FFmpeg
 All Data Structures Namespaces Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages
msrle.c
Go to the documentation of this file.
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 "internal.h"
37 #include "msrledec.h"
38 #include "libavutil/imgutils.h"
39 
40 typedef struct MsrleContext {
43 
45  const unsigned char *buf;
46  int size;
47 
48  uint32_t pal[256];
49 } MsrleContext;
50 
52 {
53  MsrleContext *s = avctx->priv_data;
54  int i;
55 
56  s->avctx = avctx;
57 
58  switch (avctx->bits_per_coded_sample) {
59  case 1:
61  break;
62  case 4:
63  case 8:
64  avctx->pix_fmt = AV_PIX_FMT_PAL8;
65  break;
66  case 24:
67  avctx->pix_fmt = AV_PIX_FMT_BGR24;
68  break;
69  default:
70  av_log(avctx, AV_LOG_ERROR, "unsupported bits per sample\n");
71  return AVERROR_INVALIDDATA;
72  }
73 
74  s->frame = av_frame_alloc();
75  if (!s->frame)
76  return AVERROR(ENOMEM);
77 
78  if (avctx->extradata_size >= 4)
79  for (i = 0; i < FFMIN(avctx->extradata_size, AVPALETTE_SIZE)/4; i++)
80  s->pal[i] = 0xFFU<<24 | AV_RL32(avctx->extradata+4*i);
81 
82  return 0;
83 }
84 
86  void *data, int *got_frame,
87  AVPacket *avpkt)
88 {
89  const uint8_t *buf = avpkt->data;
90  int buf_size = avpkt->size;
91  MsrleContext *s = avctx->priv_data;
92  int istride = FFALIGN(avctx->width*avctx->bits_per_coded_sample, 32) / 8;
93  int ret;
94 
95  s->buf = buf;
96  s->size = buf_size;
97 
98  if ((ret = ff_reget_buffer(avctx, s->frame)) < 0)
99  return ret;
100 
101  if (avctx->bits_per_coded_sample > 1 && avctx->bits_per_coded_sample <= 8) {
102  const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
103 
104  if (pal) {
105  s->frame->palette_has_changed = 1;
106  memcpy(s->pal, pal, AVPALETTE_SIZE);
107  }
108  /* make the palette available */
109  memcpy(s->frame->data[1], s->pal, AVPALETTE_SIZE);
110  }
111 
112  /* FIXME how to correctly detect RLE ??? */
113  if (avctx->height * istride == avpkt->size) { /* assume uncompressed */
114  int linesize = av_image_get_linesize(avctx->pix_fmt, avctx->width, 0);
115  uint8_t *ptr = s->frame->data[0];
116  uint8_t *buf = avpkt->data + (avctx->height-1)*istride;
117  int i, j;
118 
119  if (linesize < 0)
120  return linesize;
121 
122  for (i = 0; i < avctx->height; i++) {
123  if (avctx->bits_per_coded_sample == 4) {
124  for (j = 0; j < avctx->width - 1; j += 2) {
125  ptr[j+0] = buf[j>>1] >> 4;
126  ptr[j+1] = buf[j>>1] & 0xF;
127  }
128  if (avctx->width & 1)
129  ptr[j+0] = buf[j>>1] >> 4;
130  } else {
131  memcpy(ptr, buf, linesize);
132  }
133  buf -= istride;
134  ptr += s->frame->linesize[0];
135  }
136  } else {
137  bytestream2_init(&s->gb, buf, buf_size);
138  ff_msrle_decode(avctx, (AVPicture*)s->frame, avctx->bits_per_coded_sample, &s->gb);
139  }
140 
141  if ((ret = av_frame_ref(data, s->frame)) < 0)
142  return ret;
143 
144  *got_frame = 1;
145 
146  /* report that the buffer was completely consumed */
147  return buf_size;
148 }
149 
151 {
152  MsrleContext *s = avctx->priv_data;
153 
154  /* release the last frame */
155  av_frame_free(&s->frame);
156 
157  return 0;
158 }
159 
161  .name = "msrle",
162  .long_name = NULL_IF_CONFIG_SMALL("Microsoft RLE"),
163  .type = AVMEDIA_TYPE_VIDEO,
164  .id = AV_CODEC_ID_MSRLE,
165  .priv_data_size = sizeof(MsrleContext),
167  .close = msrle_decode_end,
169  .capabilities = CODEC_CAP_DR1,
170 };