libavcodec/bethsoftvideo.c

   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
  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 #include "internal.h"
  35
  36 typedef struct BethsoftvidContext {
  37     AVFrame frame;
  38     GetByteContext g;
  39 } BethsoftvidContext;
  40
  41 static av_cold int bethsoftvid_decode_init(AVCodecContext *avctx)
  42 {
  43     BethsoftvidContext *vid = avctx->priv_data;
  44     avctx->pix_fmt = AV_PIX_FMT_PAL8;
  45     return 0;
  46 }
  47
  48 static int set_palette(BethsoftvidContext *ctx)
  49 {
  50     uint32_t *palette = (uint32_t *)ctx->frame.data[1];
  51     int a;
  52
  53     if (bytestream2_get_bytes_left(&ctx->g) < 256*3)
  54         return AVERROR_INVALIDDATA;
  55
  56     for(a = 0; a < 256; a++){
  57         palette[a] = bytestream2_get_be24u(&ctx->g) * 4;
  58     }
  59     ctx->frame.palette_has_changed = 1;
  60     return 0;
  61 }
  62
  63 static int bethsoftvid_decode_frame(AVCodecContext *avctx,
  64                               void *data, int *got_frame,
  65                               AVPacket *avpkt)
  66 {
  67     BethsoftvidContext * vid = avctx->priv_data;
  68     char block_type;
  69     uint8_t * dst;
  70     uint8_t * frame_end;
  71     int remaining = avctx->width;          // number of bytes remaining on a line
  72     int wrap_to_next_line;
  73     int code, ret;
  74     int yoffset;
  75
  76     if ((ret = ff_reget_buffer(avctx, &vid->frame)) < 0) {
  77         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  78         return ret;
  79     }
  80     wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
  81
  82     if (avpkt->side_data_elems > 0 &&
  83         avpkt->side_data[0].type == AV_PKT_DATA_PALETTE) {
  84         bytestream2_init(&vid->g, avpkt->side_data[0].data,
  85                          avpkt->side_data[0].size);
  86         if ((ret = set_palette(vid)) < 0)
  87             return ret;
  88     }
  89
  90     bytestream2_init(&vid->g, avpkt->data, avpkt->size);
  91     dst = vid->frame.data[0];
  92     frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
  93
  94     switch(block_type = bytestream2_get_byte(&vid->g)){
  95         case PALETTE_BLOCK: {
  96             *got_frame = 0;
  97             if ((ret = set_palette(vid)) < 0) {
  98                 av_log(avctx, AV_LOG_ERROR, "error reading palette\n");
  99                 return ret;
 100             }
 101             return bytestream2_tell(&vid->g);
 102         }
 103         case VIDEO_YOFF_P_FRAME:
 104             yoffset = bytestream2_get_le16(&vid->g);
 105             if(yoffset >= avctx->height)
 106                 return AVERROR_INVALIDDATA;
 107             dst += vid->frame.linesize[0] * yoffset;
 108     }
 109
 110     // main code
 111     while((code = bytestream2_get_byte(&vid->g))){
 112         int length = code & 0x7f;
 113
 114         // copy any bytes starting at the current position, and ending at the frame width
 115         while(length > remaining){
 116             if(code < 0x80)
 117                 bytestream2_get_buffer(&vid->g, dst, remaining);
 118             else if(block_type == VIDEO_I_FRAME)
 119                 memset(dst, bytestream2_peek_byte(&vid->g), remaining);
 120             length -= remaining;      // decrement the number of bytes to be copied
 121             dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
 122             remaining = avctx->width;
 123             if(dst == frame_end)
 124                 goto end;
 125         }
 126
 127         // copy any remaining bytes after / if line overflows
 128         if(code < 0x80)
 129             bytestream2_get_buffer(&vid->g, dst, length);
 130         else if(block_type == VIDEO_I_FRAME)
 131             memset(dst, bytestream2_get_byte(&vid->g), length);
 132         remaining -= length;
 133         dst += length;
 134     }
 135     end:
 136
 137     if ((ret = av_frame_ref(data, &vid->frame)) < 0)
 138         return ret;
 139
 140     *got_frame = 1;
 141
 142     return avpkt->size;
 143 }
 144
 145 static av_cold int bethsoftvid_decode_end(AVCodecContext *avctx)
 146 {
 147     BethsoftvidContext * vid = avctx->priv_data;
 148     av_frame_unref(&vid->frame);
 149     return 0;
 150 }
 151
 152 AVCodec ff_bethsoftvid_decoder = {
 153     .name           = "bethsoftvid",
 154     .type           = AVMEDIA_TYPE_VIDEO,
 155     .id             = AV_CODEC_ID_BETHSOFTVID,
 156     .priv_data_size = sizeof(BethsoftvidContext),
 157     .init           = bethsoftvid_decode_init,
 158     .close          = bethsoftvid_decode_end,
 159     .decode         = bethsoftvid_decode_frame,
 160     .capabilities   = CODEC_CAP_DR1,
 161     .long_name      = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
 162 };