1/*
2 * Beam Software VB decoder
3 * Copyright (c) 2007 Konstantin Shishkov
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 * VB Video decoder
25 */
26
27#include <stdio.h>
28#include <stdlib.h>
29
30#include "avcodec.h"
31#include "bytestream.h"
32
33enum VBFlags{
34    VB_HAS_GMC     = 0x01,
35    VB_HAS_AUDIO   = 0x04,
36    VB_HAS_VIDEO   = 0x08,
37    VB_HAS_PALETTE = 0x10,
38    VB_HAS_LENGTH  = 0x20
39};
40
41typedef struct VBDecContext {
42    AVCodecContext *avctx;
43    AVFrame pic;
44
45    uint8_t *frame, *prev_frame;
46    uint32_t pal[AVPALETTE_COUNT];
47    GetByteContext stream;
48} VBDecContext;
49
50static const uint16_t vb_patterns[64] = {
51    0x0660, 0xFF00, 0xCCCC, 0xF000, 0x8888, 0x000F, 0x1111, 0xFEC8,
52    0x8CEF, 0x137F, 0xF731, 0xC800, 0x008C, 0x0013, 0x3100, 0xCC00,
53    0x00CC, 0x0033, 0x3300, 0x0FF0, 0x6666, 0x00F0, 0x0F00, 0x2222,
54    0x4444, 0xF600, 0x8CC8, 0x006F, 0x1331, 0x318C, 0xC813, 0x33CC,
55    0x6600, 0x0CC0, 0x0066, 0x0330, 0xF900, 0xC88C, 0x009F, 0x3113,
56    0x6000, 0x0880, 0x0006, 0x0110, 0xCC88, 0xFC00, 0x00CF, 0x88CC,
57    0x003F, 0x1133, 0x3311, 0xF300, 0x6FF6, 0x0603, 0x08C6, 0x8C63,
58    0xC631, 0x6310, 0xC060, 0x0136, 0x136C, 0x36C8, 0x6C80, 0x324C
59};
60
61static void vb_decode_palette(VBDecContext *c, int data_size)
62{
63    int start, size, i;
64
65    start = bytestream2_get_byte(&c->stream);
66    size = (bytestream2_get_byte(&c->stream) - 1) & 0xFF;
67    if(start + size > 255){
68        av_log(c->avctx, AV_LOG_ERROR, "Palette change runs beyond entry 256\n");
69        return;
70    }
71    if(size*3+2 > data_size){
72        av_log(c->avctx, AV_LOG_ERROR, "Palette data runs beyond chunk size\n");
73        return;
74    }
75    for(i = start; i <= start + size; i++)
76        c->pal[i] = bytestream2_get_be24(&c->stream);
77}
78
79static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)
80{
81    return buf >= start && buf < end;
82}
83
84static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)
85{
86    return buf >= start && (buf + 4) <= end;
87}
88
89static int vb_decode_framedata(VBDecContext *c, int offset)
90{
91    GetByteContext g;
92    uint8_t *prev, *cur;
93    int blk, blocks, t, blk2;
94    int blocktypes = 0;
95    int x, y, a, b;
96    int pattype, pattern;
97    const int width = c->avctx->width;
98    uint8_t *pstart = c->prev_frame;
99    uint8_t *pend = c->prev_frame + width*c->avctx->height;
100
101    g = c->stream;
102
103    prev = c->prev_frame + offset;
104    cur = c->frame;
105
106    blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
107    blk2 = 0;
108    for(blk = 0; blk < blocks; blk++){
109        if(!(blk & 3)) {
110            blocktypes = bytestream2_get_byte(&g);
111        }
112        switch(blocktypes & 0xC0){
113        case 0x00: //skip
114            for(y = 0; y < 4; y++)
115                if(check_line(prev + y*width, pstart, pend))
116                    memcpy(cur + y*width, prev + y*width, 4);
117                else
118                    memset(cur + y*width, 0, 4);
119            break;
120        case 0x40:
121            t = bytestream2_get_byte(&g);
122            if(!t){ //raw block
123                if (bytestream2_get_bytes_left(&g) < 16) {
124                    av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
125                    return -1;
126                }
127                for(y = 0; y < 4; y++)
128                    bytestream2_get_buffer(&g, cur + y * width, 4);
129            }else{ // motion compensation
130                x = ((t & 0xF)^8) - 8;
131                y = ((t >> 4) ^8) - 8;
132                t = x + y*width;
133                for(y = 0; y < 4; y++)
134                    if(check_line(prev + t + y*width, pstart, pend))
135                        memcpy(cur + y*width, prev + t + y*width, 4);
136                    else
137                        memset(cur + y*width, 0, 4);
138            }
139            break;
140        case 0x80: // fill
141            t = bytestream2_get_byte(&g);
142            for(y = 0; y < 4; y++)
143                memset(cur + y*width, t, 4);
144            break;
145        case 0xC0: // pattern fill
146            t = bytestream2_get_byte(&g);
147            pattype = t >> 6;
148            pattern = vb_patterns[t & 0x3F];
149            switch(pattype){
150            case 0:
151                a = bytestream2_get_byte(&g);
152                b = bytestream2_get_byte(&g);
153                for(y = 0; y < 4; y++)
154                    for(x = 0; x < 4; x++, pattern >>= 1)
155                        cur[x + y*width] = (pattern & 1) ? b : a;
156                break;
157            case 1:
158                pattern = ~pattern;
159            case 2:
160                a = bytestream2_get_byte(&g);
161                for(y = 0; y < 4; y++)
162                    for(x = 0; x < 4; x++, pattern >>= 1)
163                        if(pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))
164                            cur[x + y*width] = prev[x + y*width];
165                        else
166                            cur[x + y*width] = a;
167                break;
168            case 3:
169                av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n",blk);
170                return -1;
171            }
172            break;
173        }
174        blocktypes <<= 2;
175        cur  += 4;
176        prev += 4;
177        blk2++;
178        if(blk2 == (width >> 2)){
179            blk2 = 0;
180            cur  += width * 3;
181            prev += width * 3;
182        }
183    }
184    return 0;
185}
186
187static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
188{
189    VBDecContext * const c = avctx->priv_data;
190    uint8_t *outptr, *srcptr;
191    int i, j;
192    int flags;
193    uint32_t size;
194    int offset = 0;
195
196    bytestream2_init(&c->stream, avpkt->data, avpkt->size);
197
198    if(c->pic.data[0])
199        avctx->release_buffer(avctx, &c->pic);
200    c->pic.reference = 1;
201    if(avctx->get_buffer(avctx, &c->pic) < 0){
202        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
203        return -1;
204    }
205
206    flags = bytestream2_get_le16(&c->stream);
207
208    if(flags & VB_HAS_GMC){
209        i = (int16_t)bytestream2_get_le16(&c->stream);
210        j = (int16_t)bytestream2_get_le16(&c->stream);
211        offset = i + j * avctx->width;
212    }
213    if(flags & VB_HAS_VIDEO){
214        size = bytestream2_get_le32(&c->stream);
215        vb_decode_framedata(c, offset);
216        bytestream2_skip(&c->stream, size - 4);
217    }
218    if(flags & VB_HAS_PALETTE){
219        size = bytestream2_get_le32(&c->stream);
220        vb_decode_palette(c, size);
221    }
222
223    memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
224    c->pic.palette_has_changed = flags & VB_HAS_PALETTE;
225
226    outptr = c->pic.data[0];
227    srcptr = c->frame;
228
229    for(i = 0; i < avctx->height; i++){
230        memcpy(outptr, srcptr, avctx->width);
231        srcptr += avctx->width;
232        outptr += c->pic.linesize[0];
233    }
234
235    FFSWAP(uint8_t*, c->frame, c->prev_frame);
236
237    *data_size = sizeof(AVFrame);
238    *(AVFrame*)data = c->pic;
239
240    /* always report that the buffer was completely consumed */
241    return avpkt->size;
242}
243
244static av_cold int decode_init(AVCodecContext *avctx)
245{
246    VBDecContext * const c = avctx->priv_data;
247
248    c->avctx = avctx;
249    avctx->pix_fmt = PIX_FMT_PAL8;
250
251    c->frame      = av_mallocz(avctx->width * avctx->height);
252    c->prev_frame = av_mallocz(avctx->width * avctx->height);
253
254    return 0;
255}
256
257static av_cold int decode_end(AVCodecContext *avctx)
258{
259    VBDecContext *c = avctx->priv_data;
260
261    av_freep(&c->frame);
262    av_freep(&c->prev_frame);
263    if(c->pic.data[0])
264        avctx->release_buffer(avctx, &c->pic);
265
266    return 0;
267}
268
269AVCodec ff_vb_decoder = {
270    .name           = "vb",
271    .type           = AVMEDIA_TYPE_VIDEO,
272    .id             = CODEC_ID_VB,
273    .priv_data_size = sizeof(VBDecContext),
274    .init           = decode_init,
275    .close          = decode_end,
276    .decode         = decode_frame,
277    .long_name = NULL_IF_CONFIG_SMALL("Beam Software VB"),
278};
279
280