What is transcoding used for?

• A. To convert analog voice to digital.
• B. To convert between codecs when endpoints can't agree on a common codec.
• C. To allocate media resources across clusters.
• D. To compress video streams for bandwidth.

Answer: (B)

Transcoding is used to translate a media stream from one codec to another so devices that use different codecs can communicate. In a call path, one endpoint might support a certain codec while another supports a different one. The transcoder decodes the incoming stream and re-encodes it into the codec the next device accepts, enabling interoperability even when there isn’t a common codec both sides share. This is different from converting analog voice to digital at the capture stage, which is just converting a signal format rather than changing codecs along the path. It’s also not primarily about allocating media resources or simply compressing video for bandwidth; it specifically targets making the two endpoints able to understand each other by translating codecs.