2 * Beam Software VB decoder
3 * Copyright (c) 2007 Konstantin Shishkov
5 * This file is part of FFmpeg.
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.
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.
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
23 * @file libavcodec/vb.c
31 #include "bytestream.h"
37 VB_HAS_PALETTE = 0x10,
41 typedef struct VBDecContext {
42 AVCodecContext *avctx;
45 uint8_t *frame, *prev_frame;
47 const uint8_t *stream;
50 static 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
61 static void vb_decode_palette(VBDecContext *c)
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");
71 for(i = start; i <= start + size; i++)
72 c->pal[i] = bytestream_get_be24(&c->stream);
75 static inline int check_pixel(uint8_t *buf, uint8_t *start, uint8_t *end)
77 return buf >= start && buf < end;
80 static inline int check_line(uint8_t *buf, uint8_t *start, uint8_t *end)
82 return buf >= start && (buf + 4) <= end;
85 static int vb_decode_framedata(VBDecContext *c, const uint8_t *buf, int offset)
88 int blk, blocks, t, blk2;
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;
96 prev = c->prev_frame + offset;
99 blocks = (c->avctx->width >> 2) * (c->avctx->height >> 2);
101 for(blk = 0; blk < blocks; blk++){
103 blocktypes = bytestream_get_byte(&buf);
104 switch(blocktypes & 0xC0){
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);
110 memset(cur + y*width, 0, 4);
113 t = bytestream_get_byte(&buf);
115 for(y = 0; y < 4; y++)
116 memcpy(cur + y*width, buf + y*4, 4);
118 }else{ // motion compensation
119 x = ((t & 0xF)^8) - 8;
120 y = ((t >> 4) ^8) - 8;
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);
126 memset(cur + y*width, 0, 4);
130 t = bytestream_get_byte(&buf);
131 for(y = 0; y < 4; y++)
132 memset(cur + y*width, t, 4);
134 case 0xC0: // pattern fill
135 t = bytestream_get_byte(&buf);
137 pattern = vb_patterns[t & 0x3F];
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;
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];
155 cur[x + y*width] = a;
158 av_log(c->avctx, AV_LOG_ERROR, "Invalid opcode seen @%d\n",blk);
167 if(blk2 == (width >> 2)){
176 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt)
178 const uint8_t *buf = avpkt->data;
179 int buf_size = avpkt->size;
180 VBDecContext * const c = avctx->priv_data;
181 uint8_t *outptr, *srcptr;
189 flags = bytestream_get_le16(&c->stream);
192 if(flags & VB_HAS_GMC){
193 i = (int16_t)bytestream_get_le16(&c->stream);
194 j = (int16_t)bytestream_get_le16(&c->stream);
195 offset = i + j * avctx->width;
198 if(flags & VB_HAS_VIDEO){
199 size = bytestream_get_le32(&c->stream);
201 av_log(avctx, AV_LOG_ERROR, "Frame size is too big\n");
204 vb_decode_framedata(c, c->stream, offset);
205 c->stream += size - 4;
208 if(flags & VB_HAS_PALETTE){
209 size = bytestream_get_le32(&c->stream);
211 av_log(avctx, AV_LOG_ERROR, "Palette size is too big\n");
214 vb_decode_palette(c);
218 memcpy(c->pic.data[1], c->pal, AVPALETTE_SIZE);
219 c->pic.palette_has_changed = flags & VB_HAS_PALETTE;
221 outptr = c->pic.data[0];
224 for(i = 0; i < avctx->height; i++){
225 memcpy(outptr, srcptr, avctx->width);
226 srcptr += avctx->width;
227 outptr += c->pic.linesize[0];
230 FFSWAP(uint8_t*, c->frame, c->prev_frame);
232 *data_size = sizeof(AVFrame);
233 *(AVFrame*)data = c->pic;
235 /* always report that the buffer was completely consumed */
239 static av_cold int decode_init(AVCodecContext *avctx)
241 VBDecContext * const c = avctx->priv_data;
244 avctx->pix_fmt = PIX_FMT_PAL8;
246 if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
250 c->pic.reference = 1;
251 if(avctx->get_buffer(avctx, &c->pic) < 0){
252 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
256 c->frame = av_malloc( avctx->width * avctx->height);
257 c->prev_frame = av_malloc( avctx->width * avctx->height);
262 static av_cold int decode_end(AVCodecContext *avctx)
264 VBDecContext *c = avctx->priv_data;
267 av_freep(&c->prev_frame);
269 avctx->release_buffer(avctx, &c->pic);
274 AVCodec vb_decoder = {
278 sizeof(VBDecContext),
283 .long_name = NULL_IF_CONFIG_SMALL("Beam Software VB"),