libvpx is a free software video codec library from Google and the Alliance for Open Media (AOMedia).

It serves as the reference software implementation for the VP8 and VP9 video coding formats, and for AV1 a special fork named libaom that was stripped of backwards compatibility.

[8][9][10] Google was criticised for dumping untidy code with bad documentation for the initial release of libvpx and developing behind closed doors without involving the community in the process.

[12] In April 2015, Google released a significant update to its libvpx library, with version 1.4.0 adding support for encoding VP9 with 10-bit and 12-bit bit depth, 4:2:2 and 4:4:4 chroma subsampling (VP9 profiles 1, 2, and 3), and VP9 multithreaded decoding/encoding.

A lookahead of up to 25 frames can be configured, which improves compression efficiency but introduces latency and thereby hurts real-time performance.

[16] HEVC encoded by x265 may achieve even better quality,[16] but the royalty-free nature of VP9 makes it a compelling option for delivering high resolution video on supported platforms.