Operation of the second HDMI Output Port in the HSR72Q HDMI Board
used in the SP3 and SP4 products

The following explanations were provided by the board manufacturer 
Momentum Data Systems
17-Aug-2018
Stan Bleszynski
Bryston

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The Primary Output (Out1, by the edge of the board) is HDMI 2.0 and HDCP 2.2 capable.
The Secondary Output is HDMI 1.4 and HDCP 1.4 capable.

HDMI 1.4 supports 4K 24Hz and 4K 30Hz video timings. So some 4K can be supported on the Secondary Output.

In general (there are exceptions) anything provided in 4K is going to be protected by HDCP 2.2.
When a Source provides this type of content and it is capable of being sent out on the
Secondary Output (so its an HDMI 1.4 video timing format) one of two things can happen...

1) The Source provides the video and the Secondary Output is blanked by the 72Q due to copy protection restrictions.

2) The Source drops the video timing to 1080p (or lower) so that the 72Q is allowed to output the video to both outputs.

One never knows for sure which will happen (Source device dependent).

In general (there are exceptions)...

- Streaming Source devices (like Roku, FireTV) will output video at 4K and let the 72Q disable the Secondary output.

- Disc players (like UHD Bluray playing a UHD disc), if they ever output video in an HDMI 1.4 format
where the 72Q Secondary output would be activated (possibly during a movie startup screen),
 they will keep their video timing at 1080p so all the downstream HDCP 1.4 protected devices
can see the picture and not be blanked. This can be hit and miss and can vary from one playback of a disc to another.
Very frustrating and difficult to explain to customers.

Recommendations...

- Turn off the TV on the Secondary output port before selecting a 72Q input that is connected to a source device
 that you want to watch 4K content from. This will generally allow 4K content to flow from all source devices.
There is one exception to this and is very TV dependent.... Some TVs when placed into Standby,
still look like they are On from an HDMI perspective. They will authenticate and continue normal operations on the HDMI ports.
When this happens it is possible that the Source will not provide 4K content (conditions described above).


Note that the HSR82P had similar problems (only one output was HDCP 2.2 protected).

Written by B.P. (MDS)