Portsdown repeater streaming

[G8GKQ]

Hi Mike

The latest production software allows you to set the PMT, Video and Audio PIDs independently for MPEG-2. It is the PCR PID that is tied to the video PID. As I understand it, GB3UD needs the PMT PID set to 32 which is possible with the Portsdown. Grateful if you get a chance to test it.

Dave

[ON1AVO]

Why is the audio freq. range limited to +/- 6 kHz?
Tested with a stereo audiogenerator and UTV007 USB Videograbber.
Attached a screenshot of the VLC Codecinformation, Samplerate 11025 Hz instead of 48000.

Portsdown audio sample rate.jpg (59.68 KiB) Viewed 6516 times

Freddy

[G4WIM]

Hi Dave,

re latency - I was using the picam on my portsdown txing on 146.5MHz 333ksps into GB3FT but from looking at the local signal progress the delay seems to be in the streaming rx on 1315MHz which is a Comag SL30/12 into videocap dongle into RPI3 Portsdown code streaming to BATC.

So my bet is it's something to do with the videocap dongle /rpi streaming.

Quite amazed it has enough memory to buffer up so much video, but I do notice that sometimes just as it's about caught up it sometimes gets a bit confused and sends stuff out of order.

For instance if it is streaming the test card and I start to transmit, then after about 30 seconds it'll send a few frames of my transmission, then test card for a few seconds then finally my transmission.

This despite my transmission being solid as witnessed locally direct.

Hope all this makes sense and is of some use.

73 Tim

[G8GKQ]

I've been doing some work on how best to stream repeater outputs using the Portsdown. I've come to the conclusion that if people have a noisy signal to stream, then they are going to have to modify the Portsdown code themselves to suit their individual situation. This is easy to do.

I've started a Wiki Page here https://wiki.batc.tv/Repeater_Streaming and will update it with details of the hardware switching when that is released.

I have not yet managed to reproduce the long delays being reported. Next time someone sees it, please can they close their browser and restart it and see if the delay reduces. I think that some of the problem might be in the receiving browser, but am happy to be proved wrong - I just need to know!

Dave

[G4WIM]

re streaming latency - I'll do my best to provide some hints as to where to look, including the BATC streaming web page because as a test I recently turned off my RPI streaming box but I continued to see video for about 20 seconds so I guess it could be the BATC box or even my local browser.

73 Tim

[g0lgj]

Hi GB3TN is now using the Portsdown S/W to stream and not seeing any delay in the input
Regards Mark G0LGJ

[G8GKQ]

Hi Mark

Good to see!

Dave, G8GKQ

[g0lgj]

Hi Dave all good , we are getting the odd bang and pop on the audio though not sure what that is.
Mark

[G8GKQ]

Hi Mark

Yes, I've been hunting down the cause of the crackles, but it seems to be fairly deep in the driver for the EasyCap.

Has the stream kept running OK?

Dave

[g0lgj]

Yes no problems running 24 x 7 without problems,
Mark