Function create_encoder 

pub fn create_encoder(
    codec: VideoCodec,
    cfg: EncoderConfig,
) -> Result<Box<dyn Encodable + Send>>

Construct an encoder for the given codec.

Currently only VideoCodec::Vp9Profile0Level10Bit8 is supported, backed by the pure-Rust crate::vp9::Vp9Encoder. Any other codec returns an error.