SDK Architecture Introduction

1. Keywords

Abbr Full name Introduction
SYS
System
 Realize MI system initialization, memory buffer pool management, and data flow management between various modules
VDEC Video Decoder H264/H265/JPEG video decoder
DIVP Deinterlace&Video Post Process Engine DIVP Engine has two main functions:
1.Converting the format of the decoded data
2.Scaling the decoded data
VDISP Vitrual Display Software puzzle
DISP Display Engine DISP does a hardware puzzle for the image output by the VDEC/DIVP processing unit, and encodes it together with the AO output audio signal into an HDMI/VGA/CVBS output signal unit
VENC Video Encoder H264/H265/MotionJpeg video decoder
AI Audio Input Interface I2S audio input acquisition unit
AO Audio Output Interface Audio output
GFX Graphics Engine Graphic Engine provides basic hardware acceleration support for 2D drawing, reducing CPU load
FB FrameBuffer UI display
HDMI High Definition Multimedia Interface HDMI/VGA standard output

2. Software Architecture

  • The function realization function is divided into MI API layer, MI implement layer, Hal hardware abstraction layer, Driver layer and chip hardware layer from top to bottom.

  • The SDK function code is implemented in the Kernel mode, which reduces the scheduling from kernel to User mode and improves the efficiency of logic function implementation.

  • For the User Mode interface of the MI API provided by the upper-level client, the user-level APP directly calls the MI interface to call the corresponding MI function.

3. SDK directory structure

catalog module function
project board PCB board information storage path
project configs Pre-configuration file storage path
project image The storage path of image file and library that generate image file
project kbuild Kernel compilation environmentkernel
project release Target pool, storing external header files, library files, kernel modules and third-party libraries
SDK Verify/feature Verification folder, which stores module unit test and feature test files
SDK Verify/demo Overall function test demo

4. Memory management

Please refer to Memory Layout for details.

  • Memory reserved through mmap.ini

  • Support mma to manage module memory, each module is allocated from the size reserved by mma

5. Basic Concepts

  • Data Stream

    Each mi module can be regarded as a data processing unit, and the data flow is uniformly scheduled by MI SYS. The input data stream represents the data received by the unit, and the output data stream represents the data processed by the unit.

  • Control Stream

    APP controls the parameters of each mi module data processing process, such as setting MI_VENC encoding parameters, starting and stopping MI_VPE channel, setting MI_VPE channel output port resolution and format, etc.

  • Channel

    • For an mi module that needs to process or output a stream, a channel represents the time-multiplexed context and related control flow settings that it processes or outputs a stream.

    • The time-multiplexed module can support multiple channels, such as MI_VDEC, MI_DIVP, MI_DISP.

  • Port

    • Port is divided into two types, input port and output port. The input port is the location of the channel's input data stream, and the output port is the location of the channel's output data stream.

    • A channel can have multiple input ports and output ports.

6. API

Please refer to SDK Module API for details.

7. DEBUG method

Please refer to the corresponding chapter PROCFS INTRODUCTION of each module API in SDK Module API for details.