Recording & Streaming your event – Miscellaneous 6/7

This is the sixth article on the “Recording and Streaming your event”.
In this post, I cover some other areas I couldn’t quite put elsewhere.

Table of content of the series:



A few other tips I find worth mentioning, and who did not really fit other section.

About Extra viewing screens

One of the PSConfEU feedback I’ve seen because it happened on twitter, was a request for additional TVs so it’s easier to see the code in some deep (long) rooms.

As I said, HDMI cables (out of your repeater for instance), can only be ran for up to 10 meters. An alternative could an adapter from HDMI to something else (SDI or Cat 5/6 network cable), but this is non-trivial and would need to be tested.

Steve and others suggested streaming so people with Laptop could just follow along, and Thorsten rightfully said the conference WiFi (as we know it for Hanover Conference Centrum) would not sustain that many devices. The problem is probably because of the Access points are not capable of handling that many devices (think a phone for at least each international traveller, plus many attendees’ laptops).

Even if we get the bandwidth requirement down by using a local RTMP server, then turning it into a multicast stream with VLC, or just using NDI with OBS to make the stream multicast (and assuming that will work in such “protected” WiFi semi-public access), I doubt the Access point would be reliable enough to deliver the packets. But the main challenge is that’s another worries to engineer and support for the organisers, and extra costs.

And no, I don’t think that wiring our own network and setting up access point for everyone is a viable option for a community-driven conference of 300 people that spans over several floors and several thousands square meters…

Lastly, but as important as the above if no more: taking the feed after software processing will add significant delay to the AV feed, between 2 to 6 seconds at least in my experience, depending on what is mixed and how the software is configured and doing (streaming, syncing streams, buffering…). This is in fact so distracting that when I operate a stream, I use my noise cancelling headphones, and focus on the screen, because it’s impossible to have such a difference in image and sound.

To me, the only viable option is to take the signal directly from the presenter’s laptop (maybe on the HDMI splitter) and send it via a cable (not HDMI) to another TV further down, probably by converting it first to SDI (up to 100 meters), and maybe back to HDMI if the TV does not support SDI input. Having hardware transceiver like that would probably add between 20 and 130 millisecond delay each from input, which should be perfectly bearable, especially when you take the projector latency in consideration as well.

As a side note for self, long rooms with PA systems can also create some challenges as the sound travel slower than electrical signals, so a second set of PA speakers towards the end of the room needs to be delayed by the time the sound takes to come from the front of the room.


HDMI Audio Extractors

Despite the capability for HDMI to carry the sound of the laptop, when the laptop is adequately configured, some HDMI splitters just don’t… Or sometime they do carry sound but only to the device connected on their output 1.

Or maybe you just want more flexibility to do your own mix between your microphones and the presenter’s laptop audio.

I haven’t used them yet, but be aware that HDMI audio extractor exists and are cheap. That said, it’s another in-line equipment adding single failure points in your chain.


3M Dual Lock and 3M Command Damage-free hanging

With all those tiny pieces and connections, I love to make sure my stuff does not slip off the table, and does not move everywhere, during the event or transport.

To that effect, I use those two type of scratch pads/strips, sometimes together, to make sure they won’t move. For instance, I use them to secure the recording device or the HDMI splitter on the lectern when I need too.

They are easy to remove and, as advertised, do not damage the property when removed.

I also have some on my extension lead, so that if it’s carpeted floor, the extension lead won’t move when someone walks where they shouldn’t…


NEXT: Conclusion and Suggested Kits

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