libavcodec/tmv.c

   1 /*
   2  * 8088flex TMV video decoder
   3  * Copyright (c) 2009 Daniel Verkamp <daniel at drv.nu>
   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  * 8088flex TMV video decoder
  25  * @author Daniel Verkamp
  26  * @see http://www.oldskool.org/pc/8088_Corruption
  27  */
  28
  29 #include <string.h>
  30
  31 #include "avcodec.h"
  32 #include "internal.h"
  33 #include "libavutil/internal.h"
  34
  35 #include "cga_data.h"
  36
  37 static int tmv_decode_frame(AVCodecContext *avctx, void *data,
  38                             int *got_frame, AVPacket *avpkt)
  39 {
  40     AVFrame *frame     = data;
  41     const uint8_t *src = avpkt->data;
  42     uint8_t *dst;
  43     unsigned char_cols = avctx->width >> 3;
  44     unsigned char_rows = avctx->height >> 3;
  45     unsigned x, y, fg, bg, c;
  46     int ret;
  47
  48     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
  49         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
  50         return ret;
  51     }
  52
  53     if (avpkt->size < 2*char_rows*char_cols) {
  54         av_log(avctx, AV_LOG_ERROR,
  55                "Input buffer too small, truncated sample?\n");
  56         *got_frame = 0;
  57         return AVERROR_INVALIDDATA;
  58     }
  59
  60     frame->pict_type = AV_PICTURE_TYPE_I;
  61     frame->key_frame = 1;
  62     dst              = frame->data[0];
  63
  64     frame->palette_has_changed = 1;
  65     memcpy(frame->data[1], ff_cga_palette, 16 * 4);
  66
  67     for (y = 0; y < char_rows; y++) {
  68         for (x = 0; x < char_cols; x++) {
  69             c  = *src++;
  70             bg = *src  >> 4;
  71             fg = *src++ & 0xF;
  72             ff_draw_pc_font(dst + x * 8, frame->linesize[0],
  73                             ff_cga_font, 8, c, fg, bg);
  74         }
  75         dst += frame->linesize[0] * 8;
  76     }
  77
  78     *got_frame = 1;
  79
  80     return avpkt->size;
  81 }
  82
  83 static av_cold int tmv_decode_init(AVCodecContext *avctx)
  84 {
  85     avctx->pix_fmt = AV_PIX_FMT_PAL8;
  86     return 0;
  87 }
  88
  89 AVCodec ff_tmv_decoder = {
  90     .name           = "tmv",
  91     .type           = AVMEDIA_TYPE_VIDEO,
  92     .id             = AV_CODEC_ID_TMV,
  93     .init           = tmv_decode_init,
  94     .decode         = tmv_decode_frame,
  95     .capabilities   = CODEC_CAP_DR1,
  96     .long_name      = NULL_IF_CONFIG_SMALL("8088flex TMV"),
  97 };