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 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 
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 
43  const unsigned char *buf;
44  int size;
45 
46  uint32_t pal[256];
47 } MsrleContext;
48 
50 {
51  MsrleContext *s = avctx->priv_data;
52 
53  s->avctx = avctx;
54 
55  switch (avctx->bits_per_coded_sample) {
56  case 4:
57  case 8:
58  avctx->pix_fmt = PIX_FMT_PAL8;
59  break;
60  case 24:
61  avctx->pix_fmt = PIX_FMT_BGR24;
62  break;
63  default:
64  av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
65  return -1;
66  }
67 
68  s->frame.data[0] = NULL;
69 
70  return 0;
71 }
72 
74  void *data, int *data_size,
75  AVPacket *avpkt)
76 {
77  const uint8_t *buf = avpkt->data;
78  int buf_size = avpkt->size;
79  MsrleContext *s = avctx->priv_data;
80  int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
81 
82  s->buf = buf;
83  s->size = buf_size;
84 
85  s->frame.reference = 1;
87  if (avctx->reget_buffer(avctx, &s->frame)) {
88  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
89  return -1;
90  }
91 
92  if (avctx->bits_per_coded_sample <= 8) {
93  const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
94 
95  if (pal) {
97  memcpy(s->pal, pal, AVPALETTE_SIZE);
98  }
99 
100  /* make the palette available */
101  memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
102  }
103 
104  /* FIXME how to correctly detect RLE ??? */
105  if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
106  int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
107  uint8_t *ptr = s->frame.data[0];
108  uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
109  int i, j;
110 
111  for (i = 0; i < avctx->height; i++) {
112  if (avctx->bits_per_coded_sample == 4) {
113  for (j = 0; j < avctx->width - 1; j += 2) {
114  ptr[j+0] = buf[j>>1] >> 4;
115  ptr[j+1] = buf[j>>1] & 0xF;
116  }
117  if (avctx->width & 1)
118  ptr[j+0] = buf[j>>1] >> 4;
119  } else {
120  memcpy(ptr, buf, linesize);
121  }
122  buf -= istride;
123  ptr += s->frame.linesize[0];
124  }
125  } else {
126  ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, buf, buf_size);
127  }
128 
129  *data_size = sizeof(AVFrame);
130  *(AVFrame*)data = s->frame;
131 
132  /* report that the buffer was completely consumed */
133  return buf_size;
134 }
135 
137 {
138  MsrleContext *s = avctx->priv_data;
139 
140  /* release the last frame */
141  if (s->frame.data[0])
142  avctx->release_buffer(avctx, &s->frame);
143 
144  return 0;
145 }
146 
148  .name = "msrle",
149  .type = AVMEDIA_TYPE_VIDEO,
150  .id = CODEC_ID_MSRLE,
151  .priv_data_size = sizeof(MsrleContext),
155  .capabilities = CODEC_CAP_DR1,
156  .long_name= NULL_IF_CONFIG_SMALL("Microsoft RLE"),
157 };