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Troubles with NVENC & Mic recording

Posted: Sun May 07, 2017 6:51 pm
by Longjohn
Everytime i do fast motions while recording, the actual .mp4 file looks like this

Current settings are NVENC H264 (VBR) 300 keyint
Full Size 60fps 80q

I did import it in a video editor and those frames went away, but it seems they are cut out since the video lags instead of the weird frames.

Bandicam always says that it can't capture the audio whenever i have 2 audio tracks. Disable the mic inside the settings works if i restart the application but is that intended?


Edit: On further inspection, it's the VBR that makes the video look like that.
Specifically in Nier: Automata and staring at the water ripples, the bitrate shoots up to 182mb/s even on 80quality. Tried CBR with 50.000kbps as roof and the video plays fine all through, but it got a bit pixelated since the roof was lower than VBR.

Not sure how VBR and CBR is calculated since there's no options for it really, but i understand that Shadowplay for example uses high bitrates to tackle the encoding speed. Less time spent encoding frames = more bitrate needed, which is kind of what VBR is doing but on crack.

I'm going on my memory here, but the VBV buffer or what its called for main 4.2 profile is about 47.000kbps or so? That could explain why the .mp4 file is screwed upon playback.

Edit 2: Running Bandicam as admin removes the Audio capture error.

Re: Troubles with NVENC & Mic recording

Posted: Mon May 08, 2017 8:27 am
by Dfactor
I've had a similar issue on my older card.
viewtopic.php?f=10&t=3443 (disregard the imgur album link, it's been deleted)
In my case a couple of frames would go corrupt for no reason. It never got resolved.

On the other hand it doesn't seem to happen on my Pascal card anymore.
Here's a sample

Re: Troubles with NVENC & Mic recording

Posted: Mon May 08, 2017 10:17 am
by Longjohn
I did purchase a GTX1070 a week ago. Did a clean install for it with DDU but it happened on my GTX970 as well so not sure. I'm not sure it's corrupted frames i'm having since i can play it somewhat normal in MPC-HC but it has some amazing decoding in it, which eats up my CPU while decoding it.

The reason i wrote about VBV buffer is i think that's the actual problem for the weird playbacks and buggy renders from premiere pro.

Bandicam's encoding has Main@L4.2 as format profile for x264 which means it's not unrestricted. I think the absolute VBV maximum bitrate you can have with 4.2 is 62500kbps for it to actually run normally in video players and function as a container. The VBV buffer is how much it can buffer on top of that maximum bitrate (correct me if i'm wrong). According to my external x264 encoder, maximum VBV buffer is 78125kbps (wrote wrong in the first post) that should mean that, if at any point in time in the video, the bitrate goes higher than 140625kbps the container can't handle it and discards frames (in video editors) and make artifacts in playbacks since it's cutting data away from the stream.

It's hard to explain but see it as a bottle with a hole in the bottom as the VBV maximum bitrate and the cone you fill water in that goes down the bottle the VBV buffer. If you pour too much water (bitrate) in the cone the bottle hole can't empty itself fast enough for the water in the cone to not spill over.

I'm not too versed in how it actually works outside of my own experience with x264 encoding, but something that might fix it would be to change Main@L4.2 to High@L4.2, color prim could be bt.601 (SD) instead of bt.709 (HD) since 709 needs more encoding time to be more efficient than 601 and as we are working with Ultrafast presets we need higher bitrate for the video to look good, so 601 will look as good as 709 in this case. The real culprit i think is the Quantizer compression of some sort. If it's too tight it will shoot extremely high on the bitrate scale to cope with what's needed while a smoother one will go up more slowly and won't be that aggressive.

Re: Troubles with NVENC & Mic recording

Posted: Mon May 08, 2017 4:51 pm
by Bandicam Company
Hello Longjohn,

Regarding the issue with Adobe Premiere, please refer to the following page and select the "Prefer CFR" option.

Bandicam - Best settings for Adobe Premiere, video editing

Regarding the "Failed to start audio capture" error message, Windows allows programs to use only one audio device at one time.
If the microphone device is used by another program, you will see the "Failed to start audio capture" error message.
Please see the second solution on the linked page. ... o-capture/

We will answer the rest of your questions later.
Thank you.

Re: Troubles with NVENC & Mic recording

Posted: Wed May 17, 2017 3:50 am
by Longjohn
Is that really true about the audio capture? I have Discord and Teamspeak running at all times while recording my mic fine with Dxtory or Audition.

Re: Troubles with NVENC & Mic recording

Posted: Wed May 17, 2017 10:36 pm
by Bandicam Company
Hello Longjohn,

We've done some tests on Windows 10 and found that it became possible to use a microphone device with multiple applications.

What is your microphone model?
Are you able to record with the Screen Recording Mode?

We look forward to your reply.
Thank you.

Re: Troubles with NVENC & Mic recording

Posted: Sat May 27, 2017 2:13 am
by Longjohn
Sorry for the late reply.

I'm using a Snowball microphone.

I did some tests regarding the audio capture and it seems it's only Shadowplay / Share from Nvidia that makes this error occur.

I enabled Shadowplay while also running Discord in the background alongside Audition and Audacity recording my microphone. This did not work.

I then disabled Shadowplay and ran all those programs and Bandicam worked fine after restarting it.

My guess is that since Shadowplay has the "Instant Replay" it reserves the microphone in some way? I never use the microphone with it since it doesn't split the audio tracks (bandicam <3).

I did install the new update you guys made and it seems to be working with Shadowplay enabled at the moment, but i'm not sure since it wasn't everytime i got the Audio Capture error in the later builds. I can monitor it a bit i guess and see if it comes up again.

Re: Troubles with NVENC & Mic recording

Posted: Mon May 29, 2017 3:54 pm
by Bandicam Company
Hello Longjohn,

Thank you for your additional report.
We will keep an eye on this issue.

Thank you.