What is a video codec (H.264 / HEVC)?

A codec — short for coder/decoder — is the algorithm that squeezes raw video into a manageable file and then reconstructs it for viewing. Uncompressed video is enormous, so codecs exploit redundancy between frames and within each frame to shrink the data dramatically while keeping the picture close to the original. H.264 (also called AVC) is the long-standing standard: it is supported almost everywhere, from browsers to phones to editors, making it the safest choice for compatibility. HEVC (H.265) is its successor, achieving similar quality at roughly half the bitrate but with heavier decoding demands and narrower support.

It helps to distinguish the codec from the container. A file like .mp4 or .mov is a container — a wrapper that holds the video, and optionally audio and metadata — while the codec is how the video stream inside is actually encoded. That is why two .mp4 files can behave differently in an app: one may use H.264 and another HEVC. Choosing a codec is a trade-off between file size, quality, playback compatibility, and how much processing power encoding and decoding require on both your machine and the viewer's.

Limelight exports standard mp4 files encoded with widely supported codecs, so your screen recordings play back reliably across browsers, devices, and video editors without conversion headaches. For screen content — sharp UI text, solid colors, and precise edges — a good encoder preserves legibility while keeping files small. That means your polished Limelight recordings, complete with auto-zoom and on-screen keystrokes, share and upload smoothly wherever you post them.