summaryrefslogtreecommitdiffstats
path: root/libavcodec/vb.c
blob: 96387b6d1d9e175da3fbaae6b5869c89253a3577 (plain)
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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
/*
 * Beam Software VB decoder
 * Copyright (c) 2007 Konstantin Shishkov
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * VB Video decoder
 */

#include <stdio.h>
#include <stdlib.h>

#include "avcodec.h"
#include "bytestream.h"

enum VBFlags{
    VB_HAS_GMC     = 0x01,
    VB_HAS_AUDIO   = 0x04,
    VB_HAS_VIDEO   = 0x08,
    VB_HAS_PALETTE = 0x10,
    VB_HAS_LENGTH  = 0x20
};

typedef struct VBDecContext {
    AVCodecContext *avctx;
    AVFrame pic;

    uint8_t *frame, *prev_frame;
    uint32_t pal[AVPALETTE_COUNT];
    const uint8_t *stream;
} VBDecContext;

static const uint16_t vb_patterns[64] = {
    0x0660, 0xFF00, 0xCCCC, 0xF000, 0x8888, 0x000F, 0x1111, 0xFEC8,
    0x8CEF, 0x137F, 0xF731, 0xC800, 0x008C, 0x0013, 0x3100, 0xCC00,
    0x00CC, 0x0033, 0x3300, 0x0FF0, 0x6666, 0x00F0, 0x0F00, 0x2222,
    0x4444, 0xF600, 0x8CC8, 0x006F, 0x1331, 0x318C, 0xC813, 0x33CC,
    0x6600, 0x0CC0, 0x0066, 0x0330, 0xF900, 0xC88C, 0x009F, 0x3113,
    0x6000, 0x0880, 0x0006, 0x0110, 0xCC88, 0xFC00, 0x00CF, 0x88CC,
    0x003F, 0x1133, 0x3311, 0xF300, 0x6FF6, 0x0603, 0x08C6, 0x8C63,
    0xC631, 0x6310, 0xC060, 0x0136, 0x136C, 0x36C8, 0x6C80, 0x324C
};

static void vb_decode_palette(VBDecContext *c, int data_size)
{
    int start, size, i;

    start = bytestream_get_byte(&c->stream);
    size = (bytestream_get_byte(&c->stream) - 1) & 0xFF;
    if(start + size > 255){
        av_log(c->avctx, AV_LOG_ERROR, "Palette change runs beyond entry 256\n");
        return;
    }
    if(size*3+2 > data_size){
        av_log(c->avctx, AV_LOG_ERROR, "Palette data runs beyond chunk size\n");
        return;
    }
    for(i = start; i <= start + size; i++)
        c->pal[i] = bytestream_get_be24(&c->stream);
}

static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)
{
    return buf >= start && buf < end;
}

static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)
{
    return buf >= start && (buf + 4) <= end;
}

static int vb_decode_framedata(VBDecContext *c, const uint8_t *buf, int data_size, int offset)
{
    uint8_t *prev, *cur;
    const uint8_t* data_end = buf + data_size;
    int blk, blocks, t, blk2;
    int blocktypes = 0;
    int x, y, a, b;
    int pattype, pattern;
    const int width = c->avctx->width;
    uint8_t *pstart = c->prev_frame;
    uint8_t *pend = c->prev_frame + width*c->avctx->height;

    prev = c->prev_frame + offset;
    cur = c->frame;

    blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
    blk2 = 0;
    for(blk = 0; blk < blocks; blk++){
        if(!(blk & 3)) {
            if(buf >= data_end){
                av_log(c->avctx, AV_LOG_ERROR, "Data pointer out of bounds\n");
                return -1;
            }
            blocktypes = bytestream_get_byte(&buf);
        }
        switch(blocktypes & 0xC0){
        case 0x00: //skip
            for(y = 0; y < 4; y++)
                if(check_line(prev + y*width, pstart, pend))
                    memcpy(cur + y*width, prev + y*width, 4);
                else
                    memset(cur + y*width, 0, 4);
            break;
        case 0x40:
            t = bytestream_get_byte(&buf);
            if(!t){ //raw block
                if(buf + 16 > data_end){
                    av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
                    return -1;
                }
                for(y = 0; y < 4; y++)
                    memcpy(cur + y*width, buf + y*4, 4);
                buf += 16;
            }else{ // motion compensation
                x = ((t & 0xF)^8) - 8;
                y = ((t >> 4) ^8) - 8;
                t = x + y*width;
                for(y = 0; y < 4; y++)
                    if(check_line(prev + t + y*width, pstart, pend))
                        memcpy(cur + y*width, prev + t + y*width, 4);
                    else
                        memset(cur + y*width, 0, 4);
            }
            break;
        case 0x80: // fill
            t = bytestream_get_byte(&buf);
            for(y = 0; y < 4; y++)
                memset(cur + y*width, t, 4);
            break;
        case 0xC0: // pattern fill
            if(buf + 2 > data_end){
                av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
                return -1;
            }
            t = bytestream_get_byte(&buf);
            pattype = t >> 6;
            pattern = vb_patterns[t & 0x3F];
            switch(pattype){
            case 0:
                a = bytestream_get_byte(&buf);
                b = bytestream_get_byte(&buf);
                for(y = 0; y < 4; y++)
                    for(x = 0; x < 4; x++, pattern >>= 1)
                        cur[x + y*width] = (pattern & 1) ? b : a;
                break;
            case 1:
                pattern = ~pattern;
            case 2:
                a = bytestream_get_byte(&buf);
                for(y = 0; y < 4; y++)
                    for(x = 0; x < 4; x++, pattern >>= 1)
                        if(pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))
                            cur[x + y*width] = prev[x + y*width];
                        else
                            cur[x + y*width] = a;
                break;
            case 3:
                av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n",blk);
                return -1;
            }
            break;
        }
        blocktypes <<= 2;
        cur  += 4;
        prev += 4;
        blk2++;
        if(blk2 == (width >> 2)){
            blk2 = 0;
            cur  += width * 3;
            prev += width * 3;
        }
    }
    return 0;
}

static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    VBDecContext * const c = avctx->priv_data;
    uint8_t *outptr, *srcptr;
    int i, j;
    int flags;
    uint32_t size;
    int rest = buf_size;
    int offset = 0;

    if(c->pic.data[0])
        avctx->release_buffer(avctx, &c->pic);
    c->pic.reference = 1;
    if(avctx->get_buffer(avctx, &c->pic) < 0){
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }

    c->stream = buf;
    flags = bytestream_get_le16(&c->stream);
    rest -= 2;

    if(flags & VB_HAS_GMC){
        i = (int16_t)bytestream_get_le16(&c->stream);
        j = (int16_t)bytestream_get_le16(&c->stream);
        offset = i + j * avctx->width;
        rest -= 4;
    }
    if(flags & VB_HAS_VIDEO){
        size = bytestream_get_le32(&c->stream);
        if(size > rest){
            av_log(avctx, AV_LOG_ERROR, "Frame size is too big\n");
            return -1;
        }
        vb_decode_framedata(c, c->stream, size, offset);
        c->stream += size - 4;
        rest -= size;
    }
    if(flags & VB_HAS_PALETTE){
        size = bytestream_get_le32(&c->stream);
        if(size > rest){
            av_log(avctx, AV_LOG_ERROR, "Palette size is too big\n");
            return -1;
        }
        vb_decode_palette(c, size);
        rest -= size;
    }

    memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
    c->pic.palette_has_changed = flags & VB_HAS_PALETTE;

    outptr = c->pic.data[0];
    srcptr = c->frame;

    for(i = 0; i < avctx->height; i++){
        memcpy(outptr, srcptr, avctx->width);
        srcptr += avctx->width;
        outptr += c->pic.linesize[0];
    }

    FFSWAP(uint8_t*, c->frame, c->prev_frame);

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = c->pic;

    /* always report that the buffer was completely consumed */
    return buf_size;
}

static av_cold int decode_init(AVCodecContext *avctx)
{
    VBDecContext * const c = avctx->priv_data;

    c->avctx = avctx;
    avctx->pix_fmt = PIX_FMT_PAL8;

    c->frame      = av_mallocz(avctx->width * avctx->height);
    c->prev_frame = av_mallocz(avctx->width * avctx->height);

    return 0;
}

static av_cold int decode_end(AVCodecContext *avctx)
{
    VBDecContext *c = avctx->priv_data;

    av_freep(&c->frame);
    av_freep(&c->prev_frame);
    if(c->pic.data[0])
        avctx->release_buffer(avctx, &c->pic);

    return 0;
}

AVCodec ff_vb_decoder = {
    .name           = "vb",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = CODEC_ID_VB,
    .priv_data_size = sizeof(VBDecContext),
    .init           = decode_init,
    .close          = decode_end,
    .decode         = decode_frame,
    .long_name = NULL_IF_CONFIG_SMALL("Beam Software VB"),
};

OpenPOWER on IntegriCloud