YCbCr 转 RGB 保存成JPEG文件

/**
通过YCbCr保存成Jpeg文件
YCbCr采样格式为 4:2:0;(Y:16*16 Cb:8*8 Cr:8*8)
yuvData:图像数据宽度高度都要归一化为16的倍数，
*/
void write_YUV_JPEG_file (char * filename, char* yuvData, int quality,
                      int image_width,int image_height)
{
try
{
    struct jpeg_compress_struct cinfo;

    struct jpeg_error_mgr jerr;

    FILE * outfile; /* target file */
    //JSAMPROW row_pointer[1]; /* pointer to JSAMPLE row[s] */
    //int row_stride; /* physical row width in image buffer */
    JSAMPIMAGE buffer;

    int band,i,buf_width[3],buf_height[3];
    cinfo.err = jpeg_std_error(&jerr);

    jpeg_create_compress(&cinfo);

    if ((outfile = fopen(filename, "wb")) == NULL) {
        fprintf(stderr, "can't open %s\n", filename);
        exit(1);
    }
    jpeg_stdio_dest(&cinfo, outfile);

    cinfo.image_width = image_width; /* image width and height, in pixels */
    cinfo.image_height = image_height;
    cinfo.input_components = 3; /* # of color components per pixel */
    cinfo.in_color_space = JCS_RGB; /* colorspace of input image */


    jpeg_set_defaults(&cinfo);


    jpeg_set_quality(&cinfo, quality, TRUE );

    //////////////////////////////
    cinfo.raw_data_in = TRUE;
  cinfo.do_fancy_downsampling=FALSE;
    cinfo.jpeg_color_space = JCS_YCbCr;
    cinfo.comp_info[0].h_samp_factor = 2;
    cinfo.comp_info[0].v_samp_factor = 2;
    /////////////////////////

    jpeg_start_compress(&cinfo, TRUE);

    buffer = (JSAMPIMAGE) (*cinfo.mem->alloc_small) ((j_common_ptr) &cinfo,  
        JPOOL_IMAGE, 3 * sizeof(JSAMPARRAY));   
    for(band=0; band<3; band++)
    {
        buf_width[band] = cinfo.comp_info[band].width_in_blocks * DCTSIZE;
        buf_height[band] = cinfo.comp_info[band].v_samp_factor * DCTSIZE;
        buffer[band] = (*cinfo.mem->alloc_sarray) ((j_common_ptr) &cinfo,
            JPOOL_IMAGE, buf_width[band], buf_height[band]);
    }   

    char *rawData[3];
    rawData[0]=yuvData;
    rawData[1]=yuvData+image_width*image_height;//100*124;//
    rawData[2]=yuvData+image_width*image_height*5/4;//iImageWidthCb*iImageHeightCb;//rawData[1]+52*62;//

    int max_line = cinfo.max_v_samp_factor*DCTSIZE; 
    for(int counter=0; cinfo.next_scanline < cinfo.image_height; counter++)
{
        //buffer image copy.
        for(band=0; band<3; band++)
        {
            int mem_size = buf_width[band];
            unsigned char *pDst = (unsigned char *) buffer[band][0];
            unsigned char *pSrc = (unsigned char *) (rawData[band] + //yuv.data[band]分别表示YUV起始地址
                counter*buf_height[band] * buf_width[band]);

            for(i=0; i<buf_height[band]; i++)
            {
                memcpy(pDst, pSrc, mem_size);
                pSrc += buf_width[band];
pDst += buf_width[band];
            }
        }

        jpeg_write_raw_data(&cinfo, buffer, max_line);
    }

    jpeg_finish_compress(&cinfo);
    fclose(outfile);
    jpeg_destroy_compress(&cinfo);
}
catch(...)
{
DisplayMsg(_T("error dd"));
}
}