Portsdown 2019 Software Update 201904290

Discussion about this major DATV Project. See also https://wiki.batc.org.uk/The_Portsdown_Transmitter
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G8GKQ
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Portsdown 2019 Software Update 201904290

Post by G8GKQ » Wed May 01, 2019 9:20 pm

Hi

I have just published another update to the Portsdown software. The main aim of this update is to try to improve the reliability of the 24/7 streaming functionality in use at repeater sites. The RPi will now reboot at 3pm and 3am to try to prevent the need for site visits. Another change should also improve the streaming reliability in the first place. Please soak test this thoroughly before installing at a remote repeater site!

Other features include error-checking to prevent LimeSDR lock-ups after incorrect FEC corrections for DVB-S2 from the console, and the addition of the "menu" alias suggested by G6KMM. So, instead of having to type

Code: Select all

rpidatv/scripts/menu.sh menu
to bring up the console menu, you now simply have to type

Code: Select all

menu
Dave, G8GKQ

HB9IAM
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Re: Portsdown 2019 Software Update 201904290

Post by HB9IAM » Sun May 05, 2019 8:32 am

Congratulations on all the work on Portsdown !

Problem: In H264 it is not possible to use an Audio PID with value different from 1
relative to the Video PID, example PID Video 33 and PID Audio 49.
No problem in MPG-2

We have a lot of Relays that use this couple of PIDs

73's de HB9IAM = F8BXA

G8GKQ
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Re: Portsdown 2019 Software Update 201904290

Post by G8GKQ » Sun May 05, 2019 9:11 am

Hi

Unfortunately the H264 Audio PID is hardcoded (in software that is not mine) to be the Video PID + 1. It is a lot of work to fix it and it won't be done soon, but it is on my to-do list.

Dave, G8GKQ

HB9IAM
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Re: Portsdown 2019 Software Update 201904290

Post by HB9IAM » Mon May 06, 2019 7:40 am

Hi Dave

I understand your problem for the PID correction, so we wait patiently ...

73's Pierre HB9IAM = F8BXA

g8bxh
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Re: Portsdown 2019 Software Update 201904290

Post by g8bxh » Mon May 06, 2019 6:09 pm

Hi
Since latest update I am getting "glitches" in the modulation. ie the mod stops for around 1 to 100mS (carrier remains) at random intervals from around 10sec to a min or so. Spent some time trying all variations of mod types, freq, source etc. Setup is pi 3b+ and lime mini. All other devices cameras etc. removed. The only clue I have is it gets worse with higher symbol rates. Very bad at 2Ms (I know this is not suported) but still not usable at 250k (breaks on average every 30sec but very random). This shows as loss of video lock on minitiouner and mod collapse on realtime analyser (signal hound). I don't have a spare lime or rpi to narrow down further. Rebooted and re loaded programe and lime firmware several times. It feels like the rpi or lime is either getting interrupted or just running out of steam. Tried different psu.
Other than this prob all great. I love it.
Very many thanks
John

g3zgz
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Re: Portsdown 2019 Software Update 201904290

Post by g3zgz » Mon May 06, 2019 8:47 pm

I've seen the same problem as well.

I notice it if Iset the PDown for SR333, FEC 1/2 and set source to TC animation.

It also is present using VMIX input and the PD set to TS input.

It does also occure on other SR and is worse on FEC's like 1/4 1/3.

Problem not noticed if testcard or easycap video selected.

As John mentions the transmission is OK for a few minutes then shows the random drop outs.

I've got a PI3 (not plus) and the latest software for PD and Lime (It has happened with all software versions since I got my lime which was about 4 weeks ago, so is not just the latest release).

I have tried another PI with the same result (also not + version).

73

Dave.

G8GKQ
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Re: Portsdown 2019 Software Update 201904290

Post by G8GKQ » Mon May 06, 2019 9:01 pm

Hi John and Dave

Yes - I'm trying to track this problem down. It only happens with the LimeSDR and is a software issue, not a hardware failure.

There are some SRs and FECs that work well, and others that don't work at all. Different video sources work at different SRs and FECs. I am just testing a minor improvement for the next release, but the testing is incredibly time-consuming, and I don't want to release something that makes it worse.

I know that with the Easycap DVB-S2 QPSK 500KS and FEC 1/2 works well. It copes with G4KLB-length overs!

I have just found that with a C920 DVB-S2 QPSK 333 FEC 1/2 is OK, as is 250 2/3.

The older software used a different method of driving the Lime that is no longer supported By the current Lime Firmware.

IDave, G8GKQ

g8bxh
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Re: Portsdown 2019 Software Update 201904290

Post by g8bxh » Tue May 07, 2019 9:58 am

Hi Dave
I realise these types of problems are very difficult to track down and take a lot of time.
I will try some of the settings you suggest and see how it goes.
Again very many thanks for all your work.
73s
John

G8GKQ
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Re: Portsdown 2019 Software Update 201904290

Post by G8GKQ » Thu May 09, 2019 9:32 pm

I have investigated the problems with Portsdown and LimeSDR Mini in this release. There seem to be 3 separate problems, depending on the video source, SR and FEC. While I try to sort things out, here is a guide to which H264 modes work and which don't in this release. Note that the green boxes still suffer occasional RF/picture dropouts. The amber boxes give a picture to start with, but soon lose lock. The red boxes never achieve lock. "C920" refers to WebCam mode using a C920 webcam, not the button labelled C920.

Sad to say, I did most of my pre-release testing using the Pi Cam and other combinations that happened to work. Note that if you set 250KS, FEC 3/4 all video sources seem to work.

Dave, G8GKQ
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