Video Codecs
Video codecs are algorithms that compress and decompress digital video data, enabling practical storage and transmission of large video files. A codec analyzes consecutive frames to identify and remove redundant information—both visible repetition across frames and imperceptible details beyond human perception—then reconstructs the video during playback. This compression is essential for applications ranging from streaming services to archiving, where uncompressed video would demand prohibitive storage space and bandwidth.
Compression Methods
Codecs employ two primary compression strategies. Lossy compression discards some video information to achieve higher compression ratios, accepting minor quality reduction in exchange for smaller file sizes; most modern codecs use this approach. Lossless compression preserves all original data but achieves more modest compression ratios, making it suitable for archival or professional work where quality loss is unacceptable. Most codecs combine both methods, applying lossy compression to color information and spatial details while using lossless techniques for structural frame data.
Common Codecs
Standard video codecs include H.264 (also called AVC), widely used in streaming and broadcasting; H.265 (HEVC), offering better compression but higher processing demands; VP9 and AV1, developed as open alternatives; and older formats like MPEG-2. The choice of codec involves trade-offs between compression efficiency, computational cost for encoding and decoding, compatibility with playback devices, and licensing considerations. Different applications favor different codecs—streaming services often use H.264 or H.265 for balance between quality and bandwidth, while professional video production may use less aggressive compression formats.
Source Notes
- 2026-04-14: Compressing Video