skl_mpg4_dec.cpp

mpeg4编解码器

/********************************************************
 * Some code. Copyright (C) 2003 by Pascal Massimino.   *
 * All Rights Reserved.      (http://skal.planet-d.net) *
 * For Educational/Academic use ONLY. See 'LICENSE.TXT'.*
 ********************************************************/
/*
 * skl_mpg4_dec.cpp
 *
 * MPEG4 decoder
 ********************************************************/

#include "./skl_mpg4i.h"
#include "skl_syst/skl_exception.h"

//////////////////////////////////////////////////////////
// Decoding tables & values
//////////////////////////////////////////////////////////

//////////////////////////////////////////////////////////

struct SKL_VLC { SKL_INT16 Val, Len; };
struct SKL_DCT_VLC { SKL_INT16 Run; SKL_INT8 Level, Len; };

  // table 6-14. Shape type
#define GRAYSCALE   3
#define BINARY_ONLY 2
#define BINARY      1
#define RECTANGULAR 0

  // Table 6-21
static const int DC_Thresh_Tab[] = { 512, 13, 15, 17, 19, 21, 23, 0 };

  // Table 6-27
static const int DQuant_Tab[4] = {-1,-2, 1, 2 };
  // Table 6-28
static const int DBQuant_Tab[4] = { 0, 0,-2, 2 };

  // Table 7-1
const int SKL_MP4_I::DC_Scales[2][31] = {   // index: [Lum][AC_Q-1]
 {  /* DC_Q_chroma = (Q<5) ? 8 : (Q<24) ? (Q+13)/2 : Q-6; */
   8,  8,  8,  8,
   9,  9, 10, 10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18,
  18, 19, 20, 21, 22, 23, 24, 25 },
 {  /* DC_Q_Lum = (Q<5) ? 8 : (Q<9) ? 2*Q : (Q<25) ? Q+8 : Q*2-16; */
   8,  8,  8,  8,
  10, 12, 14, 16,
  17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,
  32, 34, 36, 38, 40, 42, 44, 46 }
};

  // Table 7-6 (K=4)  (modified)
const int SKL_MB::Rnd_Tab_76[16] = { 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1 };
  // Table 7-8 (K=2)  (modified)
const int SKL_MB::Rnd_Tab_78[ 8] = { 0,    0,    1,    1,    0,    0,    0,    1    };
  // Table 7-9 (K=1)  (modified)
const int SKL_MB::Rnd_Tab_79[ 4] = { 0,          1,          0,          0          };

  // Table B-4
static const SKL_VLC BType_Tab_B4[15] = {
                      { SKL_MB_FWD,    4},{ SKL_MB_BWD,    3},{ SKL_MB_BWD,    3}
, { SKL_MB_INTERP, 2},{ SKL_MB_INTERP, 2},{ SKL_MB_INTERP, 2},{ SKL_MB_INTERP, 2}
, { SKL_MB_DIRECT, 1},{ SKL_MB_DIRECT, 1},{ SKL_MB_DIRECT, 1},{ SKL_MB_DIRECT, 1}
, { SKL_MB_DIRECT, 1},{ SKL_MB_DIRECT, 1},{ SKL_MB_DIRECT, 1},{ SKL_MB_DIRECT, 1}
};

  // Table B-6 packed: MB_Type = bits 2,3,4 / CBPC for blocks 5,6 = bits 0,1

static const SKL_VLC MCBPC_Intra_B6_0[63] = {
  {17, 6},{18, 6},{19, 6},{16, 4},{16, 4},{16, 4},{16, 4}
, {13, 3},{13, 3},{13, 3},{13, 3},{13, 3},{13, 3},{13, 3},{13, 3}
, {14, 3},{14, 3},{14, 3},{14, 3},{14, 3},{14, 3},{14, 3},{14, 3}
, {15, 3},{15, 3},{15, 3},{15, 3},{15, 3},{15, 3},{15, 3},{15, 3}
, {12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1}
, {12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1}
, {12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1}
, {12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1},{12, 1}
};

  // Table B-7 packed: MB_Type = bits 2,3,4 / CBPC for blocks 5,6 = bits 0,1

static const SKL_VLC MCBPC_Inter_B7_0[13+1] = {
  { 0x00, 0 }, // special code for leading bit = 1  

  {12, 4},{ 2, 3},{ 2, 3},{ 1, 3},{ 1, 3}
, { 8, 2},{ 8, 2},{ 8, 2},{ 8, 2},{ 4, 2},{ 4, 2},{ 4, 2},{ 4, 2}
};

static const SKL_VLC MCBPC_Inter_B7_1[46] = {
  {19, 8},{18, 8},{17, 8},{ 7, 8},{14, 7},{14, 7}
, {13, 7},{13, 7},{11, 7},{11, 7},{15, 6},{15, 6},{15, 6},{15, 6}
, {10, 6},{10, 6},{10, 6},{10, 6},{ 9, 6},{ 9, 6},{ 9, 6},{ 9, 6}
, { 6, 6},{ 6, 6},{ 6, 6},{ 6, 6},{ 5, 6},{ 5, 6},{ 5, 6},{ 5, 6}
, {16, 5},{16, 5},{16, 5},{16, 5},{16, 5},{16, 5},{16, 5},{16, 5}
, { 3, 5},{ 3, 5},{ 3, 5},{ 3, 5},{ 3, 5},{ 3, 5},{ 3, 5},{ 3, 5}
};

  // Table B-8. CBPY (bits 2,3,4,5)
static const SKL_VLC CBPY_Tab[62] = {
  {24, 6},{36, 6},{32, 5},{32, 5},{16, 5},{16, 5}
, { 8, 5},{ 8, 5},{ 4, 5},{ 4, 5},{ 0, 4},{ 0, 4},{ 0, 4},{ 0, 4}
, {48, 4},{48, 4},{48, 4},{48, 4},{40, 4},{40, 4},{40, 4},{40, 4}
, {56, 4},{56, 4},{56, 4},{56, 4},{20, 4},{20, 4},{20, 4},{20, 4}
, {52, 4},{52, 4},{52, 4},{52, 4},{12, 4},{12, 4},{12, 4},{12, 4}
, {44, 4},{44, 4},{44, 4},{44, 4},{28, 4},{28, 4},{28, 4},{28, 4}
, {60, 2},{60, 2},{60, 2},{60, 2},{60, 2},{60, 2},{60, 2},{60, 2}
, {60, 2},{60, 2},{60, 2},{60, 2},{60, 2},{60, 2},{60, 2},{60, 2}
};


  // Table B-12. Motion vectors multiplied by 2, without 
  // sign (trailing bit) and leading bit (dealt with separately)
  // Length is incremented by 1.
static const SKL_VLC MV_Tab_B12_0[7] = {
  { 3, 4},{ 2, 3},{ 2, 3},{ 1, 2},{ 1, 2},{ 1, 2},{ 1, 2}
};
static const SKL_VLC MV_Tab_B12_1[60] = {
  {24,10},{23,10},{22,10},{21,10}
, {20,10},{19,10},{18,10},{17,10},{16,10},{15,10},{14,10},{13,10}
, {12,10},{11,10},{10, 9},{10, 9},{ 9, 9},{ 9, 9},{ 8, 9},{ 8, 9}
, { 7, 7},{ 7, 7},{ 7, 7},{ 7, 7},{ 7, 7},{ 7, 7},{ 7, 7},{ 7, 7}
, { 6, 7},{ 6, 7},{ 6, 7},{ 6, 7},{ 6, 7},{ 6, 7},{ 6, 7},{ 6, 7}
, { 5, 7},{ 5, 7},{ 5, 7},{ 5, 7},{ 5, 7},{ 5, 7},{ 5, 7},{ 5, 7}
, { 4, 6},{ 4, 6},{ 4, 6},{ 4, 6},{ 4, 6},{ 4, 6},{ 4, 6},{ 4, 6}
, { 4, 6},{ 4, 6},{ 4, 6},{ 4, 6},{ 4, 6},{ 4, 6},{ 4, 6},{ 4, 6}
};
static const SKL_VLC MV_Tab_B12_2[14] = {
  {32,12},{31,12},{30,11},{30,11},{29,11},{29,11}
, {28,11},{28,11},{27,11},{27,11},{26,11},{26,11},{25,11},{25,11}
};

  // Table B-13, restricted to code size <= 3
static const SKL_VLC DC_Size_Lum_B13_0[7] = {
  { 4, 3},{ 3, 3},{ 0, 3},{ 2, 2},{ 2, 2},{ 1, 2},{ 1, 2}
};

  // Table B-14, restricted to code size <= 2
  // Unused (hardcoded)
// static const SKL_VLC DC_Size_Chrom_B14_0[3] = { { 2, 2},{ 1, 2},{ 0, 2} }; 

  // Table B-16

static const SKL_DCT_VLC Intra_B16_0[52] = {
  { 0,-2, 6},{ 5, 1, 6},{ 2,-1, 6},{ 1,-1, 6}
, { 4, 1, 6},{ 3, 1, 6},{ 0, 8, 6},{ 0, 7, 6},{ 1, 2, 6},{ 0, 6, 6},{ 2, 1, 5},{ 2, 1, 5}
, { 0, 5, 5},{ 0, 5, 5},{ 0, 4, 5},{ 0, 4, 5},{ 0,-1, 4},{ 0,-1, 4},{ 0,-1, 4},{ 0,-1, 4}
, { 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2}
, { 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2}
, { 0, 2, 3},{ 0, 2, 3},{ 0, 2, 3},{ 0, 2, 3},{ 0, 2, 3},{ 0, 2, 3},{ 0, 2, 3},{ 0, 2, 3}
, { 1, 1, 4},{ 1, 1, 4},{ 1, 1, 4},{ 1, 1, 4},{ 0, 3, 4},{ 0, 3, 4},{ 0, 3, 4},{ 0, 3, 4}
};
static const SKL_DCT_VLC Intra_B16_1[29] = {
  { 8,-1, 8},{ 7,-1, 8},{ 6,-1, 8},{ 0,-3, 8},{10, 1, 8}
, { 9, 1, 8},{ 8, 1, 8},{ 9,-1, 8},{ 3, 2, 8},{ 1, 4, 8},{ 0,12, 8},{ 0,11, 8},{ 0,10, 8}
, { 4,-1, 7},{ 4,-1, 7},{ 3,-1, 7},{ 3,-1, 7},{ 6, 1, 7},{ 6, 1, 7},{ 5,-1, 7},{ 5,-1, 7}
, { 7, 1, 7},{ 7, 1, 7},{ 2, 2, 7},{ 2, 2, 7},{ 1, 3, 7},{ 1, 3, 7},{ 0, 9, 7},{ 0, 9, 7}
};
static const SKL_DCT_VLC Intra_B16_2[104] = {
    // These are the ESC codes
  {-1, 0, 8},{-1, 0, 8},{-1, 0, 8},{-1, 0, 8},{-1, 0, 8},{-1, 0, 8},{-1, 0, 8},{-1, 0, 8}
, {-2, 0, 9},{-2, 0, 9},{-2, 0, 9},{-2, 0, 9},{-3, 0, 9},{-3, 0, 9},{-3, 0, 9},{-3, 0, 9}

, { 0,18,10},{ 0,18,10},{ 0,17,10},{ 0,17,10},{14,-1, 9},{14,-1, 9},{14,-1, 9},{14,-1, 9}
, {13,-1, 9},{13,-1, 9},{13,-1, 9},{13,-1, 9},{12,-1, 9},{12,-1, 9},{12,-1, 9},{12,-1, 9}
, {11,-1, 9},{11,-1, 9},{11,-1, 9},{11,-1, 9},{10,-1, 9},{10,-1, 9},{10,-1, 9},{10,-1, 9}
, { 1,-2, 9},{ 1,-2, 9},{ 1,-2, 9},{ 1,-2, 9},{ 0,-4, 9},{ 0,-4, 9},{ 0,-4, 9},{ 0,-4, 9}
, {12, 1, 9},{12, 1, 9},{12, 1, 9},{12, 1, 9},{11, 1, 9},{11, 1, 9},{11, 1, 9},{11, 1, 9}
, { 7, 2, 9},{ 7, 2, 9},{ 7, 2, 9},{ 7, 2, 9},{ 6, 2, 9},{ 6, 2, 9},{ 6, 2, 9},{ 6, 2, 9}
, { 5, 2, 9},{ 5, 2, 9},{ 5, 2, 9},{ 5, 2, 9},{ 3, 3, 9},{ 3, 3, 9},{ 3, 3, 9},{ 3, 3, 9}
, { 2, 3, 9},{ 2, 3, 9},{ 2, 3, 9},{ 2, 3, 9},{ 1, 6, 9},{ 1, 6, 9},{ 1, 6, 9},{ 1, 6, 9}
, { 1, 5, 9},{ 1, 5, 9},{ 1, 5, 9},{ 1, 5, 9},{ 0,16, 9},{ 0,16, 9},{ 0,16, 9},{ 0,16, 9}
, { 4, 2, 9},{ 4, 2, 9},{ 4, 2, 9},{ 4, 2, 9},{ 0,15, 9},{ 0,15, 9},{ 0,15, 9},{ 0,15, 9}
, { 0,14, 9},{ 0,14, 9},{ 0,14, 9},{ 0,14, 9},{ 0,13, 9},{ 0,13, 9},{ 0,13, 9},{ 0,13, 9}
};
static const SKL_DCT_VLC Intra_B16_3[88] = {
  { 0,-7,11},{ 0,-7,11},{ 0,-6,11},{ 0,-6,11},{ 0,22,11},{ 0,22,11},{ 0,21,11},{ 0,21,11}
, { 2,-2,10},{ 2,-2,10},{ 2,-2,10},{ 2,-2,10},{ 1,-3,10},{ 1,-3,10},{ 1,-3,10},{ 1,-3,10}
, { 0,-5,10},{ 0,-5,10},{ 0,-5,10},{ 0,-5,10},{13, 1,10},{13, 1,10},{13, 1,10},{13, 1,10}
, { 5, 3,10},{ 5, 3,10},{ 5, 3,10},{ 5, 3,10},{ 8, 2,10},{ 8, 2,10},{ 8, 2,10},{ 8, 2,10}
, { 4, 3,10},{ 4, 3,10},{ 4, 3,10},{ 4, 3,10},{ 3, 4,10},{ 3, 4,10},{ 3, 4,10},{ 3, 4,10}
, { 2, 4,10},{ 2, 4,10},{ 2, 4,10},{ 2, 4,10},{ 1, 7,10},{ 1, 7,10},{ 1, 7,10},{ 1, 7,10}
, { 0,20,10},{ 0,20,10},{ 0,20,10},{ 0,20,10},{ 0,19,10},{ 0,19,10},{ 0,19,10},{ 0,19,10}
, { 0,23,11},{ 0,23,11},{ 0,24,11},{ 0,24,11},{ 1, 8,11},{ 1, 8,11},{ 9, 2,11},{ 9, 2,11}
, { 3,-2,11},{ 3,-2,11},{ 4,-2,11},{ 4,-2,11},{15,-1,11},{15,-1,11},{16,-1,11},{16,-1,11}
, { 0,25,12},{ 0,26,12},{ 0,27,12},{ 1, 9,12},{ 6, 3,12},{ 1,10,12},{ 2, 5,12},{ 7, 3,12}
, {14, 1,12},{ 0,-8,12},{ 5,-2,12},{ 6,-2,12},{17,-1,12},{18,-1,12},{19,-1,12},{20,-1,12}
};

  // Table B-17
static const SKL_DCT_VLC Inter_B17_0[52] = {
  { 4,-1, 6},{ 3,-1, 6},{ 2,-1, 6},{ 1,-1, 6}
, { 9, 1, 6},{ 8, 1, 6},{ 7, 1, 6},{ 6, 1, 6},{ 1, 2, 6},{ 0, 3, 6},{ 5, 1, 5},{ 5, 1, 5}
, { 4, 1, 5},{ 4, 1, 5},{ 3, 1, 5},{ 3, 1, 5},{ 0,-1, 4},{ 0,-1, 4},{ 0,-1, 4},{ 0,-1, 4}
, { 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2}
, { 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2},{ 0, 1, 2}
, { 1, 1, 3},{ 1, 1, 3},{ 1, 1, 3},{ 1, 1, 3},{ 1, 1, 3},{ 1, 1, 3},{ 1, 1, 3},{ 1, 1, 3}
, { 2, 1, 4},{ 2, 1, 4},{ 2, 1, 4},{ 2, 1, 4},{ 0, 2, 4},{ 0, 2, 4},{ 0, 2, 4},{ 0, 2, 4}
};
static const SKL_DCT_VLC Inter_B17_1[29] = {
  {16,-1, 8},{15,-1, 8},{14,-1, 8},{13,-1, 8},{12,-1, 8}
, {11,-1, 8},{10,-1, 8},{ 9,-1, 8},{14, 1, 8},{13, 1, 8},{ 2, 2, 8},{ 1, 3, 8},{ 0, 5, 8}
, { 8,-1, 7},{ 8,-1, 7},{ 7,-1, 7},{ 7,-1, 7},{ 6,-1, 7},{ 6,-1, 7},{ 5,-1, 7},{ 5,-1, 7}
, {12, 1, 7},{12, 1, 7},{11, 1, 7},{11, 1, 7},{10, 1, 7},{10, 1, 7},{ 0, 4, 7},{ 0, 4, 7}
};
static const SKL_DCT_VLC Inter_B17_2[52] = {
    // These are the ESC codes
  {-1, 0, 8},{-1, 0, 8},{-1, 0, 8},{-1, 0, 8},{-2, 0, 9},{-2, 0, 9},{-3, 0, 9},{-3, 0, 9}

, { 0, 9,10},{ 0, 8,10},{24,-1, 9},{24,-1, 9},{23,-1, 9},{23,-1, 9},{22,-1, 9},{22,-1, 9}
, {21,-1, 9},{21,-1, 9},{20,-1, 9},{20,-1, 9},{19,-1, 9},{19,-1, 9},{18,-1, 9},{18,-1, 9}
, {17,-1, 9},{17,-1, 9},{ 0,-2, 9},{ 0,-2, 9},{22, 1, 9},{22, 1, 9},{21, 1, 9},{21, 1, 9}
, {20, 1, 9},{20, 1, 9},{19, 1, 9},{19, 1, 9},{18, 1, 9},{18, 1, 9},{17, 1, 9},{17, 1, 9}
, {16, 1, 9},{16, 1, 9},{15, 1, 9},{15, 1, 9},{ 4, 2, 9},{ 4, 2, 9},{ 3, 2, 9},{ 3, 2, 9}
, { 0, 7, 9},{ 0, 7, 9},{ 0, 6, 9},{ 0, 6, 9}
};
static const SKL_DCT_VLC Inter_B17_3[88] = {
  { 1,-2,11},{ 1,-2,11},{ 0,-3,11},{ 0,-3,11},{ 0,11,11},{ 0,11,11},{ 0,10,11},{ 0,10,11}
, {28,-1,10},{28,-1,10},{28,-1,10},{28,-1,10},{27,-1,10},{27,-1,10},{27,-1,10},{27,-1,10}
, {26,-1,10},{26,-1,10},{26,-1,10},{26,-1,10},{25,-1,10},{25,-1,10},{25,-1,10},{25,-1,10}
, { 9, 2,10},{ 9, 2,10},{ 9, 2,10},{ 9, 2,10},{ 8, 2,10},{ 8, 2,10},{ 8, 2,10},{ 8, 2,10}
, { 7, 2,10},{ 7, 2,10},{ 7, 2,10},{ 7, 2,10},{ 6, 2,10},{ 6, 2,10},{ 6, 2,10},{ 6, 2,10}
, { 5, 2,10},{ 5, 2,10},{ 5, 2,10},{ 5, 2,10},{ 3, 3,10},{ 3, 3,10},{ 3, 3,10},{ 3, 3,10}
, { 2, 3,10},{ 2, 3,10},{ 2, 3,10},{ 2, 3,10},{ 1, 4,10},{ 1, 4,10},{ 1, 4,10},{ 1, 4,10}
, { 0,12,11},{ 0,12,11},{ 1, 5,11},{ 1, 5,11},{23, 1,11},{23, 1,11},{24, 1,11},{24, 1,11}
, {29,-1,11},{29,-1,11},{30,-1,11},{30,-1,11},{31,-1,11},{31,-1,11},{32,-1,11},{32,-1,11}
, { 1, 6,12},{ 2, 4,12},{ 4, 3,12},{ 5, 3,12},{ 6, 3,12},{10, 2,12},{25, 1,12},{26, 1,12}
, {33,-1,12},{34,-1,12},{35,-1,12},{36,-1,12},{37,-1,12},{38,-1,12},{39,-1,12},{40,-1,12}
};

  // Table B-19
static const int Max_LEVEL_Intra_Last0[15] =      /* INTRA */
  { 27,10,5, 4, 3, 3, 3, 3, 2, 2, 1, 1, 1, 1, 1 };
static const int Max_LEVEL_Intra_Last1[21] =      /* INTRA */
  { 8, 3, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1 };

  // Table B-20
static const int Max_LEVEL_Inter_Last0[27] =      /* INTER */
  { 12,6, 4, 3, 3, 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 1,
     1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
static const int Max_LEVEL_Inter_Last1[41] =      /* INTER */
  { 3, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1 };

const int *(Max_LEVEL[2][2]) = {    // index: [intra][last][run/level]
  { Max_LEVEL_Intra_Last0, Max_LEVEL_Intra_Last1 },
  { Max_LEVEL_Inter_Last0, Max_LEVEL_Inter_Last1 }
};

  // Table B-21 (+1 included)
static const int Max_RUN_Intra_Last0[28-1] =
  { 15, 10, 8, 4, 3, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 };
static const int Max_RUN_Intra_Last1[9-1] =
  { 21, 7, 2, 1, 1, 1, 1, 1 };

  // Table B-22
static const int Max_RUN_Inter_Last0[13-1] =
  { 27, 11, 7, 3, 2, 2, 1, 1, 1, 1, 1, 1 };
static const int Max_RUN_Inter_Last1[4-1] =
  { 41, 2, 1 };

static const int *(Max_RUN[2][2]) = {
  { Max_RUN_Intra_Last0, Max_RUN_Intra_Last1 },
  { Max_RUN_Inter_Last0, Max_RUN_Inter_Last1 }
};

  // Table B-33 (first part)
static const SKL_VLC Spr_Tab_B33[8] = {
  { 0, 2},{ 0, 2},{ 1, 3},{ 2, 3},{ 3, 3},{ 4, 3},{ 5, 3},{-1, 3}
};
  // Table B-34 for size>=6
static const SKL_VLC Spr_Tab_B34[8] = {
  { 6, 1},{ 6, 1},{ 6, 1},{ 6, 1},{ 7, 2},{ 7, 2},{ 9, 3},{10, 3}
};

//////////////////////////////////////////////////////////
// Vector decoding
//////////////////////////////////////////////////////////

static int Read_Motion_Vector(SKL_FBB *Bits, SKL_INT32 Fix)
{
  if (Bits->Get_Bits(1))
    return 0;

  Bits->Check_Bits(11);
  SKL_UINT32 Code = Bits->Bits;
  const SKL_VLC *VLC;
  if      (Code>=0x20000000)     VLC = MV_Tab_B12_0 - 1 + (Code>>(21+8));
  else if (Code>=0x02000000)     VLC = MV_Tab_B12_1 - 4 + (Code>>(21+2));
  else /*if (Code>=0x00400000)*/ VLC = MV_Tab_B12_2 - 2 + (Code>>(21+0));

  int Val;
  if (!--Fix) {   // special case for Fix==1 (residue=0)
    Val = VLC->Val;
    Code = Bits->Get_Bits(VLC->Len);  // reads 'sign bit'
    if (Code & 1) Val = -Val;
  }
  else {
    Val = ((VLC->Val-1)<<Fix) + 1;
    Code = Bits->Get_Bits(VLC->Len + Fix);  // reads 'sign bit' and 'res' too...
    const SKL_INT32 Scale = 1 << Fix;
    Val += Code & (Scale-1);        // add residue...
    if (Code & Scale) Val = -Val;   // ...and sign
  }
  return Val;
}

static void Read_Vector(SKL_FBB *Bits, SKL_INT32 Fix, SKL_MV MV)
{
  const int High  = 16 << Fix;

  int dx = MV[0] + Read_Motion_Vector(Bits, Fix);
  int dy = MV[1] + Read_Motion_Vector(Bits, Fix);

  if      (dx<-High) dx += 2*High;
  else if (dx>=High) dx -= 2*High;
  MV[0] = dx;

  if      (dy<-High) dy += 2*High;
  else if (dy>=High) dy -= 2*High;
  MV[1] = dy;
}

//////////////////////////////////////////////////////////
// Coeffs decoding
//////////////////////////////////////////////////////////

static int Read_DC_Size_Lum(SKL_FBB *Bits)
{
  int Size;
  const SKL_UINT32 Code = Bits->See_Bits_Safe(3);
  if (Code!=0) {
    const SKL_VLC *VLC = &DC_Size_Lum_B13_0[Code - 1];
    Bits->Discard_Safe( VLC->Len );
    Size = VLC->Val;
  }
  else {
    const int Val = 11 + 1 - SKL_BMASKS::Bit_Sizes[Bits->See_Bits_Safe(11)];
    Bits->Discard_Safe( Val );
    Size = Val+1;
  }
  return Size;
}

static int Read_DC_Size_Chroma(SKL_FBB *Bits)
{
  int Size;
  const SKL_UINT32 Code = Bits->See_Bits_Safe(2);
  if (Code!=0) {
    Bits->Discard_Safe( 2 );
    Size = 3-Code; // <- hardcoded version of DC_Size_Chrom_B14_0[]
  }
  else {
    const int Val = 12 + 1 - SKL_BMASKS::Log2(Bits->See_Bits_Safe(12));
    Bits->Discard_Safe( Val );
    Size = Val;
  }
  return Size;
}

static int Read_DC_Diff(SKL_FBB *Bits, int Lum)
{
  Bits->Check_Bits(12);
  const int Size = Lum ? Read_DC_Size_Lum(Bits) : Read_DC_Size_Chroma(Bits);
  if (Size==0) return 0;
  SKL_UINT32 Code;
  if (Size<=8) Code = Bits->Get_Bits(Size);
  else {
    Code = Bits->Get_Bits(Size+1);    // + marker bit
    Code >>= 1;
  }
  if (!(Code&SKL_BMASKS::Or[Size]))   // MSB not set
    Code -= SKL_BMASKS::And[Size];
  return Code;  
}

static void Read_Intra_AC(SKL_FBB *Bits, SKL_INT16 *Coeff,
                          const int * const Zigzag, int i)
{
  while(1)
  {
    const SKL_DCT_VLC *VLC;

    Bits->Check_Bits(12);
    SKL_UINT32 Code = Bits->Bits;
    SKL_ASSERT(Code>=0x00800000);

         if (Code>=0x30000000) VLC = Intra_B16_0 - 12 + (Code>>(20+6));
    else if (Code>=0x13000000) VLC = Intra_B16_1 - 19 + (Code>>(20+4));
    else if (Code>=0x06000000) VLC = Intra_B16_2 - 48 + (Code>>(20+1));
    else /*if (Code>=0x00800000)*/ VLC = Intra_B16_3 -  8 + (Code>>(20+0));
    //else break; /* error */        

    int Run = VLC->Run;