The core of audio and video processing lies in understanding the basic process and optimization methods. 1. The basic process includes acquisition, encoding, transmission, decoding and playback, and each link has technical difficulties; 2. Common problems such as audio and video aberration, lag delay, sound noise, blurred picture, etc. can be solved through synchronous adjustment, encoding optimization, noise reduction module, parameter adjustment, etc.; 3. It is recommended to use FFmpeg, OpenCV, WebRTC, GStreamer and other tools to achieve functions; 4. In terms of performance management, we should pay attention to hardware acceleration, reasonable setting of resolution frame rates, control concurrency and memory leakage problems. Mastering these key points will help improve development efficiency and user experience.

Audio and video processing is actually not that mysterious, but it is indeed a technical job. Many people think that when they hear this word, they think it is editing or adjusting the volume, but in fact the things involved are much more complicated. If you are a developer, content creator who is new to this content, or just want to understand some basic concepts, this article can help you sort out a few key points.

1. Basic process of audio and video processing

Whether it is live broadcast, short video or conference system, the basic process of audio and video processing generally includes acquisition, encoding, transmission, decoding and playback. Every link has its "pit".

• Collect : Camera and microphone collect raw data, and you may encounter problems such as resolution mismatch, unstable frame rate, and high noise.
• Encoding : In order to reduce the amount of data, audio and video need to be compressed. Commonly used encoding formats include H.264, AAC, etc. Improper encoding parameters can lead to poor image quality or too large files.
• Transmission : Network fluctuations will affect the transmission quality. At this time, protocols such as RTMP and WebRTC are needed to ensure real-time and stability.
• Decoding and playback : The formats supported by different devices are different. For example, some Android phones do not support H.265, so compatibility issues must be considered at this time.

2. Frequently Asked Questions and Optimization Suggestions

In actual development, you may encounter these problems:

• Audio and video out of synchronization : This is one of the most common problems. It is usually caused by inconsistent timestamps between audio and video during acquisition or processing. The solution is to make synchronous adjustments on the playback side, such as aligning the video with audio as the benchmark.
• Stop/high latency : Especially in live broadcast scenarios, too high latency will seriously affect the user experience. It can be alleviated by reducing the encoding rate, using more efficient encoders (such as H.265), optimizing network transmission strategies, etc.
• Noise or echo : This is usually caused by microphone pickup or speaker feedback. You can consider adding noise reduction modules, such as the AEC, NS modules that come with WebRTC, or a third-party SDK.
• Blurry or screen-display : It may be due to unreasonable encoding parameters, or it may be due to packet loss during transmission. It will be helpful to properly increase the keyframe interval (GOP) and bitrate.

3. Tools and framework recommendations

If you plan to implement audio and video processing by yourself, these tools and libraries are worth learning about:

• FFmpeg : It can be said to be a Swiss army knife for audio and video processing. Almost all format conversion, editing, and splicing can be done. The learning curve is a bit steep, but it is very practical once you master it.
• OpenCV : It is mainly aimed at image processing and is suitable for visual enhancement operations such as filters, beauty, and facial recognition.
• WebRTC : If you want to create real-time communication applications, such as video conferencing and online education, this framework is almost standard.
• GStreamer : A relatively powerful multimedia processing framework suitable for building complex audio and video pipelines.

For beginners, it is recommended to start with FFmpeg, because it covers most common tasks and is relatively well documented.

4. Performance and resource management

Audio and video processing consumes a lot of CPU and memory, especially when you process multiple streams at the same time. There are a few tips to help you control resource usage:

• Using hardware accelerated encoding (such as NVIDIA NVENC, Intel Quick Sync) can significantly reduce CPU load
• Set the resolution and frame rate reasonably, there is no need to go to 4K 60 frames from the beginning
• Control the number of concurrency to avoid system overload
• Pay attention to memory leaks, especially in long-running applications

Basically that's it. Audio and video processing looks complicated, but in fact many of them are routines. The key is to understand the entire process, know the possible problems in each link, and be able to quickly locate and solve them. It may feel difficult at first, but it will be smooth if you practice a few more times.

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