Audio de-sync problems with mismatched fps videos

My capture card for some reason records videos in miss-matched amounts around 30fps instead of an exact amount.

In Hitfilm Express, I try going to media, clicking on a source's gear, then unchecking "from file" from frame rate, while keeping the source's frame rate at 29.97. When I add the source to the editor, the end of the audio has a no sound part with that's marked with diagonal lines.

I tried using handbrake to convert it as 29.97 and it either freezes my pc eventually or handbrake closes not far into converting. It also does the same when I set it to 30, and I've been able to convert videos to 30 fps in the past, for light works.

EDIT: It's still not working, but I just tried converting the videos with Any Video Converter to convert the video to 29.97 fps. The sound in the end of the clip is fine when I play it in VLC Media Player, but in hitfilms it's still de-synced.


  • CleverTagline
    CleverTagline Posts: 3,345 Ambassador

    The "mis-matched amounts around 30fps" means the video was encoded with a variable frame rate. What you're trying to do by running it through Handbrake to force it to 29.97 is correct. That's called transcoding, and it's highly recommended even if VFR issues don't need to be fixed. However, having your computer or Handbrake fail in the middle of the process is a mystery.

    What are your system specs? OS, CPU, GPU, RAM, and free hard drive space.

    I almost asked you about your capitalization of "Any Video Converter," but a quick search tells me that it's actually the name of a piece of software (that I've not heard of). I suggest trying MPEG Streamclip. It hasn't been updated in a while, but it's still pretty useful, and used to be my go-to transcoding tool before I started messing with Handbrake fairly recently. Another option is VirtualDub. 

    Here's a thread you might want to peruse re: options for transcoding to a specially-designed AVC file (that we call Norman AVC around here) that's optimized for editing, and not just in HitFilm.


  • Dragon3025
    Dragon3025 Posts: 2
    edited January 2019

    I tried MPEG Streamclip and my PC also crashed with that. These are my PC's specs:

    • Windows 10
    • Processor: Intel(R) Core(TM) i3-4170 CPU @ 3.70GHz 3.70 GHz
    • Installed RAM: 12.0 GB (11.8 GB usable)
    • System type: 64-bit operating system, x64-based processor

    I just realized the video has a corrupted spot where the video freezes for about 5 seconds, not far into the video. I tried using the Handbrake settings in the link and it converted the video, but the video freezes from the corrupted spot to the end of the video while the audio continues.

    The video was recorded with a Capture Card that records to a USB and I looked at another video that failed to convert with handbrake earlier and also has a corrupted spot. Now I'm worried that the majority of my videos has corrupted spots in them. Is there anything I can do to fix the video, or stop my capture card from recording videos with corrupted frames in it (my capture card: HDML-Cloner Box)

  • CleverTagline
    CleverTagline Posts: 3,345 Ambassador

    Corrupt video files? Yikes. Not good. :( That's beyond my experience, so I'm gonna tag @NormanPCN to see if he's got any suggestions.

  • NormanPCN
    NormanPCN Posts: 4,385 Expert

    The only thing I can think of is when you find out where the a corrupt section is then use something like VirtualDub to transcode up to just before the corrupt point. Then transcode from a point after the corruption. The trick is how to find the points of corruption. If there are multiple corruptions this becomes tedious. Any way you look at it you have to drop the corrupt data and keep the good. Something will be lost. One frame or seconds or minutes. Whatever it is.

    If the media is a LongGOP format (like AVC), VirtualDub is able to skip from I/IDR frame to I/IDR frame. This can, maybe, help get past corrupt/problem spots in LongGOP media.

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