What is AV1?
Definition
AV1 is an open, royalty-free video codec from the Alliance for Open Media. It is the most efficient mainstream codec, producing smaller files than H.265 or VP9 at the same quality, at the cost of much slower encoding.
AV1 compresses video using newer, more advanced techniques than older codecs, so it can hit the same visual quality at a lower bitrate. In practice that means roughly 30 percent smaller files than H.265 (HEVC) and VP9, or better quality at the same file size. Because it is royalty-free, anyone can use it without paying licensing fees, which is a major reason streaming platforms adopted it.
The main trade-off is speed: AV1 is very slow and CPU-heavy to encode, often many times slower than H.264. Decoding (playback) is lighter, and hardware support is growing in newer phones, GPUs, and TVs, though it is not yet universal. This is why AV1 makes the most sense for streaming at scale, where you encode a video once and millions of people watch it.
A common mistake is treating AV1 as a file format. AV1 is the codec (the compression method); the file itself is usually an MP4, WebM, or MKV container that holds the AV1 video stream plus an audio track such as Opus or AAC. AV1 should also not be confused with AVC, which is another name for the older H.264 codec.
Quick facts
- Open and royalty-free, developed by the Alliance for Open Media (AOMedia)
- Roughly 30 percent more efficient than H.265 (HEVC) and VP9 at the same quality
- Encoding is very slow and CPU-intensive; decoding is much lighter
- Used by YouTube and Netflix; playback supported in Chrome, Firefox, and Edge
- Best suited for streaming at scale, less so for fast one-off exports