There are a lot of settings in the web interfaces of TX an RX. I picked a few to give you an idea.
In the transmitter we can set some interesting network parameters:
Both for the Realtime Streaming Protocol (RSTP) communication and for the actual Transport Stream (TS). The stream doesn’t actually start until there’s a RSTP connection with the RX. This happens when you subscribe to the stream on the RX.
The bitrate can be sett from 200Mb/s – 750Mb/s
- Time to Live (TTL)
A packet start its life with a certain TTL value, e.g. 64. Every time the packet passes a router, the router deceases this value by one. When TLL reaches 1, the router will drop the packet.
Normally, multicast packets do no leave the local network. Therefore, manufacturers often assign a TTL of 1. However, if you do want do route multicast (using PIM) you’re in trouble. It’s nice to be able to set the TTL value as desired.
- Differentiated Services Code Point (DSCP)
This a Quality of Service (QoS) setting for the packet. Crestron has a default value of 32 / CS4. This value can be maintained throughout the packet’s life, crossing router boundaries. As I stated earlier, I prefer to have enough bandwidth so QoS won’t be necessary at all. But with the NVX / NETGEAR M4300 Switch it’s very easy to use QoS as a life saver: QoS and DSCP Trust is activated by default in the Switch. The only thing you have to do is map the appropriated DSCP values (0 and 32) to the right queues (higher queue is better) and you’re good to go.
For every input you can choose a different EDID on the TX. Predefined EDID’s or copy the EDID from the display connected to HDMI output of the TX.
We can disable HDCP support on the input, or force HDCP version 1.4 or 2.2. The latter is the latest HDCP version, mainly used for protecting 4K content. I will give you a Crestron NVX example why this HDCP setting is important. I connected a Chromecast Ultra to the TX input and used two displays: 4k TV to RX output and a local 1080 display to the TX ouput. 4K display worked fine, 1080 display stayed black.
What’s going on? The Chromecast Ultra support HDCP 2.2 and so does the 4K TV. But the 1080 display only supports HDCP 1.4. Forcing HDCP 1.4 on the TX solved the problem.
The DM-NVX350 has two HDMI inputs and one HDMI output. On top of that it has two analog audio connection that can be set as audio input or output. You can de-embed the HDMI audio or insert analog audio in the stream, nice!
At first I was confused by the primary and secondary audio concept that can be found in the manual, but I think I figured it out. A TX sends out a combined audio and video stream to the “even” multicast address (last octet). Simultaneously, the TX sends out secondary audio-only stream to the “uneven” multicast address. The reason is that a RX can receive video from one TX and audio from another one (breakaway). One RX receiving two AV streams will not work, bandwidth-wise.
On the RX can control the built-in video scaler: resolution, aspect ratio, color depth, color space subsampling and underscan.
Here you see the scaler options to control the color space and chroma subsampling. The scaler can handle resolutions up to 4K60 4:4:4.
Finally I would like to mention the videowall capabilities. You’re able to setup a videowall with a maximum size of 8×8. Ofcourse you would need 64 RX units for the videowall only in that case….