BATC Forum

Folks,

Can the Portsdown 2020 output Audio via the HDMI? I get video, no audio.

Justin.

I used it to watch the news on gb2rs the other week and had to use a sound card plugged into a spare USB port.
73
Nick

Hi Justin

The Portsdown (2020 or 4) has never been intended to use the HDMI port. The only valid display devices are

• Waveshare 3.5 inch screen Type B (2020 only)
• Composite video output (2020 only)
• Raspberry Pi Foundation Official 7 inch display (both versions)

Depending on testing, the DFRobot DFR0550 5 inch LCD touchscreen may be approved for the Portsdown 4 in future.

If you want to view the stream on HDMI, use the Ryde Receiver and select the stream in the SSH Console Menu.

Dave, G8GKQ

Hi David,

OK, actually I found that if you "Force Audio to HDMI" then the HDMI output works just fine, with audio, but I note that this is unsupported.

A bit of news on the HDMI front (good and bad):

Firstly, on the Ryde, is is possible to mirror the Ryde output on both HDMI ports? (same resolution).

I set up GB3JV with a Ryde receiver feeding an HDMI splitter to the Tx and the Streamer, but I've run into issues with the stability of the set-up, the configuration is as follows:

Ryde (output set to 1280x720@50Hz)
Chinese Streamer (Input set to 1280x720@50Hz)
Tx input, takes whatever it is offered, there is no manual setting.

The issue is that sometimes when the Ryde does its reboot the Streamer and the Tx lock up (no HDMI sync). The Tx is fine directly connected to a Ryde as it auto switches, but via a splitter it gets confused. I had not noticed this before at home because I was using a commercial satellite receiver for the streamer.

I have found what i think to be a solution and that is to use an inline EDID emulator on each output, and probably input for belt and braces, I've not bought one yet, but this one looks interesting, I just need to confirm it supports HD or FHD @50Hz, most seem to be 60Hz, but if 60Hz is all I can get then it will have to be 60Hz.

Unless you know of a splitter where you can fix the EDID for each output?

https://www.amazon.co.uk/gp/product/B08 ... _qh_dp_hza

On an HDMI switch I am seriously thinking that we should consider the ATEM Mini or (similar).

1. It provides both an HDMI and Webcam output (streaming output on the Mini Pro, which works well with the BATC stream inputs.
2. It can provide sexy transitions and overlay graphics, it stores the graphics also Colour Bars and test card graphics, pictures (slideshow)
3. It supports input scaling (720 or 1080) to a fixed output scale avoiding HDMI switching issues
4. it has a straightforward supported API that the Repeater logic can use, lots of code out there already, also supports the Elgato StreamDeck etc.
5. It supports the Hyperdeck Media player, but there are Pi emulations of this too
5. 4 HDMI inputs, but you can pay more and get more inputs, alternatively you can cascade the Minis to add another 3 inputs with API control.
6. You can remote control it via the PC/Mac App or API!

Given it has a supported API, we don't have to get involved with any challenging HDMI switching issues, like I've experienced. Price is very reasonable too. Thor offer the best price, but CVP will price match, I find the CVP support to be excellent.

https://www.blackmagicdesign.com/uk/dev ... oduct/atem

Justin.

Hi Justin

No, the Ryde can't mirror the video on both HDMI ports - unless you can find the code to do it?

We are investigating the options for an HDMI rebuild for 'HV and will be monitoring for the HDMI problems that you have identified as part of the build. My first thought is that the problem lies in your HDMI splitter. I have a Pro-signal splitter here that I use for the streaming of the QO-100 net (Ryde input, outputs to an HDMI monitor and an LKV373A H264 encoder) and not had any issues with it yet - even during Ryde reboots.

Whilst an ATEM Mini might be the ideal technical solution, I am not sure that it is within the budget of many repeater groups. It is also quite a valuable and attractive item to leave at some of the more isolated repeater sites.

73

Dave

Thanks Dave,

Which model of the splitter do you have? I'll order one.

The ATEM Mini is £238 inc VAT and shipping from Thor, hide it in a metal box? Given what it does it seems very cheap when you add up the cost of all the other HDMI bits. Also there is an Arduino library for controlling it, though I would likely use the Windows option running on a £100 mini Chinese PC. The Pro version with H.264 Streaming built in is £389. Both models can simultaneously output HDMI and Webcam.

One the Pi4 there are some commands for mirroring, but I've not got it working yet, it would solve my splitter issue for now.

"You can also use the command line to mirror the display using the --reflect option. Reflection can be one of 'normal' 'x', 'y' or 'xy'. This causes the output contents to be reflected across the specified axes. For example:

xrandr --output HDMI-1 --reflect x

If you are using the console only (no graphical desktop) then you will need to set the appropriate kernel command line flags. Change the console settings as described on the this page."

https://www.raspberrypi.com/documentati ... mmand-line

Justin.

Hi Justin

Not sure on the splitter model as it is deep inside my "hdmi streaming kit" box (which is in the middle of a rack). I'll let you know next time I open it up.

On the mirroring front, the xrandr utility only works for desktops running X, which neither Portsdown or Ryde do.

Dave

Thanks Dave.

Dave,

I'm getting to the bottom of what's going on now. I set the Pi to boot at 1280x720 in the config.txt, but even so when booting it seems to start in 4x3 mode and the sink device (streamer/TX etc.) sticks with that mode, the sink device then needs a reboot to get it right. It's the same with both splitters that i have and a decent "ATEN" HDMI switch, non of these devices provide a reliable sink, so I think the solution runs with a pass-through EDID emulator that will present the Pi with a dummy "monitor" at all times, particularly during the boot sequence. Basically the Pi goes wrong if it can't see a monitor when it boots.

https://www.amazon.co.uk/dp/B07CGCSXLX? ... yp_imgToDp

I'll let you know how I get on...

Justin.

That's correct, the Pi defaults to composite if it can't see an HDMI load on boot up - I just keep a 2 way splitter in line on my Ryde....

73
Noel