Transcoding Vs Multiple Streaming

Sandeep, thanks for asking, good question. I'll let Sean answer in detail but, at a high level, it seems multi-streaming has become most common as most IP cameras can simultaneously deliver multiple streams whereas transcoding on the recorder / server side incurs non-trival costs on that side.

I have seen some systems (Nx Witness, Hanwha WAVE, DW Spectrum) that uses both.  For the client live viewing and recording, it uses dual streaming.  This way it just works and you have high/low streams.

When you use the mobile app and Web UI, where bandwidth may be very low or vary greatly, it uses transcoding, when available on the server.  If the server doesn't support transcoding, or it is disabled, then it uses dual streaming.

Genetec supports dual/triple, and I believe even quad streaming, if the camera supports it.  

I personally love multi-streaming, because you don't have to worry about an operator's load impacting server performance.

It more fully utilizes the edge devices that you have purchased and distributes the load...

A couple quick thoughts and questions first:

Are you choosing a new VMS to buy, sell or support? Or are you just researching and getting feedback on the differences in general terms? Transcoding vs Multistreaming would seem to be low on the feature/capability concerns list in any of those situations.

Simply put, transcoding video is going to require more server resources (typically more CPU) than multi-streaming. Quad-streaming will require slightly more management than single or dual streaming but overall should have a limited impact.

Transcoding should give the most options for the output video from a resolution, compression and frame rate perspective (since you're decoding and re-encoding the stream to whatever is needed), however, the primary concerns with transcoding are:

• How much more processing power do you need (as noted above)? Depending on the efficiency of the transcoding, it can have a big impact on server requirements.
  
• What type of latency does this incur relative to not using it?  How does that impact live PTZ control, alarm notifications, real-time monitoring, etc.

Quad or Multi-streaming should not require additional processing power and would not impact latency in any meaningful way, however, the VMS will only be able to stream the resolutions available within the camera, and may be limited to 1 or 2 streams based on the camera driver.