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 * @see http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
27 * @see http://www.svatopluk.com/andux/docs/dfvid.html
28 */
29
30#include "libavutil/common.h"
31#include "avcodec.h"
32#include "bethsoftvideo.h"
33#include "bytestream.h"
34#include "codec_internal.h"
35#include "internal.h"
36
37typedef struct BethsoftvidContext {
38    AVFrame *frame;
39    GetByteContext g;
40} BethsoftvidContext;
41
42static av_cold int bethsoftvid_decode_init(AVCodecContext *avctx)
43{
44    BethsoftvidContext *vid = avctx->priv_data;
45    avctx->pix_fmt = AV_PIX_FMT_PAL8;
46
47    vid->frame = av_frame_alloc();
48    if (!vid->frame)
49        return AVERROR(ENOMEM);
50
51    return 0;
52}
53
54static int set_palette(BethsoftvidContext *ctx)
55{
56    uint32_t *palette = (uint32_t *)ctx->frame->data[1];
57    int a;
58
59    if (bytestream2_get_bytes_left(&ctx->g) < 256*3)
60        return AVERROR_INVALIDDATA;
61
62    for(a = 0; a < 256; a++){
63        palette[a] = 0xFFU << 24 | bytestream2_get_be24u(&ctx->g) * 4;
64        palette[a] |= palette[a] >> 6 & 0x30303;
65    }
66    ctx->frame->palette_has_changed = 1;
67    return 0;
68}
69
70static int bethsoftvid_decode_frame(AVCodecContext *avctx, AVFrame *rframe,
71                                    int *got_frame, AVPacket *avpkt)
72{
73    BethsoftvidContext * vid = avctx->priv_data;
74    char block_type;
75    uint8_t * dst;
76    uint8_t * frame_end;
77    int remaining = avctx->width;          // number of bytes remaining on a line
78    int wrap_to_next_line;
79    int code, ret;
80    int yoffset;
81
82    if ((ret = ff_reget_buffer(avctx, vid->frame, 0)) < 0)
83        return ret;
84    wrap_to_next_line = vid->frame->linesize[0] - avctx->width;
85
86    if (avpkt->side_data_elems > 0 &&
87        avpkt->side_data[0].type == AV_PKT_DATA_PALETTE) {
88        bytestream2_init(&vid->g, avpkt->side_data[0].data,
89                         avpkt->side_data[0].size);
90        if ((ret = set_palette(vid)) < 0)
91            return ret;
92    }
93
94    bytestream2_init(&vid->g, avpkt->data, avpkt->size);
95    dst = vid->frame->data[0];
96    frame_end = vid->frame->data[0] + vid->frame->linesize[0] * avctx->height;
97
98    switch(block_type = bytestream2_get_byte(&vid->g)){
99        case PALETTE_BLOCK: {
100            *got_frame = 0;
101            if ((ret = set_palette(vid)) < 0) {
102                av_log(avctx, AV_LOG_ERROR, "error reading palette\n");
103                return ret;
104            }
105            return bytestream2_tell(&vid->g);
106        }
107        case VIDEO_YOFF_P_FRAME:
108            yoffset = bytestream2_get_le16(&vid->g);
109            if(yoffset >= avctx->height)
110                return AVERROR_INVALIDDATA;
111            dst += vid->frame->linesize[0] * yoffset;
112        case VIDEO_P_FRAME:
113        case VIDEO_I_FRAME:
114            break;
115        default:
116            return AVERROR_INVALIDDATA;
117    }
118
119    // main code
120    while((code = bytestream2_get_byte(&vid->g))){
121        int length = code & 0x7f;
122
123        // copy any bytes starting at the current position, and ending at the frame width
124        while(length > remaining){
125            if(code < 0x80)
126                bytestream2_get_buffer(&vid->g, dst, remaining);
127            else if(block_type == VIDEO_I_FRAME)
128                memset(dst, bytestream2_peek_byte(&vid->g), remaining);
129            length -= remaining;      // decrement the number of bytes to be copied
130            dst += remaining + wrap_to_next_line;    // skip over extra bytes at end of frame
131            remaining = avctx->width;
132            if(dst == frame_end)
133                goto end;
134        }
135
136        // copy any remaining bytes after / if line overflows
137        if(code < 0x80)
138            bytestream2_get_buffer(&vid->g, dst, length);
139        else if(block_type == VIDEO_I_FRAME)
140            memset(dst, bytestream2_get_byte(&vid->g), length);
141        remaining -= length;
142        dst += length;
143    }
144    end:
145
146    if ((ret = av_frame_ref(rframe, vid->frame)) < 0)
147        return ret;
148
149    *got_frame = 1;
150
151    return avpkt->size;
152}
153
154static av_cold int bethsoftvid_decode_end(AVCodecContext *avctx)
155{
156    BethsoftvidContext * vid = avctx->priv_data;
157    av_frame_free(&vid->frame);
158    return 0;
159}
160
161const FFCodec ff_bethsoftvid_decoder = {
162    .p.name         = "bethsoftvid",
163    .p.long_name    = NULL_IF_CONFIG_SMALL("Bethesda VID video"),
164    .p.type         = AVMEDIA_TYPE_VIDEO,
165    .p.id           = AV_CODEC_ID_BETHSOFTVID,
166    .priv_data_size = sizeof(BethsoftvidContext),
167    .init           = bethsoftvid_decode_init,
168    .close          = bethsoftvid_decode_end,
169    FF_CODEC_DECODE_CB(bethsoftvid_decode_frame),
170    .p.capabilities = AV_CODEC_CAP_DR1,
171    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE,
172};
173