/*****************************************************************************
 *
 *  XVID MPEG-4 VIDEO CODEC
 *  - Decoder Module -
 *
 *  Copyright(C) 2002      MinChen <chenm001@163.com>
 *               2002-2003 Peter Ross <pross@xvid.org>
 *
 *  This program is free software ; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation ; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY ; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program ; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 * $Id: decoder.cpp,v 1.1 2005/01/04 13:44:37 jeanlf Exp $
 *
 ****************************************************************************/

#include "quant.h"
#include "quant_matrix.h"
#include "interpolate8x8.h"
#include "reduced.h"
#include "mbprediction.h"
#include "gmc.h"
#include "mem_align.h"

#ifdef __SYMBIAN32__
#include <e32base.h>
#endif

//----------------------------

#ifdef _MSC_VER

#if _MSC_VER <= 1200
# define DECLARE_ALIGNED_MATRIX(name,sizex,sizey,type,alignment) \
                type name##_storage[(sizex)*(sizey)+(alignment)-1]; \
                type * name = (type *) (((int) name##_storage+(alignment - 1)) & ~((int)(alignment)-1))
#else
# define DECLARE_ALIGNED_MATRIX(name,sizex,sizey,type,alignment) __declspec(align(alignment)) type name[(sizex)*(sizey)]
#endif

#else

#define DECLARE_ALIGNED_MATRIX(name, sizex, sizey, type, alignment) \
   type name##_storage[(sizex)*(sizey)+(alignment)-1]; \
   type * name = (type *) (((dword) name##_storage+(alignment - 1)) & ~((dword)(alignment)-1))

#endif

//----------------------------
//----------------------------
/* K = 4 */
static const dword roundtab_76[16] = { 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1 };

/* K = 1 */
const dword roundtab_79[4] = { 0, 1, 0, 0 };

//----------------------------

int S_decoder::Resize(){
                              //free existing
   image_destroy(&cur, edged_width, edged_height);
   image_destroy(&refn[0], edged_width, edged_height);
   image_destroy(&refn[1], edged_width, edged_height);
   image_destroy(&tmp, edged_width, edged_height);
   image_destroy(&qtmp, edged_width, edged_height);

   image_destroy(&gmc, edged_width, edged_height);

   if(last_mbs)
      xvid_free(last_mbs);
   if(mbs)
      xvid_free(mbs);

                              //realloc
   mb_width = (width + 15) / 16;
   mb_height = (height + 15) / 16;

   edged_width = 16 * mb_width + 2 * EDGE_SIZE;
   edged_height = 16 * mb_height + 2 * EDGE_SIZE;

   if(image_create(&cur, edged_width, edged_height)){
      xvid_free(this);
      return XVID_ERR_MEMORY;
   }

   if(image_create(&refn[0], edged_width, edged_height)){
      image_destroy(&cur, edged_width, edged_height);
      xvid_free(this);
      return XVID_ERR_MEMORY;
   }

                              //support B-frame to reference last 2 frame
   if(image_create(&refn[1], edged_width, edged_height)){
      image_destroy(&cur, edged_width, edged_height);
      image_destroy(&refn[0], edged_width, edged_height);
      xvid_free(this);
      return XVID_ERR_MEMORY;
   }
   if(image_create(&tmp, edged_width, edged_height)){
      image_destroy(&cur, edged_width, edged_height);
      image_destroy(&refn[0], edged_width, edged_height);
      image_destroy(&refn[1], edged_width, edged_height);
      xvid_free(this);
      return XVID_ERR_MEMORY;
   }

   if(image_create(&qtmp, edged_width, edged_height)){
      image_destroy(&cur, edged_width, edged_height);
      image_destroy(&refn[0], edged_width, edged_height);
      image_destroy(&refn[1], edged_width, edged_height);
      image_destroy(&tmp, edged_width, edged_height);
      xvid_free(this);
      return XVID_ERR_MEMORY;
   }

   if(image_create(&gmc, edged_width, edged_height)){
      image_destroy(&qtmp, edged_width, edged_height);
      image_destroy(&cur, edged_width, edged_height);
      image_destroy(&refn[0], edged_width, edged_height);
      image_destroy(&refn[1], edged_width, edged_height);
      image_destroy(&tmp, edged_width, edged_height);
      xvid_free(this);
      return XVID_ERR_MEMORY;
   }

   mbs = (MACROBLOCK*)xvid_malloc(sizeof(MACROBLOCK) * mb_width * mb_height, CACHE_LINE);
   if(mbs == NULL){
      image_destroy(&cur, edged_width, edged_height);
      image_destroy(&refn[0], edged_width, edged_height);
      image_destroy(&refn[1], edged_width, edged_height);
      image_destroy(&tmp, edged_width, edged_height);
      image_destroy(&qtmp, edged_width, edged_height);
      xvid_free(this);
      return XVID_ERR_MEMORY;
   }
   MemSet(mbs, 0, sizeof(MACROBLOCK) * mb_width * mb_height);

                              //for skip MB flag
   last_mbs = (MACROBLOCK*)xvid_malloc(sizeof(MACROBLOCK) * mb_width * mb_height, CACHE_LINE);
   if(!last_mbs){
      xvid_free(mbs);
      image_destroy(&cur, edged_width, edged_height);
      image_destroy(&refn[0], edged_width, edged_height);
      image_destroy(&refn[1], edged_width, edged_height);
      image_destroy(&tmp, edged_width, edged_height);
      image_destroy(&qtmp, edged_width, edged_height);
      xvid_free(this);
      return XVID_ERR_MEMORY;
   }
   MemSet(last_mbs, 0, sizeof(MACROBLOCK) * mb_width * mb_height);

   return 0;
}

//----------------------------

int decoder_create(xvid_dec_create_t *create){

   if(XVID_VERSION_MAJOR(create->version) != 1)   /* v1.x.x */
      return XVID_ERR_VERSION;

   //S_decoder *dec = (S_decoder*)xvid_malloc(sizeof(S_decoder), CACHE_LINE);
   S_decoder *dec = new(ELeave) S_decoder(create);
   if(!dec)
      return XVID_ERR_MEMORY;

   return dec->Init(create);
}

//----------------------------

S_decoder::S_decoder(xvid_dec_create_t *create):
#ifdef PROFILE
   prof(*create->prof),
#endif
   time_inc_resolution(0),
   fixed_time_inc(0),
   time_inc_bits(0),
   shape(0),
   quant_bits(0),
   quant_type(0),
   mpeg_quant_matrices(0),
   quarterpel(0),
   complexity_estimation_disable(0),
   interlacing(false),
   top_field_first(0),
   alternate_vertical_scan(0),
   aspect_ratio(0),
   par_width(0),
   par_height(0),
   sprite_enable(0),
   sprite_warping_points(0),
   sprite_warping_accuracy(0),
   sprite_brightness_change(0),
   newpred_enable(0),
   reduced_resolution_enable(false),
   bs_version(0),
   width(0),
   height(0),
   edged_width(0),
   edged_height(0),
   mb_width(0),
   mb_height(0),
   mbs(0),
   last_mbs(0),
   last_coding_type(0),
   frames(0),
   time(0),
   time_base(0),
   last_time_base(0),
   last_non_b_time(0),
   time_pp(0),
   time_bp(0),
   fixed_dimensions(false),
   scalability(false),
   low_delay(false),
   low_delay_default(false),
   last_reduced_resolution(false),
   packed_mode(false)
{
   MemSet(&p_fmv, 0, sizeof(p_fmv));
   MemSet(&p_bmv, 0, sizeof(p_bmv));
}

//----------------------------

S_decoder::~S_decoder(){

   xvid_free(last_mbs);
   xvid_free(mbs);

                              //image based GMC
   image_destroy(&gmc, edged_width, edged_height);

   image_destroy(&refn[0], edged_width, edged_height);
   image_destroy(&refn[1], edged_width, edged_height);
   image_destroy(&tmp, edged_width, edged_height);
   image_destroy(&qtmp, edged_width, edged_height);
   image_destroy(&cur, edged_width, edged_height);
   xvid_free(mpeg_quant_matrices);
}

//----------------------------

int S_decoder::Init(xvid_dec_create_t *create){

   mpeg_quant_matrices = (dword*)xvid_malloc(sizeof(dword) * 64 * 8, CACHE_LINE);
   if(!mpeg_quant_matrices){
      delete this;
      return XVID_ERR_MEMORY;
   }

   create->handle = this;

   width = create->width;
   height = create->height;

   cur.Null();
   refn[0].Null();
   refn[1].Null();
   tmp.Null();
   qtmp.Null();

                              //image based GMC
   gmc.Null();


   mbs = NULL;
   last_mbs = NULL;

   init_mpeg_matrix(mpeg_quant_matrices);

                              //For B-frame support (used to save reference frame's time
   frames = 0;
   time = time_base = last_time_base = 0;
   low_delay = false;
   packed_mode = false;

   fixed_dimensions = (width > 0 && height > 0);

   init_vlc_tables();
   idct_int32_init();

   if(fixed_dimensions)
      return Resize();
   return 0;
}

//----------------------------

static const int dquant_table[4] = {
   -1, -2, 1, 2
};

//----------------------------

static dword get_dc_scaler(dword quant, dword lum){

   if(quant < 5)
      return 8;
   if(quant < 25 && !lum)
      return (quant + 13) / 2;
   if(quant < 9)
      return 2 * quant;
   if(quant < 25)
      return quant + 8;
   if(lum)
      return 2 * quant - 16;
   return quant - 6;
}

//---------------------------

#ifdef _ARM_
extern"C"
void XVID_ClearMatrix(void *dst);

#else
void XVID_ClearMatrix(void *dst);
#ifndef __MARM__
inline void XVID_ClearMatrix(void *dst){ MemSet(dst, 0, 64 * sizeof(int)); }
#endif
#endif

//--------------------------
/* decode an intra macroblock */
void S_decoder::MBIntra(MACROBLOCK *pMB, dword x_pos, dword y_pos, dword acpred_flag, dword cbp, Bitstream *bs,
   dword quant, dword intra_dc_threshold, dword bound, bool reduced_resolution){

   DECLARE_ALIGNED_MATRIX(block, 6, 64, int, CACHE_LINE);
   DECLARE_ALIGNED_MATRIX(data, 6, 64, int, CACHE_LINE);

   int i;

   dword stride = edged_width;
   const dword stride2 = stride / 2;
   byte *pY_Cur, *pU_Cur, *pV_Cur;

   if(reduced_resolution) {
      pY_Cur = cur.y + (y_pos << 5) * stride + (x_pos << 5);
      pU_Cur = cur.u + (y_pos << 4) * stride2 + (x_pos << 4);
      pV_Cur = cur.v + (y_pos << 4) * stride2 + (x_pos << 4);
   }else{
      pY_Cur = cur.y + (y_pos << 4) * stride + (x_pos << 4);
      pU_Cur = cur.u + (y_pos << 3) * stride2 + (x_pos << 3);
      pV_Cur = cur.v + (y_pos << 3) * stride2 + (x_pos << 3);
   }

   MemSet(block, 0, 6 * 64 * sizeof(int));  //clear

   const dword iQuant = pMB->quant;
   for(i = 0; i < 6; i++){
      dword iDcScaler = get_dc_scaler(iQuant, i < 4);
      int predictors[8];
      int start_coeff;

      predict_acdc(mbs, x_pos, y_pos, mb_width, i, &block[i * 64], iQuant, iDcScaler, predictors, bound);
      if(!acpred_flag)
         pMB->acpred_directions[i] = 0;

      if(quant < intra_dc_threshold){
         PROF_S(PROF_1);
         int dc_size;
         int dc_dif;

         dc_size = i < 4 ? bs->get_dc_size_lum() : bs->get_dc_size_chrom();
         dc_dif = dc_size ? bs->get_dc_dif(dc_size) : 0;

         if (dc_size > 8) {
            bs->Skip(1);   /* marker */
         }

         block[i * 64 + 0] = dc_dif;
         start_coeff = 1;

         DPRINTF(XVID_DEBUG_COEFF,"block[0] %i\n", dc_dif);
         PROF_E(PROF_1);
      }else{
         start_coeff = 0;
      }
      if(cbp & (1 << (5 - i))){
                              //coded
         int direction = alternate_vertical_scan ? 2 : pMB->acpred_directions[i];
         get_intra_block(bs, &block[i * 64], direction, start_coeff);
      }
      add_acdc(pMB, i, &block[i * 64], iDcScaler, predictors);
      if(quant_type == 0){
         dequant_h263_intra(&data[i * 64], &block[i * 64], iQuant, iDcScaler, mpeg_quant_matrices);
      }else{
         dequant_mpeg_intra(&data[i * 64], &block[i * 64], iQuant, iDcScaler, mpeg_quant_matrices);
      }
      InverseDiscreteCosineTransform(&data[i * 64]);
   }

   dword next_block = stride * 8;
   if(interlacing && pMB->field_dct){
      next_block = stride;
      stride *= 2;
   }
   if(reduced_resolution){
      next_block*=2;
      copy_upsampled_8x8_16to8(pY_Cur, &data[0 * 64], stride);
      copy_upsampled_8x8_16to8(pY_Cur + 16, &data[1 * 64], stride);
      copy_upsampled_8x8_16to8(pY_Cur + next_block, &data[2 * 64], stride);
      copy_upsampled_8x8_16to8(pY_Cur + 16 + next_block, &data[3 * 64], stride);
      copy_upsampled_8x8_16to8(pU_Cur, &data[4 * 64], stride2);
      copy_upsampled_8x8_16to8(pV_Cur, &data[5 * 64], stride2);
   }else{
      transfer_16to8copy(pY_Cur, &data[0 * 64], stride);
      transfer_16to8copy(pY_Cur + 8, &data[1 * 64], stride);
      transfer_16to8copy(pY_Cur + next_block, &data[2 * 64], stride);
      transfer_16to8copy(pY_Cur + 8 + next_block, &data[3 * 64], stride);
      transfer_16to8copy(pU_Cur, &data[4 * 64], stride2);
      transfer_16to8copy(pV_Cur, &data[5 * 64], stride2);
   }
}

//----------------------------

void S_decoder::mb_decode(const dword cbp, Bitstream * bs, byte * pY_Cur, byte * pU_Cur, byte * pV_Cur, bool reduced_resolution, const MACROBLOCK *pMB){

   DECLARE_ALIGNED_MATRIX(block, 1, 64, int, CACHE_LINE);
   DECLARE_ALIGNED_MATRIX(data, 6, 64, int, CACHE_LINE);

   int i;
   int stride = edged_width;
   const int stride2 = stride/2;

   const dword iQuant = pMB->quant;
   const int direction = alternate_vertical_scan ? 2 : 0;
   const quant_interFuncPtr dequant = quant_type == 0 ? dequant_h263_inter : dequant_mpeg_inter;
   for(i = 0; i < 6; i++){
      if(cbp & (1 << (5 - i))){
                              //coded
         XVID_ClearMatrix(block);
         get_inter_block(bs, block, direction);
         dequant(&data[i * 64], block, iQuant, mpeg_quant_matrices);
         InverseDiscreteCosineTransform(&data[i * 64]);
      }
   }

   int next_block = stride * (reduced_resolution ? 16 : 8);
   if(interlacing && pMB->field_dct){
      next_block = stride;
      stride *= 2;
   }

   if(reduced_resolution){
      if(cbp & 32)
         add_upsampled_8x8_16to8(pY_Cur, &data[0 * 64], stride);
      if(cbp & 16)
         add_upsampled_8x8_16to8(pY_Cur + 16, &data[1 * 64], stride);
      if(cbp & 8)
         add_upsampled_8x8_16to8(pY_Cur + next_block, &data[2 * 64], stride);
      if(cbp & 4)
         add_upsampled_8x8_16to8(pY_Cur + 16 + next_block, &data[3 * 64], stride);
      if(cbp & 2)
         add_upsampled_8x8_16to8(pU_Cur, &data[4 * 64], stride2);
      if(cbp & 1)
         add_upsampled_8x8_16to8(pV_Cur, &data[5 * 64], stride2);
   }else{
      if(cbp & 32)
         transfer_16to8add(pY_Cur, &data[0 * 64], stride);
      if(cbp & 16)
         transfer_16to8add(pY_Cur + 8, &data[1 * 64], stride);
      if(cbp & 8)
         transfer_16to8add(pY_Cur + next_block, &data[2 * 64], stride);
      if(cbp & 4)
         transfer_16to8add(pY_Cur + 8 + next_block, &data[3 * 64], stride);
      if(cbp & 2)
         transfer_16to8add(pU_Cur, &data[4 * 64], stride2);
      if(cbp & 1)
         transfer_16to8add(pV_Cur, &data[5 * 64], stride2);
   }
}

//----------------------------

void S_decoder::DecodeInterMacroBlock(const MACROBLOCK * pMB, dword x_pos, dword y_pos, dword cbp, Bitstream *bs,
   bool rounding, bool reduced_resolution, int ref){

   dword stride = edged_width;
   dword stride2 = stride / 2;
   dword i;

   byte *pY_Cur, *pU_Cur, *pV_Cur;

   int uv_dx, uv_dy;
   VECTOR mv[4];              //local copy of mvs

   if(reduced_resolution){
      pY_Cur = cur.y + (y_pos << 5) * stride + (x_pos << 5);
      pU_Cur = cur.u + (y_pos << 4) * stride2 + (x_pos << 4);
      pV_Cur = cur.v + (y_pos << 4) * stride2 + (x_pos << 4);
      for (i = 0; i < 4; i++) {
         mv[i].x = RRV_MV_SCALEUP(pMB->mvs[i].x);
         mv[i].y = RRV_MV_SCALEUP(pMB->mvs[i].y);
      }
   }else{
      pY_Cur = cur.y + (y_pos << 4) * stride + (x_pos << 4);
      pU_Cur = cur.u + (y_pos << 3) * stride2 + (x_pos << 3);
      pV_Cur = cur.v + (y_pos << 3) * stride2 + (x_pos << 3);
      for(i = 0; i < 4; i++)
         mv[i] = pMB->mvs[i];
   }

   if(pMB->mode != MODE_INTER4V){
                              //INTER, INTER_Q, NOT_CODED, FORWARD, BACKWARD

      uv_dx = mv[0].x;
      uv_dy = mv[0].y;
      if (quarterpel) {
         uv_dx /= 2;
         uv_dy /= 2;
      }
      uv_dx = (uv_dx >> 1) + roundtab_79[uv_dx & 0x3];
      uv_dy = (uv_dy >> 1) + roundtab_79[uv_dy & 0x3];

      if(reduced_resolution)
         interpolate32x32_switch(cur.y, refn[0].y, 32*x_pos, 32*y_pos, mv[0].x, mv[0].y, stride, rounding);
      else
      if(quarterpel)
         interpolate16x16_quarterpel(cur.y, refn[ref].y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos, mv[0].x, mv[0].y, stride, rounding);
      else
         interpolate16x16_switch(cur.y, refn[ref].y, 16*x_pos, 16*y_pos, mv[0].x, mv[0].y, stride, rounding);
   }else{
                              //MODE_INTER4V

      if(quarterpel) {
         uv_dx = (mv[0].x / 2) + (mv[1].x / 2) + (mv[2].x / 2) + (mv[3].x / 2);
         uv_dy = (mv[0].y / 2) + (mv[1].y / 2) + (mv[2].y / 2) + (mv[3].y / 2);
      }else{
         uv_dx = mv[0].x + mv[1].x + mv[2].x + mv[3].x;
         uv_dy = mv[0].y + mv[1].y + mv[2].y + mv[3].y;
      }

      uv_dx = (uv_dx >> 3) + roundtab_76[uv_dx & 0xf];
      uv_dy = (uv_dy >> 3) + roundtab_76[uv_dy & 0xf];

      if(reduced_resolution){
         interpolate16x16_switch(cur.y, refn[0].y, 32*x_pos,      32*y_pos,      mv[0].x, mv[0].y, stride, rounding);
         interpolate16x16_switch(cur.y, refn[0].y, 32*x_pos + 16, 32*y_pos,      mv[1].x, mv[1].y, stride, rounding);
         interpolate16x16_switch(cur.y, refn[0].y, 32*x_pos,      32*y_pos + 16, mv[2].x, mv[2].y, stride, rounding);
         interpolate16x16_switch(cur.y, refn[0].y, 32*x_pos + 16, 32*y_pos + 16, mv[3].x, mv[3].y, stride, rounding);
         interpolate16x16_switch(cur.u, refn[0].u, 16*x_pos,      16*y_pos,      uv_dx,   uv_dy,   stride2, rounding);
         interpolate16x16_switch(cur.v, refn[0].v, 16*x_pos,      16*y_pos,      uv_dx,   uv_dy,   stride2, rounding);
      }else
      if(quarterpel){
         interpolate8x8_quarterpel(cur.y, refn[0].y , qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos, mv[0].x, mv[0].y, stride, rounding);
         interpolate8x8_quarterpel(cur.y, refn[0].y , qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos + 8, 16*y_pos, mv[1].x, mv[1].y, stride, rounding);
         interpolate8x8_quarterpel(cur.y, refn[0].y , qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos + 8, mv[2].x, mv[2].y, stride, rounding);
         interpolate8x8_quarterpel(cur.y, refn[0].y , qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos + 8, 16*y_pos + 8, mv[3].x, mv[3].y, stride, rounding);
      } else {
         interpolate8x8_switch(cur.y, refn[0].y , 16*x_pos, 16*y_pos, mv[0].x, mv[0].y, stride, rounding);
         interpolate8x8_switch(cur.y, refn[0].y , 16*x_pos + 8, 16*y_pos, mv[1].x, mv[1].y, stride, rounding);
         interpolate8x8_switch(cur.y, refn[0].y , 16*x_pos, 16*y_pos + 8, mv[2].x, mv[2].y, stride, rounding);
         interpolate8x8_switch(cur.y, refn[0].y , 16*x_pos + 8, 16*y_pos + 8, mv[3].x, mv[3].y, stride, rounding);
      }
   }
                              //chroma
   if(reduced_resolution){
      interpolate16x16_switch(cur.u, refn[0].u, 16*x_pos, 16*y_pos, uv_dx, uv_dy, stride2, rounding);
      interpolate16x16_switch(cur.v, refn[0].v, 16*x_pos, 16*y_pos, uv_dx, uv_dy, stride2, rounding);
   }else{
      interpolate8x8_switch(cur.u, refn[ref].u,  8*x_pos,  8*y_pos, uv_dx, uv_dy, stride2, rounding);
      interpolate8x8_switch(cur.v, refn[ref].v,  8*x_pos,  8*y_pos, uv_dx, uv_dy, stride2, rounding);
   }
   if(cbp)
      mb_decode(cbp, bs, pY_Cur, pU_Cur, pV_Cur, reduced_resolution, pMB);
}

//----------------------------

inline int gmc_sanitize(int value, int quarterpel, int fcode){

   int length = 1 << (fcode+4);

#if 0
   if (quarterpel) value *= 2;
#endif

   if (value < -length)
      return -length;
   else if (value >= length)
      return length-1;
   else return value;
}

//----------------------------

void S_decoder::mbgmc(MACROBLOCK *pMB, dword x_pos, dword y_pos, dword fcode, dword cbp, Bitstream * bs, bool rounding){

   const dword stride = edged_width;
   const dword stride2 = stride / 2;

   byte *const pY_Cur=cur.y + (y_pos << 4) * stride + (x_pos << 4);
   byte *const pU_Cur=cur.u + (y_pos << 3) * stride2 + (x_pos << 3);
   byte *const pV_Cur=cur.v + (y_pos << 3) * stride2 + (x_pos << 3);

   NEW_GMC_DATA *gmc_data = &new_gmc_data;

   pMB->mvs[0] = pMB->mvs[1] = pMB->mvs[2] = pMB->mvs[3] = pMB->amv;

                              //this is where the calculations are done
   gmc_data->predict_16x16(gmc_data, cur.y + y_pos*16*stride + x_pos*16, refn[0].y, stride, stride, x_pos, y_pos, rounding);
   gmc_data->predict_8x8(gmc_data, cur.u + y_pos*8*stride2 + x_pos*8, refn[0].u, cur.v + y_pos*8*stride2 + x_pos*8, refn[0].v, stride2, stride2, x_pos, y_pos, rounding);
   gmc_data->get_average_mv(gmc_data, &pMB->amv, x_pos, y_pos, quarterpel);

   pMB->amv.x = gmc_sanitize(pMB->amv.x, quarterpel, fcode);
   pMB->amv.y = gmc_sanitize(pMB->amv.y, quarterpel, fcode);

   pMB->mvs[0] = pMB->mvs[1] = pMB->mvs[2] = pMB->mvs[3] = pMB->amv;

   if(cbp)
      mb_decode(cbp, bs, pY_Cur, pU_Cur, pV_Cur, 0, pMB);
}

//----------------------------

void S_decoder::I_Frame(Bitstream * bs, bool reduced_resolution, int quant, int intra_dc_threshold){

   dword bound;
   dword x, y;
   //dword mb_width = mb_width;
   //dword mb_height = mb_height;

   if (reduced_resolution) {
      mb_width = (width + 31) / 32;
      mb_height = (height + 31) / 32;
   }

   bound = 0;

   for (y = 0; y < mb_height; y++) {
      for (x = 0; x < mb_width; x++) {
         dword mcbpc;
         dword cbpc;
         dword acpred_flag;
         dword cbpy;
         dword cbp;

         while(bs->ShowBits(9) == 1)
            bs->Skip(9);

         if(bs->check_resync_marker(0)){
            bound = read_video_packet_header(bs, 0, &quant, NULL, NULL, &intra_dc_threshold);
            x = bound % mb_width;
            y = bound / mb_width;
         }
         MACROBLOCK *mb = &mbs[y * mb_width + x];

         //DPRINTF(XVID_DEBUG_MB, "macroblock (%i,%i) %08x\n", x, y, bs->ShowBits(32));

         mcbpc = bs->get_mcbpc_intra();
         mb->mode = mcbpc & 7;
         cbpc = (mcbpc >> 4);

         acpred_flag = bs->GetBit();

         cbpy = bs->GetCbpy(1);
         cbp = (cbpy << 2) | cbpc;

         if (mb->mode == MODE_INTRA_Q) {
            quant += dquant_table[bs->GetBits(2)];
            if (quant > 31) {
               quant = 31;
            } else if (quant < 1) {
               quant = 1;
            }
         }
         mb->quant = quant;
         mb->mvs[0].x = mb->mvs[0].y =
         mb->mvs[1].x = mb->mvs[1].y =
         mb->mvs[2].x = mb->mvs[2].y =
         mb->mvs[3].x = mb->mvs[3].y =0;

         if(interlacing){
            mb->field_dct = bs->GetBit();
            DPRINTF(XVID_DEBUG_MB,"deci: field_dct: %i\n", mb->field_dct);
         }
         MBIntra(mb, x, y, acpred_flag, cbp, bs, quant, intra_dc_threshold, bound, reduced_resolution);
      }
      /*
#ifdef XVID_CSP_SLICE
      if(out_frm)
         output_slice(&cur, edged_width,width,out_frm,0,y,mb_width);
#endif
         */
   }
}

//----------------------------

void S_decoder::GetMotionVector(Bitstream * bs, int x, int y, int k, VECTOR *ret_mv, int fcode, int bound){

   const int scale_fac = 1 << (fcode - 1);
   const int high = (32 * scale_fac) - 1;
   const int low = ((-32) * scale_fac);
   const int range = (64 * scale_fac);

   const VECTOR pmv = get_pmv2(mbs, mb_width, bound, x, y, k);
   VECTOR mv;

   mv.x = bs->GetMoveVector(fcode);
   mv.y = bs->GetMoveVector(fcode);

   //DPRINTF(XVID_DEBUG_MV,"mv_diff (%i,%i) pred (%i,%i) result (%i,%i)\n", mv.x, mv.y, pmv.x, pmv.y, mv.x+pmv.x, mv.y+pmv.y);

   mv.x += pmv.x;
   mv.y += pmv.y;

   if(mv.x < low){
      mv.x += range;
   }else
   if(mv.x > high){
      mv.x -= range;
   }

   if(mv.y < low){
      mv.y += range;
   }else
   if(mv.y > high){
      mv.y -= range;
   }

   ret_mv->x = mv.x;
   ret_mv->y = mv.y;
}

//----------------------------
// for P_VOP set gmc_warp to NULL
void S_decoder::P_Frame(Bitstream *bs, int rounding, bool reduced_resolution, int quant, int fcode,
   int intra_dc_threshold, const WARPPOINTS *gmc_warp){

   //dword mb_width = mb_width;
   //dword mb_height = mb_height;

   if(reduced_resolution){
      mb_width = (width + 31) / 32;
      mb_height = (height + 31) / 32;
   }

   SetEdges(refn[0]);

   if(gmc_warp){
                              //accuracy: 0==1/2, 1=1/4, 2=1/8, 3=1/16
      generate_GMCparameters(sprite_warping_points, sprite_warping_accuracy, gmc_warp, width, height, &new_gmc_data);
                              //image warping is done block-based in decoder_mbgmc(), now
   }

   PROF_S(PROF_FRM_P);
   dword bound = 0;

   for(dword y = 0; y < mb_height; y++){
      //int cp_mb = 0, st_mb = 0;
      for(dword x = 0; x < mb_width; x++){
                              //skip stuffing
         while(bs->ShowBits(10) == 1)
            bs->Skip(10);

         if(bs->check_resync_marker(fcode - 1)){
            bound = read_video_packet_header(bs, fcode - 1, &quant, &fcode, NULL, &intra_dc_threshold);
            x = bound % mb_width;
            y = bound / mb_width;
         }
         MACROBLOCK *mb = &mbs[y * mb_width + x];

         //DPRINTF(XVID_DEBUG_MB, "macroblock (%i,%i) %08x\n", x, y, bs->ShowBits(32));

         if(!(bs->GetBit())){
                              //block _is_ coded
            int mcsel = 0;    //mcsel: '0'=local motion, '1'=GMC

            //cp_mb++;
            dword mcbpc = bs->GetMcbpcInter();
            mb->mode = mcbpc & 7;
            dword cbpc = (mcbpc >> 4);

            DPRINTF(XVID_DEBUG_MB, "mode %i\n", mb->mode);
            DPRINTF(XVID_DEBUG_MB, "cbpc %i\n", cbpc);

            dword intra = (mb->mode == MODE_INTRA || mb->mode == MODE_INTRA_Q);

            dword acpred_flag = 0;
            if(gmc_warp && (mb->mode == MODE_INTER || mb->mode == MODE_INTER_Q))
               mcsel = bs->GetBit();
            else
            if(intra)
               acpred_flag = bs->GetBit();

            dword cbpy = bs->GetCbpy(intra);
            //DPRINTF(XVID_DEBUG_MB, "cbpy %i mcsel %i \n", cbpy,mcsel);

            dword cbp = (cbpy << 2) | cbpc;

            if(mb->mode == MODE_INTER_Q || mb->mode == MODE_INTRA_Q){
               int dquant = dquant_table[bs->GetBits(2)];
               DPRINTF(XVID_DEBUG_MB, "dquant %i\n", dquant);
               quant += dquant;
               if (quant > 31) {
                  quant = 31;
               } else if (quant < 1) {
                  quant = 1;
               }
               DPRINTF(XVID_DEBUG_MB, "quant %i\n", quant);
            }
            mb->quant = quant;

            if(interlacing){
               if((cbp || intra) && !mcsel){
                  mb->field_dct = bs->GetBit();
                  DPRINTF(XVID_DEBUG_MB,"decp: field_dct: %i\n", mb->field_dct);
               }

               if(mb->mode == MODE_INTER || mb->mode == MODE_INTER_Q){
                  mb->field_pred = bs->GetBit();
                  DPRINTF(XVID_DEBUG_MB, "decp: field_pred: %i\n", mb->field_pred);

                  if(mb->field_pred){
                     mb->field_for_top = bs->GetBit();
                     DPRINTF(XVID_DEBUG_MB,"decp: field_for_top: %i\n", mb->field_for_top);
                     mb->field_for_bot = bs->GetBit();
                     DPRINTF(XVID_DEBUG_MB,"decp: field_for_bot: %i\n", mb->field_for_bot);
                  }
               }
            }
            if(mcsel){
               mbgmc(mb, x, y, fcode, cbp, bs, rounding);
               PROF_E(PROF_0);
               continue;

            }else
            if(mb->mode == MODE_INTER || mb->mode == MODE_INTER_Q){
               if(interlacing && mb->field_pred){
                  GetMotionVector(bs, x, y, 0, &mb->mvs[0], fcode, bound);
                  GetMotionVector(bs, x, y, 0, &mb->mvs[1], fcode, bound);
               }else{
                  GetMotionVector(bs, x, y, 0, &mb->mvs[0], fcode, bound);
                  mb->mvs[1] = mb->mvs[2] = mb->mvs[3] = mb->mvs[0];
               }
            }else
            if(mb->mode == MODE_INTER4V){
               GetMotionVector(bs, x, y, 0, &mb->mvs[0], fcode, bound);
               GetMotionVector(bs, x, y, 1, &mb->mvs[1], fcode, bound);
               GetMotionVector(bs, x, y, 2, &mb->mvs[2], fcode, bound);
               GetMotionVector(bs, x, y, 3, &mb->mvs[3], fcode, bound);
            }else{    /* MODE_INTRA, MODE_INTRA_Q */
               mb->mvs[0].x = mb->mvs[1].x = mb->mvs[2].x = mb->mvs[3].x = 0;
               mb->mvs[0].y = mb->mvs[1].y = mb->mvs[2].y = mb->mvs[3].y = 0;
               MBIntra(mb, x, y, acpred_flag, cbp, bs, quant, intra_dc_threshold, bound, reduced_resolution);
               continue;
            }
            PROF_S(PROF_5);
            DecodeInterMacroBlock(mb, x, y, cbp, bs, rounding, reduced_resolution, 0);
            PROF_E(PROF_5);
         }else
         if(gmc_warp){
                              //a not coded S(GMC)-VOP macroblock
            mb->mode = MODE_NOT_CODED_GMC;
            mbgmc(mb, x, y, fcode, 0x00, bs, rounding);

            /*
#ifdef XVID_CSP_SLICE
            if(out_frm && cp_mb > 0) {
               output_slice(&cur, edged_width,width,out_frm,st_mb,y,cp_mb);
               cp_mb = 0;
            }
            st_mb = x+1;
#endif
            */
         }else{
                              //not coded P_VOP macroblock
            mb->mode = MODE_NOT_CODED;

            mb->mvs[0].x = mb->mvs[1].x = mb->mvs[2].x = mb->mvs[3].x = 0;
            mb->mvs[0].y = mb->mvs[1].y = mb->mvs[2].y = mb->mvs[3].y = 0;

            DecodeInterMacroBlock(mb, x, y, 0, bs, rounding, reduced_resolution, 0);
            /*
#ifdef XVID_CSP_SLICE
            if(out_frm && cp_mb > 0) {
               output_slice(&cur, edged_width,width,out_frm,st_mb,y,cp_mb);
               cp_mb = 0;
            }
            st_mb = x+1;
#endif
            */
         }
      }
      /*
#ifdef XVID_CSP_SLICE
      if(out_frm && cp_mb > 0)
         output_slice(&cur, edged_width,width,out_frm,st_mb,y,cp_mb);
#endif
         */
   }
   PROF_E(PROF_FRM_P);
}

//----------------------------
/* decode B-frame motion vector */
static void get_b_motion_vector(Bitstream * bs, VECTOR * mv, int fcode, const VECTOR pmv){

   const int scale_fac = 1 << (fcode - 1);
   const int high = (32 * scale_fac) - 1;
   const int low = ((-32) * scale_fac);
   const int range = (64 * scale_fac);

   int mv_x = bs->GetMoveVector(fcode);
   int mv_y = bs->GetMoveVector(fcode);

   mv_x += pmv.x;
   mv_y += pmv.y;

   if (mv_x < low)
      mv_x += range;
   else if (mv_x > high)
      mv_x -= range;

   if (mv_y < low)
      mv_y += range;
   else if (mv_y > high)
      mv_y -= range;

   mv->x = mv_x;
   mv->y = mv_y;
}

//----------------------------
/* decode an B-frame direct & interpolate macroblock */
void S_decoder::BFrameInterpolateMBInter(const IMAGE &forward, const IMAGE &backward, const MACROBLOCK *pMB, dword x_pos, dword y_pos, Bitstream *bs, int direct){

   PROF_S(PROF_BINT_MBI);
   dword stride = edged_width;
   dword stride2 = stride / 2;
   int uv_dx, uv_dy;
   int b_uv_dx, b_uv_dy;
   byte *pY_Cur, *pU_Cur, *pV_Cur;
   const dword cbp = pMB->cbp;

   pY_Cur = cur.y + (y_pos << 4) * stride + (x_pos << 4);
   pU_Cur = cur.u + (y_pos << 3) * stride2 + (x_pos << 3);
   pV_Cur = cur.v + (y_pos << 3) * stride2 + (x_pos << 3);

   if(!direct){
      uv_dx = pMB->mvs[0].x;
      uv_dy = pMB->mvs[0].y;

      b_uv_dx = pMB->b_mvs[0].x;
      b_uv_dy = pMB->b_mvs[0].y;

      if(quarterpel){
         uv_dx /= 2;
         uv_dy /= 2;
         b_uv_dx /= 2;
         b_uv_dy /= 2;
      }
      uv_dx = (uv_dx >> 1) + roundtab_79[uv_dx & 0x3];
      uv_dy = (uv_dy >> 1) + roundtab_79[uv_dy & 0x3];

      b_uv_dx = (b_uv_dx >> 1) + roundtab_79[b_uv_dx & 0x3];
      b_uv_dy = (b_uv_dy >> 1) + roundtab_79[b_uv_dy & 0x3];
   }else{
      if(quarterpel) {
         uv_dx = (pMB->mvs[0].x / 2) + (pMB->mvs[1].x / 2) + (pMB->mvs[2].x / 2) + (pMB->mvs[3].x / 2);
         uv_dy = (pMB->mvs[0].y / 2) + (pMB->mvs[1].y / 2) + (pMB->mvs[2].y / 2) + (pMB->mvs[3].y / 2);
         b_uv_dx = (pMB->b_mvs[0].x / 2) + (pMB->b_mvs[1].x / 2) + (pMB->b_mvs[2].x / 2) + (pMB->b_mvs[3].x / 2);
         b_uv_dy = (pMB->b_mvs[0].y / 2) + (pMB->b_mvs[1].y / 2) + (pMB->b_mvs[2].y / 2) + (pMB->b_mvs[3].y / 2);
      } else {
         uv_dx = pMB->mvs[0].x + pMB->mvs[1].x + pMB->mvs[2].x + pMB->mvs[3].x;
         uv_dy = pMB->mvs[0].y + pMB->mvs[1].y + pMB->mvs[2].y + pMB->mvs[3].y;
         b_uv_dx = pMB->b_mvs[0].x + pMB->b_mvs[1].x + pMB->b_mvs[2].x + pMB->b_mvs[3].x;
         b_uv_dy = pMB->b_mvs[0].y + pMB->b_mvs[1].y + pMB->b_mvs[2].y + pMB->b_mvs[3].y;
      }

      uv_dx = (uv_dx >> 3) + roundtab_76[uv_dx & 0xf];
      uv_dy = (uv_dy >> 3) + roundtab_76[uv_dy & 0xf];
      b_uv_dx = (b_uv_dx >> 3) + roundtab_76[b_uv_dx & 0xf];
      b_uv_dy = (b_uv_dy >> 3) + roundtab_76[b_uv_dy & 0xf];
   }

   if(quarterpel){
      if(!direct){
         interpolate16x16_quarterpel(cur.y, forward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos, pMB->mvs[0].x, pMB->mvs[0].y, stride, 0);
      }else{
         interpolate8x8_quarterpel(cur.y, forward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos, pMB->mvs[0].x, pMB->mvs[0].y, stride, 0);
         interpolate8x8_quarterpel(cur.y, forward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos + 8, 16*y_pos, pMB->mvs[1].x, pMB->mvs[1].y, stride, 0);
         interpolate8x8_quarterpel(cur.y, forward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos + 8, pMB->mvs[2].x, pMB->mvs[2].y, stride, 0);
         interpolate8x8_quarterpel(cur.y, forward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos + 8, 16*y_pos + 8, pMB->mvs[3].x, pMB->mvs[3].y, stride, 0);
      }
   }else{
      interpolate8x8_switch(cur.y, forward.y, 16 * x_pos, 16 * y_pos, pMB->mvs[0].x, pMB->mvs[0].y, stride, 0);
      interpolate8x8_switch(cur.y, forward.y, 16 * x_pos + 8, 16 * y_pos, pMB->mvs[1].x, pMB->mvs[1].y, stride, 0);
      interpolate8x8_switch(cur.y, forward.y, 16 * x_pos, 16 * y_pos + 8, pMB->mvs[2].x, pMB->mvs[2].y, stride, 0);
      interpolate8x8_switch(cur.y, forward.y, 16 * x_pos + 8, 16 * y_pos + 8, pMB->mvs[3].x, pMB->mvs[3].y, stride, 0);
   }

   interpolate8x8_switch(cur.u, forward.u, 8 * x_pos, 8 * y_pos, uv_dx, uv_dy, stride2, 0);
   interpolate8x8_switch(cur.v, forward.v, 8 * x_pos, 8 * y_pos, uv_dx, uv_dy, stride2, 0);

   if(quarterpel){
      if(!direct){
         interpolate16x16_quarterpel(tmp.y, backward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos, pMB->b_mvs[0].x, pMB->b_mvs[0].y, stride, 0);
      }else{
         interpolate8x8_quarterpel(tmp.y, backward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos, pMB->b_mvs[0].x, pMB->b_mvs[0].y, stride, 0);
         interpolate8x8_quarterpel(tmp.y, backward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos + 8, 16*y_pos, pMB->b_mvs[1].x, pMB->b_mvs[1].y, stride, 0);
         interpolate8x8_quarterpel(tmp.y, backward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos, 16*y_pos + 8, pMB->b_mvs[2].x, pMB->b_mvs[2].y, stride, 0);
         interpolate8x8_quarterpel(tmp.y, backward.y, qtmp.y, qtmp.y + 64, qtmp.y + 128, 16*x_pos + 8, 16*y_pos + 8, pMB->b_mvs[3].x, pMB->b_mvs[3].y, stride, 0);
      }
   }else{
      interpolate8x8_switch(tmp.y, backward.y, 16 * x_pos, 16 * y_pos, pMB->b_mvs[0].x, pMB->b_mvs[0].y, stride, 0);
      interpolate8x8_switch(tmp.y, backward.y, 16 * x_pos + 8, 16 * y_pos, pMB->b_mvs[1].x, pMB->b_mvs[1].y, stride, 0);
      interpolate8x8_switch(tmp.y, backward.y, 16 * x_pos, 16 * y_pos + 8, pMB->b_mvs[2].x, pMB->b_mvs[2].y, stride, 0);
      interpolate8x8_switch(tmp.y, backward.y, 16 * x_pos + 8, 16 * y_pos + 8, pMB->b_mvs[3].x, pMB->b_mvs[3].y, stride, 0);
   }

   interpolate8x8_switch(tmp.u, backward.u, 8 * x_pos, 8 * y_pos, b_uv_dx, b_uv_dy, stride2, 0);
   interpolate8x8_switch(tmp.v, backward.v, 8 * x_pos, 8 * y_pos, b_uv_dx, b_uv_dy, stride2, 0);

   interpolate8x8_avg2(cur.y + (16 * y_pos * stride) + 16 * x_pos, cur.y + (16 * y_pos * stride) + 16 * x_pos,
      tmp.y + (16 * y_pos * stride) + 16 * x_pos, stride, 1, 8);

   interpolate8x8_avg2(cur.y + (16 * y_pos * stride) + 16 * x_pos + 8, cur.y + (16 * y_pos * stride) + 16 * x_pos + 8,
      tmp.y + (16 * y_pos * stride) + 16 * x_pos + 8, stride, 1, 8);

   interpolate8x8_avg2(cur.y + ((16 * y_pos + 8) * stride) + 16 * x_pos, cur.y + ((16 * y_pos + 8) * stride) + 16 * x_pos,
      tmp.y + ((16 * y_pos + 8) * stride) + 16 * x_pos, stride, 1, 8);

   interpolate8x8_avg2(cur.y + ((16 * y_pos + 8) * stride) + 16 * x_pos + 8, cur.y + ((16 * y_pos + 8) * stride) + 16 * x_pos + 8,
      tmp.y + ((16 * y_pos + 8) * stride) + 16 * x_pos + 8, stride, 1, 8);

   interpolate8x8_avg2(cur.u + (8 * y_pos * stride2) + 8 * x_pos, cur.u + (8 * y_pos * stride2) + 8 * x_pos,
      tmp.u + (8 * y_pos * stride2) + 8 * x_pos, stride2, 1, 8);

   interpolate8x8_avg2(cur.v + (8 * y_pos * stride2) + 8 * x_pos, cur.v + (8 * y_pos * stride2) + 8 * x_pos,
      tmp.v + (8 * y_pos * stride2) + 8 * x_pos, stride2, 1, 8);

   if(cbp)
      mb_decode(cbp, bs, pY_Cur, pU_Cur, pV_Cur, 0, pMB);
   PROF_E(PROF_BINT_MBI);
}

//----------------------------
/* for decode B-frame dbquant */
static int get_dbquant(Bitstream * bs){
   if (!bs->GetBit())     /*  '0' */
      return (0);
   else if (!bs->GetBit())   /* '10' */
      return (-2);
   else                    /* '11' */
      return (2);
}

//----------------------------
/*
 * decode B-frame mb_type
 * bit      ret_value
 * 1     0
 * 01    1
 * 001      2
 * 0001     3
 */
static int get_mbtype(Bitstream * bs){
   int mb_type;

   for (mb_type = 0; mb_type <= 3; mb_type++)
      if (bs->GetBit())
         return (mb_type);

   return -1;
}

//----------------------------

void S_decoder::B_Frame(Bitstream *bs, int quant, int fcode_forward, int fcode_backward){

   dword x, y;
   VECTOR mv;
   const VECTOR zeromv = {0,0};
   const int64_t TRB = time_pp - time_bp, TRD = time_pp;
   int i;

   PROF_S(PROF_FRM_B);
   SetEdges(refn[0]);
   SetEdges(refn[1]);

   for(y = 0; y < mb_height; y++){
                              //initialize Pred Motion Vector
      p_fmv = p_bmv = zeromv;
      for(x = 0; x < mb_width; x++){
         MACROBLOCK *mb = &mbs[y * mb_width + x];
         MACROBLOCK *last_mb = &last_mbs[y * mb_width + x];
         const int fcode_max = (fcode_forward>fcode_backward) ? fcode_forward : fcode_backward;

         if(bs->check_resync_marker(fcode_max  - 1)){
            dword intra_dc_threshold; /* fake variable */
            int bound = read_video_packet_header(bs, fcode_max - 1, &quant, &fcode_forward, &fcode_backward, (int*)&intra_dc_threshold);
            x = bound % mb_width;
            y = bound / mb_width;
                              //reset predicted macroblocks
            p_fmv = p_bmv = zeromv;
         }

         mv = mb->b_mvs[0] = mb->b_mvs[1] = mb->b_mvs[2] = mb->b_mvs[3] = mb->mvs[0] = mb->mvs[1] = mb->mvs[2] = mb->mvs[3] = zeromv;
         mb->quant = quant;

         /*
          * skip if the co-located P_VOP macroblock is not coded
          * if not codec in co-located S_VOP macroblock is _not_
          * automatically skipped
          */

         if(last_mb->mode == MODE_NOT_CODED){
            mb->cbp = 0;
            mb->mode = MODE_FORWARD;
            DecodeInterMacroBlock(mb, x, y, mb->cbp, bs, 0, 0, 1);
            continue;
         }

         if(!bs->GetBit()){
                              //modb=='0'
            const byte modb2 = bs->GetBit();

            mb->mode = get_mbtype(bs);

            if (!modb2)    /* modb=='00' */
               mb->cbp = bs->GetBits(6);
            else
               mb->cbp = 0;

            if (mb->mode && mb->cbp) {
               quant += get_dbquant(bs);
               if (quant > 31)
                  quant = 31;
               else if (quant < 1)
                  quant = 1;
            }
            mb->quant = quant;

            if(interlacing){
               if (mb->cbp) {
                  mb->field_dct = bs->GetBit();
                  DPRINTF(XVID_DEBUG_MB,"decp: field_dct: %i\n", mb->field_dct);
               }

               if (mb->mode) {
                  mb->field_pred = bs->GetBit();
                  DPRINTF(XVID_DEBUG_MB, "decp: field_pred: %i\n", mb->field_pred);

                  if (mb->field_pred) {
                     mb->field_for_top = bs->GetBit();
                     DPRINTF(XVID_DEBUG_MB,"decp: field_for_top: %i\n", mb->field_for_top);
                     mb->field_for_bot = bs->GetBit();
                     DPRINTF(XVID_DEBUG_MB,"decp: field_for_bot: %i\n", mb->field_for_bot);
                  }
               }
            }

         }else{
            mb->mode = MODE_DIRECT_NONE_MV;
            mb->cbp = 0;
         }

         switch(mb->mode){
         case MODE_DIRECT:
            get_b_motion_vector(bs, &mv, 1, zeromv);
                              //flow...
         case MODE_DIRECT_NONE_MV:
            for(i=0; i<4; i++){
               mb->mvs[i].x = (int)((int(TRB) * last_mb->mvs[i].x) / (int)TRD + mv.x);
               mb->b_mvs[i].x = (int) ((mv.x == 0) ?
                  (int(TRB - TRD) * last_mb->mvs[i].x) / (int)TRD :
                  mb->mvs[i].x - last_mb->mvs[i].x);
               mb->mvs[i].y = (int) ((int(TRB) * last_mb->mvs[i].y) / (int)TRD + mv.y);
               mb->b_mvs[i].y = (int) ((mv.y == 0) ?
                  (int(TRB - TRD) * last_mb->mvs[i].y) / int(TRD) :
                  int(mb->mvs[i].y - last_mb->mvs[i].y));
            }
            BFrameInterpolateMBInter(refn[1], refn[0], mb, x, y, bs, 1);
            break;

         case MODE_INTERPOLATE:
            get_b_motion_vector(bs, &mb->mvs[0], fcode_forward, p_fmv);
            p_fmv = mb->mvs[1] = mb->mvs[2] = mb->mvs[3] =   mb->mvs[0];

            get_b_motion_vector(bs, &mb->b_mvs[0], fcode_backward, p_bmv);
            p_bmv = mb->b_mvs[1] = mb->b_mvs[2] = mb->b_mvs[3] = mb->b_mvs[0];

            BFrameInterpolateMBInter(refn[1], refn[0], mb, x, y, bs, 0);
            break;

         case MODE_BACKWARD:
            get_b_motion_vector(bs, &mb->mvs[0], fcode_backward, p_bmv);
            p_bmv = mb->mvs[1] = mb->mvs[2] = mb->mvs[3] =   mb->mvs[0];

            DecodeInterMacroBlock(mb, x, y, mb->cbp, bs, 0, 0, 0);
            break;

         case MODE_FORWARD:
            get_b_motion_vector(bs, &mb->mvs[0], fcode_forward, p_fmv);
            p_fmv = mb->mvs[1] = mb->mvs[2] = mb->mvs[3] =   mb->mvs[0];

            DecodeInterMacroBlock(mb, x, y, mb->cbp, bs, 0, 0, 1);
            break;

         default:
            DPRINTF(XVID_DEBUG_ERROR,"Not supported B-frame mb_type = %i\n", mb->mode);
         }
      }
   }
   PROF_E(PROF_FRM_B);
}

//----------------------------
/* perform post processing if necessary, and output the image */
/*
void S_decoder::Output(IMAGE *img, xvid_dec_frame_t *frame, xvid_dec_stats_t *stats, int coding_type){

   //image_output(img, width, height, edged_width, (byte**)frame->output.plane, (unsigned int*)frame->output.stride, frame->output.csp, interlacing);
   yv12_to_bgr((byte*)frame->output.plane, frame->output.stride, img->y, img->u, img->v, edged_width, edged_width/2, width, height, false);

   if(stats){
      stats->type = coding2type(coding_type);
      stats->data.vop.time_base = (int)time_base;
      stats->data.vop.time_increment = 0; //XXX: todo
   }
}
*/

//----------------------------

int S_decoder::Decode(xvid_dec_frame_t *frame, xvid_dec_stats_t *stats){

   PROF_S(PROF_DECODE);

   Bitstream bs;
   bool rounding;
   bool reduced_resolution;
   dword quant;
   dword fcode_forward;
   dword fcode_backward;
   dword intra_dc_threshold;
   WARPPOINTS gmc_warp;
   int coding_type;

   frame->img_out = NULL;

   if(XVID_VERSION_MAJOR(frame->version) != 1 || (stats && XVID_VERSION_MAJOR(stats->version) != 1)){ //v1.x.x
      PROF_E(PROF_DECODE);
      return XVID_ERR_VERSION;
   }

   //start_global_timer();

   low_delay_default = (frame->general & XVID_LOWDELAY);
   if((frame->general & XVID_DISCONTINUITY))
      frames = 0;
   /*
#ifdef XVID_CSP_SLICE
   out_frm = (frame->output.csp == XVID_CSP_SLICE) ? &frame->output : NULL;
#endif
   */

   if(frame->length < 0){
                              //decoder flush
      int ret;
                              //if not decoding "low_delay/packed", and this isn't low_delay and
                              // we have a reference frame, then outout the reference frame
      if(!(low_delay_default && packed_mode) && !low_delay && frames>0){
         //Output(&refn[0], frame, stats, last_coding_type);
         frame->img_out = &refn[0];
         frames = 0;
         ret = 0;
      } else {
         if (stats) stats->type = XVID_TYPE_NOTHING;
         ret = XVID_ERR_END;
      }
      //stop_global_timer();
      PROF_E(PROF_DECODE);
      return ret;
   }

   bs.Init(frame->bitstream, frame->length);

                              //XXX: 0x7f is only valid whilst decoding vfw xvid/divx5 avi's
   if(low_delay_default && frame->length == 1 && bs.ShowBits(8) == 0x7f){
      //image_output(&refn[0], width, height, edged_width, (byte**)frame->output.plane, (unsigned int*)frame->output.stride, frame->output.csp, interlacing);
      if(stats)
         stats->type = XVID_TYPE_NOTHING;
      PROF_E(PROF_DECODE);
      return 1;               //one byte consumed
   }

   bool success = false;
   bool output = false;
   bool seen_something = false;

   /*
   cur.Clear(width, height, edged_width, 0, 0, 0);
   refn[0].Clear(width, height, edged_width, 0, 0, 0);
   refn[1].Clear(width, height, edged_width, 0, 0, 0);
   */

repeat:

   coding_type = BitstreamReadHeaders(&bs, rounding, &reduced_resolution, &quant, &fcode_forward, &fcode_backward, &intra_dc_threshold, &gmc_warp);

   //DPRINTF(XVID_DEBUG_HEADER, "coding_type=%i, packed=%i, time=%lli, time_pp=%i, time_bp=%i\n", coding_type, packed_mode, time, time_pp, time_bp);

   if(coding_type == -1){
                              //nothing
      if(success)
         goto done;
      if(stats)
         stats->type = XVID_TYPE_NOTHING;
      PROF_E(PROF_DECODE);
      return bs.Pos()/8;
   }

   if(coding_type == -2 || coding_type == -3){
                              //vol and/or resize

      if(coding_type == -3)
         Resize();
      /*
      if(stats){
         stats->type = XVID_TYPE_VOL;
         stats->data.vol.general = 0;
         //XXX: if (interlacing) stats->data.vol.general |= ++INTERLACING;
         stats->data.vol.width = width;
         stats->data.vol.height = height;
         stats->data.vol.par = aspect_ratio;
         stats->data.vol.par_width = par_width;
         stats->data.vol.par_height = par_height;
         return bs.Pos()/8;   //number of bytes consumed
      }
      */
      goto repeat;
   }
   p_bmv.x = p_bmv.y = p_fmv.y = p_fmv.y = 0;

                              //packed_mode: special-N_VOP treament
   if(packed_mode && coding_type == N_VOP){
      if(low_delay_default && frames > 0){
         //Output(&refn[0], frame, stats, last_coding_type);
         frame->img_out = &refn[0];
         output = true;
      }
                              //ignore otherwise
   }else
   if(coding_type != B_VOP){
      switch(coding_type){
      case I_VOP:
         PROF_S(PROF_FRM_I);
         I_Frame(&bs, reduced_resolution, quant, intra_dc_threshold);
         PROF_E(PROF_FRM_I);
         break;
      case P_VOP:
         P_Frame(&bs, rounding, reduced_resolution, quant, fcode_forward, intra_dc_threshold, NULL);
         break;
      case S_VOP:
                              //not called (or very rare)
         P_Frame(&bs, rounding, reduced_resolution, quant, fcode_forward, intra_dc_threshold, &gmc_warp);
         break;
      case N_VOP:
                              //XXX: not_coded vops are not used for forward prediction we should not swap(last_mbs,mbs)
         cur.Copy(&refn[0], edged_width, height);
         break;
      }
      if(reduced_resolution)
         cur.deblock_rrv(edged_width, mbs, (width + 31) / 32, (height + 31) / 32, mb_width, 16, 0);

                              //note: for packed_mode, output is performed when the special-N_VOP is decoded
      if(!(low_delay_default && packed_mode)){
         if(low_delay){
            //Output(&cur, frame, stats, coding_type);
            frame->img_out = &cur;
            output = true;
         }else
         if(frames > 0){
                              //is the reference frame valid?
                              // output the reference frame
            //Output(&refn[0], frame, stats, last_coding_type);
            frame->img_out = &refn[1];
            output = true;
         }
      }
      refn[0].Swap(&refn[1]);
      cur.Swap(&refn[0]);
      Swap(mbs, last_mbs);
      last_reduced_resolution = reduced_resolution;
      last_coding_type = coding_type;

      frames++;
      seen_something = true;
   }else{
                              //B_VOP
      if(low_delay){
         DPRINTF(XVID_DEBUG_ERROR, "warning: bvop found in low_delay==1 stream\n");
         low_delay = true;
      }

      if(frames < 2){
         /* attemping to decode a bvop without atleast 2 reference frames */
         cur.Print(edged_width, height, 16, 16, "broken b-frame, mising ref frames");
      }else
      if(time_pp <= time_bp){
                              //this occurs when dx50_bvop_compatibility==0 sequences are decoded in vfw
         cur.Print(edged_width, height, 16, 16, "broken b-frame");
      }else{
         B_Frame(&bs, quant, fcode_forward, fcode_backward);
      }
      //Output(&cur, frame, stats, coding_type);
      frame->img_out = &cur;
      output = true;
      frames++;
   }

   bs.ByteAlign();

                              //low_delay_default mode: repeat in packed_mode
   if(low_delay_default && packed_mode && !output && !success){
      success = true;
      goto repeat;
   }
done:
                              //low_delay_default mode: if we've gotten here without outputting anything,
                              // then output the recently decoded frame, or print an error message
   if(low_delay_default && !output){
      if(packed_mode && seen_something){
                              //output the recently decoded frame
         //Output(&refn[0], frame, stats, last_coding_type);
         frame->img_out = &refn[0];
      }else{
         cur.Clear(width, height, edged_width, 0, 128, 128);
         cur.Print(edged_width, height, 16, 16, "warning: nothing to output");
         cur.Print(edged_width, height, 16, 64, "bframe decoder lag");

         //Output(&cur, frame, stats, P_VOP);
         frame->img_out = &cur;
         if(stats)
            stats->type = XVID_TYPE_NOTHING;
      }
   }

   PROF_E(PROF_DECODE);
                              //number of bytes consumed
   return bs.Pos() / 8;
}

//----------------------------