libvpx
libvpx is the reference software library for the VP8 and VP9 video coding formats. It is part of the WebM project and is maintained by Google and the open-source community. The library provides a stable C API for encoding and decoding video frames, along with tools for bitstream parsing, rate control, motion estimation, and intra prediction. It supports both VP8 and VP9 profiles, bit depths, and color spaces, and can operate in live encoding scenarios or offline transcoding.
The API centers on a vpx_codec interface, with context objects (vpx_codec_ctx_t) used for encoding or decoding
In practice, libvpx is widely used as the encoder/decoder backbone in the WebM ecosystem and in many
See also WebM, VP8, VP9, and the libvpx repository for source code and documentation.