/************************************************* * libr263: fast H.263 encoder library * * Copyright (C) 1996, Roalt Aalmoes, Twente University * SPA multimedia group * * Based on Telenor TMN 1.6 encoder (Copyright (C) 1995, Telenor R&D) * created by Karl Lillevold  * * Author encoder: Roalt Aalmoes, <aalmoes@huygens.nl> *  * Date: 31-07-96 **************************************************/#include "sim.h"#include "huffman.h"/* static libr263.c prototypes */static void init_motion_detection(void);  static int Check8x8(unsigned int *orig, 			       unsigned int *recon, int pos);static int HasMoved(int call_time,  void *real, void *recon, int x, int y); int InitCompress(CParam *params){  pic = (Pict *)malloc(sizeof(Pict));  if(!pic) {    return -1;  }  pic->unrestricted_mv_mode = DEF_UMV_MODE;  pic->use_gobsync = DEF_INSERT_SYNC;  pic->PB = 0;  pic->TR = 0;  pic->QP_mean = 0.0;  if(params->format == CPARAM_QCIF) {    pels = QCIF_YWIDTH;    lines = QCIF_YHEIGHT;    cpels = QCIF_YWIDTH/2;    pic->source_format = SF_QCIF;  } else if (params->format == CPARAM_CIF) {    pels = CIF_YWIDTH;    lines = CIF_YHEIGHT;    cpels = CIF_YWIDTH/2;    pic->source_format = SF_CIF;  } else if (params->format == CPARAM_SQCIF) {    pels = SQCIF_YWIDTH;    lines = SQCIF_YHEIGHT;    cpels = SQCIF_YWIDTH/2;    pic->source_format = SF_SQCIF;  } else if (params->format == CPARAM_4CIF) {    pels = CIF4_YWIDTH;    lines = CIF4_YHEIGHT;    cpels = CIF4_YWIDTH/2;    pic->source_format = SF_4CIF;    } else if (params->format == CPARAM_16CIF) {    pels = CIF16_YWIDTH;    lines = CIF16_YHEIGHT;    cpels = CIF16_YWIDTH/2;    pic->source_format = SF_16CIF;  } else {    pels = params->pels;    lines = params->lines;    cpels = params->pels / 2;    pic->source_format = 0;	/* ILLEGAL H.263! Use it only for testing */  }    mbr = lines / MB_SIZE;  mbc = pels / MB_SIZE;  uskip = lines*pels;  vskip = uskip + lines*pels/4;  sizeof_frame = (vskip + lines*pels/4)*sizeof(int);  headerlength = DEF_HEADERLENGTH;  /* Initalize VLC_tables */  InitHuff();  mwinit();  /* Init motion detection */  init_motion_detection();#ifdef VERYFASTIDCT  init_idct();			/* Do this in case of VERYFASTIDCT */#elif STANDARDIDCT  init_idctref();		/* Do this in case of standard IDCT */#endif				/* Do nothing for FASTIDCT */  /* Set internal variables */  advanced = DEF_ADV_MODE;  mv_outside_frame = DEF_UMV_MODE || DEF_ADV_MODE;  long_vectors = DEF_UMV_MODE;  pb_frames = DEF_PBF_MODE;  search_p_frames = DEF_SPIRAL_SEARCH;  trace = DEF_WRITE_TRACE;  params->half_pixel_searchwindow = CPARAM_DEFAULT_SEARCHWINDOW;   params->inter = CPARAM_DEFAULT_INTER;  params->search_method = CPARAM_DEFAULT_SEARCH_METHOD;  params->advanced_method = CPARAM_DEFAULT_ADVANCED_METHOD;  params->Q_inter = CPARAM_DEFAULT_INTER_Q;  params->Q_intra = CPARAM_DEFAULT_INTRA_Q;  params->interpolated_lum = malloc(pels*lines*4*sizeof(int));  if(!params->interpolated_lum)    return -1;  params->recon = malloc(sizeof_frame);  if(!params->recon) {    free(params->interpolated_lum);    free(pic);    return -1;  }  return 0;}void SkipH263Frames(int frames_to_skip){  pic->TR += frames_to_skip % 256;}
int CompressToH263(CParam *params, Bits *bits){  if(!params->inter) {    CodeIntraH263(params, bits);  } else {    CodeInterH263(params, bits);  }  bits->header += zeroflush();  /* pictures shall be byte aligned */ // 填滿一個比特  pic->TR += 1 % 256; /* one means 30 fps */  return 0;}void CloseCompress(CParam *params){  mwcloseinit();  free(params->interpolated_lum);  free(params->recon);  free(pic);  return;}/* Motion Detection part */static int global_mb_threshold;static int global_pixel_threshold;/* This array is computed for QCIF  movement_detection[] = {0, 354, 528, 177,                          3, 353, 531, 178,		          352, 179, 530, 1,		          355, 176, 2, 529 };			  *//* This array determines the order in a pixel is checked per 4x4 block *//* {x, y} within [0..3] */

/*運動坐標*/static unsigned int movement_coords[16][2] = { {0,0}, {2,2},{0,3},{1,1},		               		       {3,0},{1,2},{3,3},{2,1},				               {0,2},{3,1},{2,3},{1,0},				               {3,2},{0,1},{2,0},{1,3} };static int movement_detection[16][4];//??????????????????????void init_motion_detection(){  unsigned int counter, pos;  for(counter = 0; counter < 16; counter++) {    pos = movement_coords[counter][0] + movement_coords[counter][1]*pels;    movement_detection[counter][0] = pos;    movement_detection[counter][1] = pos + 4;    movement_detection[counter][2] = pos + pels*4;    movement_detection[counter][3] = pos + pels*4 + 4;  }  return;}

// 檢查8*8塊,在原始數據和重建數據是否有大的差距,每4*4塊檢測, 返回差距值,為0到4
// 移動情況,返回值,0到4間static  int Check8x8(unsigned int *orig, unsigned int *recon, int pos){  int value, index;  register int thres = global_pixel_threshold;//門限在findmotion函數中, 設定為2  value = 0;  /* Mark pixel changed when lum value differs more than "thres" */  index = movement_detection[pos][0];  value += abs(*(orig + index) - *(recon+index)) > thres;  index = movement_detection[pos][1];  value += abs(*(orig + index) - *(recon+index)) > thres;  index = movement_detection[pos][2];				  value += abs(*(orig + index) - *(recon+index)) > thres;  index = movement_detection[pos][3];			  value += abs(*(orig + index) - *(recon+index)) > thres;  return value;}

//16*16宏塊, 判斷real和recon中有無大的差距,  有1,無0 
// real當前宏塊數據,recon 重建宏塊static int HasMoved(int call_time,  void *real,	     void *recon, int x, int y){  int offset1;  unsigned int *MB_orig;  unsigned int *MB_recon;  int position;  int value = 0;  offset1 = (y*pels+x)*MB_SIZE;  position = call_time;   //   /* Integration of 8x8 and 4x4 check might improve performance,      but is not done here */
  //檢測8*8塊,原始和重建數據是否有大的差距  MB_orig = (unsigned int *) real + offset1;  MB_recon = (unsigned int *) recon + offset1;  value += Check8x8(MB_orig, MB_recon, position); // 返回值為0到4  MB_orig += 8; MB_recon += 8;  value += Check8x8(MB_orig, MB_recon, position);   MB_orig += 8*pels - 8; MB_recon += 8*pels - 8;  value += Check8x8(MB_orig, MB_recon, position);  MB_orig += 8; MB_recon += 8;  value += Check8x8(MB_orig, MB_recon, position);  return value > global_mb_threshold;	    //門限在findmotino函數中定為2  /* Mark MB changed if more than "global_mb_threshold" pixels are changed */}

// 判斷原始數據和重建數據差別,返回差距值,// mb_threshold宏塊門限,y亮度4個8*8塊中move了幾個,  pixel_threshold象素門限,8*8塊中四個代表象素中move了幾個int FindMotion(CParam *params, int mb_threshold, int pixel_threshold){  static int call_time = 0; // 定義為0,檢查(0,0),(9,3),(3,0),(3,3)四個位置  int j,i;  int counter = 0;  global_mb_threshold = mb_threshold;  global_pixel_threshold = pixel_threshold;  for(j = 0; j < mbr; j++) {    for(i = 0; i < mbc; i++) {
		                     //EncodeThisBlock ,判斷宏塊原始數據和重建數據是否差距大,是1,否0       *(params->EncodeThisBlock + j*mbc + i) = HasMoved(call_time, params->data, params->recon, i,j);       counter += *(params->EncodeThisBlock +j*mbc + i);   // 個數    }  }  call_time = (call_time + 1) % 16;   return counter;}