Libav
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 "internal.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 = AV_PIX_FMT_PAL8;
60  break;
61  case 24:
62  avctx->pix_fmt = AV_PIX_FMT_BGR24;
63  break;
64  default:
65  av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
66  return AVERROR_INVALIDDATA;
67  }
68 
69  s->frame = av_frame_alloc();
70  if (!s->frame)
71  return AVERROR(ENOMEM);
72 
73  return 0;
74 }
75 
77  void *data, int *got_frame,
78  AVPacket *avpkt)
79 {
80  const uint8_t *buf = avpkt->data;
81  int buf_size = avpkt->size;
82  MsrleContext *s = avctx->priv_data;
83  int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
84  int ret;
85 
86  s->buf = buf;
87  s->size = buf_size;
88 
89  if ((ret = ff_reget_buffer(avctx, s->frame)) < 0) {
90  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
91  return ret;
92  }
93 
94  if (avctx->bits_per_coded_sample <= 8) {
96 
97  if (pal) {
98  s->frame->palette_has_changed = 1;
99  memcpy(s->pal, pal, AVPALETTE_SIZE);
100  }
101 
102  /* make the palette available */
103  memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
104  }
105 
106  /* FIXME how to correctly detect RLE ??? */
107  if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
108  int linesize = avctx->width * avctx->bits_per_coded_sample / 8;
109  uint8_t *ptr = s->frame->data[0];
110  uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
111  int i, j;
112 
113  for (i = 0; i < avctx->height; i++) {
114  if (avctx->bits_per_coded_sample == 4) {
115  for (j = 0; j < avctx->width - 1; j += 2) {
116  ptr[j+0] = buf[j>>1] >> 4;
117  ptr[j+1] = buf[j>>1] & 0xF;
118  }
119  if (avctx->width & 1)
120  ptr[j+0] = buf[j>>1] >> 4;
121  } else {
122  memcpy(ptr, buf, linesize);
123  }
124  buf -= istride;
125  ptr += s->frame->linesize[0];
126  }
127  } else {
128  bytestream2_init(&s->gb, buf, buf_size);
129  ff_msrle_decode(avctx, (AVPicture*)s->frame, avctx->bits_per_coded_sample, &s->gb);
130  }
131 
132  if ((ret = av_frame_ref(data, s->frame)) < 0)
133  return ret;
134 
135  *got_frame = 1;
136 
137  /* report that the buffer was completely consumed */
138  return buf_size;
139 }
140 
142 {
143  MsrleContext *s = avctx->priv_data;
144 
145  /* release the last frame */
146  av_frame_free(&s->frame);
147 
148  return 0;
149 }
150 
152  .name = "msrle",
153  .long_name = NULL_IF_CONFIG_SMALL("Microsoft RLE"),
154  .type = AVMEDIA_TYPE_VIDEO,
155  .id = AV_CODEC_ID_MSRLE,
156  .priv_data_size = sizeof(MsrleContext),
160  .capabilities = CODEC_CAP_DR1,
161 };