Video Codec Formats Explained

Video Encoding Basics

Video encoding is the process of compressing raw video data into a specific format. Raw video data is enormous - a single uncompressed 1920x1080 frame is about 6MB. At 30 frames per second, one minute of video requires about 10GB of storage. Video encoding dramatically reduces file size by removing redundant information while maintaining acceptable quality.

Video compression primarily exploits two types of redundancy: spatial redundancy (similarity of adjacent pixels within a frame) and temporal redundancy (similarity between adjacent frames). Modern video encoders achieve compression ratios of 100:1 or higher through motion estimation, transform coding, quantization, and entropy coding.

H.264/AVC

H.264 (also known as AVC, Advanced Video Coding) is the most widely used video codec standard, jointly developed by ITU-T and ISO/IEC. Released in 2003, H.264 became the de facto standard thanks to its excellent compression efficiency and broad hardware support.

H.264 features: supports applications from low-bitrate mobile video to high-bitrate broadcast video; extensive hardware decoding support; moderate encoding complexity enabling real-time software encoding; supports various resolutions and frame rates.

H.265/HEVC

H.265 (also known as HEVC, High Efficiency Video Coding) is H.264's successor, released in 2013. H.265 can reduce bitrate by about 50% at the same quality, or provide higher quality at the same bitrate. This is particularly important for 4K and 8K ultra-high-definition video.

VP9 and AV1

VP9 is an open-source video codec developed by Google, primarily used for YouTube and Chrome. VP9's compression efficiency is comparable to H.265 but without patent fees.

AV1 is a next-generation open-source video codec developed by the Alliance for Open Media (AOMedia). AV1 improves compression efficiency by about 30% over H.265 and VP9, also without patent fees.