What is Video Compression?
Video compression is the process of encoding a video file in such a way that it consumes less space than the original file. Video compression makes it possible to stream video over networks with limited bandwidth and store large quantities of video data on devices with limited storage.
Video compression algorithms combine lossy and lossless data compression techniques to achieve a balance between file size and visual quality.
- Lossy algorithms discard data that (hopefully) won’t be noticed by human viewers.
- Lossless algorithms represent data more efficiently by removing statistical redundancies.
Key Takeaways
- Video compression techniques rely on algorithms to reduce video file size.
- The software or hardware tools that implement specific compression algorithms are called codecs.
- Commonly used video compression codecs include H.264, H.265, and VP9.
- Once a video is compressed, it is packaged in a container that contains additional information before it is transmitted.
- Commonly used container formats include MP4, MKV, or WebM for VP9.
How Does Video Compression Work?
Video streaming involves using video codecs (coder-decoders) to compress the video data, which is then encapsulated within a container format called a wrapper for transmission and playback.
The choice of codec depends on factors like the desired compression ratio and compatibility with playback devices:
- H.264 (AVC) is one of the most widely used video codecs. It provides good video quality at relatively low bit rates.
- H.265 (HEVC) is the successor to H.264. It features up to 50% better data compression and is especially beneficial for high-resolution videos.
- VP9 is an open source and royalty-free codec that competes with H.265. VP9 was developed by Google and is used to deliver high-quality video at reduced bit rates on YouTube.
Video Streaming Compression Formats
After compression, the video’s format will reflect the codec used, and a container will encapsulate the compressed video stream along with other elements like audio and metadata.
- MP4 can contain H.264 or H.265 video and support a wide variety of audio codecs. It is compatible with nearly all software and hardware players.
- MKV (Matroska) is a flexible container format that can hold an unlimited number of videos, audio, pictures, or subtitle tracks in one file. It is known for supporting multiple codecs, including H.264, H.265, and VP9.
- WebM is an open, royalty-free container that commonly contains video streams encoded with VP9 or its predecessor VP8.
To play a compressed video, the video player must be able to understand the new format. If the player doesn’t have built-in support, it can use an external codec library or component to handle the decoding process.
Five Factors Affecting Video Compression
It’s important to consider the following five factors during the compression process to optimize a video for various applications:
Application of Video Compression
Video compression is used extensively in online streaming services like Netflix and video conferencing tools like Zoom. It also plays an important role in the IP surveillance industry by making it possible to store high-resolution video footage with less storage space.
Additionally, compression can be beneficial for virtual private network (VPN) users because it reduces the amount of video data that needs to be transmitted. This can potentially reduce buffering issues and provide a more enjoyable user experience (UX).
When choosing the best VPN for streaming, look for a provider that offers a wide range of server locations, does not throttle bandwidth, and does not block popular streaming platforms.
Video Compression Tools
Video compression software tools make it easier to store, stream, and share videos across social media and video streaming platforms. There are video compression tools available for every budget and skill level.
Free video compression tools like HandBrake or FFmpeg provide an accessible way for average users to compress large video files.
Professional video editing software like Adobe Media Encoder offers more advanced compression settings and batch processing options for experienced users and content creators.
Video Compression Pros and Cons
Pros
- Upload (and download) video files faster
- Reduce bandwidth requirements
- Save storage space
- Reduce latency and buffering issues
Cons
- Potential loss of video quality, especially from lossy algorithms
- Possibly introduce undesired compression artifacts
- Potential compatibility issues with different compression formats
- May require increased processing power for encoding and decoding
The Bottom Line
Video compression’s meaning can be understood as the process of encoding video content so it takes up less space and uses less bandwidth.
The extent to which compression affects quality depends on several factors, including:
FAQs
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References
- The WebM Project | Welcome to the WebM Project (Webmproject)
- HandBrake: Open Source Video Transcoder (Handbrake)
- FFmpeg (Ffmpeg)
- Media Encoder. Rock solid rendering. (Adobe)