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 libavcodec/vb.c
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[256];
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)
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    for(i = start; i <= start + size; i++)
72        c->pal[i] = bytestream_get_be24(&c->stream);
73}
74
75static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)
76{
77    return buf >= start && buf < end;
78}
79
80static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)
81{
82    return buf >= start && (buf + 4) <= end;
83}
84
85static int vb_decode_framedata(VBDecContext *c, const uint8_t *buf, int offset)
86{
87    uint8_t *prev, *cur;
88    int blk, blocks, t, blk2;
89    int blocktypes = 0;
90    int x, y, a, b;
91    int pattype, pattern;
92    const int width = c->avctx->width;
93    uint8_t *pstart = c->prev_frame;
94    uint8_t *pend = c->prev_frame + width*c->avctx->height;
95
96    prev = c->prev_frame + offset;
97    cur = c->frame;
98
99    blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
100    blk2 = 0;
101    for(blk = 0; blk < blocks; blk++){
102        if(!(blk & 3))
103            blocktypes = bytestream_get_byte(&buf);
104        switch(blocktypes & 0xC0){
105        case 0x00: //skip
106            for(y = 0; y < 4; y++)
107                if(check_line(prev + y*width, pstart, pend))
108                    memcpy(cur + y*width, prev + y*width, 4);
109                else
110                    memset(cur + y*width, 0, 4);
111            break;
112        case 0x40:
113            t = bytestream_get_byte(&buf);
114            if(!t){ //raw block
115                for(y = 0; y < 4; y++)
116                    memcpy(cur + y*width, buf + y*4, 4);
117                buf += 16;
118            }else{ // motion compensation
119                x = ((t & 0xF)^8) - 8;
120                y = ((t >> 4) ^8) - 8;
121                t = x + y*width;
122                for(y = 0; y < 4; y++)
123                    if(check_line(prev + t + y*width, pstart, pend))
124                        memcpy(cur + y*width, prev + t + y*width, 4);
125                    else
126                        memset(cur + y*width, 0, 4);
127            }
128            break;
129        case 0x80: // fill
130            t = bytestream_get_byte(&buf);
131            for(y = 0; y < 4; y++)
132                memset(cur + y*width, t, 4);
133            break;
134        case 0xC0: // pattern fill
135            t = bytestream_get_byte(&buf);
136            pattype = t >> 6;
137            pattern = vb_patterns[t & 0x3F];
138            switch(pattype){
139            case 0:
140                a = bytestream_get_byte(&buf);
141                b = bytestream_get_byte(&buf);
142                for(y = 0; y < 4; y++)
143                    for(x = 0; x < 4; x++, pattern >>= 1)
144                        cur[x + y*width] = (pattern & 1) ? b : a;
145                break;
146            case 1:
147                pattern = ~pattern;
148            case 2:
149                a = bytestream_get_byte(&buf);
150                for(y = 0; y < 4; y++)
151                    for(x = 0; x < 4; x++, pattern >>= 1)
152                        if(pattern & 1 && check_pixel(prev + x + y*width, pstart, pend))
153                            cur[x + y*width] = prev[x + y*width];
154                        else
155                            cur[x + y*width] = a;
156                break;
157            case 3:
158                av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n",blk);
159                return -1;
160            }
161            break;
162        }
163        blocktypes <<= 2;
164        cur  += 4;
165        prev += 4;
166        blk2++;
167        if(blk2 == (width >> 2)){
168            blk2 = 0;
169            cur  += width * 3;
170            prev += width * 3;
171        }
172    }
173    return 0;
174}
175
176static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size)
177{
178    VBDecContext * const c = avctx->priv_data;
179    uint8_t *outptr, *srcptr;
180    int i, j;
181    int flags;
182    uint32_t size;
183    int rest = buf_size;
184    int offset = 0;
185
186    c->stream = buf;
187    flags = bytestream_get_le16(&c->stream);
188    rest -= 2;
189
190    if(flags & VB_HAS_GMC){
191        i = (int16_t)bytestream_get_le16(&c->stream);
192        j = (int16_t)bytestream_get_le16(&c->stream);
193        offset = i + j * avctx->width;
194        rest -= 4;
195    }
196    if(flags & VB_HAS_VIDEO){
197        size = bytestream_get_le32(&c->stream);
198        if(size > rest){
199            av_log(avctx, AV_LOG_ERROR, "Frame size is too big\n");
200            return -1;
201        }
202        vb_decode_framedata(c, c->stream, offset);
203        c->stream += size - 4;
204        rest -= size;
205    }
206    if(flags & VB_HAS_PALETTE){
207        size = bytestream_get_le32(&c->stream);
208        if(size > rest){
209            av_log(avctx, AV_LOG_ERROR, "Palette size is too big\n");
210            return -1;
211        }
212        vb_decode_palette(c);
213        rest -= size;
214    }
215
216    memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
217    c->pic.palette_has_changed = flags & VB_HAS_PALETTE;
218
219    outptr = c->pic.data[0];
220    srcptr = c->frame;
221
222    for(i = 0; i < avctx->height; i++){
223        memcpy(outptr, srcptr, avctx->width);
224        srcptr += avctx->width;
225        outptr += c->pic.linesize[0];
226    }
227
228    FFSWAP(uint8_t*, c->frame, c->prev_frame);
229
230    *data_size = sizeof(AVFrame);
231    *(AVFrame*)data = c->pic;
232
233    /* always report that the buffer was completely consumed */
234    return buf_size;
235}
236
237static av_cold int decode_init(AVCodecContext *avctx)
238{
239    VBDecContext * const c = avctx->priv_data;
240
241    c->avctx = avctx;
242    avctx->pix_fmt = PIX_FMT_PAL8;
243
244    if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
245        return -1;
246    }
247
248    c->pic.reference = 1;
249    if(avctx->get_buffer(avctx, &c->pic) < 0){
250        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
251        return -1;
252    }
253
254    c->frame      = av_malloc( avctx->width * avctx->height);
255    c->prev_frame = av_malloc( avctx->width * avctx->height);
256
257    return 0;
258}
259
260static av_cold int decode_end(AVCodecContext *avctx)
261{
262    VBDecContext *c = avctx->priv_data;
263
264    av_freep(&c->frame);
265    av_freep(&c->prev_frame);
266    if(c->pic.data[0])
267        avctx->release_buffer(avctx, &c->pic);
268
269    return 0;
270}
271
272AVCodec vb_decoder = {
273    "vb",
274    CODEC_TYPE_VIDEO,
275    CODEC_ID_VB,
276    sizeof(VBDecContext),
277    decode_init,
278    NULL,
279    decode_end,
280    decode_frame,
281    .long_name = NULL_IF_CONFIG_SMALL("Beam Software VB"),
282};
283
284