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Reduced Framerate when using NDi

Hi there,

I am running the latest version Wirecast Pro on an i9 Tower-PC (w/ rtx 3080 adnd 32gb of ram) which is connected via a GB-Switch to two NDI-Cameras. Everything works fine so far.

Now I tried to stream to another Lapt using NDI (the Laptop has Studio Monitor installed). As soon as I start the NDI, the Framerate on the Wirecast Interface drops from 30 FPS (1080p) to around 2-6 Frames. After around 10 minutes, the framerate recovers and runs stable at 30 FPS.

Afterwards I tried to stream to another Laptop (same config). Again the FPS dropped as soon as I started (also on the first Laptop), after around 10 min it recovered on both and is stable ever since.

The CPU-usage did not go over 10%; Everything should be set to 1080p/30

Do you have any idea why it behaves like that?

Thanks

Franz

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  • I'm not sure I understand your complete workflow?
    I'm not sure I understand what your NDI source is or what the Wirecast is doing since you're mentioning another laptop and Studio Monitor installed.
    I'm not sure what you mean by "Wirecast Interface" or how you are measuring the frame rate change.

    Please describe in a way an engineer can build a matching workflow.

    Like
  • Hi there,

    and thanks for your reply.

    1. First, I was streaming the signal from Wirecast via NDI to one Laptop. The Laptop picked up the signal with the Software "Studio Monitor". There I discovered the drop of frame rate. After the stream rate recovered at 30 FPS, I set up a second Laptop to check if the problem occurs again, which did. So in the end I fed the signal from Wirecast via a Gigabit-Switch to two Laptops.

    2. "Wirecast Interface" -> the main window of wirecast. At the bottom-right corner there is CPU-usage and the like and also the frame rates.

    3. The Source which feeds a video into Wirecast is just a normal Camera with HDMI.

     

    Like that:

    [CAM1-HDMI] => [WIRECAST] => [GB-SWITCH] => [Laptop 1 and 2]

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  • Franz said:
    1. First, I was streaming the signal from Wirecast via NDI to one Laptop. The Laptop picked up the signal with the Software "Studio Monitor". There I discovered the drop of frame rate.

     Please explain further. You were using Studio Monitor on the receiving computer and how did you determine the low frame rate?

    Franz said:
    set up a second Laptop to check if the problem occurs again, which did.

     It could be an issue on the network. Skip Wirecast and play a Youtube video in a browser, from the Wirecast computer. Use Newtek Scan Converter to send that to one of your receiving laptops and check that in Studio Monitor for low frame rate.

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  • Thank you!

     

    1. Exactly! The video on the receiving computer was freezing multiple times per minute for some seconds. At the same time the frame rate in Wirecast showed 2-6 FPS and "dropped frames" were counting on and on. After some minutes it recovered and showed 30 fps in Wirecast, the video shown on the receiving Computer was smooth.

    2. That's what I thought as well. Thus instead of using the hdmi-camera, I plugged in a NDI-PTZ-Camera (wiring diagram see Attachment) today. The problems occured again using it that way: [PTZ-Camera] => [WIRECAST] => [RECEIVING LAPTOP]

    In Studio Monitor, I then chose the NDI Camera instead of the signal from Wirecast and... the Video was smooth. So by bypassing Wirecast and directly fetching the signal of the camera through the network, it was no problem. [PTZ-Camera] => [RECEIVING LAPTOP]

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      • CraigSModerator
      • Telestream Desktop Forum Moderator
      • CraigS
      • 11 mths ago
      • Reported - view

      Franz Can you confirm Wirecast is version 14.2.1?

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  • Franz said:
    In Studio Monitor, I then chose the NDI Camera instead of the signal from Wirecast and... the Video was smooth. So by bypassing Wirecast and directly fetching the signal of the camera through the network,

     But that isn't from the Wirecast computer. 
    You must test another NDI source from the Wirecast computer.
    Please follow my instruction using NDI ScanConverter from the Wirecast Computer.

    NDI from the Wirecast computer may be the problem and not Wirecast itself. ScanConverter would be the easiest way to confirm the computer itself.

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  • Hey Craig,

    thanks for the clarification, now I get your point. I will test it ASAP on Monday. Thanks in the meantime for your great support.

    I can confirm it's the latest version of Wirecast.

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  • It sounds to be the computer itself. Take a look at the utilisation of the computer. NDI needs some processing power. Another problem could be the network. Bandwidth can sum up very quickly. I made a video to show the bandwidth usage of NDI.

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  • Hello again,

    so I checked it with Newtek Screen Capture (it's the new name of Scan Converter). No problems from the beginning. Then another try with Wirecast and Screen Capture (the built-in feature): Imediately reducing frame rate to 5 fps, CPU at 5%. It took  7 mins for the rate to recover to 30fps. In this 7 minutes 14.000 frames were dropped. After that everything ran smoothely.

    I then tried it with OBS (same screen to capture) instead of Wirecast: no problems

    Wirecast is version: 14.2.1

    Thanks for your help!

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      • CraigSModerator
      • Telestream Desktop Forum Moderator
      • CraigS
      • 11 mths ago
      • Reported - view

      Franz Thanks for that. 
      Can you please detail your workflow in the above test as if it were a signal flow diagram?
      Also explain how you are determining Wirecast frame rate?
      This for example?
       

      Please understand that if the developers have to guess at anything or make assumptions then they may not be able to confirm the issue.

      Describe as if you were walking an engineer through your test procedure with signal flow. Then I can write your steps precisely. 

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  • Hey Craig,

    thanks again for your help. I hope the attached image can show my workflow? If not, please tell me.

    Yes, the frame rate and cpu comes from the attachment you showed me.

    Thanks

    Franz

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      • CraigSModerator
      • Telestream Desktop Forum Moderator
      • CraigS
      • 11 mths ago
      • 1
      • Reported - view

      Franz Thanks. That's very useful. Started the investigation WIRE-18949

      Like 1
      • CraigSModerator
      • Telestream Desktop Forum Moderator
      • CraigS
      • 11 mths ago
      • Reported - view

      Franz We'd like to look at the System logs.

      Run Wirecast with NDI Out causing the issue.
      Then go to
      Wirecast > Help > Send Support Information...
      and select Save Report.
      Attach the generated report to a forum post.
      That may tell us why Wirecast is not sending all the frames.

      Developers would also like to know if you're using any Blackmagic video devices (and driver version if you are).

      Like
  • Hey Craig, I will test it tomorrow morning.

    In the meantime I can tell you that we are using a Decklink Quad HDMI Recorder and a Decklink Duo 2. As the test was done, nothing was pluged into these pci-cards but of course drivers were installed. With the cards everything seems to work normal.

    Thanks a lot for looking into that in depth. Great support :)

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      • CraigSModerator
      • Telestream Desktop Forum Moderator
      • CraigS
      • 11 mths ago
      • Reported - view

      Franz Developers are curious about the frame rate you get if you use Wirecast Blackmagic Decklink Video Out feature, If you can test that as well.

      Like
  • Hey Craig, I don't get it, everything runs stable now from the first frame, so I cannot reproduce the error. Everything I did this time was to connect the GB Switch to the internet whereas the previous times only the source pc was connected to the internet and the gb switch not.

    Could this have caused the problem? Does NDI somehow need Internet to work?

    I've attached the old and new wiring diagram

    Like
  • Franz said:
    Does NDI somehow need Internet to work?

    It shouldn't but perhaps something else changed in the process of hooking it up which impacted bandwidth or performance.

    Like
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