MCU 4210 Low Resolution - Polycom

[mfisher]

We have a 4210 on 4.5.(1.72) that appears to keep connecting at 4cif resolution regardless of bandwidth in.  We tested the same systems on 4500 series, 8700 series, 8500 series, etc. with all connections being 720P+ with the same bandwidth. The endpoints in questions are polycom both HDX and Group series.  31.2 for group and 6.1.2 for hdx. This seems to be a fairly new issue with no changes made.  Any known problems or settings that may induce this issue with polycoms?  

[PJMack]

The 4500, 8510 and 8710 are all HD bridges, the 4200's are not. They can do 720p but only at 15 FPS, not 30. 

From the datasheet:

Video Resolution

• From QCIF to 480p at up to 30 fps and 720p (1280 x 720) at up to 15 fps, including interlaced iCIF and iSIF • 4:3 and 16:9 aspect ratios

As for your endpoints, I'm not sure about group series, but I know that the HDX does not support any 16:9 aspect ratios below 720p (so no w288p or w448p), so depending on your call rate that could also be stopping you, the best resolution you'll get from an HDX to a non HD bridge is 4CIF. 

Hope this helps

[Wayne DeNardi]

There are many settings which can affect the quality of the call with respect to size and resolutions, both on the endpoints and the MCU itself.

A couple of things you can check:

On the Polycom devices, make sure they're capable of H.264 instead of just H.263+.

On the MCU, check all your settings about maximum video size, video transmit size optimisation, video resolution selection, motion / sharpness trade-off, transmitted video resolutions, default bandwidth to/from MCU.

Note: The 4210 itself is quite an old device, and is approaching its End of Support date of 30 September 2018, so you should also be looking at replacing this with something that is more capable and supportable.