encode.c

linux环境下jpeg编解码算法的实现

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <sysexits.h>
#include <unistd.h>
#include <stdint.h>
#include <signal.h>
#include <alloca.h>
#include <limits.h>
#include <ctype.h>
#include <poll.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/time.h>

#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */
#include "zeviojpegapi.h"
//#include "zsp_jpeglib.h"

//#define TRACE fprintf(stdout, "( %s : %s : %d )\n", __FILE__, __func__, __LINE__);
#define TRACE

static struct jpeg_compress_struct cinfo;
static struct jpeg_error_mgr jerr;
static FILE *output_file;

void encodeStart( zJpegDecompressPtr decompressCinfo, char *filename, unsigned int oWidth, unsigned int oHeight, unsigned int quality )
{
  char outfilename[128];

  sprintf(outfilename, "%s.jpg", filename);

  output_file = fopen(outfilename, "wb");
  assert(output_file);

  cinfo.err = jpeg_std_error(&jerr);
  jpeg_create_compress(&cinfo);

  cinfo.in_color_space = JCS_RGB;
  jpeg_set_defaults(&cinfo);

  cinfo.data_precision   = 8;
  cinfo.image_width      = oWidth;
  cinfo.image_height     = oHeight;
  cinfo.input_components = 3;

  jpeg_default_colorspace(&cinfo);

  cinfo.arith_code = FALSE;
  cinfo.optimize_coding = FALSE;
	cinfo.dct_method = JDCT_IFAST;

  zJpegSetCompressCinfo(decompressCinfo, &cinfo);

	jpeg_set_quality( &cinfo, quality, FALSE);

  jpeg_stdio_dest(&cinfo, output_file);

  /* Start compressor */
  jpeg_start_compress(&cinfo, TRUE);
}

void encodeEnd( void )
{
  jpeg_finish_compress(&cinfo);

  jpeg_destroy_compress(&cinfo);

  fclose(output_file);
}

void encodeWriteAPP1( unsigned char *pHeader, unsigned int length)
{
	jpeg_write_marker ( &cinfo, JPEG_APP0+1, pHeader, length );
}