OBS via IPTSin on the PortsDown

Discussion about this major DATV Project. See also https://wiki.batc.org.uk/The_Portsdown_Transmitter
G7JTT
Posts: 116
Joined: Fri Jun 10, 2016 5:05 pm

Re: OBS via IPTSin on the PortsDown

Post by G7JTT » Wed May 29, 2019 9:55 am

Yes that's it the error before was using a "-" instead of just leaving a space between each instruction. Still have to wait at the beginning of the transmission for the video to settle down, but once it has seems to be ok there after. I seem to be ok up to 500Ks but depends on what I have running at the same time on the laptop. I've also found different sources work better than others, so your still need to experiment a bit to see what works on your setup. And remember this is all experimental and is likely to not work as often as it does hi.

All best John

2i0jmt
Posts: 58
Joined: Tue Apr 16, 2019 2:48 pm

Re: OBS via IPTSin on the PortsDown

Post by 2i0jmt » Wed May 29, 2019 11:37 am

Thanks John. I also note that the buffer size is different than from orignal.

Your settings really helped me get going. I haven't tried the amended setting, but with the old one, I can get up to 250ks working really well with IPTSin.

Will try later this evening with the new setting and report back.

Thanks

Jonny

G7JTT
Posts: 116
Joined: Fri Jun 10, 2016 5:05 pm

Re: OBS via IPTSin on the PortsDown

Post by G7JTT » Wed May 29, 2019 11:58 am

Read some where that the buffer should be 2x the muxrate that's why I've changed it, seemed to help my setup.

John

2i0jmt
Posts: 58
Joined: Tue Apr 16, 2019 2:48 pm

Re: OBS via IPTSin on the PortsDown

Post by 2i0jmt » Thu May 30, 2019 10:47 am

Hi John

I think I'm still in the same position as before with regards to keeping the signal going. For anything 250ks or above, the signal just dies outs after some time. For 250, it maybe last 1 or 2 minutes, for 333 it last only a few seconds. Before the signal fails, all is working well though!

125 and 66 work well, although I do wonder if I left them running long enough would they also stop...

I assume you're not seeing the same. Are you using an older version of Portsdown? I think these issues were introduced in a recent release, due to some changes with Lime's API

Thanks

Jonny

2i0jmt
Posts: 58
Joined: Tue Apr 16, 2019 2:48 pm

Re: OBS via IPTSin on the PortsDown

Post by 2i0jmt » Thu May 30, 2019 10:26 pm

Thanks to a local ham, just wanted to update that for at least FEC1/2, I'm now able to get a stable signal up to 1000ks/s. I had to change line 1397 in a.sh to call dvb2iq2 (opposed to dvb2iq as it currently stands)

It's been a great evening.

Cheers

JT

G7JTT
Posts: 116
Joined: Fri Jun 10, 2016 5:05 pm

Re: OBS via IPTSin on the PortsDown

Post by G7JTT » Fri May 31, 2019 2:09 am

Hi Jonny sorry didn't get back quicker, work has been busy. Anyway yes changing the line in a.sh has helped and will be in the next update when it's released. But there also seems to be an issue with ffmpeg and it's standard install on a Windows based PC. It appears that w32threads are not stable for UDP and you need to change some files to pthreads instead. Only found this yesterday and I'm still testing but once I've confirmed it's working properly I'll put up the instructions on here. This may explain why those using Linux based systems are not seeing the same issues as Windows users ?

All the best for now John G7JTT

2i0jmt
Posts: 58
Joined: Tue Apr 16, 2019 2:48 pm

Re: OBS via IPTSin on the PortsDown

Post by 2i0jmt » Fri May 31, 2019 9:41 am

No worries at all my friend! I mentioned that a local ham helped me as I simply didn't want to take credit for the discovery :)

Indeed, it is possible that the UDP stability could be better in Linux. I must try that sometime with a separate Linux box (another pi?!)

Do you know what the story is with the 2 versions of dvb2iq ? My understanding is that dvb2iq2 is the older version that was deprecated due to some changes with the Lime firmware. However, it still works, so I'm keen to understand if there are any drawbacks in using it. Could it be that the Lime API that dvb2iq2 is using is deprecated by Lime, and may be removed in a future version of the firmware?

On a separate note, I managed to get my Portsdown (using IPTSIN) to stream content to my commercial satellite receiver (£20ish from ebay). As long as the bitrate and symbol rate is high enough, it works quite well! For me personally, this is a real happy achievement, as what started my DATV projects was: "wouldn't it be cool if I could get a commercial satellite receiver to tune into something I've modulated?"

Thanks

Jonny

G7JTT
Posts: 116
Joined: Fri Jun 10, 2016 5:05 pm

Re: OBS via IPTSin on the PortsDown

Post by G7JTT » Fri May 31, 2019 11:11 am

I need to do some more testing over the weekend but I'm fairly confident now that the IPTSIN with OBS is working as well as it can. Certain video sources and pictures seem to throw a wobbly still, but at least no pulsing of the PA or cuts to transmissions.

All best John

G7JTT
Posts: 116
Joined: Fri Jun 10, 2016 5:05 pm

Re: OBS via IPTSin on the PortsDown

Post by G7JTT » Sun Jun 02, 2019 7:17 am

Good Morning all,

I now have a stable signal with IPTSin in the portsdown, the main thing for me as a windows user was that FFmpeg was using w32threads which according to this web site has know issues when used with UDP ( https://github.com/jaskie/Server/wiki/C ... ort-stream ). If you look in section 2 on that page there is a download that has both the w32threads and pthreads, download the file and copy the pthreads to your ffmpeg directory as instructed and thats it. It cured all the drop outs and PA pulsing that I'd experienced. The only other thing I did was to go back to using the original basic.ini file with just one addition to the file path/url "udp://230.0.0.11:20000?pkt_size=1316&bitrate=495700". Note that this is entered without the quotes and the number at the end is the muxrate for the SR/FEC your using. There is also a line that can be changed in the portsdown software but I found that this made little difference to me once I wad using the Pthreads with FFmpeg. And lastly if there is one thing I've gained from all this, is that there are so many variables when setting this up that what may work well on one set up may not work so well on another. So use this as a starting point and play with the settings until you have it working perfectly on your system, good luck.


All the best John G7JTT

2i0jmt
Posts: 58
Joined: Tue Apr 16, 2019 2:48 pm

Re: OBS via IPTSin on the PortsDown

Post by 2i0jmt » Sun Jun 02, 2019 9:43 am

Hey John

I'm glad things are working well for you now! I have a couple of questions:

1) In a.sh on the portsdown, are you using dvb2iq (the new binary that's in use by default), or dvb2iq2 (the old one)?

2) are you changing the ffmpeg binary that OBS uses? Or merely the intermediary step binary?

3) when you say you reverted to the basic ini file, are you no longer setting the video bandwidth, or enforcing CBR mode ?

Thanks

Jonny

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