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
  46     vid->frame = av_frame_alloc();
  47     if (!vid->frame)
  48         return AVERROR(ENOMEM);
  49
  50     return 0;
  51 }
  52
  53 static int set_palette(BethsoftvidContext *ctx)
  54 {
  55     uint32_t *palette = (uint32_t *)ctx->frame->data[1];
  56     int a;
  57
  58     if (bytestream2_get_bytes_left(&ctx->g) < 256*3)
  59         return AVERROR_INVALIDDATA;
  60
  61     for(a = 0; a < 256; a++){
  62         palette[a] = bytestream2_get_be24u(&ctx->g) * 4;
  63     }
  64     ctx->frame->palette_has_changed = 1;
  65     return 0;
  66 }
  67
  68 static int bethsoftvid_decode_frame(AVCodecContext *avctx,
  69                               void *data, int *got_frame,
  70                               AVPacket *avpkt)
  71 {
  72     BethsoftvidContext * vid = avctx->priv_data;
  73     char block_type;
  74     uint8_t * dst;
  75     uint8_t * frame_end;
  76     int remaining = avctx->width;          // number of bytes remaining on a line
  77     int wrap_to_next_line;
  78     int code, ret;
  79     int yoffset;
  80
  81     if ((ret = ff_reget_buffer(avctx, vid->frame)) < 0) {
  82         av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
  83         return ret;
  84     }
  85     wrap_to_next_line = vid->frame->linesize[0] - avctx->width;
  86
  87     if (avpkt->side_data_elems > 0 &&
  88         avpkt->side_data[0].type == AV_PKT_DATA_PALETTE) {
  89         bytestream2_init(&vid->g, avpkt->side_data[0].data,
  90                          avpkt->side_data[0].size);
  91         if ((ret = set_palette(vid)) < 0)
  92             return ret;
  93     }
  94
  95     bytestream2_init(&vid->g, avpkt->data, avpkt->size);
  96     dst = vid->frame->data[0];
  97     frame_end = vid->frame->data[0] + vid->frame->linesize[0] * avctx->height;
  98
  99     switch(block_type = bytestream2_get_byte(&vid->g)){
 100         case PALETTE_BLOCK: {
 101             *got_frame = 0;
 102             if ((ret = set_palette(vid)) < 0) {
 103                 av_log(avctx, AV_LOG_ERROR, "error reading palette\n");
 104                 return ret;
 105             }
 106             return bytestream2_tell(&vid->g);
 107         }
 108         case VIDEO_YOFF_P_FRAME:
 109             yoffset = bytestream2_get_le16(&vid->g);
 110             if(yoffset >= avctx->height)
 111                 return AVERROR_INVALIDDATA;
 112             dst += vid->frame->linesize[0] * yoffset;
 113     }
 114
 115     // main code
 116     while((code = bytestream2_get_byte(&vid->g))){
 117         int length = code & 0x7f;
 118
 119         // copy any bytes starting at the current position, and ending at the frame width
 120         while(length > remaining){
 121             if(code < 0x80)
 122                 bytestream2_get_buffer(&vid->g, dst, remaining);
 123             else if(block_type == VIDEO_I_FRAME)
 124                 memset(dst, bytestream2_peek_byte(&vid->g), remaining);
 125             length -= remaining;      // decrement the number of bytes to be copied
 126             dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
 127             remaining = avctx->width;
 128             if(dst == frame_end)
 129                 goto end;
 130         }
 131
 132         // copy any remaining bytes after / if line overflows
 133         if(code < 0x80)
 134             bytestream2_get_buffer(&vid->g, dst, length);
 135         else if(block_type == VIDEO_I_FRAME)
 136             memset(dst, bytestream2_get_byte(&vid->g), length);
 137         remaining -= length;
 138         dst += length;
 139     }
 140     end:
 141
 142     if ((ret = av_frame_ref(data, vid->frame)) < 0)
 143         return ret;
 144
 145     *got_frame = 1;
 146
 147     return avpkt->size;
 148 }
 149
 150 static av_cold int bethsoftvid_decode_end(AVCodecContext *avctx)
 151 {
 152     BethsoftvidContext * vid = avctx->priv_data;
 153     av_frame_free(&vid->frame);
 154     return 0;
 155 }
 156
 157 AVCodec ff_bethsoftvid_decoder = {
 158     .name           = "bethsoftvid",
 159     .long_name      = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
 160     .type           = AVMEDIA_TYPE_VIDEO,
 161     .id             = AV_CODEC_ID_BETHSOFTVID,
 162     .priv_data_size = sizeof(BethsoftvidContext),
 163     .init           = bethsoftvid_decode_init,
 164     .close          = bethsoftvid_decode_end,
 165     .decode         = bethsoftvid_decode_frame,
 166     .capabilities   = AV_CODEC_CAP_DR1,
 167     .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
 168 };