Audio issue during capture/stream FB Live x264 WC 8.3 Windows 10


My show VOBS.TV just upgraded systems again, including $300 WC 8 upgrade and $2500 custom PC.

We did our first live show using a newly built custom PC, specifically to run Wirecast.

We had a disasterous issue with the audio chopping up during the stream and capture at x264 1080p. As an audio engineer, this is the first time I've ever experienced this problem in my 7 years streaming professionally.

Here is the episode:

Audio interface is an Allen & Heath XB10 USB broadcast console with a 10' USB cable going directly to the PC (no hubs, extenders). 


Specs are as follows:

Intel Core i7-8600K Coffee Lake 6-Core 3.6 GHz, GIGABYTE Z370 AORUS Gaming 5 MB, CORSAIR Vengeance LPX 16GB DDR4 3000, 500GB SSD, Phanteks Case, EVGA 700W PSU, Corsair Cooler
Magewell Pro Capture Quad SDI Four Channel HD Capture Card #11090

Seagate BarraCuda Pro ST4000DM006 4TB 7200 RPM 128MB Cache SATA 6.0Gb/s 3.5" Hard Drive

GIGABYTE GeForce GTX 1050 DirectX 12 GV-N1050OC-2GD 2GB 128-Bit GDDR5 PCI Express 3.0 x16 ATX Video Card

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  • Sorry about your experience. 

    I like to know what was happening on Wirecast's side. Did you monitor Wirecast audio pre record/stream?

    What was your CPU in Wirecast (not in Skype or whatever communication software you were using)?

    What presets specifically where you using to stream and record with?

    What was the Wirecast > Preferences > General set to and was that changed without restarting Wirecast or rebooting the computer?

    There's a number of situations that can cause that in a system config.

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  • CraigS I am checking with our TD about some of these questions.

    I was working remotely that day.

    I know CPU is usually under 40%.

    I guess you mean the AUDIO setting? Yes, they repatched the USB audio codec USB cable and did not restart Wirecast. 

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  • CraigS From our TD:


    During the pre-record/stream, there were no issues. It actually sounded fine to me during the entire session, but it was choppy on FB Live and then the recorded version was also choppy.

    CPU usage? Was between 27% - 34%

    Preset: Facebook x264 4000mpbs 1080p

    I'm not 100% sure what the Preference setting is that they are talking about. As far as I know, all the settings were set in advance of this show and I just used the same ones.

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  • George Whittam said:
    It actually sounded fine to me during the entire session,

     Sounded monitoring how?
    According to your comment that it did not sound fine while live seems to conflict with the above. It depends on where and how monitored.

    George Whittam said:
    but it was choppy on FB Live and then the recorded version was also choppy.

     That's often indicative of a change in audio device after the computer booted and possible after Wirecast started.

    CraigS said:
    What was the Wirecast > Preferences > General set to and was that changed without restarting Wirecast or rebooting the computer?

    As per my question above.

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  • CraigS Monitored via Wirecast output. Our TD monitors the Wirecast output for quality in sealed headphones, as we must know how the Wirecast audio processing sounds. It's frustrating for her as she is in the same room and the latency is distracting. What is heard on FB Live is not monitored by anyone on production staff, but that will change starting today. We rely on what our live chatroom tells us, but that isn't good enough. 

    Yes, the audio interface was changed without a restart of Wirecast. This was something we did occassionally on the Mac OS version without issue.

    Now that we know there is an issue involved in changing audio devices without a restart of Wirecast on Windows, we'll know to look out and avoid that situation in the future. Perhaps your coding team could add a warning, or a mandatory restart dialogue to help it's users avoid a similar embarrasing fate. 

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  • George Whittam Thank for the info. If the output device changes it's possible that Wirecast direct monitoring will be OK but recording/streaming will have a "chop." This can happen on both Mac and Windows.

    My general rule of thumb is to set audio end to end and reboot and start Wirecast. At that point I don't change anything. I do a quick test recording in Wirecast and play that back to confirm the audio is good.

    I always setup a second computer to monitor the stream.

    I believe Wirecast adding Audio Device Control in Preferences may have alleviated the issue (giving you the ability to change it rather than using the system sound controls) as I haven't had it happen recently. I'd still do a quick record check before going live.

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  • CraigS Well, as usual, I did everything you told me to do, but we had distasterous results. This is a repeating pattern where I come to you for guidance, I follow your suggestions, pay for upgrades, etc, and things don't go smoothly. This is not a reflection on you at all, but on the stability of Wirecast software. 

    First we had problems with NDI during setup. The feed from NDI Scan Converter from a Macbook Air would freeze and we couldn't get it to refresh. We restarted Wirecast, but same thing. We restarted the PC, and then started getting errors from Wirecast saying that it can't initialize our audio hardware. Now a new problem to troubleshoot. We eventually figured out after a few restarts that we just had to click Cancel and hope for the best... 

    We tested everything 10 mins before go time, I monitored FB Live and YT live streams audio, and all was fine. We started the show and about 15 mins in the audio started to chop up again. It happened right as we came out of a commercial break:

    Now completely flustered, we stopped the show to fix the problem. I had no idea what was causing it. We checked all sample rates and everything seemed consistent in our audio drivers. I figured the issue was our USB Audio Codec driver, so I worked to remove the USB audio device from the system. We scrambled to find analog patch cables and adapters long enough to reach from our console to the PC Line In jack, and 30 mins later we were back online again. 

    It seemed we fixed the issue because it was not choppy, until:

    Again, coming out of commercial break it fell apart. 
    Now I am thinking there is an issue with sample rates differing between our playback sources and our audio interfaces? Really clueless here. This was not an issue on our Mac based system.

    Realizing we can't count on the audio any longer, we stopped, I connected my Macbook Air to the USB port on our broadcast console (XB10 from Allen and Heath, USB Audio Codec), and recorded the audio for the rest of the show that way. Our live listeners suffered through the over modulated and then choppy audio.
    Here's where it happened the final time:


    So now, I've indeed found a pattern. Coming from playback to audio input, distaster strikes.
    Now knowing this, what do we do about it so it never, ever happens again?

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  • George Whittam said:
    We started the show and about 15 mins in the audio started to chop up again.

     If it's happening 15 minutes in that wouldn't be due to change in audio device.
    None of your YouTube links are working for me but I believe your description.

    If it's consistently relative to file playback perhaps it's codec related. You may want to transcode the files to Apple ProRes or Apple ProResLT.


    You may want to run a simple test by using one of your source files in question and transitioning to another shot with audio from your interface and just do a local recording. No need to stream because if it's happening in an encoder the issue would be present in the recording.

    As a second test you can run the same but take audio in from a simple USB mic or even webcam audio.  These could confirm that it's specific to the files and your interface or the files as cause.

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  • CraigS I appreciate your suggestions.

    What it comes down to is the problem is either related to Windows or Wirecast, and we can't figure out which one. This issue did not exist on WC 7.7 on Mac.
    Needing to transcode to ProRes is a workaround, not a fix.

    I've changed the permissions on those videos to "unlisted" so you can view them now.


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  • George Whittam said:
    This issue did not exist on WC 7.7 on Mac.

     Please do reinstall 7.7 and confirm that the issue is only with 8.3. 

    George Whittam said:
    Needing to transcode to ProRes is a workaround, not a fix.

     H.264 files present a variety of challenges when decoding in real time depending on the source. We'd have to investigate specific files. In the meantime the use of I Frame codecs is a universally accepted practice when H.264 files present problems. You have to do the transcode to confirm that's the issue though. Please test and confirm it fixes the issue (or not).

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  • CraigS We finally found out the culprit:  NDI.  When we have NDI Output set to "Match canvas" the audio falls apart. Our canvas is 1080p. When we have NDI Output set to 720p, the problem seems to go away. Is this a known bug? 

    Reply Like 1
  • George Whittam That's an interesting discovery. Newtek is in the process of another NDI update which may address some issues.

    Do report it and include step by step for us to reproduce the issue.
    Wirecast Support Form

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  • I've spoken too soon. I went back and watched the video and within 3 seconds of our cold open (after we start the official show) the audio broke up for a few seconds, then went smooth again, but now with video ahead of picture 1.5 seconds.  It remained out of sync for the remainder of the show (but didn't appear to drift, thank goodness, so we could re-sync in post).

    At this time I don't think we can trust Wirecast 8.3 for our live webcasting needs. I am going to install 7.7 and do some more tests. If you feel issues like these have been resolved in WC 9, please get us access to the beta for testing.

    We're hanging from a thread here...


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  • CraigS  I submitted a support ticket chronicalling the experience. 

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  • George Whittam Beta is a work in progress but here's the link

    The issue, as you describe, sounds like your having dropped frames or similar issue. That could result a change of sync whose offset is maintained (unless there are further dropped frames). This certainly isn't a commonly reported problem though so there may be something about your config impacting the encoder momentarily.

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  • CraigS WC9 was used tonight on our 'cast out of desperation to get a useable audio feed. We tested it numerous times before showtime and all was working great with NDI Outputs and NDI Inputs, running at 1080p. 
    Then, showtime came and we started the show, and the audio started to fall apart. However, it didn't go out of sync, it would just get choppy and then clear up seemingly at random. We cut off NDI Output and the audio stabilized.

    Then, our NDI INPUT which we use to bring Zoom in from another machine froze (fortunately before we introduced our remote guest). From experience, the only way to restore the NDI input function is to restart Wirecast. We stopped the output, restarted, and the NDI input came right back. Of course that meant starting new FB and YT streams and embedding them again...

    We also had a problem with audio. Coming out of a break, the audio signal came in very, very low and then jumped back to full-volume when the USB Audio Codec was double clicked to see what was wrong. 

    Our take-away is two fold: NDI can't be trusted yet for live production, and WC9 may still have some bugs. 

    Reply Like 1
  • George Whittam Thanks for that report. Do post that in the Wirecast 9 Beta Forum so we can get to work on fixing it. The developers monitor those posts directly. That the audio tested find but developed problems during the stream might indicate a problem that accumulates over time, for example. Regarding NDI, Newtek is working on a new release which may be helpful in solving some of these issues.

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  • CraigS Well, it's been a heck of a journey. Thanks for all of the support you've provided us over the years to try to make our show run smoothly. We've reached the end of the road with Wirecast. We're moving on...

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  • George Whittam Sorry to hear that. Wirecast 9 release version out today just in case you want one last look.

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