What is Video Codec and How to Choose the Best One for Your Needs
Video content is becoming increasingly prevalent due to the ease and convenience of obtaining large amounts of information through video. Live video, video-on-demand, short videos, and video chats have become integral parts of daily life. According to Cisco's latest report, video data will account for up to 82% of mobile internet traffic by 2022. However, the massive amounts of video data pose challenges for transmission and storage.
Firstly, raw uncompressed video data can be very large, especially for high-resolution and high-frame-rate videos. For example, a 10-minute uncompressed video at 1080p resolution and 30 frames per second can have hundreds of gigabytes of data. As video quality continues to improve, storage costs also increase. Video data is compressed using video codec, which can reduce storage costs and allow users to store more video content.
Secondly, the bandwidth of the Internet and mobile networks is limited, especially in congested network environments. Direct transmission of uncompressed video data can lead to severe network congestion and latency. Video data can be compressed using video codec to smoothly transmit video with limited bandwidth and improve user experience.
Additionally, uncompressed video data requires more computing resources to process, leading to higher energy consumption. Compressing video data using video codec can reduce energy consumption during processing, especially for mobile devices, resulting in longer battery life.
Finally, different application scenarios have different requirements for video quality and bitrate. Video codec can be used to compress video to varying degrees according to needs, adapting to various application scenarios such as online video, webinars, surveillance, and virtual reality.
In summary, video codec plays a crucial role in reducing the amount of video data, improving transmission efficiency, and saving storage costs, making it a core technology in the field of digital video.
What is Video Codec
Video codec is a technology used to process digital video data, involving the compression, transmission, and decompression of video data. The goal of video codec is to reduce the cost of storing and transmitting video data while ensuring video quality. Video codec mainly includes two processes: encoding and decoding.
The main role of video codec is to pursue the highest possible video reconstruction quality and compression ratio within the available computing resources to meet the requirements of bandwidth and storage capacity. The emphasis on "quality of reconstruction" is important because video encoding is a lossy process, meaning that users can only parse the "reconstructed" image from the received video stream, which is already different from the original image. The basic goal of video coding is to maintain the quality of the video as much as possible under a certain bandwidth occupation, or to reduce the bandwidth utilization as much as possible while maintaining the quality. In technical terms, this is the "rate distortion" performance of video codec standards. "Rate" refers to the bitrate or bandwidth occupied, and "distortion" is used to describe the quality of the reconstructed video. The counterpart to encoding is the process of decoding or decompression, which is the reproduction of a stream of compressed codes received or stored on a medium into a video signal and then displayed on various devices.
Video Encoding
The video encoding process is the compression of video data to reduce storage and transmission requirements. It is commonly used in video conferencing, streaming, and other applications that require video data to be transmitted or stored. The encoding process involves reducing redundancy in the video signal to achieve efficient compression. Common video encoding algorithms include H.264, H.265, VP9, and AV1.
In the coding process, two main techniques are used: intra-frame encoding and inter-frame encoding. Intra-frame encoding involves compressing a single video frame using techniques such as spatial prediction, transformation coding, quantization, and entropy coding. Inter-frame encoding, on the other hand, involves compressing video frames based on their correlation with previous frames, using techniques such as motion estimation and motion compensation.
There are several steps involved in video encoding, including:
- Input: The first step in video encoding is to receive the video signal as an input. This signal can come from a variety of sources, such as cameras, video files, or live feeds.
- Preprocessing: Before encoding, the video signal may need to be preprocessed to ensure that it is in the appropriate format for the encoder. This may involve resizing the video, changing the frame rate, or adjusting other parameters.
- Feature extraction: The next step in video encoding is to extract features from the video signal. This involves analyzing the content of the video and identifying key frames, which are used to represent the video in the compressed format.
