Audio issue

I’ve been recording excellent audio / video recordings on Datavideo NVS 34 encoder - open/played file and excellent.
Load video into shortcut latest version and immediately convert the video recorded variable format.
Shortcut on HP 2020 15” 15.6” HD Touchscreen - 10th Gen Intel Core i5 - 1035G1, 16GB DDR4, 512GB SSD, USB Type -C, HDMI, Windows 10.
It is immediately obvious the audio track is garbled / distorted.
I edit the video with garbled audio.
I export in Youtube default settings.
The exported edited version video / audio is good.
It’s a real pain to have to edit video with garbled audio.
I did not have this problem until I loaded latest Shotcut version.
Please help,

I was unaware of the Datavideo NVS 34 enconder.

NVS-34 - Datavideo Technologies Co.

I searched to see the audio and video recording specifications as well as the format.
It would be useful to know more information about the original file before converting.
On the other hand, I don’t think this is the case but I remember that enabling the proxy function and scaling the preview in Shotcut avoids performance issues that also affect the audio in the form of distortion and choppy audio. To find out more about this do a search on this forum and you will find information about this. If this is not your case, we need more information about the original media file.

What NVS 34 specific tech recording info do you need?

Recorded yesterday / Sunday service using Data tech NVS 34 encoder onto a best SansDisc card - recommended by Data Tech -and had same experience (4th time since loading newest version of Shotcut).

Playback of Sunday’s service recorded video/audio file on laptop was clear and in sync, loaded / converted file into Shotcut and audio track became bad, edited service in Shotcut, and then exported using Shotcut YouTube preset - sound was once again clean and in sync on YouTube and posting on our Church web-page(?).

It seems that the problem only occurs when trying to play the file in Shotcut for editing, and (as far as I can understand) after editing in Shotcut and subsequent export, the resulting file is fine and there are no problems with the audio.

One of the often recurring situations is that the resources required for viewing (and listening to) the recorded material in Shotcut editing sometimes exceed the capabilities of the user’s hardware or equipment configuration.
There is a way to increase the performance of the laptop for smoother editing in Shotcut.
By activating the proxy function and the preview scaling function, we can make the editing experience smoother. This will help to avoid delays in audio playback and a smoother sequence of frames.

I include information about these functions and a video tutorial by @bentacular.

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I included my laptop hardware specs in 1st message - the HP laptop was specifically chosen a year ago according to Shotcut recommendations - and up to now, it’s been fine converting and editing video without audio issues.

Have recent - latest - Shotcut versions created the need now for better laptop specs?

If you go back to a previous version of Shotcut, does the garbled preview still happen?

There have been a number of audio library changes in Shotcut for the Windows build in recent months. Some people reported certain libraries not working with their audio drivers while other people were perfectly fine. Isolating which versions of Shotcut work and don’t work with your system could help determine if the library change is the root issue.

Also consider making sure the laptop’s audio drivers are up to date.

The audio driver would also explain why preview is distorted but export is not.

Sorry, I read the OT days ago and when I responded this time I didn’t even remember (or re-read) about the initial problem.
This time, I just read your answer and then I went to the simple and most common thing that solves many of the queries about preview problems.
My fault.

Thanks for suggestions.

After discovering the audio issue/s with the latest version I did uninstall and reinstall the newest version several times without any improvement. However, I did not / have not attempted to reinstall the previous version that I was using without audio issue/s - I don’t know which version it would be.

Before Covid I’d never seen, much less used, any editing software and there have been so many new versions to Shotcut I’ve intentionally avoided changing versions - if it ain’t broken, don’t fix it! Most changes always appeared to benefit the more experienced / creative users. But alas after several new versions were announced, I’d occasionally update my version to see if newer would be “easier” / better.
All that to say I don’t know which previous version was working.
And I’m not sure If I understand the other more technical setting changes recommended to attempt(?).

Thanks for this forum and responses

There is something you can do without uninstalling and reinstalling.
You can try a portable version that does not require installation.
Just unzip the file to a folder of your choice and open the executable.
Try it with a small audio and video file to avoid wasting time with large renderings.
Older versions can be found here.
Releases · mltframework/shotcut · GitHub

I’ll check my 1 year old HP laptop for driver updates.

I’ll attempt to find and better understand “Proxy Editing” and procedure…

I do add / insert a 26 second intro / opening audio / video clip and 10 second closing pic after the Conversion processing from playlist screen when I begin editing a typical @ 1 hour recording - typically end up with a edited 1 hour production.
I’ve checked the main / video recording file audio quality post conversion before / without addition of playlist 26 sec intro clip and
the 10 sec post pic, and the converted main file audio is corrupted during conversion process, not after any playlist additions / editing / filters are added.

When I place NVS 34 SDI medium bitrate recorded file into Shotcut, I leave the Shotcut default conversion setting in the “good” setting - not the better or best.

Post editing / pre exporting, the only change I make to Shotcut YouTube default settings is to raise the Codex 55% to 80 %

Thanks again

If you have a project file (.mlt) to hand, the version of Shotcut is shown within it. So have a look with a simple text editor and check out the second line line that looks like:

<mlt LC_NUMERIC="C" version="6.23.0" title="Shotcut version 20.11.28" producer="main_bin">

Updated HP drivers, opened Shotcut, placed good video / audio into Shotcut, converted it and then tested audio before placing and after placing video on Timeline for editing - poor distorted garbled audio still the same…

Just finished editing this past Sunday 5-2-21 church service to post on YouTube. It’s in export mode now.
I still have same audio issue after Shotcut conversion process.
FYI: prior to conversion the following appears:

“Lossy: I-frame-only H.264/AC-3 MP4”

Update and question;
I loaded our church video today into Shotcut just as I’ve done over the past few months to convert, edit and export in default YouTube format.
But unlike the past few months experiences of the original clear recording audio becoming distorted post conversion, today unexpectedly the audio was as clear as recorded!

Today there was 1 variable introduced. At the end of each video editing I add a unedited single pic clip without any audio track from my Playlist which I extend to a 10 - 15 sec clip.

This time prior to inserting into Playlist, I loaded the single unedited pic into Shotcut - no conversion process was initiated - then edited, ie stretched to 15 sec clip on Shotcut video track, exported to YouTube format after matching clip video Frames/secs (to 30) to main recorded video F/S.

I inserted the edited 15 sec clip into playlist.
After the main source video/audio recording was converted, I immediately checked the audio and it was/is good.

Any ideas as to why?

I’ve received notification that this is the last month of this conversation.

Thanks for all your efforts and responses. The problem still continues when dumping recording into Shotcut and it’s converted.

Maybe if I was more experienced I could figure the problem out. I continue to limp thru editing with the distorted audio and for the life of me I can’t understand why the audio clears up when it’s exported(?).

I’m afraid to load latest Shotcut updates for fear of new additional problems.

I remember someone with Shotcut noted early on that they were unaware that there was a Datavideo NVS 34 version - I suspect the issue is between NVS 34 settings and the updated Shotcut version I loaded months ago.

Unfortunately after a year with Shotcut and riding the waves of updated Shotcut versions during that time, I guess I need to change / purchase a new editing software product that’s more stable and with tech support.


Are you able to post a sample file from that Datavideo encoder so that others could try it? Maybe we can find a way to make it work better.

In Shotcut settings, there is an option called “Realtime (frame dropping)”. Do you have that enabled?

Sharing a small excerpt from the original media file would be a start to prove that this is happening. In addition, you can add comments relating to that excerpt, such as where you notice the problems.
As with so many other consultations, it is not necessary to share sensitive personal material. Just make a short recording with your hardware encoder (a recording you feel you can share publicly) and tell us what happens when you edit in Shotcut. From that common element, we can all make some progress together.

Thanks for your response Brian.

Busy today at church recording this morning and then editing and posting - just finished -

Not sure what you’re requesting ie “sample file”?

Each Sunday I save a file copy of 1) the unedited recording, 2) Shotcut converted, and 3) the edited / exported ie finished / posted to an external drive.
Are you asking for a short “sample” / section of one of those? I can provide a sample of the 1) clear audio/video recording and then one of the “distorted” 2) Shotcut conversion.

Good evening all - only have 19 more days for comments - I place this past Sundays video recording again into Shotcut version 21.03.21.
The same audio degradation occurred after video conversion process and loaded for editing.
I did check, and found in Shotcut “Settings” the Realtime (frame dropping) - it and Progressive both had a check in front of them (I assume meaning they are “ON”?).
I also found in Settings” “Scrub Audio” checked(?). I’ve never been into “Settings” and so did not check any of these(?). I assume they are default settings with version 21.03.21.
I have no idea what “Scrub Audio” is or does, but I do know the following;

I loaded, converted and placed the same Sunday video recording in my desk PC for editing and the audio is as clear as a bell - no audio distortion or degradation!
My desk PC has an older Shotcut version 20.11.28, and in the Shotcut “Settings” “Realtime” and Progressive default settings are both checked, but “Scrub Audio” IS NOT?

Have I stumbled onto the problem with the newer Shotcut version or possibly the newer version’s default setting of “Scrub Audio” check YES???

Yes. If you could share a sample of the unedited file, other people could try to recreate your problem.

I think this is unlikely a problem. “Scrub Audio” is a setting to tell Shotcut if it should play audio while you drag the playhead on the timeline.

I extended the time on this topic