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TOPIC: Audio and video moving out of sync

Audio and video moving out of sync 5 days, 19 hours ago #204833

  • Haxnicks
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  • 5 days, 19 hours ago
Hi, the audio and video (recorded separately) are going out of sync - any ideas how i stop this happening please? I get it all synced and then when i come back into Lightworks its all out again.

I set the project up as a mixed frame rate as the footage was taken on two cameras with different frame rates and wondering if that causes a problem?

The data of the audio and video files is attached. (please keep answers as jargon free as poss as I am not a professional video editor!)
Sorry about the format - I did try and produce it from MediInfo but had no luck as didn't know which option to choose.

Newly attached files

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Last Edit: 5 days, 19 hours ago by Haxnicks.

Re: Audio and video moving out of sync 5 days, 19 hours ago #204834

  • hugly
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Hello again,

I don't understand what your file shows, so I skip this.

Mixing frame rates in one video is never a good idea, separately recorded audio or not, since frame rate conversion creates more or less visible artifacts, but I don't think that it's the cause of your sync problems.

See if this information helps: www.lwks.com/index.php?option=com_kunena&func=view&catid=6&id=204690&Itemid=81#204710
It's better to travel well than to arrive...

Re: Audio and video moving out of sync 5 days, 19 hours ago #204836

  • Haxnicks
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Hi - I have already found and tried that post and it hasn't helped. Hence trying to attach the file data. I only hope someone else can make sense of it.

Thanks for replying anyway.

Makes me wonder why there is an option to allow mixed frame rates - I guess it must be possible for it to work.

Re: Audio and video moving out of sync 5 days, 19 hours ago #204837

  • hugly
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Mediainfo would be helpful. Here you'll find an explanation how to create and post:

www.lwks.com/index.php?option=com_kunena&func=view&catid=23&id=66072&Itemid=81#66072

The 'Text' format from the 'View' menu' of Mediainfo is the key to easy reading after cut and paste.
It's better to travel well than to arrive...

Re: Audio and video moving out of sync 5 days, 19 hours ago #204838

  • hugly
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Haxnicks wrote:
Makes me wonder why there is an option to allow mixed frame rates - I guess it must be possible for it to work.

Sometimes editor have to deal with mixed frame rates, and it's convenient for those who don't care, but that doesn't mean that mixing frame rates is a good approach.
It's better to travel well than to arrive...

Re: Audio and video moving out of sync 5 days, 19 hours ago #204839

  • briandrys
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Are you shooting with two cameras at different rates, but being synced to the same external audio that was recorded at the same time?

Re: Audio and video moving out of sync 5 days, 19 hours ago #204841

  • Haxnicks
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Brilliant - @hugly you are my saviour today! Files now attached properly

Re: Audio and video moving out of sync 5 days, 19 hours ago #204842

  • Haxnicks
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No @briandrys - the second camera is shooting close ups with no view of the speakers mouth so that video doesn't need to sync with the track as the track becomes a voice -over at that point.

Re: Audio and video moving out of sync 5 days, 18 hours ago #204844

  • hugly
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From technical data, setting pre-ingest sync for audio only media to Picture @29.97 should fix the problem with drifting sound.

I'd suggest giving it a second try, unless you run a version different from V14.5.

If you run V14.0, you are in trouble.
It's better to travel well than to arrive...

Re: Audio and video moving out of sync 4 days, 15 hours ago #204899

  • Haxnicks
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  • 4 days, 15 hours ago
Hi I am just giving this another go - following the instructions on the other page. I am starting from scratch again with a new project. My clips are at 29.97 FPS but when I go into Lightroom to set up the new project it gives me the choice of 25 FPS or 30 FPS but not 29.97. So I chose 30, it being the closest but when I come to the pre-ingest-sync it gives me the choice of 29.97 or 30. Which do I choose please? The 29.97 my clips are or the 30FPs I chose for the project?

Oh and PS I am on 14.5 so at least I am not "in trouble" lol

Re: Audio and video moving out of sync 4 days, 14 hours ago #204901

  • hugly
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Lightworks, not Lightroom, please.

The project frame rates in Lightworks represent "project families". This is a set of frame rates, combined with related frame rate conversions, and import and export options.

The 30 fps project is best suitable for straight 30 fps and 29.97 fps. 30 fps is played in real time, 29.97 fps is slowed down by the factor of 1000/1001. The frame rate settings for preview and export do not have impact on audio sync, only the pre-ingest sync settings (and some issue which can happen when recording).

To match the video you show above, set 'Pre-ingest sync' to 'Picture @ 29.97 fps' prior to import of the separately recorded sound, and see what happens.
It's better to travel well than to arrive...
Last Edit: 4 days, 14 hours ago by hugly.
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