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 
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 
54  s->avctx = avctx;
55 
56  switch (avctx->bits_per_coded_sample) {
57  case 4:
58  case 8:
59  avctx->pix_fmt = PIX_FMT_PAL8;
60  break;
61  case 24:
62  avctx->pix_fmt = PIX_FMT_BGR24;
63  break;
64  default:
65  av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
66  return -1;
67  }
68 
69  s->frame.data[0] = NULL;
70 
71  return 0;
72 }
73 
75  void *data, int *data_size,
76  AVPacket *avpkt)
77 {
78  const uint8_t *buf = avpkt->data;
79  int buf_size = avpkt->size;
80  MsrleContext *s = avctx->priv_data;
81  int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
82 
83  s->buf = buf;
84  s->size = buf_size;
85 
86  s->frame.reference = 1;
88  if (avctx->reget_buffer(avctx, &s->frame)) {
89  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
90  return -1;
91  }
92 
93  if (avctx->bits_per_coded_sample <= 8) {
94  const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
95 
96  if (pal) {
98  memcpy(s->pal, pal, AVPALETTE_SIZE);
99  }
100 
101  /* make the palette available */
102  memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);
103  }
104 
105  /* FIXME how to correctly detect RLE ??? */
106  if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
107  int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
108  uint8_t *ptr = s->frame.data[0];
109  uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
110  int i, j;
111 
112  for (i = 0; i < avctx->height; i++) {
113  if (avctx->bits_per_coded_sample == 4) {
114  for (j = 0; j < avctx->width - 1; j += 2) {
115  ptr[j+0] = buf[j>>1] >> 4;
116  ptr[j+1] = buf[j>>1] & 0xF;
117  }
118  if (avctx->width & 1)
119  ptr[j+0] = buf[j>>1] >> 4;
120  } else {
121  memcpy(ptr, buf, linesize);
122  }
123  buf -= istride;
124  ptr += s->frame.linesize[0];
125  }
126  } else {
127  bytestream2_init(&s->gb, buf, buf_size);
128  ff_msrle_decode(avctx, (AVPicture*)&s->frame, avctx->bits_per_coded_sample, &s->gb);
129  }
130 
131  *data_size = sizeof(AVFrame);
132  *(AVFrame*)data = s->frame;
133 
134  /* report that the buffer was completely consumed */
135  return buf_size;
136 }
137 
139 {
140  MsrleContext *s = avctx->priv_data;
141 
142  /* release the last frame */
143  if (s->frame.data[0])
144  avctx->release_buffer(avctx, &s->frame);
145 
146  return 0;
147 }
148 
150  .name = "msrle",
151  .type = AVMEDIA_TYPE_VIDEO,
152  .id = CODEC_ID_MSRLE,
153  .priv_data_size = sizeof(MsrleContext),
157  .capabilities = CODEC_CAP_DR1,
158  .long_name= NULL_IF_CONFIG_SMALL("Microsoft RLE"),
159 };