Libav
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 "avcodec.h"
32 #include "bethsoftvideo.h"
33 #include "bytestream.h"
34 #include "internal.h"
35 
36 typedef struct BethsoftvidContext {
40 
42 {
43  BethsoftvidContext *vid = avctx->priv_data;
44  avctx->pix_fmt = AV_PIX_FMT_PAL8;
45 
46  vid->frame = av_frame_alloc();
47  if (!vid->frame)
48  return AVERROR(ENOMEM);
49 
50  return 0;
51 }
52 
54 {
55  uint32_t *palette = (uint32_t *)ctx->frame->data[1];
56  int a;
57 
58  if (bytestream2_get_bytes_left(&ctx->g) < 256*3)
59  return AVERROR_INVALIDDATA;
60 
61  for(a = 0; a < 256; a++){
62  palette[a] = bytestream2_get_be24u(&ctx->g) * 4;
63  }
64  ctx->frame->palette_has_changed = 1;
65  return 0;
66 }
67 
69  void *data, int *got_frame,
70  AVPacket *avpkt)
71 {
72  BethsoftvidContext * vid = avctx->priv_data;
73  char block_type;
74  uint8_t * dst;
76  int remaining = avctx->width; // number of bytes remaining on a line
77  int wrap_to_next_line;
78  int code, ret;
79  int yoffset;
80 
81  if ((ret = ff_reget_buffer(avctx, vid->frame)) < 0) {
82  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
83  return ret;
84  }
85  wrap_to_next_line = vid->frame->linesize[0] - avctx->width;
86 
87  if (avpkt->side_data_elems > 0 &&
88  avpkt->side_data[0].type == AV_PKT_DATA_PALETTE) {
89  bytestream2_init(&vid->g, avpkt->side_data[0].data,
90  avpkt->side_data[0].size);
91  if ((ret = set_palette(vid)) < 0)
92  return ret;
93  }
94 
95  bytestream2_init(&vid->g, avpkt->data, avpkt->size);
96  dst = vid->frame->data[0];
97  frame_end = vid->frame->data[0] + vid->frame->linesize[0] * avctx->height;
98 
99  switch(block_type = bytestream2_get_byte(&vid->g)){
100  case PALETTE_BLOCK: {
101  *got_frame = 0;
102  if ((ret = set_palette(vid)) < 0) {
103  av_log(avctx, AV_LOG_ERROR, "error reading palette\n");
104  return ret;
105  }
106  return bytestream2_tell(&vid->g);
107  }
108  case VIDEO_YOFF_P_FRAME:
109  yoffset = bytestream2_get_le16(&vid->g);
110  if(yoffset >= avctx->height)
111  return AVERROR_INVALIDDATA;
112  dst += vid->frame->linesize[0] * yoffset;
113  }
114 
115  // main code
116  while((code = bytestream2_get_byte(&vid->g))){
117  int length = code & 0x7f;
118 
119  // copy any bytes starting at the current position, and ending at the frame width
120  while(length > remaining){
121  if(code < 0x80)
122  bytestream2_get_buffer(&vid->g, dst, remaining);
123  else if(block_type == VIDEO_I_FRAME)
124  memset(dst, bytestream2_peek_byte(&vid->g), remaining);
125  length -= remaining; // decrement the number of bytes to be copied
126  dst += remaining + wrap_to_next_line; // skip over extra bytes at end of frame
127  remaining = avctx->width;
128  if(dst == frame_end)
129  goto end;
130  }
131 
132  // copy any remaining bytes after / if line overflows
133  if(code < 0x80)
134  bytestream2_get_buffer(&vid->g, dst, length);
135  else if(block_type == VIDEO_I_FRAME)
136  memset(dst, bytestream2_get_byte(&vid->g), length);
137  remaining -= length;
138  dst += length;
139  }
140  end:
141 
142  if ((ret = av_frame_ref(data, vid->frame)) < 0)
143  return ret;
144 
145  *got_frame = 1;
146 
147  return avpkt->size;
148 }
149 
151 {
152  BethsoftvidContext * vid = avctx->priv_data;
153  av_frame_free(&vid->frame);
154  return 0;
155 }
156 
158  .name = "bethsoftvid",
159  .long_name = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
160  .type = AVMEDIA_TYPE_VIDEO,
162  .priv_data_size = sizeof(BethsoftvidContext),
166  .capabilities = CODEC_CAP_DR1,
167 };