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 "dsputil.h"
  32 #include "bethsoftvideo.h"
  33 #include "bytestream.h"
  34
  35 typedef struct BethsoftvidContext {
  36     AVFrame frame;
  37     GetByteContext g;
  38 } BethsoftvidContext;
  39
  40 static av_cold int bethsoftvid_decode_init(AVCodecContext *avctx)
  41 {
  42     BethsoftvidContext *vid = avctx->priv_data;
  43     vid->frame.reference = 1;
  44     vid->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
  45         FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
  46     avctx->pix_fmt = AV_PIX_FMT_PAL8;
  47     return 0;
  48 }
  49
  50 static int set_palette(BethsoftvidContext *ctx)
  51 {
  52     uint32_t *palette = (uint32_t *)ctx->frame.data[1];
  53     int a;
  54
  55     if (bytestream2_get_bytes_left(&ctx->g) < 256*3)
  56         return AVERROR_INVALIDDATA;
  57
  58     for(a = 0; a < 256; a++){
  59         palette[a] = bytestream2_get_be24u(&ctx->g) * 4;
  60     }
  61     ctx->frame.palette_has_changed = 1;
  62     return 0;
  63 }
  64
  65 static int bethsoftvid_decode_frame(AVCodecContext *avctx,
  66                               void *data, int *got_frame,
  67                               AVPacket *avpkt)
  68 {
  69     BethsoftvidContext * vid = avctx->priv_data;
  70     char block_type;
  71     uint8_t * dst;
  72     uint8_t * frame_end;
  73     int remaining = avctx->width;          // number of bytes remaining on a line
  74     int wrap_to_next_line;
  75     int code, ret;
  76     int yoffset;
  77
  78     if ((ret = avctx->reget_buffer(avctx, &vid->frame)) < 0) {
  79         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  80         return ret;
  81     }
  82     wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
  83
  84     if (avpkt->side_data_elems > 0 &&
  85         avpkt->side_data[0].type == AV_PKT_DATA_PALETTE) {
  86         bytestream2_init(&vid->g, avpkt->side_data[0].data,
  87                          avpkt->side_data[0].size);
  88         if ((ret = set_palette(vid)) < 0)
  89             return ret;
  90     }
  91
  92     bytestream2_init(&vid->g, avpkt->data, avpkt->size);
  93     dst = vid->frame.data[0];
  94     frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
  95
  96     switch(block_type = bytestream2_get_byte(&vid->g)){
  97         case PALETTE_BLOCK: {
  98             *got_frame = 0;
  99             if ((ret = set_palette(vid)) < 0) {
 100                 av_log(avctx, AV_LOG_ERROR, "error reading palette\n");
 101                 return ret;
 102             }
 103             return bytestream2_tell(&vid->g);
 104         }
 105         case VIDEO_YOFF_P_FRAME:
 106             yoffset = bytestream2_get_le16(&vid->g);
 107             if(yoffset >= avctx->height)
 108                 return AVERROR_INVALIDDATA;
 109             dst += vid->frame.linesize[0] * yoffset;
 110     }
 111
 112     // main code
 113     while((code = bytestream2_get_byte(&vid->g))){
 114         int length = code & 0x7f;
 115
 116         // copy any bytes starting at the current position, and ending at the frame width
 117         while(length > remaining){
 118             if(code < 0x80)
 119                 bytestream2_get_buffer(&vid->g, dst, remaining);
 120             else if(block_type == VIDEO_I_FRAME)
 121                 memset(dst, bytestream2_peek_byte(&vid->g), remaining);
 122             length -= remaining;      // decrement the number of bytes to be copied
 123             dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
 124             remaining = avctx->width;
 125             if(dst == frame_end)
 126                 goto end;
 127         }
 128
 129         // copy any remaining bytes after / if line overflows
 130         if(code < 0x80)
 131             bytestream2_get_buffer(&vid->g, dst, length);
 132         else if(block_type == VIDEO_I_FRAME)
 133             memset(dst, bytestream2_get_byte(&vid->g), length);
 134         remaining -= length;
 135         dst += length;
 136     }
 137     end:
 138
 139     *got_frame = 1;
 140     *(AVFrame*)data = vid->frame;
 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     if(vid->frame.data[0])
 149         avctx->release_buffer(avctx, &vid->frame);
 150     return 0;
 151 }
 152
 153 AVCodec ff_bethsoftvid_decoder = {
 154     .name           = "bethsoftvid",
 155     .type           = AVMEDIA_TYPE_VIDEO,
 156     .id             = AV_CODEC_ID_BETHSOFTVID,
 157     .priv_data_size = sizeof(BethsoftvidContext),
 158     .init           = bethsoftvid_decode_init,
 159     .close          = bethsoftvid_decode_end,
 160     .decode         = bethsoftvid_decode_frame,
 161     .capabilities   = CODEC_CAP_DR1,
 162     .long_name      = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
 163 };