Portsdown 4 - OBS source freezes

[M0MBO]

Hi,

I've been chasing this issue for a while without success, so hoped someone could point me in the right direction!

Portsdown4(P4) with source Pi Cam or Comp Video gives perfect TX via Pluto, with RX on Ryde and SDR Television/LibreSDR.

Source (H264) OBS/FreeStreamCoder to P4. M2>IPTS Monitor works fine. But TX works but then freezes after a couple of seconds.

Appreciate any suggestions.
73
Malc
M0MBO

[G3GJA]

Malc

Please supply more information.

Have you followed the instructions here:https://wiki.batc.org.uk/OBS_-_Open_Broadcast_Studio?

if yes, then answer these queries:

• 1.What symbol rate have you set the P4 and FSC to?
  2. What is the default resolution in OBS and FSC?
  3. What are the specs of the PC including the graphics card if fitted?
  4. What encoder option have you selected in FSC?

73
Clive

[g0mjw]

Hi,

I've been chasing this issue for a while without success, so hoped someone could point me in the right direction!

Portsdown4(P4) with source Pi Cam or Comp Video gives perfect TX via Pluto, with RX on Ryde and SDR Television/LibreSDR.

Source (H264) OBS/FreeStreamCoder to P4. M2>IPTS Monitor works fine. But TX works but then freezes after a couple of seconds.

Appreciate any suggestions.
73
Malc
M0MBO

This is usually because you are sending too much data to pass through the channel you are sending. Do the maths and tell us the result.

[M0MBO]

Hi Clive and thanks for responding.

1.What symbol rate have you set the P4 and FSC to? 333ks
2. What is the default resolution in OBS and FSC? OBS = 1280X720, FSC tried 1280X720 & 960X540
3. What are the specs of the PC including the graphics card if fitted? Intel i5-4570 @3.2gHz, Intel HD Graphics 4600, 8gb RAM
4. What encoder option have you selected in FSC? = Intel

Malc

[g0mjw]

So 333ks but what FEC? - needs to be set correctly in both places.

If for example the SR is 333ks and the FEC 2/3 gives you a data rate of about 440kb/s. So that's what the encoder needs to send, ideally a little less. Then there is the H264. I would not exceed 720p and ideally only 15 frames per second. Ideally the audio should be 32k or similar.

Oh yes, and don't expect WiFi to work.

Mike

[M0MBO]

FEC is 2/3 in FSC and P4

[g0mjw]

FEC is 2/3 in FSC and P4

OK - lower the resolution and frame rate. That's a very old CPU incidentally, from 2013, so may struggle.

[G3GJA]

As Mike says it will struggle.

The CPU is too old to have video encoding that will be of use to you and you don't have a graphics card as an alternative.

Your only option with that computer is to drop the frame rate to 15fps and set the resolution in OBS and FSC to no more than 960 x 540, possibly as low as 640 x 360. Your PC just doesn't have the power.

Clive

[M0MBO]

Thanks Clive & Mike.

Following your suggested tweaks I can now TX video from P4 to Pluto successfully.

Reducing image size did the trick; with 950X540 25 fps still works.

Malc
M0MBO

[G3GJA]

There's a lot going on with the OBS/FreeStreamCoder system. In OBS anything being played out has to be decoded by ffmpeg for the mixing and other features to work. It's then 'boxed-up' and sent to FSC which does the ffmpeg encoding of the stream sent to the P4.

I use an HP Z2 workstation with a 13th gen i7, 32GB DDR5 RAM and a 12GB nVidia RTX-A2000 graphics card; that allows me to run HD (1280 x 720) @ 25fps using 333kS/s for an hour or more. It needs to as I read the GB2RS News over GB3EY.

Glad to hear you've been able to make it work.

Clive