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NDI Loop Back Test - Dropping Frames, 1sec delay!
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Hi vMixers, May I introduce you a failed NDI test? This is a testsetup to create a live video visual with the help of the software resolume and NDI. In this setup we are using CAT 5e cable (gigabit cables) and a gigabit switch for NDI. All of the PC does have gigabit ethernet, even the switch shows a green light if there is a gigabit signal attached. Before this setup, we tested a direct cable connection and got the same problem. We think that either, the resolume PC's hardware is too weak (even though we are far away from the 100% GPU, RAM, CPU), or NDI hates looping a video signal back through the same cord. - The production pc is an i7-6700K, 32GB RAM, 2GB GTX960 GPU. Running at ~ 30% GPU, RAM, CPU in this configuration. - The resolume PC is an i7 4700HQ, 16GB RAM, 2GB GTX765M GPU. Running at ~ 55% GPU, RAM, CPU in this configuration. - The streaming PC is an i7-4700QM, 12GB RAM, 2GB GeForce GT740M GPU. Running at ~ 30% GPU, RAM, CPU in this configuration. Setup Video[We are out of ideas] - Sascha.
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If the resolume PC is at 55% CPU, that is at it's max. Disable hyperthreading in the bios so you can see better what's happening. The i7 4700HQ is a cpu with hyperthreading, so it can do a little bit more than 50% to fill up it's cores entirely.
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Have you tried running resolume on the more-powerful production PC?
- Tom
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Mathijs wrote:If the resolume PC is at 55% CPU, that is at it's max. Disable hyperthreading in the bios so you can see better what's happening. The i7 4700HQ is a cpu with hyperthreading, so it can do a little bit more than 50% to fill up it's cores entirely. Ha! You might be right, we'll test that for sure. Hope that this is the only problem THANKS!
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sinc747 wrote:Have you tried running resolume on the more-powerful production PC?
- Tom No. We don't want to. We really want to seperate our productions. So that we have a fail save. We really want to use NDI :) And I don't think that the production PC can handle both. Thanks, Tom :)
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Streamverse.tv wrote:sinc747 wrote:Have you tried running resolume on the more-powerful production PC?
- Tom No. We don't want to. We really want to seperate our productions. So that we have a fail save. We really want to use NDI :) And I don't think that the production PC can handle both. Thanks, Tom :) Wasn't really thinking of both on the same PC permanently, but rather a test to see if resolume would benefit by more power. - Tom
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Is the issue that you are concerned with the difference in latency between the production feed and the resolume feed? If so think about what is happening at the switch. The production stream is being passsed at 1 gbit to the streaming PC. one way traffic , apart from acks back to the originating source. The connection to the resolume PC is now taking 1080p NDI feed from the production PC and passing it back on the one port and the one NIC on the laptop. In other words it is handling at least double the traffic of the other port. So, start with the switch. Have a look to see if a different brand will move the traffic better for you. You may even need to look at a managed swicth so you can apply QOS. Next, see what you can do to optimise the NIC settings on the laptop. I don't really think the issue is with any of the PC's or with NDI as a protocol.
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ask wrote:Is the issue that you are concerned with the difference in latency between the production feed and the resolume feed? If so think about what is happening at the switch. The production stream is being passsed at 1 gbit to the streaming PC. one way traffic , apart from acks back to the originating source. The connection to the resolume PC is now taking 1080p NDI feed from the production PC and passing it back on the one port and the one NIC on the laptop. In other words it is handling at least double the traffic of the other port. So, start with the switch. Have a look to see if a different brand will move the traffic better for you. You may even need to look at a managed swicth so you can apply QOS. Next, see what you can do to optimise the NIC settings on the laptop. I don't really think the issue is with any of the PC's or with NDI as a protocol. Thanks for your intel. We thought about that and removed the switch. We once used only one cable from Resolume PC to Production PC, but still had the problem with the delay (which would be ok if there where no dropping/skipping frames). We thought, making a triangular setup with the 3rd Streaming PC would solve the problem. But it didn't. - Sascha
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sinc747 wrote:Streamverse.tv wrote:sinc747 wrote:Have you tried running resolume on the more-powerful production PC?
- Tom No. We don't want to. We really want to seperate our productions. So that we have a fail save. We really want to use NDI :) And I don't think that the production PC can handle both. Thanks, Tom :) Wasn't really thinking of both on the same PC permanently, but rather a test to see if resolume would benefit by more power. - Tom Unfortunately not. We tested it again and hat a max. of 27% CPU/GPU/RAM on the Resolume PC. - Sascha
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UPDATE!
We asked a guy from NewTek at IBC and he recommended us the triangular setup, as we did in the video.
He said something like: "NDI protocol sends the video in a specific resolution and framerate. So if you use the same port/cable to send a video back and forward + the video gets changed, a framedrop can occure. We also had that problem once here at IBC. But if you use a 3rd PC which is going to get both videos in a separate way, you should not have any problem. If it works, or have any idea on how to fix it, please let us know."
But we still have the problem.
The problem I have with his statment was that if you are changing titles or some other things on a different pc, dropping frames doesn't occure. We tested that (vMix <----> vMix). So he might be wrong.
What's funny about the whole setup is:
- The resolume Pc isn't too weak, we had tests running at around 30% CPU, GPU, RAM. - NDI input on the resolume pc does indeed have a variable framerate. - If I change the vMix production framerate to 60p/59,94p (i does not effect anything) the dropping frames are lower, at around 3-7 per second.
Somewhere in this whole configuration is a bug. But I can't see it :s
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Network is not an issiue, if it would be an issiue you could not use it at all..can you transfer 1Gbit/s ? if yes then its more probably resolume issiue that NDI input is not optimized and cant use 60P in FullHD ..try lower FPS or resolution - for test
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Kalink wrote:Network is not an issiue, if it would be an issiue you could not use it at all..can you transfer 1Gbit/s ? if yes then its more probably resolume issiue that NDI input is not optimized and cant use 60P in FullHD ..try lower FPS or resolution - for test
We tested every production scenario. But If I lower the framerate, dropping frames are increasing. 60p/59,94p -> ~3-7 dropping frames/second 30p/60i/29,97p/59,94i -> ~9-13 frames/second Dropping frames are more noticeable on a lower framerate. Strange, isn't it?
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Did you tied to look into NDI stream in vMix? it could be that source is problem. How you measure missed frames? in 30p is 9-13frames almost 40% of all frames per sec.
Try watch NDI stream into resolume and vMix at same time if in both is same problem then its source. If not, its resolume problem.
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What if you used vMix on the 2nd PC instead of resolume? That is, eliminate the processing time and CPU use of resolume. Compare that result with your first result. You could also check the individual runs for latency and dropped frames using some of the NewTek NDI tools.
- Tom
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sinc747 wrote:What if you used vMix on the 2nd PC instead of resolume? That is, eliminate the processing time and CPU use of resolume. Compare that result with your first result. You could also check the individual runs for latency and dropped frames using some of the NewTek NDI tools.
- Tom We installed every software on the Video Production Machine and surprisingly it took all work very well.. ~ 55%. No dropping frames, internal NDI transport and multiple vMix instances. We are now looking forward to a OSI based controlling solution for resolume and vmix, instead on transporting all the video load via NDI. But we are going to try the NDI solution again, after his (and my) setup gets updated.
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