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 libavcodec/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                               AVPacket *avpkt)
  62 {
  63     const uint8_t *buf = avpkt->data;
  64     int buf_size = avpkt->size;
  65     BethsoftvidContext * vid = avctx->priv_data;
  66     char block_type;
  67     uint8_t * dst;
  68     uint8_t * frame_end;
  69     int remaining = avctx->width;          // number of bytes remaining on a line
  70     const int wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
  71     int code;
  72     int yoffset;
  73
  74     if (avctx->reget_buffer(avctx, &vid->frame)) {
  75         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  76         return -1;
  77     }
  78     dst = vid->frame.data[0];
  79     frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
  80
  81     switch(block_type = *buf++){
  82         case PALETTE_BLOCK:
  83             set_palette(&vid->frame, buf);
  84             return 0;
  85         case VIDEO_YOFF_P_FRAME:
  86             yoffset = bytestream_get_le16(&buf);
  87             if(yoffset >= avctx->height)
  88                 return -1;
  89             dst += vid->frame.linesize[0] * yoffset;
  90     }
  91
  92     // main code
  93     while((code = *buf++)){
  94         int length = code & 0x7f;
  95
  96         // copy any bytes starting at the current position, and ending at the frame width
  97         while(length > remaining){
  98             if(code < 0x80)
  99                 bytestream_get_buffer(&buf, dst, remaining);
 100             else if(block_type == VIDEO_I_FRAME)
 101                 memset(dst, buf[0], remaining);
 102             length -= remaining;      // decrement the number of bytes to be copied
 103             dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
 104             remaining = avctx->width;
 105             if(dst == frame_end)
 106                 goto end;
 107         }
 108
 109         // copy any remaining bytes after / if line overflows
 110         if(code < 0x80)
 111             bytestream_get_buffer(&buf, dst, length);
 112         else if(block_type == VIDEO_I_FRAME)
 113             memset(dst, *buf++, length);
 114         remaining -= length;
 115         dst += length;
 116     }
 117     end:
 118
 119     *data_size = sizeof(AVFrame);
 120     *(AVFrame*)data = vid->frame;
 121
 122     return buf_size;
 123 }
 124
 125 static av_cold int bethsoftvid_decode_end(AVCodecContext *avctx)
 126 {
 127     BethsoftvidContext * vid = avctx->priv_data;
 128     if(vid->frame.data[0])
 129         avctx->release_buffer(avctx, &vid->frame);
 130     return 0;
 131 }
 132
 133 AVCodec bethsoftvid_decoder = {
 134     .name = "bethsoftvid",
 135     .type = CODEC_TYPE_VIDEO,
 136     .id = CODEC_ID_BETHSOFTVID,
 137     .priv_data_size = sizeof(BethsoftvidContext),
 138     .init = bethsoftvid_decode_init,
 139     .close = bethsoftvid_decode_end,
 140     .decode = bethsoftvid_decode_frame,
 141     .capabilities = CODEC_CAP_DR1,
 142     .long_name = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
 143 };