Current problems with ATT UVERSE streams (Sep 2017).

 

1.       Picture flashes on a number of channels. The flashes are due to merged fields from different points of time indicating an encoder- decoder problem.

flashing.mp4

merged 2 different fields.png

2.       Streaks on picture and static on audio indicating extreme corruption on the uncompressed link. Most probably due to a failure of the IP switch carrying SMPTE2022 SDI traffic. SDI introduced about 2 decades ago was very well characterized, robust and capable of reproducing audio and video clocks closely since they are based on Phase locked Loops (PLLs) tracking every clock edge. These kinds of  artifacts were seen,  only in a lab setting, about 20 yrs ago while perturbing Deserializer / Serializer PLLs to assess link stability . Providers who are launching  SDI over IP (SMPTE 2022)  may now have  to contend with these problems again because of the inherent weakness in recovering audio and video clocks with fidelity from a packetized stream subject to transient issues on the switching network.

smpte2022_sdi_over_ip_when the_IP_switch_has_problems.mp4