Question / Help UDP Multicast Issues

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Ben_Derzgreat

New Member
https://gist.github.com/54a4b9e9bd434a409de26e0ed4260445

I am trying to output a desktop stream via RTP/UDP to a multicast stream and keep receiving an unspecified error message when I start the recording. I am currently using VLC to stream to this same address via UDP or RTP no problem, I have ffmpeg installed on my system as well. Is there something I'm missing?
 

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Ben_Derzgreat

New Member
So now that it is displaying I am trying to troubleshoot issues with the display. I have tried decreasing the frame rate and bitrate, and altering the keyframes, but nothing seems to help much. It will work for a second and then start displaying like this. I run a desktop show via VLC with similar settings and it works better, but I am looking to switch to OBS for more stability, am I better off sticking with VLC?
 

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Boildown

Boildown

Active Member
You probably don't want to use OBS to play back the multicast stream. For generating it sure, but not for playing it back. Is that what you were doing?
 
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Ben_Derzgreat

New Member
Boildown said:
You probably don't want to use OBS to play back the multicast stream. For generating it sure, but not for playing it back. Is that what you were doing?
Click to expand...

I was generating it with OBS sending it out multicast, where an IPTV system picks it up, and then viewing it via URL to the server on a LFD TV.
 
Boildown

Boildown

Active Member
If you play it back in VLC on a PC does it look normal? Do you have other multicast streams that the TV plays back fine? If yes to both, I'd guess you need to look up the specs of the IPTV box or the TV (whatever the actual player is) and check out its requirements.
 
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Ben_Derzgreat

New Member
Boildown said:
If you play it back in VLC on a PC does it look normal? Do you have other multicast streams that the TV plays back fine? If yes to both, I'd guess you need to look up the specs of the IPTV box or the TV (whatever the actual player is) and check out its requirements.
Click to expand...


I can't get it to open in VLC, I'm putting in all the correct information, and it's not giving me an error, but it won't play the stream. I will keep playing with that. As far as the TV goes, it is playing the other multicast streams fine. I work for a sports stadium and the other multicast streams are our IPTV and dedicated hardware encoders, I was looking to see if I could use OBS for client power point presentations instead of expanding with more expensive dedicated encoders.
 
Boildown

Boildown

Active Member
To play back in VLC you'll want to do udp://@MulticastIP:Port

For example, udp://@239.3.86.197:1234

Is that how you were doing it?
 
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ICAN

New Member
Guys, while this is an old thread, I am facing the same issues.
I am able to muticast from OBS, but VLC does not decode the stream. It shows no video.
The Tx PC task manager shows that the stream bits are being transmitted. On the other side VLC-PC is receving the stream bits, but the video is not getting decoded.
The VLC error logs suggest a 'ts error (libdvbpsi error): TS discontunity received (received #, expected #)'. where, # are some integer numbers.
It seems to me that VLC is unable to decode the Transport stream from OBS. however I suppose there is only one setting: mpegts to encapsulate the stream, so I dont know if we can change that.
I am using aac and h264 encoding.
Anybody who has received OBS multicast successfully?
 
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ICAN

New Member
Thanks Tom for your interest and support.

PFA OBS and VLC logs for most recent test.
AFAIK OBS streams fine, but VLC (opened on the same machine though) indicates receipt of stream, but fails to decode. Maybe there is a TS header mismatch.
 

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ICAN

New Member
The text error file was too big for upload. sending zipped one
 

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ICAN

New Member
Hello Tomas,
PFA new logs for perusal.
Turned Off Game DVR. No change in results.

I am not sure the issue is in i3. This is 7 Gen. I see only 15-30% CPU and 30% GPU load.
I am reimphaisizing that as per my mind OBS seems to be tramitting successfully, but the output format of transport stream isnot being decoded by VLC. So, maybe if somebidy who has done this setup can check again my settings and suggest.

OBS screenshot.png
OBS screenshot.png
 

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Tomasz Góral

Active Member
Why you use address 239.1.1.1?
Keyframe 120, now you have 30 fps, 4 second to Intra frame, too long.
For test use mpeg2 not libx264.
Use ffplay from ffmpeg package instead VLC.
 
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ICAN

New Member
I supposed we can use any Class D address unless conflicted within the network. Changed to 238.1.1.1:9000
Changed to 30 KFI
Used mpeg2 video and mp2 audio

what is 'zamiast VLC'? how do I choose ffplay. amd where?
 
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ICAN

New Member
Solved. It is not a OBS issue.
Actually, It is a VLC issue. Fixed partially in 4.0 64-bit, with a number of additional settings.
 
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