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Media Data Processing V1 (Single-Image, Multi-ROI Cropping)

Sample Obtaining

Refer to batchcrop to obtain the sample.

Description

In this example, eight 224 x 224 child images (YUV420SP NV12) are cropped out from the YUV420SP (NV12) input based on the specified cropping areas.

Principles

The following table lists the key functions involved in this sample.

Initialization
  • aclInit: initializes AscendCL.
  • aclFinalize: deinitializes AscendCL.

Device Management
  • aclrtSetDevice: sets the compute device.
  • aclrtGetRunMode: obtains the run mode of the software stack. The internal processing varies depending on the run mode.
  • aclrtResetDevice: resets the compute device and cleans up all resources associated with the device.

Stream Management
  • aclrtCreateStream: creates a stream.
  • aclrtDestroyStream: destroys a stream.
  • aclrtSynchronizeStream: waits for stream tasks to complete.

Memory Management
  • aclrtMallocHost: allocates host memory.
  • aclrtFreeHost: frees host memory.
  • aclrtMalloc: allocates device memory.
  • aclrtFree: frees device memory.

In media data processing, if you need to allocate device memory to store the input or output data, call acldvppMalloc to allocate memory and call acldvppFree to free up memory.

Data Transfer

aclrtMemcpy:

  • Transfers decode source data from the host to the device.
  • Transfers the inference result from the device to the host.

Data transfer is not required if your app runs in the board environment.

Media Data Processing
  • Cropping

    acldvppVpcBatchCropResizeAsync: crops one or more selected ROIs from each input image and loads the cropped one or more images to the output buffer.

Directory Structure

The sample directory is organized as follows:

├── data
│   ├── dvpp_vpc_1920x1080_nv12.yuv            //Test image. Obtain the test image according to the guide and save it to the data directory.

├── inc
│   ├── dvpp_process.h               //Header file that declares functions related to media data processing
│   ├── sample_process.h               //Header file that declares functions related to model processing
│   ├── utils.h                       //Header file that declares common functions (such as the file reading function)

├── src
│   ├── acl.json              //Configuration file for system initialization
│   ├── CMakeLists.txt         //Build script
│   ├── dvpp_process.cpp       //Implementation file of functions related to media data processing
│   ├── main.cpp               //Implementation file of the main function, for single-image, multi-ROI cropping
│   ├── sample_process.cpp     //Implementation file of functions related to resource initialization and destruction
│   ├── utils.cpp              //Implementation file of common functions (such as the file reading function)

├── CMakeLists.txt    //Build script that calls the CMakeLists file in the src directory

App Build and Run (Ascend EP Mode)

Refer to batchcrop to obtain the sample. View the README file in the sample.

App Build and Run (Ascend RC Mode)

Refer to batchcrop to obtain the sample. View the README file in the sample.

Parent topic: App Samples