jcint.c

这是一个JPEG编码源代码

/* We used function ceil(); */
#include <math.h>

#include "jinclude.h"
#include "jcint.h"

/* This function is internal implemention, you shouldn't use this function 
 * nomarlly. But If you want to invoke it, you must clear that 'cinfo->inbuf'
 * must all (full-filled) with you valide data. Otherwise you will not get right 
 * compress data.
 */
void 
jint_process_rows(jpeg_compress_info *cinfo) {
  
  int mn; /* current mcu in buffer */
  JSAMPLE *mcu_start;  int mcu_delta;
  
  /* Color convertion invoke select.
   * Note: We just implemente RGB -> YCrCb converte. 
   */
  if (cinfo->in_color_space == JCS_RGB)
    jutl_cc_rgb2ycc( cinfo->inbuf, 
                     cinfo->inbuf_width * cinfo->inbuf_height);
  
  
  /* Process each of MCU data.
   * Separate the 'inbuf' data to each color component's dct table,
   * and 'Make' down sample for every component.
   */
  mcu_start = &cinfo->inbuf[0];
  mcu_delta = cinfo->mcu_width*cinfo->num_comp*sizeof(JSAMPLE);
  for (mn=0; mn<cinfo->mcu_per_row; mn++) {
    /* For every color component.
     * Down sample and save to each color component.
     */
    int cn;  /* component counter */
    for (cn=0; cn<cinfo->num_comp; cn++) {    
      JSAMPLE *comp_start = (JSAMPLE *)(mcu_start + cn);
      /* init data-point sample delta */
      int h_samp_delta = cinfo->max_h_factor / cinfo->comp[cn].h_factor 
                       * cinfo->num_comp * sizeof(JSAMPLE);
      int v_samp_delta = cinfo->max_v_factor / cinfo->comp[cn].v_factor
                       * cinfo->num_comp * sizeof(JSAMPLE) 
                       * cinfo->inbuf_width;
      
      /* for every block */
      int bn;  /* block counter */
      int pn;  /* point of data */
      for (bn=0; bn<cinfo->comp[cn].num_dct_table; bn++) {
        /* init block start address */
        JSAMPLE *block_start = (JSAMPLE *)(comp_start 
                + (bn%cinfo->comp[cn].h_factor)*DCTSIZE*h_samp_delta 
                + (bn/cinfo->comp[cn].v_factor)*DCTSIZE*v_samp_delta);
        /* dct table element */
        DCTVAL *dct = 
          (DCTVAL *)&cinfo->comp[cn].dct_table[bn];
        
        /* for each element  */
        for (pn=0; pn<DCTSIZE2; pn++) {
          JSAMPLE *pdata;
          if (pn % DCTSIZE == 0) {
            pdata = (JSAMPLE *)(pn/DCTSIZE * v_samp_delta + block_start);
          }
          dct[pn] = *pdata;
          pdata += h_samp_delta;
        }
      }
    } /* End of color component loop */
    mcu_start += mcu_delta;
    
   
    /* Process current MCU data.
     */
    jint_process_mcu(cinfo);
    /* for example : call jint_process_mcu(cinfo) */
  }
}

/* Process one MCU data in all component.
 */
void 
jint_process_mcu(jpeg_compress_info *cinfo) {
  /* process every color component */
  int cn, tn;
  for (cn=0; cn<cinfo->num_comp; cn++) {
    /* Variable used in component. */
    
    
    /* process every DCT table -- 'Block'
     */    
    for (tn=0; tn<cinfo->comp[cn].num_dct_table; tn++) {

	  compress_dxx(cinfo,cn,tn);
	}
  }  
}

void compress_dxx(jpeg_compress_info *cinfo, int cn, int tn){
    DCTBLOCK   *dct_table = cinfo->comp[cn].dct_table;
    JQUANT_TBL *quant_table = cinfo->quant_table[cinfo->comp[cn].quant_tbl_no];
    JHUFF_TBL  *dc_table = cinfo->dc_huff_table[cinfo->comp[cn].dc_tbl_no];
    JHUFF_TBL  *ac_table = cinfo->ac_huff_table[cinfo->comp[cn].ac_tbl_no];


      DCTVAL tmp=0;
      DCTVAL *val = dct_table[tn];
      int i;
      
      
      /* 正向DCT变换前数据平移 
       */
      for (i=0; i<DCTSIZE2; i++) {
        val[i] -= 128;
      }
      

      /* 正向DCT变换开始    
       */
      /* fdct1_8x8(val);   */
       fdct2_8x8((short *)val);
	  
     
       /* Z字形排序
     */
      jutl_zigzag_sort(val);
     
	
      
      /* 量化 
       */
      for (i=0; i<DCTSIZE2; i++) {
        val[i] = (DCTVAL)((float)val[i]/(float)quant_table->quantval[i]+0.5);
      }
     
     
      

      /* DC系数的线性预测编码 */ 
      tmp = val[0];
      val[0] -= cinfo->comp[cn].preval;
      cinfo->comp[cn].preval = tmp;
      
      
      /* 哈夫曼编码 */
      jhuff_encode_one_block(cinfo, val, dc_table, ac_table);
    }

void
jint_add_quant_table( jpeg_compress_info *cinfo, 
                      unsigned int which_tbl, const UINT16 *base_tbl, 
                      float quality) 
{
  int i;
  DCTVAL *qtblptr;
  cinfo->quant_table[which_tbl] = (JQUANT_TBL *)malloc(sizeof(JQUANT_TBL));
  if (!cinfo->quant_table[which_tbl]) {
    exit(1);
  }
  qtblptr = cinfo->quant_table[which_tbl]->quantval;
  for (i=0; i<DCTSIZE2; i++) {
    qtblptr[i] = (INT16)(base_tbl[i] * quality + 0.5);
  }
  jutl_zigzag_sort(qtblptr);
}

void 
jint_std_quant_tables( jpeg_compress_info *cinfo ) {
  static const INT16 std_luminance_quant_tbl[DCTSIZE2] = {
    16,  11,  10,  16,  24,  40,  51,  61,
    12,  12,  14,  19,  26,  58,  60,  55,
    14,  13,  16,  24,  40,  57,  69,  56,
    14,  17,  22,  29,  51,  87,  80,  62,
    18,  22,  37,  56,  68, 109, 103,  77,
    24,  35,  55,  64,  81, 104, 113,  92,
    49,  64,  78,  87, 103, 121, 120, 101,
    72,  92,  95,  98, 112, 100, 103,  99
  };
  static const INT16 std_chrominance_quant_tbl[DCTSIZE2] = {
    17,  18,  24,  47,  99,  99,  99,  99,
    18,  21,  26,  66,  99,  99,  99,  99,
    24,  26,  56,  99,  99,  99,  99,  99,
    47,  66,  99,  99,  99,  99,  99,  99,
    99,  99,  99,  99,  99,  99,  99,  99,
    99,  99,  99,  99,  99,  99,  99,  99,
    99,  99,  99,  99,  99,  99,  99,  99,
    99,  99,  99,  99,  99,  99,  99,  99
  };
  jint_add_quant_table(cinfo, 0, std_luminance_quant_tbl, cinfo->quality);
  jint_add_quant_table(cinfo, 1, std_chrominance_quant_tbl, cinfo->quality);
}

void 
jint_add_huff_table ( jpeg_compress_info *cinfo,
                      unsigned int which_tbl, int what_tbl, 
                      const UINT8 *bits, const UINT8 *value) 
{
  JHUFF_TBL **hpp;   /* this value used to Left-Value */
  int nsymbols, len;
  
  if (which_tbl > NUM_HUFF_TBLS)
    exit(1);
  
  if (what_tbl == 0) /* DC table */
    hpp = cinfo->dc_huff_table;
  else if (what_tbl == 1) /* AC table */
    hpp = cinfo->ac_huff_table;
  else 
    exit(1);
  
  /* set value of 'bits' */
  hpp[which_tbl] = (JHUFF_TBL *)malloc(sizeof(JHUFF_TBL));
  memcpy(hpp[which_tbl]->bits, bits, sizeof(hpp[which_tbl]->bits));
  
  /* calculate # of symbols in huffval */
  nsymbols = 0;
  for (len=1; len<=16; len++) {
    nsymbols += bits[len];
  }
  /* set huffval */
  memcpy(hpp[which_tbl]->huffval, value, nsymbols*sizeof(UINT8));
  
  /* calculate and set huffman code & size table 
   * across this we can use 'ECODE & ESIZE' table in huffman encoding.
   */
  memset(hpp[which_tbl]->ecode, 0, sizeof(hpp[which_tbl]->ecode));
  memset(hpp[which_tbl]->esize, 0, sizeof(hpp[which_tbl]->esize));
  jint_calc_huff_tbl(hpp[which_tbl]);
}

void 
jint_std_huff_tables (jpeg_compress_info *cinfo) 
{
  /* All these table specified by JPEG */
  
  static const UINT8 bits_dc_luminance[17] =
    { /* 0-base */ 0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0 };
  static const UINT8 val_dc_luminance[] =
    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
  
  static const UINT8 bits_dc_chrominance[17] =
    { /* 0-base */ 0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0 };
  static const UINT8 val_dc_chrominance[] =
    { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 };
  
  static const UINT8 bits_ac_luminance[17] =
    { /* 0-base */ 0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d };
  static const UINT8 val_ac_luminance[] =
    { 0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
      0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
      0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
      0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
      0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
      0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
      0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
      0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
      0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
      0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
      0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
      0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
      0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
      0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
      0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
      0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
      0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
      0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
      0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
      0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
      0xf9, 0xfa };
  
  static const UINT8 bits_ac_chrominance[17] =
    { /* 0-base */ 0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77 };
  static const UINT8 val_ac_chrominance[] =
    { 0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
      0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
      0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
      0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
      0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
      0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
      0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
      0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
      0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
      0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
      0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
      0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
      0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
      0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
      0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
      0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
      0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
      0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
      0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
      0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
      0xf9, 0xfa };
  
  jint_add_huff_table( cinfo, 0, DC_HUFF_TBL,
		               bits_dc_luminance, val_dc_luminance );
  jint_add_huff_table( cinfo, 0, AC_HUFF_TBL,
		               bits_ac_luminance, val_ac_luminance);
  jint_add_huff_table( cinfo, 1, DC_HUFF_TBL,
		               bits_dc_chrominance, val_dc_chrominance);
  jint_add_huff_table( cinfo, 1, AC_HUFF_TBL,
		               bits_ac_chrominance, val_ac_chrominance);
}

/* generate huffman table 
 */
static UINT16 gtmp_hsize[256];
static UINT16 gtmp_hcode[256];

void 
jint_calc_huff_tbl(JHUFF_TBL *htblptr)
{
  int i, j;
  int k, lastk, code, si;
   
  /* generate EHUFFSI table */
  k=0;
  for (i=1; i<=16; i++) {
    for (j=1; j<=htblptr->bits[i]; j++) {
      gtmp_hsize[k] = i;
      k++;
    }
  }
  gtmp_hsize[k]=0;
  lastk = k;
  
  /* generate EHUFFCO table */
  k=0;
  code=0;
  si=gtmp_hsize[0];
  while(1) {
    while(1) {
      gtmp_hcode[k]=code;
      code++;
      k++;
      if (gtmp_hsize[k]!=si)
        break;
    }
    if (gtmp_hsize[k]==0)
      break;
    while(1) {
      code = code<<1;
      si++;
      if (gtmp_hsize[k]==si)
        break;
    }
  }
  
  /* order_codes */
  k=0;
  do {
    i = htblptr->huffval[k];
    htblptr->ecode[i] = gtmp_hcode[k];
    htblptr->esize[i] = gtmp_hsize[k];
    k++;
  } while(k<lastk);
}