Transcoding is the process of translating one codec to another.

Transcoding is a taxing process, requiring the decoding of one codec and then re-encoding the data using another codec.

In the context of WebRTC, transcoding may be required in two different instances:

1. When Opus is used and needs to be bridged to a legacy VoIP network or to PSTN
2. When video is used in WebRTC (using VP8) and needs to be streamed to passive viewers not using WebRTC or to interoperate with other VoIP networks