libavcodec/mimic.c

   1 /*
   2  * Copyright (C) 2005  Ole André Vadla Ravnås <oleavr@gmail.com>
   3  * Copyright (C) 2008  Ramiro Polla <ramiro@lisha.ufsc.br>
   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 #include <stdlib.h>
  23 #include <string.h>
  24 #include <stdint.h>
  25
  26 #include "avcodec.h"
  27 #include "bitstream.h"
  28 #include "bytestream.h"
  29 #include "dsputil.h"
  30
  31 #define MIMIC_HEADER_SIZE   20
  32
  33 typedef struct {
  34     AVCodecContext *avctx;
  35
  36     int             num_vblocks[3];
  37     int             num_hblocks[3];
  38
  39     uint8_t        *swap_buf;
  40     int             swap_buf_size;
  41
  42     int             cur_index;
  43     int             prev_index;
  44
  45     AVFrame         buf_ptrs    [16];
  46     AVPicture       flipped_ptrs[16];
  47
  48     DECLARE_ALIGNED_16(DCTELEM, dct_block[64]);
  49
  50     GetBitContext   gb;
  51     ScanTable       scantable;
  52     DSPContext      dsp;
  53     VLC             vlc;
  54 } MimicContext;
  55
  56 static const uint32_t huffcodes[] = {
  57     0x0000000a, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
  58     0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
  59     0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x0000000b,
  60     0x0000001b, 0x00000038, 0x00000078, 0x00000079, 0x0000007a, 0x000000f9,
  61     0x000000fa, 0x000003fb, 0x000007f8, 0x000007f9, 0x000007fa, 0x000007fb,
  62     0x00000ff8, 0x00000ff9, 0x00000001, 0x00000039, 0x0000007b, 0x000000fb,
  63     0x000001f8, 0x000001f9, 0x00000ffa, 0x00000ffb, 0x00001ff8, 0x00001ff9,
  64     0x00001ffa, 0x00001ffb, 0x00003ff8, 0x00003ff9, 0x00003ffa, 0x00000000,
  65     0x00000004, 0x0000003a, 0x000001fa, 0x00003ffb, 0x00007ff8, 0x00007ff9,
  66     0x00007ffa, 0x00007ffb, 0x0000fff8, 0x0000fff9, 0x0000fffa, 0x0000fffb,
  67     0x0001fff8, 0x0001fff9, 0x0001fffa, 0x00000000, 0x0000000c, 0x000000f8,
  68     0x000001fb, 0x0001fffb, 0x0003fff8, 0x0003fff9, 0x0003fffa, 0x0003fffb,
  69     0x0007fff8, 0x0007fff9, 0x0007fffa, 0x0007fffb, 0x000ffff8, 0x000ffff9,
  70     0x000ffffa, 0x00000000, 0x0000001a, 0x000003f8, 0x000ffffb, 0x001ffff8,
  71     0x001ffff9, 0x001ffffa, 0x001ffffb, 0x003ffff8, 0x003ffff9, 0x003ffffa,
  72     0x003ffffb, 0x007ffff8, 0x007ffff9, 0x007ffffa, 0x007ffffb, 0x00000000,
  73     0x0000003b, 0x000003f9, 0x00fffff8, 0x00fffff9, 0x00fffffa, 0x00fffffb,
  74     0x01fffff8, 0x01fffff9, 0x01fffffa, 0x01fffffb, 0x03fffff8, 0x03fffff9,
  75     0x03fffffa, 0x03fffffb, 0x07fffff8, 0x00000000, 0x000003fa, 0x07fffff9,
  76     0x07fffffa, 0x07fffffb, 0x0ffffff8, 0x0ffffff9, 0x0ffffffa, 0x0ffffffb,
  77     0x1ffffff8, 0x1ffffff9, 0x1ffffffa, 0x1ffffffb, 0x3ffffff8, 0x3ffffff9,
  78     0x3ffffffa,
  79 };
  80
  81 static const uint8_t huffbits[] = {
  82      4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
  83      0,  0,  0,  0,  2,  4,  5,  6,  7,  7,  7,  8,
  84      8, 10, 11, 11, 11, 11, 12, 12,  2,  6,  7,  8,
  85      9,  9, 12, 12, 13, 13, 13, 13, 14, 14, 14,  0,
  86      3,  6,  9, 14, 15, 15, 15, 15, 16, 16, 16, 16,
  87     17, 17, 17,  0,  4,  8,  9, 17, 18, 18, 18, 18,
  88     19, 19, 19, 19, 20, 20, 20,  0,  5, 10, 20, 21,
  89     21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23,  0,
  90      6, 10, 24, 24, 24, 24, 25, 25, 25, 25, 26, 26,
  91     26, 26, 27,  0, 10, 27, 27, 27, 28, 28, 28, 28,
  92     29, 29, 29, 29, 30, 30, 30,
  93 };
  94
  95 static const uint8_t col_zag[64] = {
  96      0,  8,  1,  2,  9, 16, 24, 17,
  97     10,  3,  4, 11, 18, 25, 32, 40,
  98     33, 26, 19, 12,  5,  6, 13, 20,
  99     27, 34, 41, 48, 56, 49, 42, 35,
 100     28, 21, 14,  7, 15, 22, 29, 36,
 101     43, 50, 57, 58, 51, 44, 37, 30,
 102     23, 31, 38, 45, 52, 59, 39, 46,
 103     53, 60, 61, 54, 47, 55, 62, 63,
 104 };
 105
 106 static av_cold int mimic_decode_init(AVCodecContext *avctx)
 107 {
 108     MimicContext *ctx = avctx->priv_data;
 109
 110     ctx->prev_index = 0;
 111     ctx->cur_index = 15;
 112
 113     if(init_vlc(&ctx->vlc, 11, FF_ARRAY_ELEMS(huffbits),
 114                  huffbits, 1, 1, huffcodes, 4, 4, 0)) {
 115         av_log(avctx, AV_LOG_ERROR, "error initializing vlc table\n");
 116         return -1;
 117     }
 118     dsputil_init(&ctx->dsp, avctx);
 119     ff_init_scantable(ctx->dsp.idct_permutation, &ctx->scantable, col_zag);
 120
 121     return 0;
 122 }
 123
 124 static const int8_t vlcdec_lookup[9][64] = {
 125     {    0, },
 126     {   -1,   1, },
 127     {   -3,   3,   -2,   2, },
 128     {   -7,   7,   -6,   6,   -5,   5,   -4,   4, },
 129     {  -15,  15,  -14,  14,  -13,  13,  -12,  12,
 130        -11,  11,  -10,  10,   -9,   9,   -8,   8, },
 131     {  -31,  31,  -30,  30,  -29,  29,  -28,  28,
 132        -27,  27,  -26,  26,  -25,  25,  -24,  24,
 133        -23,  23,  -22,  22,  -21,  21,  -20,  20,
 134        -19,  19,  -18,  18,  -17,  17,  -16,  16, },
 135     {  -63,  63,  -62,  62,  -61,  61,  -60,  60,
 136        -59,  59,  -58,  58,  -57,  57,  -56,  56,
 137        -55,  55,  -54,  54,  -53,  53,  -52,  52,
 138        -51,  51,  -50,  50,  -49,  49,  -48,  48,
 139        -47,  47,  -46,  46,  -45,  45,  -44,  44,
 140        -43,  43,  -42,  42,  -41,  41,  -40,  40,
 141        -39,  39,  -38,  38,  -37,  37,  -36,  36,
 142        -35,  35,  -34,  34,  -33,  33,  -32,  32, },
 143     { -127, 127, -126, 126, -125, 125, -124, 124,
 144       -123, 123, -122, 122, -121, 121, -120, 120,
 145       -119, 119, -118, 118, -117, 117, -116, 116,
 146       -115, 115, -114, 114, -113, 113, -112, 112,
 147       -111, 111, -110, 110, -109, 109, -108, 108,
 148       -107, 107, -106, 106, -105, 105, -104, 104,
 149       -103, 103, -102, 102, -101, 101, -100, 100,
 150        -99,  99,  -98,  98,  -97,  97,  -96,  96, },
 151     {  -95,  95,  -94,  94,  -93,  93,  -92,  92,
 152        -91,  91,  -90,  90,  -89,  89,  -88,  88,
 153        -87,  87,  -86,  86,  -85,  85,  -84,  84,
 154        -83,  83,  -82,  82,  -81,  81,  -80,  80,
 155        -79,  79,  -78,  78,  -77,  77,  -76,  76,
 156        -75,  75,  -74,  74,  -73,  73,  -72,  72,
 157        -71,  71,  -70,  70,  -69,  69,  -68,  68,
 158        -67,  67,  -66,  66,  -65,  65,  -64,  64, },
 159 };
 160
 161 static int vlc_decode_block(MimicContext *ctx, int num_coeffs, int qscale)
 162 {
 163     DCTELEM *block = ctx->dct_block;
 164     unsigned int pos;
 165
 166     ctx->dsp.clear_block(block);
 167
 168     block[0] = get_bits(&ctx->gb, 8) << 3;
 169
 170     for(pos = 1; pos < num_coeffs; pos++) {
 171         uint32_t vlc, num_bits;
 172         int value;
 173         int coeff;
 174
 175         vlc = get_vlc2(&ctx->gb, ctx->vlc.table, ctx->vlc.bits, 3);
 176         if(!vlc) /* end-of-block code */
 177             return 1;
 178         if(vlc == -1)
 179             return 0;
 180
 181         /* pos_add and num_bits are coded in the vlc code */
 182         pos +=     vlc&15; // pos_add
 183         num_bits = vlc>>4; // num_bits
 184
 185         if(pos >= 64)
 186             return 0;
 187
 188         value = get_bits(&ctx->gb, num_bits);
 189
 190         /* FFmpeg's IDCT behaves somewhat different from the original code, so
 191          * a factor of 4 was added to the input */
 192
 193         coeff = vlcdec_lookup[num_bits][value];
 194         if(pos<3)
 195             coeff <<= 4;
 196         else /* TODO Use >> 10 instead of / 1001 */
 197             coeff = (coeff * qscale) / 1001;
 198
 199         block[ctx->scantable.permutated[pos]] = coeff;
 200     }
 201
 202     return 1;
 203 }
 204
 205 static int decode(MimicContext *ctx, int quality, int num_coeffs,
 206                   int is_iframe)
 207 {
 208     int y, x, plane;
 209
 210     for(plane = 0; plane < 3; plane++) {
 211         const int is_chroma = !!plane;
 212         const int qscale = av_clip(10000-quality,is_chroma?1000:2000,10000)<<2;
 213         const int stride = ctx->flipped_ptrs[ctx->cur_index].linesize[plane];
 214         const uint8_t *src = ctx->flipped_ptrs[ctx->prev_index].data[plane];
 215         uint8_t       *dst = ctx->flipped_ptrs[ctx->cur_index ].data[plane];
 216
 217         for(y = 0; y < ctx->num_vblocks[plane]; y++) {
 218             for(x = 0; x < ctx->num_hblocks[plane]; x++) {
 219
 220                 /* Check for a change condition in the current block.
 221                  * - iframes always change.
 222                  * - Luma plane changes on get_bits1 == 0
 223                  * - Chroma planes change on get_bits1 == 1 */
 224                 if(is_iframe || get_bits1(&ctx->gb) == is_chroma) {
 225
 226                     /* Luma planes may use a backreference from the 15 last
 227                      * frames preceding the previous. (get_bits1 == 1)
 228                      * Chroma planes don't use backreferences. */
 229                     if(is_chroma || is_iframe || !get_bits1(&ctx->gb)) {
 230
 231                         if(!vlc_decode_block(ctx, num_coeffs, qscale))
 232                             return 0;
 233                         ctx->dsp.idct_put(dst, stride, ctx->dct_block);
 234                     } else {
 235                         unsigned int backref = get_bits(&ctx->gb, 4);
 236                         int index = (ctx->cur_index+backref)&15;
 237                         uint8_t *p = ctx->flipped_ptrs[index].data[0];
 238
 239                         if(p) {
 240                             p += src -
 241                                 ctx->flipped_ptrs[ctx->prev_index].data[plane];
 242                             ctx->dsp.put_pixels_tab[1][0](dst, p, stride, 8);
 243                         } else {
 244                             av_log(ctx->avctx, AV_LOG_ERROR,
 245                                      "No such backreference! Buggy sample.\n");
 246                         }
 247                     }
 248                 } else {
 249                     ctx->dsp.put_pixels_tab[1][0](dst, src, stride, 8);
 250                 }
 251                 src += 8;
 252                 dst += 8;
 253             }
 254             src += (stride - ctx->num_hblocks[plane])<<3;
 255             dst += (stride - ctx->num_hblocks[plane])<<3;
 256         }
 257     }
 258
 259     return 1;
 260 }
 261
 262 /**
 263  * Flip the buffer upside-down and put it in the YVU order to match the
 264  * way Mimic encodes frames.
 265  */
 266 static void prepare_avpic(MimicContext *ctx, AVPicture *dst, AVPicture *src)
 267 {
 268     int i;
 269     dst->data[0] = src->data[0]+( ctx->avctx->height    -1)*src->linesize[0];
 270     dst->data[1] = src->data[2]+((ctx->avctx->height>>1)-1)*src->linesize[2];
 271     dst->data[2] = src->data[1]+((ctx->avctx->height>>1)-1)*src->linesize[1];
 272     for(i = 0; i < 3; i++)
 273         dst->linesize[i] = -src->linesize[i];
 274 }
 275
 276 static int mimic_decode_frame(AVCodecContext *avctx, void *data,
 277                               int *data_size, const uint8_t *buf, int buf_size)
 278 {
 279     MimicContext *ctx = avctx->priv_data;
 280     int is_pframe;
 281     int width, height;
 282     int quality, num_coeffs;
 283     int swap_buf_size = buf_size - MIMIC_HEADER_SIZE;
 284
 285     if(buf_size < MIMIC_HEADER_SIZE) {
 286         av_log(avctx, AV_LOG_ERROR, "insufficient data\n");
 287         return -1;
 288     }
 289
 290     buf       += 2; /* some constant (always 256) */
 291     quality    = bytestream_get_le16(&buf);
 292     width      = bytestream_get_le16(&buf);
 293     height     = bytestream_get_le16(&buf);
 294     buf       += 4; /* some constant */
 295     is_pframe  = bytestream_get_le32(&buf);
 296     num_coeffs = bytestream_get_byte(&buf);
 297     buf       += 3; /* some constant */
 298
 299     if(!ctx->avctx) {
 300         int i;
 301
 302         if(!(width == 160 && height == 120) &&
 303            !(width == 320 && height == 240)) {
 304             av_log(avctx, AV_LOG_ERROR, "invalid width/height!\n");
 305             return -1;
 306         }
 307
 308         ctx->avctx     = avctx;
 309         avctx->width   = width;
 310         avctx->height  = height;
 311         avctx->pix_fmt = PIX_FMT_YUV420P;
 312         for(i = 0; i < 3; i++) {
 313             ctx->num_vblocks[i] = -((-height) >> (3 + !!i));
 314             ctx->num_hblocks[i] =     width   >> (3 + !!i) ;
 315         }
 316     } else if(width != ctx->avctx->width || height != ctx->avctx->height) {
 317         av_log(avctx, AV_LOG_ERROR, "resolution changing is not supported\n");
 318         return -1;
 319     }
 320
 321     if(is_pframe && !ctx->buf_ptrs[ctx->prev_index].data[0]) {
 322         av_log(avctx, AV_LOG_ERROR, "decoding must start with keyframe\n");
 323         return -1;
 324     }
 325
 326     ctx->buf_ptrs[ctx->cur_index].reference = 1;
 327     if(avctx->get_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index])) {
 328         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 329         return -1;
 330     }
 331
 332     prepare_avpic(ctx, &ctx->flipped_ptrs[ctx->cur_index],
 333                   (AVPicture*) &ctx->buf_ptrs[ctx->cur_index]);
 334
 335     ctx->swap_buf = av_fast_realloc(ctx->swap_buf, &ctx->swap_buf_size,
 336                                  swap_buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
 337     if(!ctx->swap_buf)
 338         return AVERROR_NOMEM;
 339
 340     ctx->dsp.bswap_buf((uint32_t*)ctx->swap_buf,
 341                         (const uint32_t*) buf,
 342                         swap_buf_size>>2);
 343     init_get_bits(&ctx->gb, ctx->swap_buf, swap_buf_size << 3);
 344
 345     if(!decode(ctx, quality, num_coeffs, !is_pframe)) {
 346         avctx->release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);
 347         return -1;
 348     }
 349
 350     ctx->buf_ptrs[ctx->cur_index].pict_type = is_pframe ? FF_P_TYPE:FF_I_TYPE;
 351     *(AVFrame*)data = ctx->buf_ptrs[ctx->cur_index];
 352     *data_size = sizeof(AVFrame);
 353
 354     ctx->prev_index = ctx->cur_index;
 355     ctx->cur_index--;
 356     ctx->cur_index &= 15;
 357
 358     /* Only release frames that aren't used for backreferences anymore */
 359     if(ctx->buf_ptrs[ctx->cur_index].data[0])
 360         avctx->release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);
 361
 362     return buf_size;
 363 }
 364
 365 static av_cold int mimic_decode_end(AVCodecContext *avctx)
 366 {
 367     MimicContext *ctx = avctx->priv_data;
 368     int i;
 369
 370     av_free(ctx->swap_buf);
 371     for(i = 0; i < 16; i++)
 372         if(ctx->buf_ptrs[i].data[0])
 373             avctx->release_buffer(avctx, &ctx->buf_ptrs[i]);
 374     free_vlc(&ctx->vlc);
 375
 376     return 0;
 377 }
 378
 379 AVCodec mimic_decoder = {
 380     "mimic",
 381     CODEC_TYPE_VIDEO,
 382     CODEC_ID_MIMIC,
 383     sizeof(MimicContext),
 384     mimic_decode_init,
 385     NULL,
 386     mimic_decode_end,
 387     mimic_decode_frame,
 388     CODEC_CAP_DR1,
 389     .long_name = NULL_IF_CONFIG_SMALL("Mimic"),
 390 };