AnsweredAssumed Answered

Video issues related to HDCP handshake

Question asked by reshmi on Feb 21, 2013
Latest reply on Apr 10, 2013 by mattp



We use the ADV repeater software, which uses ADV 7612 and ADV 7511. Recently we started seeing issues which we believe are related to HDCP handshake. The video does not look right in some cases.


We did use the evaluation board and it does not happen with that.


Few things that the box does different from the evaluation board:

- Our repeater box can stream from different inputs like HDMI, Internet content(IP), AES, SDI, and video output is always HDMI.

- When we switch to a new mode or if the input content type changes, we reconfigure our output video and audio clocks. So we disable the VSYNC/HSYNC/TMDS etc for a few seconds, and only after the clocks are configured and Tx PLLs are locked do we enable the video syncgen (output VSYNC/HSYNC/TMDS) module on the FPGA.

- Each time we change our input source, we send the AVI frame and audio info frame based on the current content detected.


On reconfiguring the clocks, we notice that the HDCP reauthenticates. We see that we always get one "Unknown HDCP error" or "Bad BKSV error" and soon after we get HDCP authenticated message. But in a couple of cases the video does not look right.

1. When the input is SDI,  and we switch from HD to SD, on some of the switches, the video looks totally wrong with vertical and horizontal bands, and video is only displayed on the top left and top right corner of the screen. In this we notice that on disabling HDCP, and re-enabling it, we can fix this problem.


2. When the input is HDMI from a Roku2 box, the output video is red in color. Some disconnect and reconnects fix this, while others don't.


There seems to be some relation between HD and SD rates, and the way authentication takes place. But we don't really understand that.


Our repeater s/w is configured in HDCP_FOLLOW_INPUT mode.


Is there any particular order to changing video clocks, sending info frames etc. that would help this problem?


Any pointers to this problem would be helpful. Please find attached pictures of the video in the SDI case.