aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/bethsoftvideo.c
blob: 4ed48c2a1aa8651d12b32dd6d94afc1b3ba23bb7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/*
 * Bethesda VID video decoder
 * Copyright (C) 2007 Nicholas Tung
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file libavcodec/bethsoftvideo.c
 * @brief Bethesda Softworks VID Video Decoder
 * @author Nicholas Tung [ntung (at. ntung com] (2007-03)
 * @sa http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
 * @sa http://www.svatopluk.com/andux/docs/dfvid.html
 */

#include "libavutil/common.h"
#include "dsputil.h"
#include "bethsoftvideo.h"
#include "bytestream.h"

typedef struct BethsoftvidContext {
    AVFrame frame;
} BethsoftvidContext;

static av_cold int bethsoftvid_decode_init(AVCodecContext *avctx)
{
    BethsoftvidContext *vid = avctx->priv_data;
    vid->frame.reference = 1;
    vid->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
        FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
    avctx->pix_fmt = PIX_FMT_PAL8;
    return 0;
}

static void set_palette(AVFrame * frame, const uint8_t * palette_buffer)
{
    uint32_t * palette = (uint32_t *)frame->data[1];
    int a;
    for(a = 0; a < 256; a++){
        palette[a] = AV_RB24(&palette_buffer[a * 3]) * 4;
    }
    frame->palette_has_changed = 1;
}

static int bethsoftvid_decode_frame(AVCodecContext *avctx,
                              void *data, int *data_size,
                              AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    BethsoftvidContext * vid = avctx->priv_data;
    char block_type;
    uint8_t * dst;
    uint8_t * frame_end;
    int remaining = avctx->width;          // number of bytes remaining on a line
    const int wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
    int code;
    int yoffset;

    if (avctx->reget_buffer(avctx, &vid->frame)) {
        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
        return -1;
    }
    dst = vid->frame.data[0];
    frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;

    switch(block_type = *buf++){
        case PALETTE_BLOCK:
            set_palette(&vid->frame, buf);
            return 0;
        case VIDEO_YOFF_P_FRAME:
            yoffset = bytestream_get_le16(&buf);
            if(yoffset >= avctx->height)
                return -1;
            dst += vid->frame.linesize[0] * yoffset;
    }

    // main code
    while((code = *buf++)){
        int length = code & 0x7f;

        // copy any bytes starting at the current position, and ending at the frame width
        while(length > remaining){
            if(code < 0x80)
                bytestream_get_buffer(&buf, dst, remaining);
            else if(block_type == VIDEO_I_FRAME)
                memset(dst, buf[0], remaining);
            length -= remaining;      // decrement the number of bytes to be copied
            dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
            remaining = avctx->width;
            if(dst == frame_end)
                goto end;
        }

        // copy any remaining bytes after / if line overflows
        if(code < 0x80)
            bytestream_get_buffer(&buf, dst, length);
        else if(block_type == VIDEO_I_FRAME)
            memset(dst, *buf++, length);
        remaining -= length;
        dst += length;
    }
    end:

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = vid->frame;

    return buf_size;
}

static av_cold int bethsoftvid_decode_end(AVCodecContext *avctx)
{
    BethsoftvidContext * vid = avctx->priv_data;
    if(vid->frame.data[0])
        avctx->release_buffer(avctx, &vid->frame);
    return 0;
}

AVCodec bethsoftvid_decoder = {
    .name = "bethsoftvid",
    .type = AVMEDIA_TYPE_VIDEO,
    .id = CODEC_ID_BETHSOFTVID,
    .priv_data_size = sizeof(BethsoftvidContext),
    .init = bethsoftvid_decode_init,
    .close = bethsoftvid_decode_end,
    .decode = bethsoftvid_decode_frame,
    .capabilities = CODEC_CAP_DR1,
    .long_name = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
};