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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 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  * @brief Bethesda Softworks VID Video Decoder
25  * @author Nicholas Tung [ntung (at. ntung com] (2007-03)
26  * @see http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
27  * @see http://www.svatopluk.com/andux/docs/dfvid.html
28  */
29 
30 #include "libavutil/common.h"
31 #include "avcodec.h"
32 #include "bethsoftvideo.h"
33 #include "bytestream.h"
34 
35 typedef struct BethsoftvidContext {
39 
41 {
42  BethsoftvidContext *vid = avctx->priv_data;
44  vid->frame.reference = 3;
47  avctx->pix_fmt = AV_PIX_FMT_PAL8;
48  return 0;
49 }
50 
52 {
53  uint32_t *palette = (uint32_t *)ctx->frame.data[1];
54  int a;
55 
56  if (bytestream2_get_bytes_left(&ctx->g) < 256*3)
57  return AVERROR_INVALIDDATA;
58 
59  for(a = 0; a < 256; a++){
60  palette[a] = 0xFFU << 24 | bytestream2_get_be24u(&ctx->g) * 4;
61  palette[a] |= palette[a] >> 6 & 0x30303;
62  }
63  ctx->frame.palette_has_changed = 1;
64  return 0;
65 }
66 
68  void *data, int *got_frame,
69  AVPacket *avpkt)
70 {
71  BethsoftvidContext * vid = avctx->priv_data;
72  char block_type;
73  uint8_t * dst;
74  uint8_t * frame_end;
75  int remaining = avctx->width; // number of bytes remaining on a line
76  int wrap_to_next_line;
77  int code, ret;
78  int yoffset;
79 
80  if ((ret = avctx->reget_buffer(avctx, &vid->frame)) < 0) {
81  av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
82  return ret;
83  }
84  wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
85 
86  if (avpkt->side_data_elems > 0 &&
87  avpkt->side_data[0].type == AV_PKT_DATA_PALETTE) {
88  bytestream2_init(&vid->g, avpkt->side_data[0].data,
89  avpkt->side_data[0].size);
90  if ((ret = set_palette(vid)) < 0)
91  return ret;
92  }
93 
94  bytestream2_init(&vid->g, avpkt->data, avpkt->size);
95  dst = vid->frame.data[0];
96  frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
97 
98  switch(block_type = bytestream2_get_byte(&vid->g)){
99  case PALETTE_BLOCK: {
100  *got_frame = 0;
101  if ((ret = set_palette(vid)) < 0) {
102  av_log(avctx, AV_LOG_ERROR, "error reading palette\n");
103  return ret;
104  }
105  return bytestream2_tell(&vid->g);
106  }
107  case VIDEO_YOFF_P_FRAME:
108  yoffset = bytestream2_get_le16(&vid->g);
109  if(yoffset >= avctx->height)
110  return AVERROR_INVALIDDATA;
111  dst += vid->frame.linesize[0] * yoffset;
112  }
113 
114  // main code
115  while((code = bytestream2_get_byte(&vid->g))){
116  int length = code & 0x7f;
117 
118  // copy any bytes starting at the current position, and ending at the frame width
119  while(length > remaining){
120  if(code < 0x80)
121  bytestream2_get_buffer(&vid->g, dst, remaining);
122  else if(block_type == VIDEO_I_FRAME)
123  memset(dst, bytestream2_peek_byte(&vid->g), remaining);
124  length -= remaining; // decrement the number of bytes to be copied
125  dst += remaining + wrap_to_next_line; // skip over extra bytes at end of frame
126  remaining = avctx->width;
127  if(dst == frame_end)
128  goto end;
129  }
130 
131  // copy any remaining bytes after / if line overflows
132  if(code < 0x80)
133  bytestream2_get_buffer(&vid->g, dst, length);
134  else if(block_type == VIDEO_I_FRAME)
135  memset(dst, bytestream2_get_byte(&vid->g), length);
136  remaining -= length;
137  dst += length;
138  }
139  end:
140 
141  *got_frame = 1;
142  *(AVFrame*)data = vid->frame;
143 
144  return avpkt->size;
145 }
146 
148 {
149  BethsoftvidContext * vid = avctx->priv_data;
150  if(vid->frame.data[0])
151  avctx->release_buffer(avctx, &vid->frame);
152  return 0;
153 }
154 
156  .name = "bethsoftvid",
157  .type = AVMEDIA_TYPE_VIDEO,
159  .priv_data_size = sizeof(BethsoftvidContext),
163  .capabilities = CODEC_CAP_DR1,
164  .long_name = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
165 };