Low resolution when calling from a Polycom MDX to an MCU 4200 Series

Why do I receive low resolutions when calling from a Polycom HDX to a Cisco TelePresence MCU 4200 Series?

To get a Cisco TelePresence MCU 4200 Series to send w720p to a Polycom HDX endpoint, do the following:

  1. On the Cisco TelePresence MCU go to Settings > Conferences.
  2. For Maximum video size select Receive MAX, transmit MAX.
  3. For Motion/sharpness tradeoff select Favor sharpness.
  4. For Transmitted video resolutions select Allow all resolutions or 16:9 resolutions only.
  5. Click Apply changes.
  6. Make the call at between 1.5 and 2.0Mbps (becasue, at a lower bandwidth, the HDX will not do 720p and, at a higher bandwidth, it will not use H.264. If you call at more than 2Mbps, the call wil use H.263+ and the HDX does not send H.263+ at more than 4CIF).

  • The MCU 4200 Series will only send w720p to the HDX if there is sufficient information on the screen for it to be worthwhile. Using a conference custom layout with many small panes will cause the MCU to send higher resolutions to the HDX
  • HDX9002 and HDX9004 units use 720p by default to the Cisco TelePresence MCU 4500 Series and the steps above are not required

The resolution sent from the HDX to the MCU is determined by the HDX and is not within Cisco TelePresence's control. Due to incompatibilities between the HDX and MCU 4200 Series capability sets, in general, HDX units only send the MCU 4200 Series 2CIF resolution. The MCU 4200 Series is capable of higher resolutions, but those resolutions and frame rates are not currently supported by the HDX.

Note that the HDX9001 will not run at more than w480p with current HDX software: you will need a HDX9002 or higher to get w720p

While all details are correct at time of writing, using HDX version 1.0.2, behavior of third party equipment may change in subsequent software releases.

This article applies to the following products:

  • Cisco TelePresence MCU 4200 / MSE 8420

May 2nd, 2011 TAA_KB_122