Bandwidth requirements endpoints

[bbanier]

Hello,

got a question wrt the bandwidth requirements of the former Tandberg TP endpoints: why do the Cisco datasheets always state "up to 6 Mbps point-to-point", while you really only need 2,5Mbps for 1080p30 ? 

thanks,

Bart

[Burgert Kloppers]

Hi,

It is to support duel stream in HD and multipoint.

Burt,

[Tomonori Taniguchi]

This is statement of Endpoint capability.

C-series Endpoint capable to enable the 1080p30 transmission much lower bandwidth, but with full screen update scenario may require bit more bandwidth.

Also in default, while using 2^nd stream (sending PC presentation, sending 1080p30 image from 2^nd monitor, etc.), video bandwidth between 1^st channel and 2^nd channel will split half, so even after enable dual stream, main video channel will continue to have reasonable bandwidth to transmitting 1080p30 high quality video.

[bbanier]

Thanks for your replies.

- While dual stream will add some BW for sure, it won't go up to 6Mbps, or will it.  How much would it typically need BTW ?

- Multipoint would add indeed a bunch of BW, but the "up to 6Mbps" is also stated for endpoints that do NOT support multipoint at all, so in that case it's not relevant....?

- A full screen refresh will burst up to xMbps but that's only in a very small interval so I don't think that 's the reason for that statement in the datasheets either.

Bart

[Tomonori Taniguchi]

- While dual stream will add some BW for sure, it won't go up to 6Mbps, or will it.  How much would it typically need BTW ?

Even point-to-point call without dual stream, if there are full image update (i.e waving the hand front of camera all the time), main video bit rate may goes up to 6Mbps.

This is because of large volume of image update every seconds to keep up full image update captured from camera.

In "standard" conference where multiple person in screen and have no full screen/image update and while using 1080p30, 1.5~2Mbps should be provide clean image on screen.

However this is very depending on who see video image.

- Multipoint would add indeed a bunch of BW, but the "up to 6Mbps" is also stated for endpoints that do NOT support multipoint at all, so in that case it's not relevant....?

Same as above even point-to-point call without dual stream can goes up to 6Mbps depend on what image transmit/receive on main stream channel.

And using dual stream which will split bandwidth between main and secondary stream channel therefore again depend on what image transmit/receive on each channels but will goes up to 6Mbps.

- A full screen refresh will burst up to xMbps but that's only in a very small interval so I don't think that 's the reason for that statement in the datasheets either.

Correct, point is that C-series Endpoint which has statement of 6Mbps mean that codec has capability to handle and will processing image up to 6Mbps in total.

In "standard" conference you might see very high bit rate but usually just in short time of period not consistently have high bit rate in entire conference, but again this all very depend on what image transmit/receive.