bethsoftvideo.c
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1 /*
2  * Bethesda VID video decoder
3  * Copyright (C) 2007 Nicholas Tung
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 
30 #include "libavutil/common.h"
31 #include "dsputil.h"
32 #include "bethsoftvideo.h"
33 #include "bytestream.h"
34 
35 typedef struct BethsoftvidContext {
39 
41 {
42  BethsoftvidContext *vid = avctx->priv_data;
43  vid->frame.reference = 1;
46  avctx->pix_fmt = PIX_FMT_PAL8;
47  return 0;
48 }
49 
51 {
52  uint32_t *palette = (uint32_t *)ctx->frame.data[1];
53  int a;
54 
55  if (bytestream2_get_bytes_left(&ctx->g) < 256*3)
56  return AVERROR_INVALIDDATA;
57 
58  for(a = 0; a < 256; a++){
59  palette[a] = bytestream2_get_be24u(&ctx->g) * 4;
60  }
61  ctx->frame.palette_has_changed = 1;
62  return 256*3;
63 }
64 
66  void *data, int *data_size,
67  AVPacket *avpkt)
68 {
69  BethsoftvidContext * vid = avctx->priv_data;
70  char block_type;
71  uint8_t * dst;
72  uint8_t * frame_end;
73  int remaining = avctx->width; // number of bytes remaining on a line
74  const int wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
75  int code;
76  int yoffset;
77 
78  if (avctx->reget_buffer(avctx, &vid->frame)) {
79  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
80  return -1;
81  }
82 
83  bytestream2_init(&vid->g, avpkt->data, avpkt->size);
84  dst = vid->frame.data[0];
85  frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
86 
87  switch(block_type = bytestream2_get_byte(&vid->g)){
88  case PALETTE_BLOCK: {
89  return set_palette(vid);
90  }
91  case VIDEO_YOFF_P_FRAME:
92  yoffset = bytestream2_get_le16(&vid->g);
93  if(yoffset >= avctx->height)
94  return -1;
95  dst += vid->frame.linesize[0] * yoffset;
96  }
97 
98  // main code
99  while((code = bytestream2_get_byte(&vid->g))){
100  int length = code & 0x7f;
101 
102  // copy any bytes starting at the current position, and ending at the frame width
103  while(length > remaining){
104  if(code < 0x80)
105  bytestream2_get_buffer(&vid->g, dst, remaining);
106  else if(block_type == VIDEO_I_FRAME)
107  memset(dst, bytestream2_peek_byte(&vid->g), remaining);
108  length -= remaining; // decrement the number of bytes to be copied
109  dst += remaining + wrap_to_next_line; // skip over extra bytes at end of frame
110  remaining = avctx->width;
111  if(dst == frame_end)
112  goto end;
113  }
114 
115  // copy any remaining bytes after / if line overflows
116  if(code < 0x80)
117  bytestream2_get_buffer(&vid->g, dst, length);
118  else if(block_type == VIDEO_I_FRAME)
119  memset(dst, bytestream2_get_byte(&vid->g), length);
120  remaining -= length;
121  dst += length;
122  }
123  end:
124 
125  *data_size = sizeof(AVFrame);
126  *(AVFrame*)data = vid->frame;
127 
128  return avpkt->size;
129 }
130 
132 {
133  BethsoftvidContext * vid = avctx->priv_data;
134  if(vid->frame.data[0])
135  avctx->release_buffer(avctx, &vid->frame);
136  return 0;
137 }
138 
140  .name = "bethsoftvid",
141  .type = AVMEDIA_TYPE_VIDEO,
142  .id = CODEC_ID_BETHSOFTVID,
143  .priv_data_size = sizeof(BethsoftvidContext),
147  .capabilities = CODEC_CAP_DR1,
148  .long_name = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
149 };