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 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
  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 "codec_internal.h"
  33 #include "decode.h"
  34 #include "libavutil/internal.h"
  35 #include "libavutil/xga_font_data.h"
  36
  37 #include "cga_data.h"
  38
  39 static int tmv_decode_frame(AVCodecContext *avctx, AVFrame *frame,
  40                             int *got_frame, AVPacket *avpkt)
  41 {
  42     const uint8_t *src = avpkt->data;
  43     uint8_t *dst;
  44     unsigned char_cols = avctx->width >> 3;
  45     unsigned char_rows = avctx->height >> 3;
  46     unsigned x, y, fg, bg, c;
  47     int ret;
  48
  49     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
  50         return ret;
  51
  52     if (avpkt->size < 2*char_rows*char_cols) {
  53         av_log(avctx, AV_LOG_ERROR,
  54                "Input buffer too small, truncated sample?\n");
  55         *got_frame = 0;
  56         return AVERROR_INVALIDDATA;
  57     }
  58
  59     dst              = frame->data[0];
  60
  61 #if FF_API_PALETTE_HAS_CHANGED
  62 FF_DISABLE_DEPRECATION_WARNINGS
  63     frame->palette_has_changed = 1;
  64 FF_ENABLE_DEPRECATION_WARNINGS
  65 #endif
  66     memcpy(frame->data[1], ff_cga_palette, 16 * 4);
  67     memset(frame->data[1] + 16 * 4, 0, AVPALETTE_SIZE - 16 * 4);
  68
  69     for (y = 0; y < char_rows; y++) {
  70         for (x = 0; x < char_cols; x++) {
  71             c  = *src++;
  72             bg = *src  >> 4;
  73             fg = *src++ & 0xF;
  74             ff_draw_pc_font(dst + x * 8, frame->linesize[0],
  75                             avpriv_cga_font, 8, c, fg, bg);
  76         }
  77         dst += frame->linesize[0] * 8;
  78     }
  79
  80     *got_frame = 1;
  81
  82     return avpkt->size;
  83 }
  84
  85 static av_cold int tmv_decode_init(AVCodecContext *avctx)
  86 {
  87     avctx->pix_fmt = AV_PIX_FMT_PAL8;
  88     return 0;
  89 }
  90
  91 const FFCodec ff_tmv_decoder = {
  92     .p.name         = "tmv",
  93     CODEC_LONG_NAME("8088flex TMV"),
  94     .p.type         = AVMEDIA_TYPE_VIDEO,
  95     .p.id           = AV_CODEC_ID_TMV,
  96     .init           = tmv_decode_init,
  97     FF_CODEC_DECODE_CB(tmv_decode_frame),
  98     .p.capabilities = AV_CODEC_CAP_DR1,
  99 };