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The EZDVPP encapsulates the DVPP APIs to simplify the calls. The main functions include:

Image format conversion (including YUV to JPG, and JPEG to YUV), image cropping, and image resizing.

The methods of using EZDVPP APIs are as follows:

• Image format conversion

  • Convert YUV data streams obtained by the camera into JPG data streams.

    // Interface usage example: YUV-to-JPG conversion
    typedef struct DvppOutputInfo {
    //output buffer
    unsigned char *pbuf;
    //size of output buffer
    unsigned int size;
    } DvppOutput;
    Ascend::Utils::DvppProcess *pDvppProcess=nullptr;
    // Initialization parameter for converting YUV into JPG
    dvppToJpgPara.format = JPGENC_FORMAT_NV12;
    dvppToJpgPara.level = DVPP_TO_JPG_QUALITY_PARAMETER;
    dvppToJpgPara.resolution.height = height;
    dvppToJpgPara.resolution.width = width;
    // Instantiated class variable
    pDvppProcess = new Ascend::Utils::DvppProcess(dvppToJpgPara);
    // Conversion interface. dvppOutput.pbuf is the converted JPG data.
    pDvppProcess->DvppOperationProc(inputbuf,inputbufSize,&dvppOutput)
    

  • JPEG-to-YUV conversion: Convert an input JPEG image into a YUV image. The JPEG (color space: YUV, subsample: 444/422/420/400) supports only Huffman coding and does not support arithmetic coding, progressive coding, or JPEG 2000 format.

    Interface 4: JPEG-to-YUV conversion
    struct DvppJpegDOutput {
        unsigned char *buffer;  // output buffer
        uint32_t buffer_size;  // output buffer size
        uint32_t width;  // the width of output image
        uint32_t height;  // the height of output image
        uint32_t aligned_width;  // the aligned width of output image
        uint32_t aligned_height;  // the aligned height of output image
        VpcInputFormat image_format;  //output image format
    };
    ascend::utils::DvppJpegDInPara dvpp_to_yuv_para;
    dvpp_to_yuv_para.is_convert_yuv420 = true;
    ascend::utils::DvppProcess dvpp_yuv_process(dvpp_to_yuv_para);
    ascend::utils::DvppJpegDOutput dvpp_out_data = { 0 };
    dvpp_yuv_process.DvppJpegDProc(face_image_buff,
                                   face_image_size,
                                   &dvpp_out_data);
    

• Image cropping, image resizing, and format conversion

  Convert the input YUV444SP/YUV422SP/YUV420SP/YUV444Packed/YUV422Packed/BGR/RGB/ARGB/ABGR/RGBA/BGRA image into a YUV420SP image and perform image cropping and resizing.

  // Interface usage example: format conversion and image resizing (In this sample code, image cropping is not performed.)
  struct DvppVpcOutput {
      uint8_t *buffer;
      uint32_t size;
  };
  DvppBasicVpcPara resize_para;
  resize_para.input_image_type = INPUT_BGR;
  
  // get original image size and set to resize parameter
  int32_t width = image_handle->image_info.width;
  int32_t height = image_handle->image_info.height;
  
  // set source resolution ratio
  resize_para.src_resolution.width = width;
  resize_para.src_resolution.height = height;
  
  // crop parameters, only resize, no need crop, so set original image size
  // set crop left-top point (need even number)
  resize_para.crop_left = 0;
  resize_para.crop_up = 0;
  // set crop right-bottom point (need odd number)
  uint32_t crop_right = ((width >> 1) << 1) - 1;
  uint32_t crop_down = ((height >> 1) << 1) - 1;
  resize_para.crop_right = crop_right;
  resize_para.crop_down = crop_down;
  // set destination resolution ratio (need even number)
  uint32_t dst_width = ((image_handle->console_params.model_width) >> 1) << 1;
  uint32_t dst_height = ((image_handle->console_params.model_height) >> 1) << 1;
  resize_para.dest_resolution.width = dst_width;
  resize_para.dest_resolution.height = dst_height;
  
  // set input image align or not
  resize_para.is_input_align = false;
  // call
  DvppProcess dvpp_resize_img(resize_para);
  DvppVpcOutput dvpp_output;
  ret = dvpp_resize_img.DvppBasicVpcProc(
        image_handle->image_info.data.get(), image_handle->image_info.size,
        &dvpp_output);