libavcodec/bethsoftvideo.c

   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 bethsoftvideo.c
  24  * @brief Bethesda Softworks VID Video Decoder
  25  * @author Nicholas Tung [ntung (at. ntung com] (2007-03)
  26  * @sa http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
  27  * @sa http://www.svatopluk.com/andux/docs/dfvid.html
  28  */
  29
  30 #include "libavutil/common.h"
  31 #include "dsputil.h"
  32 #include "bethsoftvideo.h"
  33 #include "bytestream.h"
  34
  35 typedef struct BethsoftvidContext {
  36     AVFrame frame;
  37 } BethsoftvidContext;
  38
  39 static av_cold int bethsoftvid_decode_init(AVCodecContext *avctx)
  40 {
  41     BethsoftvidContext *vid = avctx->priv_data;
  42     vid->frame.reference = 1;
  43     vid->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
  44         FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
  45     avctx->pix_fmt = PIX_FMT_PAL8;
  46     return 0;
  47 }
  48
  49 static void set_palette(AVFrame * frame, const uint8_t * palette_buffer)
  50 {
  51     uint32_t * palette = (uint32_t *)frame->data[1];
  52     int a;
  53     for(a = 0; a < 256; a++){
  54         palette[a] = AV_RB24(&palette_buffer[a * 3]) * 4;
  55     }
  56     frame->palette_has_changed = 1;
  57 }
  58
  59 static int bethsoftvid_decode_frame(AVCodecContext *avctx,
  60                               void *data, int *data_size,
  61                               const uint8_t *buf, int buf_size)
  62 {
  63     BethsoftvidContext * vid = avctx->priv_data;
  64     char block_type;
  65     uint8_t * dst;
  66     uint8_t * frame_end;
  67     int remaining = avctx->width;          // number of bytes remaining on a line
  68     const int wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
  69     int code;
  70     int yoffset;
  71
  72     if (avctx->reget_buffer(avctx, &vid->frame)) {
  73         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  74         return -1;
  75     }
  76     dst = vid->frame.data[0];
  77     frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
  78
  79     switch(block_type = *buf++){
  80         case PALETTE_BLOCK:
  81             set_palette(&vid->frame, buf);
  82             return 0;
  83         case VIDEO_YOFF_P_FRAME:
  84             yoffset = bytestream_get_le16(&buf);
  85             if(yoffset >= avctx->height)
  86                 return -1;
  87             dst += vid->frame.linesize[0] * yoffset;
  88     }
  89
  90     // main code
  91     while((code = *buf++)){
  92         int length = code & 0x7f;
  93
  94         // copy any bytes starting at the current position, and ending at the frame width
  95         while(length > remaining){
  96             if(code < 0x80)
  97                 bytestream_get_buffer(&buf, dst, remaining);
  98             else if(block_type == VIDEO_I_FRAME)
  99                 memset(dst, buf[0], remaining);
 100             length -= remaining;      // decrement the number of bytes to be copied
 101             dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
 102             remaining = avctx->width;
 103             if(dst == frame_end)
 104                 goto end;
 105         }
 106
 107         // copy any remaining bytes after / if line overflows
 108         if(code < 0x80)
 109             bytestream_get_buffer(&buf, dst, length);
 110         else if(block_type == VIDEO_I_FRAME)
 111             memset(dst, *buf++, length);
 112         remaining -= length;
 113         dst += length;
 114     }
 115     end:
 116
 117     *data_size = sizeof(AVFrame);
 118     *(AVFrame*)data = vid->frame;
 119
 120     return buf_size;
 121 }
 122
 123 static av_cold int bethsoftvid_decode_end(AVCodecContext *avctx)
 124 {
 125     BethsoftvidContext * vid = avctx->priv_data;
 126     if(vid->frame.data[0])
 127         avctx->release_buffer(avctx, &vid->frame);
 128     return 0;
 129 }
 130
 131 AVCodec bethsoftvid_decoder = {
 132     .name = "bethsoftvid",
 133     .type = CODEC_TYPE_VIDEO,
 134     .id = CODEC_ID_BETHSOFTVID,
 135     .priv_data_size = sizeof(BethsoftvidContext),
 136     .init = bethsoftvid_decode_init,
 137     .close = bethsoftvid_decode_end,
 138     .decode = bethsoftvid_decode_frame,
 139     .long_name = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
 140 };