libavcodec/kmvc.c

   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 libavcodec/kmvc.c
  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  */
  40 typedef 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
  51 typedef 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
  70 static 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
 145 static 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
 227 static int decode_frame(AVCodecContext * avctx, void *data, int *data_size, const uint8_t * buf,
 228                         int buf_size)
 229 {
 230     KmvcContext *const ctx = avctx->priv_data;
 231     uint8_t *out, *src;
 232     int i;
 233     int header;
 234     int blocksize;
 235
 236     if (ctx->pic.data[0])
 237         avctx->release_buffer(avctx, &ctx->pic);
 238
 239     ctx->pic.reference = 1;
 240     ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID;
 241     if (avctx->get_buffer(avctx, &ctx->pic) < 0) {
 242         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 243         return -1;
 244     }
 245
 246     header = *buf++;
 247
 248     /* blocksize 127 is really palette change event */
 249     if (buf[0] == 127) {
 250         buf += 3;
 251         for (i = 0; i < 127; i++) {
 252             ctx->pal[i + (header & 0x81)] = AV_RB24(buf);
 253             buf += 4;
 254         }
 255         buf -= 127 * 4 + 3;
 256     }
 257
 258     if (header & KMVC_KEYFRAME) {
 259         ctx->pic.key_frame = 1;
 260         ctx->pic.pict_type = FF_I_TYPE;
 261     } else {
 262         ctx->pic.key_frame = 0;
 263         ctx->pic.pict_type = FF_P_TYPE;
 264     }
 265
 266     /* if palette has been changed, copy it from palctrl */
 267     if (ctx->avctx->palctrl && ctx->avctx->palctrl->palette_changed) {
 268         memcpy(ctx->pal, ctx->avctx->palctrl->palette, AVPALETTE_SIZE);
 269         ctx->setpal = 1;
 270         ctx->avctx->palctrl->palette_changed = 0;
 271     }
 272
 273     if (header & KMVC_PALETTE) {
 274         ctx->pic.palette_has_changed = 1;
 275         // palette starts from index 1 and has 127 entries
 276         for (i = 1; i <= ctx->palsize; i++) {
 277             ctx->pal[i] = bytestream_get_be24(&buf);
 278         }
 279     }
 280
 281     if (ctx->setpal) {
 282         ctx->setpal = 0;
 283         ctx->pic.palette_has_changed = 1;
 284     }
 285
 286     /* make the palette available on the way out */
 287     memcpy(ctx->pic.data[1], ctx->pal, 1024);
 288
 289     blocksize = *buf++;
 290
 291     if (blocksize != 8 && blocksize != 127) {
 292         av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
 293         return -1;
 294     }
 295     memset(ctx->cur, 0, 320 * 200);
 296     switch (header & KMVC_METHOD) {
 297     case 0:
 298     case 1: // used in palette changed event
 299         memcpy(ctx->cur, ctx->prev, 320 * 200);
 300         break;
 301     case 3:
 302         kmvc_decode_intra_8x8(ctx, buf, avctx->width, avctx->height);
 303         break;
 304     case 4:
 305         kmvc_decode_inter_8x8(ctx, buf, avctx->width, avctx->height);
 306         break;
 307     default:
 308         av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
 309         return -1;
 310     }
 311
 312     out = ctx->pic.data[0];
 313     src = ctx->cur;
 314     for (i = 0; i < avctx->height; i++) {
 315         memcpy(out, src, avctx->width);
 316         src += 320;
 317         out += ctx->pic.linesize[0];
 318     }
 319
 320     /* flip buffers */
 321     if (ctx->cur == ctx->frm0) {
 322         ctx->cur = ctx->frm1;
 323         ctx->prev = ctx->frm0;
 324     } else {
 325         ctx->cur = ctx->frm0;
 326         ctx->prev = ctx->frm1;
 327     }
 328
 329     *data_size = sizeof(AVFrame);
 330     *(AVFrame *) data = ctx->pic;
 331
 332     /* always report that the buffer was completely consumed */
 333     return buf_size;
 334 }
 335
 336
 337
 338 /*
 339  * Init kmvc decoder
 340  */
 341 static av_cold int decode_init(AVCodecContext * avctx)
 342 {
 343     KmvcContext *const c = avctx->priv_data;
 344     int i;
 345
 346     c->avctx = avctx;
 347
 348     c->pic.data[0] = NULL;
 349
 350     if (avctx->width > 320 || avctx->height > 200) {
 351         av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
 352         return -1;
 353     }
 354
 355     c->frm0 = av_mallocz(320 * 200);
 356     c->frm1 = av_mallocz(320 * 200);
 357     c->cur = c->frm0;
 358     c->prev = c->frm1;
 359
 360     for (i = 0; i < 256; i++) {
 361         c->pal[i] = i * 0x10101;
 362     }
 363
 364     if (avctx->extradata_size < 12) {
 365         av_log(NULL, 0, "Extradata missing, decoding may not work properly...\n");
 366         c->palsize = 127;
 367     } else {
 368         c->palsize = AV_RL16(avctx->extradata + 10);
 369     }
 370
 371     if (avctx->extradata_size == 1036) {        // palette in extradata
 372         uint8_t *src = avctx->extradata + 12;
 373         for (i = 0; i < 256; i++) {
 374             c->pal[i] = AV_RL32(src);
 375             src += 4;
 376         }
 377         c->setpal = 1;
 378         if (c->avctx->palctrl) {
 379             c->avctx->palctrl->palette_changed = 0;
 380         }
 381     }
 382
 383     avctx->pix_fmt = PIX_FMT_PAL8;
 384
 385     return 0;
 386 }
 387
 388
 389
 390 /*
 391  * Uninit kmvc decoder
 392  */
 393 static av_cold int decode_end(AVCodecContext * avctx)
 394 {
 395     KmvcContext *const c = avctx->priv_data;
 396
 397     av_freep(&c->frm0);
 398     av_freep(&c->frm1);
 399     if (c->pic.data[0])
 400         avctx->release_buffer(avctx, &c->pic);
 401
 402     return 0;
 403 }
 404
 405 AVCodec kmvc_decoder = {
 406     "kmvc",
 407     CODEC_TYPE_VIDEO,
 408     CODEC_ID_KMVC,
 409     sizeof(KmvcContext),
 410     decode_init,
 411     NULL,
 412     decode_end,
 413     decode_frame,
 414     .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"),
 415 };