVPALETTE_SIZE)/4; i++)
78  s->pal[i] = 0xFFU<<24 | AV_RL32(avctx->extradata+4*i);
79 
80  return 0;
81 }
82 
84  void *data, int *got_frame,
85  AVPacket *avpkt)
86 {
87  const uint8_t *buf = avpkt->data;
88  int buf_size = avpkt->size;
89  MsrleContext *s = avctx->priv_data;
90  int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
91 
92  s->buf = buf;
93  s->size = buf_size;
94 
95  s->frame.reference = 3;
97  if (avctx->reget_buffer(avctx, &s->frame)) {
98  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
99  return -1;
100  }
101 
102  if (avctx->bits_per_coded_sample > 1 && avctx->bits_per_coded_sample <= 8) {
104 
105  if (pal) {
106  s->frame.palette_has_changed = 1;
107  memcpy(s->pal, pal, AVPALETTE_SIZE);
108  }
109  /* make the palette available */
110  memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
111  }
112 
113  /* FIXME how to correctly detect RLE ??? */
114  if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
115  int linesize = (avctx->width * avctx->bits_per_coded_sample + 7) / 8;
116  uint8_t *ptr = s->frame.data[0];
117  uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
118  int i, j;
119 
120  for (i = 0; i < avctx->height; i++) {
121  if (avctx->bits_per_coded_sample == 4) {
122  for (j = 0; j < avctx->width - 1; j += 2) {
123  ptr[j+0] = buf[j>>1] >> 4;
124  ptr[j+1] = buf[j>>1] & 0xF;
125  }
126  if (avctx->width & 1)
127  ptr[j+0] = buf[j>>1] >> 4;
128  } else {
129  memcpy(ptr, buf, linesize);
130  }
131  buf -= istride;
132  ptr += s->frame.linesize[0];
133  }
134  } else {
135  bytestream2_init(&s->gb, buf, buf_size);
136  ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, &s->gb);
137  }
138 
139  *got_frame = 1;
140  *(AVFrame*)data = s->frame;
141 
142  /* report that the buffer was completely consumed */
143  return buf_size;
144 }
145 
147 {
148  MsrleContext *s = avctx->priv_data;
149 
150  /* release the last frame */
151  if (s->frame.data[0])
152  avctx->release_buffer(avctx, &s->frame);
153 
154  return 0;
155 }
156 
158  .name = "msrle",
159  .type = AVMEDIA_TYPE_VIDEO,
160  .id = AV_CODEC_ID_MSRLE,
161  .priv_data_size = sizeof(MsrleContext),
165  .capabilities = CODEC_CAP_DR1,
166  .long_name = NULL_IF_CONFIG_SMALL("Microsoft RLE"),
167 };