There are major differences between MCU Server and a software Video Conferencing Server. The difference lies in their respective functions, features as well as the underlying technology, architecture.
Unlike software video conference server, MCU server conducts group video conferences under the principle of mixing media streams, i.e. mixing and re-encoding participants’ video conferencing streams in real time. For example to create a picture-in-picture effect imposes very strict requirements on the computing capacity of MCU server.
While software servers often implement multiplexing pattern of the data streams, which implies no transcoding. A server just redirects the media streams of the video conference participants. Compression/decompression and media streams mixing undergoes in endpoint devices.

MCU | VC Server |
---|---|
Designed for H323/SIP hardware | Designed for Software and hardware both |
Bridges various H323/SIP devices | Bridges variety of soft and hard endpoints including browsers |
Not accessible through API | Accessible through API |
More Call Control functions | More client app functions |