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Audio & Video

38 articles

Summary of Audio FFT Calculation Workflow and Spectrum Interpretation

This article summarizes the principles, parameters, and calculation workflows for performing FFT on speech signal sequences to obtain their …

Working Principles and Applications of Short-Wave Infrared (SWIR) Sensors

This article briefly summarizes the technical concepts of SWIR sensors and imaging systems based on short-wave infrared band imaging, as wel…

A Detailed Summary of Gamma Correction in the Image ISP Processing Workflow

This article provides a detailed summary of the Gamma correction module in the image ISP processing workflow, explaining the reasons for inc…

Lens Shading Issues in Camera Imaging

This article provides a detailed summary of the pervasive Lens Shading issue in optical imaging, analyzing the root causes and organizing th…

Summary of Audio Interfaces in Consumer Audio Codecs

Based on a study and summary of the datasheet for the commonly used TLV320AIC3101 Audio Codec in the market, this article delves into the in…

Introduction to Audio 3A Processing: AEC, ANS, and AGC

This series of articles provides a comprehensive summary of the concepts, theories, and working principles of 3A audio processing (AGC, AEC,…

Explanation and Matching of CRA Parameters for Image Sensors and Lenses

CRA stands for Chief Ray Angle, which is the angle of the chief incoming light ray. Although both lenses and image sensors have CRA paramete…

Thoughts on AI NVRs and Ingenic's AI NVR Platform A1

Ingenic's A1 series is an integrated solution tailored for the NVR market. Compared to traditional NVR solutions, its standout feature is th…

Detailed Explanation of the G.711 Audio Compression Standard

G.711 is an audio compression standard defined by the ITU-T, widely used in telecommunication networks and VoIP fields. In practical impleme…

Summary of Features and Specifications of Mainstream US Consumer NVRs in 2024

By analyzing the basic features and specifications of the mainstream consumer NVR models promoted by leading manufacturers in the Amazon US …

Pre-Roll Battery Camera Solution Based on CV4003IoT Sensor

Pre-Roll Working Mode in Battery Cameras In a previous note (Pre-Roll Function of Ring Doorbell and Its Working Principle), I detailed and a…

The Pre-Roll Feature on Ring Doorbell and How It Works

Pre-Roll and Advanced Pre-Roll on Ring Doorbell Ring is currently a mainstream supplier in the North American and European doorbell markets,…

Working Principle and Workflow Summary of RGB-IR Sensors

Generally, the vast majority of the IP Camera (IPC) industry adopts a working mode of full color during the day and black-and-white for nigh…

A Comparison of Mainstream Wireless Casting Technologies

Wireless casting technologies can be broadly classified into two main categories based on how they are used: - Push Casting (Streaming): The…

SigmaStar's Uboot UFU Firmware Upgrade Mode

Sigmastar provides three options of firmware upgrade worflow: 1. OTA pack and unpack in application layer 2. Firmware upgrade thread running…

UCConfig Learning Notes: UCConfig Mode 0

In Reference Document 1, UCConfig Mode 0 is defined as: "Non‐scalable single layer AVC bitstream with Simulcast (number of simulcast streams…

CMOS Sensor Exposure and Readout Timing

It has been a long time since I last debugged a CMOS sensor driver myself. Recently, I started working on debugging the DOL HDR mode drivers…

UCConfig Study Notes: UCConfig Mode 1

In Reference Document 1, UCConfig Mode 1 is defined as: SVC temporal scalability with hierarchical P with Simulcast (number of simulcast str…

Study Notes on "Microsoft Skype for Business H.264 Video Encoder Specification"

For video conferencing systems seeking Microsoft Teams or Skype for Business certification that utilize H.264 for image transmission, the H.…

H.264 Basics: A Summary of SVC

SVC (Scalable Video Coding) is an extension of the H.264 (AVC) video coding standard. The Problems SVC Aims to Solve The H.264 video compres…

Long and Short Packet Structures and the Concept of Virtual Channels in the MIPI CSI Interface

When transmitting data, the MIPI protocol layer communicates in units of data packets. Depending on the type of data being transmitted, thes…

Learning Notes on the Image Sensor MIPI CSI Interface

MIPI CSI Interface and Connection Basics MIPI CSI is a standard interface used to transmit image data captured by an image sensor to an Appl…

Sensor Flicker Issues in CMOS Image Sensors

Due to the use of a rolling shutter in CMOS image sensors, the exposure start and end times vary line by line. When operating under AC mains…

A Summary of Sony's Digital Overlay (DOL) HDR Technology

Comparison Between DOL HDR and Traditional Frame-Based HDR Some Sony image sensors support DOL HDR technology in two-exposure (DOL-2) and th…

H.264 Basic Concepts Summary: Slice and NALU

VCL and NAL VCL: Video Coding Layer. NAL: Network Abstraction Layer. In the H.264/AVC video coding standard, the entire system framework is …

Summary of Basic H.264 Concepts: SPS, PPS, and SEI

SPS - Sequence Parameter Set (SPS): This non-VCL NALU contains information required to configure the decoder such as profile, level, resolut…

AAC Audio Codec Profiles and Support Across Platforms

Introduction to AAC AAC stands for Advanced Audio Codec. AAC was historically introduced as the successor to the MP3 audio codec algorithm. …

Summary of GB28181 Basics

Problems Solved by the GB28181 Standard: - Addresses protocol interoperability issues between platforms and products from different manufact…

Simplest QT+ffmpeg Based Player Example

Prerequisites: - Based on Setting up an FFmpeg Development Environment with QT Creator, complete the QT Creator + FFmpeg development environ…

Setting Up an FFmpeg Development Environment with QT Creator

Operating System: Windows 10. Download Pre-compiled FFmpeg Libraries for Windows Download address: https://ffmpeg.zeranoe.com/builds/. For d…

Reverse Control Protocol for AHD Analog Cameras - CoaxialProtocol

Background - For controlling the lens movements of a PTZ camera, using the IP protocol is straightforward: IP cameras and control hosts can …

Porting QT5.9.8 to the HiSilicon 3521 Platform

Downloading QT Source Code and Preparing Cross-Compilation Tools - QT source code download address: https://download.qt.io/archive/qt/5.9/5.…

Summary of AF Autofocus Algorithms and PDAF Working Principles

Definition and Basic Classification of AF Autofocus Algorithms - AF: Auto Focus. - Basic definition of autofocus: The image sensor in a came…

Summary of Zoom Lens Classification and Zoom Principles

Zoom Classification and Principles of Zoom Implementation The zoom capability we commonly refer to can generally be divided into two types: …

Hisilicon 35XX Series HiMPP Framework Development Reference - VI Module

Main Reference Document: "HiMPP V3.0 Media Processing Software Development Reference". Document Version: 21. Document Release Date: 2019-09-…

Understanding the Basic Concepts of BT.601/BT.656/BT.1120

To clearly explain the origins of standards like BT.656, BT.601, and BT.1120, we must start with the earliest analog video technology. Early…

Analog HD Video Transmission Technology

Background Having worked in the camera industry, my focus has always been on digital, or IP, cameras. Consequently, my understanding of anal…

Two Fundamental Concepts in H.264: IDR, dts/pts

Distinction Between IDR Frames and I Frames IDR: Instantaneous Decoding Refresh. The distinction between I frames and IDR frames involves th…