How do I use VMix with Portsdown 2019?

Discussion about this major DATV Project. See also https://wiki.batc.org.uk/The_Portsdown_Transmitter
G3YQC
Posts: 8
Joined: Mon May 06, 2019 6:42 pm

How do I use VMix with Portsdown 2019?

Post by G3YQC » Mon May 06, 2019 6:56 pm

How do I connect my PC to the 2019 Portsdown to use VMix for transmission? Is it via USB or Streaming? If streaming how do I tell Portsdown to use it as a transmit source? I suspect the wikki gen is for the older version.
G3YQC - John

G8GKQ
Site Admin
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Re: How do I use VMix with Portsdown 2019?

Post by G8GKQ » Mon May 06, 2019 8:49 pm

Hi John

It is done by sending the transport stream from the PC to the Portsdown over the network. This Wiki page has all the details: https://wiki.batc.org.uk/Feeding_Video_ ... _from_vMix.

The only thing that needs adding is that if you are using a touchscreen, you should select IPTS IN from the "Encoder" menu.

Haven't tried it recently, but it should work.

Dave

G3YQC
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Joined: Mon May 06, 2019 6:42 pm

Re: How do I use VMix with Portsdown 2019?

Post by G3YQC » Mon May 06, 2019 8:58 pm

OK Dave I will try that. Thanks a lot

G3YQC
Posts: 8
Joined: Mon May 06, 2019 6:42 pm

Re: How do I use VMix with Portsdown 2019?

Post by G3YQC » Mon May 13, 2019 5:09 pm

I have finally got the vMix output to talk to the Portsdown 2019 (thanks Dave) over my local network. But the transmitted pics received on my MiniTune RX are blocky in the extreme and, no matter what adjustments I make to vMix settings nothing makes any difference.

The Portsdown is working fine and sends the built-in test pics, as well as inputs from my camcorder – via an EasyCap capture device – without problems so, suspecting that the BATC Wiki info may be out of date for the 2019 version, I need to communicate with someone who is successfully using the 2019 Portsdown with latest software and the current version of vMix.

I have been using both the original Batch file and the later H264 version from the Wiki. With both, using 1000kS, the signal sometimes locks initially then cuts out and tries to lock again…etc. Using 333kS is much better although the pictures often start to appear (top quarter) but then they freeze and get blocky and very jerky.

Anyone able to help please?

g0mjw
Posts: 888
Joined: Sat Sep 20, 2014 9:15 am

Re: How do I use VMix with Portsdown 2019?

Post by g0mjw » Mon May 13, 2019 5:22 pm

Set a lower resolution in VMIX external output. See if that helps.

Mike

g8gtz
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Re: How do I use VMix with Portsdown 2019?

Post by g8gtz » Mon May 13, 2019 5:37 pm

Agree with Mike - try 384*288 as the "output size" for the Vmix external output (click the cog sign next to "External").

73
Noel

G4WIM
Posts: 257
Joined: Thu Jan 29, 2015 8:36 pm

Re: How do I use VMix with Portsdown 2019?

Post by G4WIM » Mon May 13, 2019 6:32 pm

photoT194129.JPG
photoT194129.JPG (70.83 KiB) Viewed 722 times
I have exactly the same problem, but maybe worse as the video usually freezes like in the above picture - have tried reducing the resolution as suggested but when I turn the output on I get "capture device is still in, close any open programs and try again'.

No error messages in the batch file window

Output #0, mpegts, to 'udp://192.168.1.8:10000?pkt_size=1316':
Metadata:
service_provider: BATC
service_name : G4WIM
encoder : Lavf58.27.103
Stream #0:0: Video: h264 (libx264), yuv420p(progressive), 768x576 [SAR 1:1 DAR 4:3], q=2-35, 428 kb/s, 25 fps, 90k tbn, 25 tbc
Metadata:
encoder : Lavc58.52.101 libx264
Side data:
cpb: bitrate max/min/avg: 428000/0/428000 buffer size: 857000 vbv_delay: -1
Stream #0:1: Audio: aac (LC), 48000 Hz, stereo, fltp, 128 kb/s
Metadata:
encoder : Lavc58.52.101 aac
frame=20605 fps= 14 q=22.0 size= 94621kB time=00:25:00.16 bitrate= 516.7kbits/s speed= 1x

I always seem to have problems ffmpeg !

G3YQC
Posts: 8
Joined: Mon May 06, 2019 6:42 pm

Re: How do I use VMix with Portsdown 2019?

Post by G3YQC » Mon May 13, 2019 7:58 pm

Many thanks for the replies gents, much appreciated.

I have tried 320-240 resolution for ext. O/P but no difference but I will try 384-288, just to see.

G4WIM - you have illustrated the problem exactly, in fact your pic is a bit better than mine. I have found that by using vMix colour bars as an input they mostly come out right! is this a pointer to a difference it outputting colour bars rather that a picture, either video or photo?

I am quite new to digital TV although I have been an ATVer since the seventies. Can I go back to analogue please? Hi

g0mjw
Posts: 888
Joined: Sat Sep 20, 2014 9:15 am

Re: How do I use VMix with Portsdown 2019?

Post by g0mjw » Mon May 13, 2019 8:04 pm

I think it means you have video bit rate issues. Not sure of a fix. You could try encoding the video and audio on your PC and sending it as UDP to the PI and LimeSDR.

I have a script from Evariste
Vmix_PI.zip
(2.31 KiB) Downloaded 58 times
It is a little old but should work when approprately edited. Not you need ffmppeg installed on your PC in C:\ffmpeg\bin\

Mike

G3YQC
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Joined: Mon May 06, 2019 6:42 pm

Re: How do I use VMix with Portsdown 2019?

Post by G3YQC » Mon May 13, 2019 8:59 pm

OK Mike, many thanks. I will look into your suggestions and see how we get on. I just find it a bit odd that users, such as yourself and several others seen regularly on the satellite, appear to use vMix without aparent problem, so why should mine, and others, setup behave differently?

Right, soldier on then, I will crack it (eventually)

John

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