1/* 2 * KMVC decoder 3 * Copyright (c) 2006 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 * Karl Morton's Video Codec decoder 25 */ 26 27#include <stdio.h> 28#include <stdlib.h> 29 30#include "avcodec.h" 31#include "bytestream.h" 32 33#define KMVC_KEYFRAME 0x80 34#define KMVC_PALETTE 0x40 35#define KMVC_METHOD 0x0F 36 37/* 38 * Decoder context 39 */ 40typedef struct KmvcContext { 41 AVCodecContext *avctx; 42 AVFrame pic; 43 44 int setpal; 45 int palsize; 46 uint32_t pal[256]; 47 uint8_t *cur, *prev; 48 uint8_t *frm0, *frm1; 49} KmvcContext; 50 51typedef struct BitBuf { 52 int bits; 53 int bitbuf; 54} BitBuf; 55 56#define BLK(data, x, y) data[(x) + (y) * 320] 57 58#define kmvc_init_getbits(bb, src) bb.bits = 7; bb.bitbuf = *src++; 59 60#define kmvc_getbit(bb, src, res) {\ 61 res = 0; \ 62 if (bb.bitbuf & (1 << bb.bits)) res = 1; \ 63 bb.bits--; \ 64 if(bb.bits == -1) { \ 65 bb.bitbuf = *src++; \ 66 bb.bits = 7; \ 67 } \ 68} 69 70static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h) 71{ 72 BitBuf bb; 73 int res, val; 74 int i, j; 75 int bx, by; 76 int l0x, l1x, l0y, l1y; 77 int mx, my; 78 79 kmvc_init_getbits(bb, src); 80 81 for (by = 0; by < h; by += 8) 82 for (bx = 0; bx < w; bx += 8) { 83 kmvc_getbit(bb, src, res); 84 if (!res) { // fill whole 8x8 block 85 val = *src++; 86 for (i = 0; i < 64; i++) 87 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val; 88 } else { // handle four 4x4 subblocks 89 for (i = 0; i < 4; i++) { 90 l0x = bx + (i & 1) * 4; 91 l0y = by + (i & 2) * 2; 92 kmvc_getbit(bb, src, res); 93 if (!res) { 94 kmvc_getbit(bb, src, res); 95 if (!res) { // fill whole 4x4 block 96 val = *src++; 97 for (j = 0; j < 16; j++) 98 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val; 99 } else { // copy block from already decoded place 100 val = *src++; 101 mx = val & 0xF; 102 my = val >> 4; 103 for (j = 0; j < 16; j++) 104 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = 105 BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my); 106 } 107 } else { // descend to 2x2 sub-sub-blocks 108 for (j = 0; j < 4; j++) { 109 l1x = l0x + (j & 1) * 2; 110 l1y = l0y + (j & 2); 111 kmvc_getbit(bb, src, res); 112 if (!res) { 113 kmvc_getbit(bb, src, res); 114 if (!res) { // fill whole 2x2 block 115 val = *src++; 116 BLK(ctx->cur, l1x, l1y) = val; 117 BLK(ctx->cur, l1x + 1, l1y) = val; 118 BLK(ctx->cur, l1x, l1y + 1) = val; 119 BLK(ctx->cur, l1x + 1, l1y + 1) = val; 120 } else { // copy block from already decoded place 121 val = *src++; 122 mx = val & 0xF; 123 my = val >> 4; 124 BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my); 125 BLK(ctx->cur, l1x + 1, l1y) = 126 BLK(ctx->cur, l1x + 1 - mx, l1y - my); 127 BLK(ctx->cur, l1x, l1y + 1) = 128 BLK(ctx->cur, l1x - mx, l1y + 1 - my); 129 BLK(ctx->cur, l1x + 1, l1y + 1) = 130 BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my); 131 } 132 } else { // read values for block 133 BLK(ctx->cur, l1x, l1y) = *src++; 134 BLK(ctx->cur, l1x + 1, l1y) = *src++; 135 BLK(ctx->cur, l1x, l1y + 1) = *src++; 136 BLK(ctx->cur, l1x + 1, l1y + 1) = *src++; 137 } 138 } 139 } 140 } 141 } 142 } 143} 144 145static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h) 146{ 147 BitBuf bb; 148 int res, val; 149 int i, j; 150 int bx, by; 151 int l0x, l1x, l0y, l1y; 152 int mx, my; 153 154 kmvc_init_getbits(bb, src); 155 156 for (by = 0; by < h; by += 8) 157 for (bx = 0; bx < w; bx += 8) { 158 kmvc_getbit(bb, src, res); 159 if (!res) { 160 kmvc_getbit(bb, src, res); 161 if (!res) { // fill whole 8x8 block 162 val = *src++; 163 for (i = 0; i < 64; i++) 164 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val; 165 } else { // copy block from previous frame 166 for (i = 0; i < 64; i++) 167 BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = 168 BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3)); 169 } 170 } else { // handle four 4x4 subblocks 171 for (i = 0; i < 4; i++) { 172 l0x = bx + (i & 1) * 4; 173 l0y = by + (i & 2) * 2; 174 kmvc_getbit(bb, src, res); 175 if (!res) { 176 kmvc_getbit(bb, src, res); 177 if (!res) { // fill whole 4x4 block 178 val = *src++; 179 for (j = 0; j < 16; j++) 180 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val; 181 } else { // copy block 182 val = *src++; 183 mx = (val & 0xF) - 8; 184 my = (val >> 4) - 8; 185 for (j = 0; j < 16; j++) 186 BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = 187 BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my); 188 } 189 } else { // descend to 2x2 sub-sub-blocks 190 for (j = 0; j < 4; j++) { 191 l1x = l0x + (j & 1) * 2; 192 l1y = l0y + (j & 2); 193 kmvc_getbit(bb, src, res); 194 if (!res) { 195 kmvc_getbit(bb, src, res); 196 if (!res) { // fill whole 2x2 block 197 val = *src++; 198 BLK(ctx->cur, l1x, l1y) = val; 199 BLK(ctx->cur, l1x + 1, l1y) = val; 200 BLK(ctx->cur, l1x, l1y + 1) = val; 201 BLK(ctx->cur, l1x + 1, l1y + 1) = val; 202 } else { // copy block 203 val = *src++; 204 mx = (val & 0xF) - 8; 205 my = (val >> 4) - 8; 206 BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my); 207 BLK(ctx->cur, l1x + 1, l1y) = 208 BLK(ctx->prev, l1x + 1 + mx, l1y + my); 209 BLK(ctx->cur, l1x, l1y + 1) = 210 BLK(ctx->prev, l1x + mx, l1y + 1 + my); 211 BLK(ctx->cur, l1x + 1, l1y + 1) = 212 BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my); 213 } 214 } else { // read values for block 215 BLK(ctx->cur, l1x, l1y) = *src++; 216 BLK(ctx->cur, l1x + 1, l1y) = *src++; 217 BLK(ctx->cur, l1x, l1y + 1) = *src++; 218 BLK(ctx->cur, l1x + 1, l1y + 1) = *src++; 219 } 220 } 221 } 222 } 223 } 224 } 225} 226 227static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, AVPacket *avpkt) 228{ 229 const uint8_t *buf = avpkt->data; 230 int buf_size = avpkt->size; 231 KmvcContext *const ctx = avctx->priv_data; 232 uint8_t *out, *src; 233 int i; 234 int header; 235 int blocksize; 236 237 if (ctx->pic.data[0]) 238 avctx->release_buffer(avctx, &ctx->pic); 239 240 ctx->pic.reference = 1; 241 ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID; 242 if (avctx->get_buffer(avctx, &ctx->pic) < 0) { 243 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); 244 return -1; 245 } 246 247 header = *buf++; 248 249 /* blocksize 127 is really palette change event */ 250 if (buf[0] == 127) { 251 buf += 3; 252 for (i = 0; i < 127; i++) { 253 ctx->pal[i + (header & 0x81)] = AV_RB24(buf); 254 buf += 4; 255 } 256 buf -= 127 * 4 + 3; 257 } 258 259 if (header & KMVC_KEYFRAME) { 260 ctx->pic.key_frame = 1; 261 ctx->pic.pict_type = FF_I_TYPE; 262 } else { 263 ctx->pic.key_frame = 0; 264 ctx->pic.pict_type = FF_P_TYPE; 265 } 266 267 /* if palette has been changed, copy it from palctrl */ 268 if (ctx->avctx->palctrl && ctx->avctx->palctrl->palette_changed) { 269 memcpy(ctx->pal, ctx->avctx->palctrl->palette, AVPALETTE_SIZE); 270 ctx->setpal = 1; 271 ctx->avctx->palctrl->palette_changed = 0; 272 } 273 274 if (header & KMVC_PALETTE) { 275 ctx->pic.palette_has_changed = 1; 276 // palette starts from index 1 and has 127 entries 277 for (i = 1; i <= ctx->palsize; i++) { 278 ctx->pal[i] = bytestream_get_be24(&buf); 279 } 280 } 281 282 if (ctx->setpal) { 283 ctx->setpal = 0; 284 ctx->pic.palette_has_changed = 1; 285 } 286 287 /* make the palette available on the way out */ 288 memcpy(ctx->pic.data[1], ctx->pal, 1024); 289 290 blocksize = *buf++; 291 292 if (blocksize != 8 && blocksize != 127) { 293 av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize); 294 return -1; 295 } 296 memset(ctx->cur, 0, 320 * 200); 297 switch (header & KMVC_METHOD) { 298 case 0: 299 case 1: // used in palette changed event 300 memcpy(ctx->cur, ctx->prev, 320 * 200); 301 break; 302 case 3: 303 kmvc_decode_intra_8x8(ctx, buf, avctx->width, avctx->height); 304 break; 305 case 4: 306 kmvc_decode_inter_8x8(ctx, buf, avctx->width, avctx->height); 307 break; 308 default: 309 av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD); 310 return -1; 311 } 312 313 out = ctx->pic.data[0]; 314 src = ctx->cur; 315 for (i = 0; i < avctx->height; i++) { 316 memcpy(out, src, avctx->width); 317 src += 320; 318 out += ctx->pic.linesize[0]; 319 } 320 321 /* flip buffers */ 322 if (ctx->cur == ctx->frm0) { 323 ctx->cur = ctx->frm1; 324 ctx->prev = ctx->frm0; 325 } else { 326 ctx->cur = ctx->frm0; 327 ctx->prev = ctx->frm1; 328 } 329 330 *data_size = sizeof(AVFrame); 331 *(AVFrame *) data = ctx->pic; 332 333 /* always report that the buffer was completely consumed */ 334 return buf_size; 335} 336 337 338 339/* 340 * Init kmvc decoder 341 */ 342static av_cold int decode_init(AVCodecContext * avctx) 343{ 344 KmvcContext *const c = avctx->priv_data; 345 int i; 346 347 c->avctx = avctx; 348 349 if (avctx->width > 320 || avctx->height > 200) { 350 av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n"); 351 return -1; 352 } 353 354 c->frm0 = av_mallocz(320 * 200); 355 c->frm1 = av_mallocz(320 * 200); 356 c->cur = c->frm0; 357 c->prev = c->frm1; 358 359 for (i = 0; i < 256; i++) { 360 c->pal[i] = i * 0x10101; 361 } 362 363 if (avctx->extradata_size < 12) { 364 av_log(NULL, 0, "Extradata missing, decoding may not work properly...\n"); 365 c->palsize = 127; 366 } else { 367 c->palsize = AV_RL16(avctx->extradata + 10); 368 } 369 370 if (avctx->extradata_size == 1036) { // palette in extradata 371 uint8_t *src = avctx->extradata + 12; 372 for (i = 0; i < 256; i++) { 373 c->pal[i] = AV_RL32(src); 374 src += 4; 375 } 376 c->setpal = 1; 377 if (c->avctx->palctrl) { 378 c->avctx->palctrl->palette_changed = 0; 379 } 380 } 381 382 avctx->pix_fmt = PIX_FMT_PAL8; 383 384 return 0; 385} 386 387 388 389/* 390 * Uninit kmvc decoder 391 */ 392static av_cold int decode_end(AVCodecContext * avctx) 393{ 394 KmvcContext *const c = avctx->priv_data; 395 396 av_freep(&c->frm0); 397 av_freep(&c->frm1); 398 if (c->pic.data[0]) 399 avctx->release_buffer(avctx, &c->pic); 400 401 return 0; 402} 403 404AVCodec kmvc_decoder = { 405 "kmvc", 406 AVMEDIA_TYPE_VIDEO, 407 CODEC_ID_KMVC, 408 sizeof(KmvcContext), 409 decode_init, 410 NULL, 411 decode_end, 412 decode_frame, 413 CODEC_CAP_DR1, 414 .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"), 415}; 416