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 * 8088flex TMV video decoder
24 * @file
25 * @author Daniel Verkamp
26 * @sa http://www.oldskool.org/pc/8088_Corruption
27 */
28
29#include "avcodec.h"
30
31#include "cga_data.h"
32
33typedef struct TMVContext {
34    AVFrame pic;
35} TMVContext;
36
37static int tmv_decode_frame(AVCodecContext *avctx, void *data,
38                            int *data_size, AVPacket *avpkt)
39{
40    TMVContext *tmv    = avctx->priv_data;
41    const uint8_t *src = avpkt->data;
42    uint8_t *dst, *dst_char;
43    unsigned char_cols = avctx->width >> 3;
44    unsigned char_rows = avctx->height >> 3;
45    unsigned x, y, mask, char_y, fg, bg, c;
46
47    if (tmv->pic.data[0])
48        avctx->release_buffer(avctx, &tmv->pic);
49
50    if (avctx->get_buffer(avctx, &tmv->pic) < 0) {
51        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
52        return -1;
53    }
54
55    if (avpkt->size < 2*char_rows*char_cols) {
56        av_log(avctx, AV_LOG_ERROR,
57               "Input buffer too small, truncated sample?\n");
58        *data_size = 0;
59        return -1;
60    }
61
62    tmv->pic.pict_type = FF_I_TYPE;
63    tmv->pic.key_frame = 1;
64    dst                = tmv->pic.data[0];
65
66    tmv->pic.palette_has_changed = 1;
67    memcpy(tmv->pic.data[1], ff_cga_palette, 16 * 4);
68
69    for (y = 0; y < char_rows; y++) {
70        for (x = 0; x < char_cols; x++) {
71            c  = *src++ * 8;
72            bg = *src  >> 4;
73            fg = *src++ & 0xF;
74
75            dst_char = dst + x * 8;
76            for (char_y = 0; char_y < 8; char_y++) {
77                for (mask = 0x80; mask; mask >>= 1) {
78                    *dst_char++ = ff_cga_font[c + char_y] & mask ? fg : bg;
79                }
80                dst_char += tmv->pic.linesize[0] - 8;
81            }
82        }
83        dst += tmv->pic.linesize[0] * 8;
84    }
85
86    *data_size = sizeof(AVFrame);
87    *(AVFrame *)data = tmv->pic;
88    return avpkt->size;
89}
90
91static av_cold int tmv_decode_close(AVCodecContext *avctx)
92{
93    TMVContext *tmv = avctx->priv_data;
94
95    if (tmv->pic.data[0])
96        avctx->release_buffer(avctx, &tmv->pic);
97
98    return 0;
99}
100
101AVCodec tmv_decoder = {
102    .name           = "tmv",
103    .type           = AVMEDIA_TYPE_VIDEO,
104    .id             = CODEC_ID_TMV,
105    .priv_data_size = sizeof(TMVContext),
106    .close          = tmv_decode_close,
107    .decode         = tmv_decode_frame,
108    .capabilities   = CODEC_CAP_DR1,
109    .long_name      = NULL_IF_CONFIG_SMALL("8088flex TMV"),
110};
111