1/*
2 * Beam Software VB decoder
3 * Copyright (c) 2007 Konstantin Shishkov
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 * 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    const uint8_t *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 = bytestream_get_byte(&c->stream);
66    size = (bytestream_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] = bytestream_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, const uint8_t *buf, int data_size, int offset)
90{
91    uint8_t *prev, *cur;
92    const uint8_t* data_end = buf + data_size;
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    prev = c->prev_frame + offset;
102    cur = c->frame;
103
104    blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
105    blk2 = 0;
106    for(blk = 0; blk < blocks; blk++){
107        if(!(blk & 3)) {
108            if(buf >= data_end){
109                av_log(c->avctx, AV_LOG_ERROR, "Data pointer out of bounds\n");
110                return -1;
111            }
112            blocktypes = bytestream_get_byte(&buf);
113        }
114        switch(blocktypes & 0xC0){
115        case 0x00: //skip
116            for(y = 0; y < 4; y++)
117                if(check_line(prev + y*width, pstart, pend))
118                    memcpy(cur + y*width, prev + y*width, 4);
119                else
120                    memset(cur + y*width, 0, 4);
121            break;
122        case 0x40:
123            t = bytestream_get_byte(&buf);
124            if(!t){ //raw block
125                if(buf + 16 > data_end){
126                    av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
127                    return -1;
128                }
129                for(y = 0; y < 4; y++)
130                    memcpy(cur + y*width, buf + y*4, 4);
131                buf += 16;
132            }else{ // motion compensation
133                x = ((t & 0xF)^8) - 8;
134                y = ((t >> 4) ^8) - 8;
135                t = x + y*width;
136                for(y = 0; y < 4; y++)
137                    if(check_line(prev + t + y*width, pstart, pend))
138                        memcpy(cur + y*width, prev + t + y*width, 4);
139                    else
140                        memset(cur + y*width, 0, 4);
141            }
142            break;
143        case 0x80: // fill
144            t = bytestream_get_byte(&buf);
145            for(y = 0; y < 4; y++)
146                memset(cur + y*width, t, 4);
147            break;
148        case 0xC0: // pattern fill
149            if(buf + 2 > data_end){
150                av_log(c->avctx, AV_LOG_ERROR, "Insufficient data\n");
151                return -1;
152            }
153            t = bytestream_get_byte(&buf);
154            pattype = t >> 6;
155            pattern = vb_patterns[t & 0x3F];
156            switch(pattype){
157            case 0:
158                a = bytestream_get_byte(&buf);
159                b = bytestream_get_byte(&buf);
160                for(y = 0; y < 4; y++)
161                    for(x = 0; x < 4; x++, pattern >>= 1)
162                        cur[x + y*width] = (pattern & 1) ? b : a;
163                break;
164            case 1:
165                pattern = ~pattern;
166            case 2:
167                a = bytestream_get_byte(&buf);
168                for(y = 0; y < 4; y++)
169                    for(x = 0; x < 4; x++, pattern >>= 1)
170                        if(pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))
171                            cur[x + y*width] = prev[x + y*width];
172                        else
173                            cur[x + y*width] = a;
174                break;
175            case 3:
176                av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n",blk);
177                return -1;
178            }
179            break;
180        }
181        blocktypes <<= 2;
182        cur  += 4;
183        prev += 4;
184        blk2++;
185        if(blk2 == (width >> 2)){
186            blk2 = 0;
187            cur  += width * 3;
188            prev += width * 3;
189        }
190    }
191    return 0;
192}
193
194static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
195{
196    const uint8_t *buf = avpkt->data;
197    int buf_size = avpkt->size;
198    VBDecContext * const c = avctx->priv_data;
199    uint8_t *outptr, *srcptr;
200    int i, j;
201    int flags;
202    uint32_t size;
203    int rest = buf_size;
204    int offset = 0;
205
206    if(c->pic.data[0])
207        avctx->release_buffer(avctx, &c->pic);
208    c->pic.reference = 1;
209    if(avctx->get_buffer(avctx, &c->pic) < 0){
210        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
211        return -1;
212    }
213
214    c->stream = buf;
215    flags = bytestream_get_le16(&c->stream);
216    rest -= 2;
217
218    if(flags & VB_HAS_GMC){
219        i = (int16_t)bytestream_get_le16(&c->stream);
220        j = (int16_t)bytestream_get_le16(&c->stream);
221        offset = i + j * avctx->width;
222        rest -= 4;
223    }
224    if(flags & VB_HAS_VIDEO){
225        size = bytestream_get_le32(&c->stream);
226        if(size > rest){
227            av_log(avctx, AV_LOG_ERROR, "Frame size is too big\n");
228            return -1;
229        }
230        vb_decode_framedata(c, c->stream, size, offset);
231        c->stream += size - 4;
232        rest -= size;
233    }
234    if(flags & VB_HAS_PALETTE){
235        size = bytestream_get_le32(&c->stream);
236        if(size > rest){
237            av_log(avctx, AV_LOG_ERROR, "Palette size is too big\n");
238            return -1;
239        }
240        vb_decode_palette(c, size);
241        rest -= size;
242    }
243
244    memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
245    c->pic.palette_has_changed = flags & VB_HAS_PALETTE;
246
247    outptr = c->pic.data[0];
248    srcptr = c->frame;
249
250    for(i = 0; i < avctx->height; i++){
251        memcpy(outptr, srcptr, avctx->width);
252        srcptr += avctx->width;
253        outptr += c->pic.linesize[0];
254    }
255
256    FFSWAP(uint8_t*, c->frame, c->prev_frame);
257
258    *data_size = sizeof(AVFrame);
259    *(AVFrame*)data = c->pic;
260
261    /* always report that the buffer was completely consumed */
262    return buf_size;
263}
264
265static av_cold int decode_init(AVCodecContext *avctx)
266{
267    VBDecContext * const c = avctx->priv_data;
268
269    c->avctx = avctx;
270    avctx->pix_fmt = PIX_FMT_PAL8;
271
272    c->frame      = av_mallocz(avctx->width * avctx->height);
273    c->prev_frame = av_mallocz(avctx->width * avctx->height);
274
275    return 0;
276}
277
278static av_cold int decode_end(AVCodecContext *avctx)
279{
280    VBDecContext *c = avctx->priv_data;
281
282    av_freep(&c->frame);
283    av_freep(&c->prev_frame);
284    if(c->pic.data[0])
285        avctx->release_buffer(avctx, &c->pic);
286
287    return 0;
288}
289
290AVCodec vb_decoder = {
291    "vb",
292    AVMEDIA_TYPE_VIDEO,
293    CODEC_ID_VB,
294    sizeof(VBDecContext),
295    decode_init,
296    NULL,
297    decode_end,
298    decode_frame,
299    .long_name = NULL_IF_CONFIG_SMALL("Beam Software VB"),
300};
301
302