1/*
2 * Bethesda VID video decoder
3 * Copyright (C) 2007 Nicholas Tung
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 * @brief Bethesda Softworks VID Video Decoder
25 * @author Nicholas Tung [ntung (at. ntung com] (2007-03)
26 * @sa http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
27 * @sa http://www.svatopluk.com/andux/docs/dfvid.html
28 */
29
30#include "libavutil/common.h"
31#include "dsputil.h"
32#include "bethsoftvideo.h"
33#include "bytestream.h"
34
35typedef struct BethsoftvidContext {
36    AVFrame frame;
37} BethsoftvidContext;
38
39static av_cold int bethsoftvid_decode_init(AVCodecContext *avctx)
40{
41    BethsoftvidContext *vid = avctx->priv_data;
42    vid->frame.reference = 1;
43    vid->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
44        FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
45    avctx->pix_fmt = PIX_FMT_PAL8;
46    return 0;
47}
48
49static void set_palette(AVFrame * frame, const uint8_t * palette_buffer)
50{
51    uint32_t * palette = (uint32_t *)frame->data[1];
52    int a;
53    for(a = 0; a < 256; a++){
54        palette[a] = AV_RB24(&palette_buffer[a * 3]) * 4;
55    }
56    frame->palette_has_changed = 1;
57}
58
59static int bethsoftvid_decode_frame(AVCodecContext *avctx,
60                              void *data, int *data_size,
61                              AVPacket *avpkt)
62{
63    const uint8_t *buf = avpkt->data;
64    int buf_size = avpkt->size;
65    BethsoftvidContext * vid = avctx->priv_data;
66    char block_type;
67    uint8_t * dst;
68    uint8_t * frame_end;
69    int remaining = avctx->width;          // number of bytes remaining on a line
70    const int wrap_to_next_line = vid->frame.linesize[0] - avctx->width;
71    int code;
72    int yoffset;
73
74    if (avctx->reget_buffer(avctx, &vid->frame)) {
75        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
76        return -1;
77    }
78    dst = vid->frame.data[0];
79    frame_end = vid->frame.data[0] + vid->frame.linesize[0] * avctx->height;
80
81    switch(block_type = *buf++){
82        case PALETTE_BLOCK:
83            set_palette(&vid->frame, buf);
84            return 0;
85        case VIDEO_YOFF_P_FRAME:
86            yoffset = bytestream_get_le16(&buf);
87            if(yoffset >= avctx->height)
88                return -1;
89            dst += vid->frame.linesize[0] * yoffset;
90    }
91
92    // main code
93    while((code = *buf++)){
94        int length = code & 0x7f;
95
96        // copy any bytes starting at the current position, and ending at the frame width
97        while(length > remaining){
98            if(code < 0x80)
99                bytestream_get_buffer(&buf, dst, remaining);
100            else if(block_type == VIDEO_I_FRAME)
101                memset(dst, buf[0], remaining);
102            length -= remaining;      // decrement the number of bytes to be copied
103            dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
104            remaining = avctx->width;
105            if(dst == frame_end)
106                goto end;
107        }
108
109        // copy any remaining bytes after / if line overflows
110        if(code < 0x80)
111            bytestream_get_buffer(&buf, dst, length);
112        else if(block_type == VIDEO_I_FRAME)
113            memset(dst, *buf++, length);
114        remaining -= length;
115        dst += length;
116    }
117    end:
118
119    *data_size = sizeof(AVFrame);
120    *(AVFrame*)data = vid->frame;
121
122    return buf_size;
123}
124
125static av_cold int bethsoftvid_decode_end(AVCodecContext *avctx)
126{
127    BethsoftvidContext * vid = avctx->priv_data;
128    if(vid->frame.data[0])
129        avctx->release_buffer(avctx, &vid->frame);
130    return 0;
131}
132
133AVCodec bethsoftvid_decoder = {
134    .name = "bethsoftvid",
135    .type = AVMEDIA_TYPE_VIDEO,
136    .id = CODEC_ID_BETHSOFTVID,
137    .priv_data_size = sizeof(BethsoftvidContext),
138    .init = bethsoftvid_decode_init,
139    .close = bethsoftvid_decode_end,
140    .decode = bethsoftvid_decode_frame,
141    .capabilities = CODEC_CAP_DR1,
142    .long_name = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
143};
144