libavcodec/4xm.c

   1 /*
   2  * 4XM codec
   3  * Copyright (c) 2003 Michael Niedermayer
   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 4xm.c
  24  * 4XM codec.
  25  */
  26
  27 #include "avcodec.h"
  28 #include "dsputil.h"
  29 #include "bitstream.h"
  30 #include "bytestream.h"
  31
  32 //#undef NDEBUG
  33 //#include <assert.h>
  34
  35 #define BLOCK_TYPE_VLC_BITS 5
  36 #define ACDC_VLC_BITS 9
  37
  38 #define CFRAME_BUFFER_COUNT 100
  39
  40 static const uint8_t block_type_tab[2][4][8][2]={
  41  {
  42   {   //{8,4,2}x{8,4,2}
  43     { 0,1}, { 2,2}, { 6,3}, {14,4}, {30,5}, {31,5}, { 0,0}
  44   },{ //{8,4}x1
  45     { 0,1}, { 0,0}, { 2,2}, { 6,3}, {14,4}, {15,4}, { 0,0}
  46   },{ //1x{8,4}
  47     { 0,1}, { 2,2}, { 0,0}, { 6,3}, {14,4}, {15,4}, { 0,0}
  48   },{ //1x2, 2x1
  49     { 0,1}, { 0,0}, { 0,0}, { 2,2}, { 6,3}, {14,4}, {15,4}
  50   }
  51  },{
  52   {  //{8,4,2}x{8,4,2}
  53     { 1,2}, { 4,3}, { 5,3}, {0,2}, {6,3}, {7,3}, {0,0}
  54   },{//{8,4}x1
  55     { 1,2}, { 0,0}, { 2,2}, {0,2}, {6,3}, {7,3}, {0,0}
  56   },{//1x{8,4}
  57     { 1,2}, { 2,2}, { 0,0}, {0,2}, {6,3}, {7,3}, {0,0}
  58   },{//1x2, 2x1
  59     { 1,2}, { 0,0}, { 0,0}, {0,2}, {2,2}, {6,3}, {7,3}
  60   }
  61  }
  62 };
  63
  64 static const uint8_t size2index[4][4]={
  65   {-1, 3, 1, 1},
  66   { 3, 0, 0, 0},
  67   { 2, 0, 0, 0},
  68   { 2, 0, 0, 0},
  69 };
  70
  71 static const int8_t mv[256][2]={
  72 {  0,  0},{  0, -1},{ -1,  0},{  1,  0},{  0,  1},{ -1, -1},{  1, -1},{ -1,  1},
  73 {  1,  1},{  0, -2},{ -2,  0},{  2,  0},{  0,  2},{ -1, -2},{  1, -2},{ -2, -1},
  74 {  2, -1},{ -2,  1},{  2,  1},{ -1,  2},{  1,  2},{ -2, -2},{  2, -2},{ -2,  2},
  75 {  2,  2},{  0, -3},{ -3,  0},{  3,  0},{  0,  3},{ -1, -3},{  1, -3},{ -3, -1},
  76 {  3, -1},{ -3,  1},{  3,  1},{ -1,  3},{  1,  3},{ -2, -3},{  2, -3},{ -3, -2},
  77 {  3, -2},{ -3,  2},{  3,  2},{ -2,  3},{  2,  3},{  0, -4},{ -4,  0},{  4,  0},
  78 {  0,  4},{ -1, -4},{  1, -4},{ -4, -1},{  4, -1},{  4,  1},{ -1,  4},{  1,  4},
  79 { -3, -3},{ -3,  3},{  3,  3},{ -2, -4},{ -4, -2},{  4, -2},{ -4,  2},{ -2,  4},
  80 {  2,  4},{ -3, -4},{  3, -4},{  4, -3},{ -5,  0},{ -4,  3},{ -3,  4},{  3,  4},
  81 { -1, -5},{ -5, -1},{ -5,  1},{ -1,  5},{ -2, -5},{  2, -5},{  5, -2},{  5,  2},
  82 { -4, -4},{ -4,  4},{ -3, -5},{ -5, -3},{ -5,  3},{  3,  5},{ -6,  0},{  0,  6},
  83 { -6, -1},{ -6,  1},{  1,  6},{  2, -6},{ -6,  2},{  2,  6},{ -5, -4},{  5,  4},
  84 {  4,  5},{ -6, -3},{  6,  3},{ -7,  0},{ -1, -7},{  5, -5},{ -7,  1},{ -1,  7},
  85 {  4, -6},{  6,  4},{ -2, -7},{ -7,  2},{ -3, -7},{  7, -3},{  3,  7},{  6, -5},
  86 {  0, -8},{ -1, -8},{ -7, -4},{ -8,  1},{  4,  7},{  2, -8},{ -2,  8},{  6,  6},
  87 { -8,  3},{  5, -7},{ -5,  7},{  8, -4},{  0, -9},{ -9, -1},{  1,  9},{  7, -6},
  88 { -7,  6},{ -5, -8},{ -5,  8},{ -9,  3},{  9, -4},{  7, -7},{  8, -6},{  6,  8},
  89 { 10,  1},{-10,  2},{  9, -5},{ 10, -3},{ -8, -7},{-10, -4},{  6, -9},{-11,  0},
  90 { 11,  1},{-11, -2},{ -2, 11},{  7, -9},{ -7,  9},{ 10,  6},{ -4, 11},{  8, -9},
  91 {  8,  9},{  5, 11},{  7,-10},{ 12, -3},{ 11,  6},{ -9, -9},{  8, 10},{  5, 12},
  92 {-11,  7},{ 13,  2},{  6,-12},{ 10,  9},{-11,  8},{ -7, 12},{  0, 14},{ 14, -2},
  93 { -9, 11},{ -6, 13},{-14, -4},{ -5,-14},{  5, 14},{-15, -1},{-14, -6},{  3,-15},
  94 { 11,-11},{ -7, 14},{ -5, 15},{  8,-14},{ 15,  6},{  3, 16},{  7,-15},{-16,  5},
  95 {  0, 17},{-16, -6},{-10, 14},{-16,  7},{ 12, 13},{-16,  8},{-17,  6},{-18,  3},
  96 { -7, 17},{ 15, 11},{ 16, 10},{  2,-19},{  3,-19},{-11,-16},{-18,  8},{-19, -6},
  97 {  2,-20},{-17,-11},{-10,-18},{  8, 19},{-21, -1},{-20,  7},{ -4, 21},{ 21,  5},
  98 { 15, 16},{  2,-22},{-10,-20},{-22,  5},{ 20,-11},{ -7,-22},{-12, 20},{ 23, -5},
  99 { 13,-20},{ 24, -2},{-15, 19},{-11, 22},{ 16, 19},{ 23,-10},{-18,-18},{ -9,-24},
 100 { 24,-10},{ -3, 26},{-23, 13},{-18,-20},{ 17, 21},{ -4, 27},{ 27,  6},{  1,-28},
 101 {-11, 26},{-17,-23},{  7, 28},{ 11,-27},{ 29,  5},{-23,-19},{-28,-11},{-21, 22},
 102 {-30,  7},{-17, 26},{-27, 16},{ 13, 29},{ 19,-26},{ 10,-31},{-14,-30},{ 20,-27},
 103 {-29, 18},{-16,-31},{-28,-22},{ 21,-30},{-25, 28},{ 26,-29},{ 25,-32},{-32,-32}
 104 };
 105
 106 // this is simply the scaled down elementwise product of the standard jpeg quantizer table and the AAN premul table
 107 static const uint8_t dequant_table[64]={
 108  16, 15, 13, 19, 24, 31, 28, 17,
 109  17, 23, 25, 31, 36, 63, 45, 21,
 110  18, 24, 27, 37, 52, 59, 49, 20,
 111  16, 28, 34, 40, 60, 80, 51, 20,
 112  18, 31, 48, 66, 68, 86, 56, 21,
 113  19, 38, 56, 59, 64, 64, 48, 20,
 114  27, 48, 55, 55, 56, 51, 35, 15,
 115  20, 35, 34, 32, 31, 22, 15,  8,
 116 };
 117
 118 static VLC block_type_vlc[2][4];
 119
 120
 121 typedef struct CFrameBuffer{
 122     unsigned int allocated_size;
 123     unsigned int size;
 124     int id;
 125     uint8_t *data;
 126 }CFrameBuffer;
 127
 128 typedef struct FourXContext{
 129     AVCodecContext *avctx;
 130     DSPContext dsp;
 131     AVFrame current_picture, last_picture;
 132     GetBitContext pre_gb;          ///< ac/dc prefix
 133     GetBitContext gb;
 134     const uint8_t *bytestream;
 135     const uint16_t *wordstream;
 136     int mv[256];
 137     VLC pre_vlc;
 138     int last_dc;
 139     DECLARE_ALIGNED_8(DCTELEM, block[6][64]);
 140     uint8_t *bitstream_buffer;
 141     unsigned int bitstream_buffer_size;
 142     int version;
 143     CFrameBuffer cfrm[CFRAME_BUFFER_COUNT];
 144 } FourXContext;
 145
 146
 147 #define FIX_1_082392200  70936
 148 #define FIX_1_414213562  92682
 149 #define FIX_1_847759065 121095
 150 #define FIX_2_613125930 171254
 151
 152 #define MULTIPLY(var,const)  (((var)*(const)) >> 16)
 153
 154 static void idct(DCTELEM block[64]){
 155     int tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
 156     int tmp10, tmp11, tmp12, tmp13;
 157     int z5, z10, z11, z12, z13;
 158     int i;
 159     int temp[64];
 160
 161     for(i=0; i<8; i++){
 162         tmp10 = block[8*0 + i] + block[8*4 + i];
 163         tmp11 = block[8*0 + i] - block[8*4 + i];
 164
 165         tmp13 =          block[8*2 + i] + block[8*6 + i];
 166         tmp12 = MULTIPLY(block[8*2 + i] - block[8*6 + i], FIX_1_414213562) - tmp13;
 167
 168         tmp0 = tmp10 + tmp13;
 169         tmp3 = tmp10 - tmp13;
 170         tmp1 = tmp11 + tmp12;
 171         tmp2 = tmp11 - tmp12;
 172
 173         z13 = block[8*5 + i] + block[8*3 + i];
 174         z10 = block[8*5 + i] - block[8*3 + i];
 175         z11 = block[8*1 + i] + block[8*7 + i];
 176         z12 = block[8*1 + i] - block[8*7 + i];
 177
 178         tmp7  =          z11 + z13;
 179         tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562);
 180
 181         z5    = MULTIPLY(z10 + z12, FIX_1_847759065);
 182         tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5;
 183         tmp12 = MULTIPLY(z10, - FIX_2_613125930) + z5;
 184
 185         tmp6 = tmp12 - tmp7;
 186         tmp5 = tmp11 - tmp6;
 187         tmp4 = tmp10 + tmp5;
 188
 189         temp[8*0 + i] = tmp0 + tmp7;
 190         temp[8*7 + i] = tmp0 - tmp7;
 191         temp[8*1 + i] = tmp1 + tmp6;
 192         temp[8*6 + i] = tmp1 - tmp6;
 193         temp[8*2 + i] = tmp2 + tmp5;
 194         temp[8*5 + i] = tmp2 - tmp5;
 195         temp[8*4 + i] = tmp3 + tmp4;
 196         temp[8*3 + i] = tmp3 - tmp4;
 197     }
 198
 199     for(i=0; i<8*8; i+=8){
 200         tmp10 = temp[0 + i] + temp[4 + i];
 201         tmp11 = temp[0 + i] - temp[4 + i];
 202
 203         tmp13 = temp[2 + i] + temp[6 + i];
 204         tmp12 = MULTIPLY(temp[2 + i] - temp[6 + i], FIX_1_414213562) - tmp13;
 205
 206         tmp0 = tmp10 + tmp13;
 207         tmp3 = tmp10 - tmp13;
 208         tmp1 = tmp11 + tmp12;
 209         tmp2 = tmp11 - tmp12;
 210
 211         z13 = temp[5 + i] + temp[3 + i];
 212         z10 = temp[5 + i] - temp[3 + i];
 213         z11 = temp[1 + i] + temp[7 + i];
 214         z12 = temp[1 + i] - temp[7 + i];
 215
 216         tmp7 = z11 + z13;
 217         tmp11 = MULTIPLY(z11 - z13, FIX_1_414213562);
 218
 219         z5 = MULTIPLY(z10 + z12, FIX_1_847759065);
 220         tmp10 = MULTIPLY(z12, FIX_1_082392200) - z5;
 221         tmp12 = MULTIPLY(z10, - FIX_2_613125930) + z5;
 222
 223         tmp6 = tmp12 - tmp7;
 224         tmp5 = tmp11 - tmp6;
 225         tmp4 = tmp10 + tmp5;
 226
 227         block[0 + i] = (tmp0 + tmp7)>>6;
 228         block[7 + i] = (tmp0 - tmp7)>>6;
 229         block[1 + i] = (tmp1 + tmp6)>>6;
 230         block[6 + i] = (tmp1 - tmp6)>>6;
 231         block[2 + i] = (tmp2 + tmp5)>>6;
 232         block[5 + i] = (tmp2 - tmp5)>>6;
 233         block[4 + i] = (tmp3 + tmp4)>>6;
 234         block[3 + i] = (tmp3 - tmp4)>>6;
 235     }
 236 }
 237
 238 static av_cold void init_vlcs(FourXContext *f){
 239     int i;
 240
 241     for(i=0; i<8; i++){
 242         init_vlc(&block_type_vlc[0][i], BLOCK_TYPE_VLC_BITS, 7,
 243                  &block_type_tab[0][i][0][1], 2, 1,
 244                  &block_type_tab[0][i][0][0], 2, 1, 1);
 245     }
 246 }
 247
 248 static void init_mv(FourXContext *f){
 249     int i;
 250
 251     for(i=0; i<256; i++){
 252         if(f->version>1)
 253             f->mv[i] = mv[i][0]   + mv[i][1]  *f->current_picture.linesize[0]/2;
 254         else
 255             f->mv[i] = (i&15) - 8 + ((i>>4)-8)*f->current_picture.linesize[0]/2;
 256     }
 257 }
 258
 259 static inline void mcdc(uint16_t *dst, uint16_t *src, int log2w, int h, int stride, int scale, int dc){
 260    int i;
 261    dc*= 0x10001;
 262
 263    switch(log2w){
 264    case 0:
 265         for(i=0; i<h; i++){
 266             dst[0] = scale*src[0] + dc;
 267             if(scale) src += stride;
 268             dst += stride;
 269         }
 270         break;
 271     case 1:
 272         for(i=0; i<h; i++){
 273             ((uint32_t*)dst)[0] = scale*((uint32_t*)src)[0] + dc;
 274             if(scale) src += stride;
 275             dst += stride;
 276         }
 277         break;
 278     case 2:
 279         for(i=0; i<h; i++){
 280             ((uint32_t*)dst)[0] = scale*((uint32_t*)src)[0] + dc;
 281             ((uint32_t*)dst)[1] = scale*((uint32_t*)src)[1] + dc;
 282             if(scale) src += stride;
 283             dst += stride;
 284         }
 285         break;
 286     case 3:
 287         for(i=0; i<h; i++){
 288             ((uint32_t*)dst)[0] = scale*((uint32_t*)src)[0] + dc;
 289             ((uint32_t*)dst)[1] = scale*((uint32_t*)src)[1] + dc;
 290             ((uint32_t*)dst)[2] = scale*((uint32_t*)src)[2] + dc;
 291             ((uint32_t*)dst)[3] = scale*((uint32_t*)src)[3] + dc;
 292             if(scale) src += stride;
 293             dst += stride;
 294         }
 295         break;
 296     default: assert(0);
 297     }
 298 }
 299
 300 static void decode_p_block(FourXContext *f, uint16_t *dst, uint16_t *src, int log2w, int log2h, int stride){
 301     const int index= size2index[log2h][log2w];
 302     const int h= 1<<log2h;
 303     int code= get_vlc2(&f->gb, block_type_vlc[1-(f->version>1)][index].table, BLOCK_TYPE_VLC_BITS, 1);
 304     uint16_t *start= (uint16_t*)f->last_picture.data[0];
 305     uint16_t *end= start + stride*(f->avctx->height-h+1) - (1<<log2w);
 306
 307     assert(code>=0 && code<=6);
 308
 309     if(code == 0){
 310         src += f->mv[ *f->bytestream++ ];
 311         if(start > src || src > end){
 312             av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n");
 313             return;
 314         }
 315         mcdc(dst, src, log2w, h, stride, 1, 0);
 316     }else if(code == 1){
 317         log2h--;
 318         decode_p_block(f, dst                  , src                  , log2w, log2h, stride);
 319         decode_p_block(f, dst + (stride<<log2h), src + (stride<<log2h), log2w, log2h, stride);
 320     }else if(code == 2){
 321         log2w--;
 322         decode_p_block(f, dst             , src             , log2w, log2h, stride);
 323         decode_p_block(f, dst + (1<<log2w), src + (1<<log2w), log2w, log2h, stride);
 324     }else if(code == 3 && f->version<2){
 325         mcdc(dst, src, log2w, h, stride, 1, 0);
 326     }else if(code == 4){
 327         src += f->mv[ *f->bytestream++ ];
 328         if(start > src || src > end){
 329             av_log(f->avctx, AV_LOG_ERROR, "mv out of pic\n");
 330             return;
 331         }
 332         mcdc(dst, src, log2w, h, stride, 1, le2me_16(*f->wordstream++));
 333     }else if(code == 5){
 334         mcdc(dst, src, log2w, h, stride, 0, le2me_16(*f->wordstream++));
 335     }else if(code == 6){
 336         if(log2w){
 337             dst[0] = le2me_16(*f->wordstream++);
 338             dst[1] = le2me_16(*f->wordstream++);
 339         }else{
 340             dst[0     ] = le2me_16(*f->wordstream++);
 341             dst[stride] = le2me_16(*f->wordstream++);
 342         }
 343     }
 344 }
 345
 346 static int decode_p_frame(FourXContext *f, const uint8_t *buf, int length){
 347     int x, y;
 348     const int width= f->avctx->width;
 349     const int height= f->avctx->height;
 350     uint16_t *src= (uint16_t*)f->last_picture.data[0];
 351     uint16_t *dst= (uint16_t*)f->current_picture.data[0];
 352     const int stride= f->current_picture.linesize[0]>>1;
 353     unsigned int bitstream_size, bytestream_size, wordstream_size, extra;
 354
 355     if(f->version>1){
 356         extra=20;
 357         bitstream_size= AV_RL32(buf+8);
 358         wordstream_size= AV_RL32(buf+12);
 359         bytestream_size= AV_RL32(buf+16);
 360     }else{
 361         extra=0;
 362         bitstream_size = AV_RL16(buf-4);
 363         wordstream_size= AV_RL16(buf-2);
 364         bytestream_size= FFMAX(length - bitstream_size - wordstream_size, 0);
 365     }
 366
 367     if(bitstream_size+ bytestream_size+ wordstream_size + extra != length
 368        || bitstream_size  > (1<<26)
 369        || bytestream_size > (1<<26)
 370        || wordstream_size > (1<<26)
 371        ){
 372         av_log(f->avctx, AV_LOG_ERROR, "lengths %d %d %d %d\n", bitstream_size, bytestream_size, wordstream_size,
 373         bitstream_size+ bytestream_size+ wordstream_size - length);
 374         return -1;
 375     }
 376
 377     f->bitstream_buffer= av_fast_realloc(f->bitstream_buffer, &f->bitstream_buffer_size, bitstream_size + FF_INPUT_BUFFER_PADDING_SIZE);
 378     f->dsp.bswap_buf((uint32_t*)f->bitstream_buffer, (const uint32_t*)(buf + extra), bitstream_size/4);
 379     init_get_bits(&f->gb, f->bitstream_buffer, 8*bitstream_size);
 380
 381     f->wordstream= (const uint16_t*)(buf + extra + bitstream_size);
 382     f->bytestream= buf + extra + bitstream_size + wordstream_size;
 383
 384     init_mv(f);
 385
 386     for(y=0; y<height; y+=8){
 387         for(x=0; x<width; x+=8){
 388             decode_p_block(f, dst + x, src + x, 3, 3, stride);
 389         }
 390         src += 8*stride;
 391         dst += 8*stride;
 392     }
 393
 394     if(   bitstream_size != (get_bits_count(&f->gb)+31)/32*4
 395        || (((const char*)f->wordstream - (const char*)buf + 2)&~2) != extra + bitstream_size + wordstream_size
 396        || (((const char*)f->bytestream - (const char*)buf + 3)&~3) != extra + bitstream_size + wordstream_size + bytestream_size)
 397         av_log(f->avctx, AV_LOG_ERROR, " %d %td %td bytes left\n",
 398             bitstream_size - (get_bits_count(&f->gb)+31)/32*4,
 399             -(((const char*)f->bytestream - (const char*)buf + 3)&~3) + (extra + bitstream_size + wordstream_size + bytestream_size),
 400             -(((const char*)f->wordstream - (const char*)buf + 2)&~2) + (extra + bitstream_size + wordstream_size)
 401         );
 402
 403     return 0;
 404 }
 405
 406 /**
 407  * decode block and dequantize.
 408  * Note this is almost identical to MJPEG.
 409  */
 410 static int decode_i_block(FourXContext *f, DCTELEM *block){
 411     int code, i, j, level, val;
 412
 413     /* DC coef */
 414     val = get_vlc2(&f->pre_gb, f->pre_vlc.table, ACDC_VLC_BITS, 3);
 415     if (val>>4){
 416         av_log(f->avctx, AV_LOG_ERROR, "error dc run != 0\n");
 417     }
 418
 419     if(val)
 420         val = get_xbits(&f->gb, val);
 421
 422     val = val * dequant_table[0] + f->last_dc;
 423     f->last_dc =
 424     block[0] = val;
 425     /* AC coefs */
 426     i = 1;
 427     for(;;) {
 428         code = get_vlc2(&f->pre_gb, f->pre_vlc.table, ACDC_VLC_BITS, 3);
 429
 430         /* EOB */
 431         if (code == 0)
 432             break;
 433         if (code == 0xf0) {
 434             i += 16;
 435         } else {
 436             level = get_xbits(&f->gb, code & 0xf);
 437             i += code >> 4;
 438             if (i >= 64) {
 439                 av_log(f->avctx, AV_LOG_ERROR, "run %d oveflow\n", i);
 440                 return 0;
 441             }
 442
 443             j= ff_zigzag_direct[i];
 444             block[j] = level * dequant_table[j];
 445             i++;
 446             if (i >= 64)
 447                 break;
 448         }
 449     }
 450
 451     return 0;
 452 }
 453
 454 static inline void idct_put(FourXContext *f, int x, int y){
 455     DCTELEM (*block)[64]= f->block;
 456     int stride= f->current_picture.linesize[0]>>1;
 457     int i;
 458     uint16_t *dst = ((uint16_t*)f->current_picture.data[0]) + y * stride + x;
 459
 460     for(i=0; i<4; i++){
 461         block[i][0] += 0x80*8*8;
 462         idct(block[i]);
 463     }
 464
 465     if(!(f->avctx->flags&CODEC_FLAG_GRAY)){
 466         for(i=4; i<6; i++) idct(block[i]);
 467     }
 468
 469 /* Note transform is:
 470 y= ( 1b + 4g + 2r)/14
 471 cb=( 3b - 2g - 1r)/14
 472 cr=(-1b - 4g + 5r)/14
 473 */
 474     for(y=0; y<8; y++){
 475         for(x=0; x<8; x++){
 476             DCTELEM *temp= block[(x>>2) + 2*(y>>2)] + 2*(x&3) + 2*8*(y&3); //FIXME optimize
 477             int cb= block[4][x + 8*y];
 478             int cr= block[5][x + 8*y];
 479             int cg= (cb + cr)>>1;
 480             int y;
 481
 482             cb+=cb;
 483
 484             y = temp[0];
 485             dst[0       ]= ((y+cb)>>3) + (((y-cg)&0xFC)<<3) + (((y+cr)&0xF8)<<8);
 486             y = temp[1];
 487             dst[1       ]= ((y+cb)>>3) + (((y-cg)&0xFC)<<3) + (((y+cr)&0xF8)<<8);
 488             y = temp[8];
 489             dst[  stride]= ((y+cb)>>3) + (((y-cg)&0xFC)<<3) + (((y+cr)&0xF8)<<8);
 490             y = temp[9];
 491             dst[1+stride]= ((y+cb)>>3) + (((y-cg)&0xFC)<<3) + (((y+cr)&0xF8)<<8);
 492             dst += 2;
 493         }
 494         dst += 2*stride - 2*8;
 495     }
 496 }
 497
 498 static int decode_i_mb(FourXContext *f){
 499     int i;
 500
 501     f->dsp.clear_blocks(f->block[0]);
 502
 503     for(i=0; i<6; i++){
 504         if(decode_i_block(f, f->block[i]) < 0)
 505             return -1;
 506     }
 507
 508     return 0;
 509 }
 510
 511 static const uint8_t *read_huffman_tables(FourXContext *f, const uint8_t * const buf){
 512     int frequency[512];
 513     uint8_t flag[512];
 514     int up[512];
 515     uint8_t len_tab[257];
 516     int bits_tab[257];
 517     int start, end;
 518     const uint8_t *ptr= buf;
 519     int j;
 520
 521     memset(frequency, 0, sizeof(frequency));
 522     memset(up, -1, sizeof(up));
 523
 524     start= *ptr++;
 525     end= *ptr++;
 526     for(;;){
 527         int i;
 528
 529         for(i=start; i<=end; i++){
 530             frequency[i]= *ptr++;
 531         }
 532         start= *ptr++;
 533         if(start==0) break;
 534
 535         end= *ptr++;
 536     }
 537     frequency[256]=1;
 538
 539     while((ptr - buf)&3) ptr++; // 4byte align
 540
 541     for(j=257; j<512; j++){
 542         int min_freq[2]= {256*256, 256*256};
 543         int smallest[2]= {0, 0};
 544         int i;
 545         for(i=0; i<j; i++){
 546             if(frequency[i] == 0) continue;
 547             if(frequency[i] < min_freq[1]){
 548                 if(frequency[i] < min_freq[0]){
 549                     min_freq[1]= min_freq[0]; smallest[1]= smallest[0];
 550                     min_freq[0]= frequency[i];smallest[0]= i;
 551                 }else{
 552                     min_freq[1]= frequency[i];smallest[1]= i;
 553                 }
 554             }
 555         }
 556         if(min_freq[1] == 256*256) break;
 557
 558         frequency[j]= min_freq[0] + min_freq[1];
 559         flag[ smallest[0] ]= 0;
 560         flag[ smallest[1] ]= 1;
 561         up[ smallest[0] ]=
 562         up[ smallest[1] ]= j;
 563         frequency[ smallest[0] ]= frequency[ smallest[1] ]= 0;
 564     }
 565
 566     for(j=0; j<257; j++){
 567         int node;
 568         int len=0;
 569         int bits=0;
 570
 571         for(node= j; up[node] != -1; node= up[node]){
 572             bits += flag[node]<<len;
 573             len++;
 574             if(len > 31) av_log(f->avctx, AV_LOG_ERROR, "vlc length overflow\n"); //can this happen at all ?
 575         }
 576
 577         bits_tab[j]= bits;
 578         len_tab[j]= len;
 579     }
 580
 581     init_vlc(&f->pre_vlc, ACDC_VLC_BITS, 257,
 582              len_tab , 1, 1,
 583              bits_tab, 4, 4, 0);
 584
 585     return ptr;
 586 }
 587
 588 static int mix(int c0, int c1){
 589     int blue = 2*(c0&0x001F) + (c1&0x001F);
 590     int green= (2*(c0&0x03E0) + (c1&0x03E0))>>5;
 591     int red  = 2*(c0>>10) + (c1>>10);
 592     return red/3*1024 + green/3*32 + blue/3;
 593 }
 594
 595 static int decode_i2_frame(FourXContext *f, const uint8_t *buf, int length){
 596     int x, y, x2, y2;
 597     const int width= f->avctx->width;
 598     const int height= f->avctx->height;
 599     uint16_t *dst= (uint16_t*)f->current_picture.data[0];
 600     const int stride= f->current_picture.linesize[0]>>1;
 601
 602     for(y=0; y<height; y+=16){
 603         for(x=0; x<width; x+=16){
 604             unsigned int color[4], bits;
 605             memset(color, 0, sizeof(color));
 606 //warning following is purely guessed ...
 607             color[0]= bytestream_get_le16(&buf);
 608             color[1]= bytestream_get_le16(&buf);
 609
 610             if(color[0]&0x8000) av_log(NULL, AV_LOG_ERROR, "unk bit 1\n");
 611             if(color[1]&0x8000) av_log(NULL, AV_LOG_ERROR, "unk bit 2\n");
 612
 613             color[2]= mix(color[0], color[1]);
 614             color[3]= mix(color[1], color[0]);
 615
 616             bits= bytestream_get_le32(&buf);
 617             for(y2=0; y2<16; y2++){
 618                 for(x2=0; x2<16; x2++){
 619                     int index= 2*(x2>>2) + 8*(y2>>2);
 620                     dst[y2*stride+x2]= color[(bits>>index)&3];
 621                 }
 622             }
 623             dst+=16;
 624         }
 625         dst += 16*stride - width;
 626     }
 627
 628     return 0;
 629 }
 630
 631 static int decode_i_frame(FourXContext *f, const uint8_t *buf, int length){
 632     int x, y;
 633     const int width= f->avctx->width;
 634     const int height= f->avctx->height;
 635     uint16_t *dst= (uint16_t*)f->current_picture.data[0];
 636     const int stride= f->current_picture.linesize[0]>>1;
 637     const unsigned int bitstream_size= AV_RL32(buf);
 638     const int token_count av_unused = AV_RL32(buf + bitstream_size + 8);
 639     unsigned int prestream_size= 4*AV_RL32(buf + bitstream_size + 4);
 640     const uint8_t *prestream= buf + bitstream_size + 12;
 641
 642     if(prestream_size + bitstream_size + 12 != length
 643        || bitstream_size > (1<<26)
 644        || prestream_size > (1<<26)){
 645         av_log(f->avctx, AV_LOG_ERROR, "size mismatch %d %d %d\n", prestream_size, bitstream_size, length);
 646         return -1;
 647     }
 648
 649     prestream= read_huffman_tables(f, prestream);
 650
 651     init_get_bits(&f->gb, buf + 4, 8*bitstream_size);
 652
 653     prestream_size= length + buf - prestream;
 654
 655     f->bitstream_buffer= av_fast_realloc(f->bitstream_buffer, &f->bitstream_buffer_size, prestream_size + FF_INPUT_BUFFER_PADDING_SIZE);
 656     f->dsp.bswap_buf((uint32_t*)f->bitstream_buffer, (const uint32_t*)prestream, prestream_size/4);
 657     init_get_bits(&f->pre_gb, f->bitstream_buffer, 8*prestream_size);
 658
 659     f->last_dc= 0*128*8*8;
 660
 661     for(y=0; y<height; y+=16){
 662         for(x=0; x<width; x+=16){
 663             if(decode_i_mb(f) < 0)
 664                 return -1;
 665
 666             idct_put(f, x, y);
 667         }
 668         dst += 16*stride;
 669     }
 670
 671     if(get_vlc2(&f->pre_gb, f->pre_vlc.table, ACDC_VLC_BITS, 3) != 256)
 672         av_log(f->avctx, AV_LOG_ERROR, "end mismatch\n");
 673
 674     return 0;
 675 }
 676
 677 static int decode_frame(AVCodecContext *avctx,
 678                         void *data, int *data_size,
 679                         const uint8_t *buf, int buf_size)
 680 {
 681     FourXContext * const f = avctx->priv_data;
 682     AVFrame *picture = data;
 683     AVFrame *p, temp;
 684     int i, frame_4cc, frame_size;
 685
 686     frame_4cc= AV_RL32(buf);
 687     if(buf_size != AV_RL32(buf+4)+8 || buf_size < 20){
 688         av_log(f->avctx, AV_LOG_ERROR, "size mismatch %d %d\n", buf_size, AV_RL32(buf+4));
 689     }
 690
 691     if(frame_4cc == ff_get_fourcc("cfrm")){
 692         int free_index=-1;
 693         const int data_size= buf_size - 20;
 694         const int id= AV_RL32(buf+12);
 695         const int whole_size= AV_RL32(buf+16);
 696         CFrameBuffer *cfrm;
 697
 698         for(i=0; i<CFRAME_BUFFER_COUNT; i++){
 699             if(f->cfrm[i].id && f->cfrm[i].id < avctx->frame_number)
 700                 av_log(f->avctx, AV_LOG_ERROR, "lost c frame %d\n", f->cfrm[i].id);
 701         }
 702
 703         for(i=0; i<CFRAME_BUFFER_COUNT; i++){
 704             if(f->cfrm[i].id   == id) break;
 705             if(f->cfrm[i].size == 0 ) free_index= i;
 706         }
 707
 708         if(i>=CFRAME_BUFFER_COUNT){
 709             i= free_index;
 710             f->cfrm[i].id= id;
 711         }
 712         cfrm= &f->cfrm[i];
 713
 714         cfrm->data= av_fast_realloc(cfrm->data, &cfrm->allocated_size, cfrm->size + data_size + FF_INPUT_BUFFER_PADDING_SIZE);
 715         if(!cfrm->data){ //explicit check needed as memcpy below might not catch a NULL
 716             av_log(f->avctx, AV_LOG_ERROR, "realloc falure");
 717             return -1;
 718         }
 719
 720         memcpy(cfrm->data + cfrm->size, buf+20, data_size);
 721         cfrm->size += data_size;
 722
 723         if(cfrm->size >= whole_size){
 724             buf= cfrm->data;
 725             frame_size= cfrm->size;
 726
 727             if(id != avctx->frame_number){
 728                 av_log(f->avctx, AV_LOG_ERROR, "cframe id mismatch %d %d\n", id, avctx->frame_number);
 729             }
 730
 731             cfrm->size= cfrm->id= 0;
 732             frame_4cc= ff_get_fourcc("pfrm");
 733         }else
 734             return buf_size;
 735     }else{
 736         buf= buf + 12;
 737         frame_size= buf_size - 12;
 738     }
 739
 740     temp= f->current_picture;
 741     f->current_picture= f->last_picture;
 742     f->last_picture= temp;
 743
 744     p= &f->current_picture;
 745     avctx->coded_frame= p;
 746
 747     avctx->flags |= CODEC_FLAG_EMU_EDGE; // alternatively we would have to use our own buffer management
 748
 749     if(p->data[0])
 750         avctx->release_buffer(avctx, p);
 751
 752     p->reference= 1;
 753     if(avctx->get_buffer(avctx, p) < 0){
 754         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 755         return -1;
 756     }
 757
 758     if(frame_4cc == ff_get_fourcc("ifr2")){
 759         p->pict_type= FF_I_TYPE;
 760         if(decode_i2_frame(f, buf-4, frame_size) < 0)
 761             return -1;
 762     }else if(frame_4cc == ff_get_fourcc("ifrm")){
 763         p->pict_type= FF_I_TYPE;
 764         if(decode_i_frame(f, buf, frame_size) < 0)
 765             return -1;
 766     }else if(frame_4cc == ff_get_fourcc("pfrm") || frame_4cc == ff_get_fourcc("pfr2")){
 767         p->pict_type= FF_P_TYPE;
 768         if(decode_p_frame(f, buf, frame_size) < 0)
 769             return -1;
 770     }else if(frame_4cc == ff_get_fourcc("snd_")){
 771         av_log(avctx, AV_LOG_ERROR, "ignoring snd_ chunk length:%d\n", buf_size);
 772     }else{
 773         av_log(avctx, AV_LOG_ERROR, "ignoring unknown chunk length:%d\n", buf_size);
 774     }
 775
 776     p->key_frame= p->pict_type == FF_I_TYPE;
 777
 778     *picture= *p;
 779     *data_size = sizeof(AVPicture);
 780
 781     emms_c();
 782
 783     return buf_size;
 784 }
 785
 786
 787 static void common_init(AVCodecContext *avctx){
 788     FourXContext * const f = avctx->priv_data;
 789
 790     dsputil_init(&f->dsp, avctx);
 791
 792     f->avctx= avctx;
 793 }
 794
 795 static av_cold int decode_init(AVCodecContext *avctx){
 796     FourXContext * const f = avctx->priv_data;
 797
 798     if(avctx->extradata_size != 4 || !avctx->extradata) {
 799         av_log(avctx, AV_LOG_ERROR, "extradata wrong or missing\n");
 800         return 1;
 801     }
 802
 803     f->version= AV_RL32(avctx->extradata)>>16;
 804     common_init(avctx);
 805     init_vlcs(f);
 806
 807     if(f->version>2) avctx->pix_fmt= PIX_FMT_RGB565;
 808     else             avctx->pix_fmt= PIX_FMT_RGB555;
 809
 810     return 0;
 811 }
 812
 813
 814 static av_cold int decode_end(AVCodecContext *avctx){
 815     FourXContext * const f = avctx->priv_data;
 816     int i;
 817
 818     av_freep(&f->bitstream_buffer);
 819     f->bitstream_buffer_size=0;
 820     for(i=0; i<CFRAME_BUFFER_COUNT; i++){
 821         av_freep(&f->cfrm[i].data);
 822         f->cfrm[i].allocated_size= 0;
 823     }
 824     free_vlc(&f->pre_vlc);
 825
 826     return 0;
 827 }
 828
 829 AVCodec fourxm_decoder = {
 830     "4xm",
 831     CODEC_TYPE_VIDEO,
 832     CODEC_ID_4XM,
 833     sizeof(FourXContext),
 834     decode_init,
 835     NULL,
 836     decode_end,
 837     decode_frame,
 838     /*CODEC_CAP_DR1,*/
 839     .long_name = NULL_IF_CONFIG_SMALL("4X Movie"),
 840 };
 841