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TOPIC: Audio export weirdness

Audio export weirdness 3 months, 1 week ago #191312

  • pulck
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Currently I am working on a little project where the rushes audio is extremely quiet. If I put as much audio gain as is available on Lightworks, it is still too quiet and yet beginning to distort. So I decided to finish the edit first and then export the audio to Audacity for cleaning up and to compress it before reimporting back into Lightworks.

However, when I do this the audio comes back in at a different length (shorter).

I'm imagining this is some sort of sample rate issue but I can't work out how to resolve it.

I'm using Lightworks free so my own export option into Audacity is via MP4.

I'm exporting from Audacity as WAV 48Khz.

Any thoughts?

Re: Audio export weirdness 3 months, 1 week ago #191314

  • hugly
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Hello,

I don't think that this is an issue related to sample rate. It could be an issue with speed compensation drop-frame vs non-drop-frame on import and/or on export. There are settings to adjust. What is the frame rate of your material, 29.97?

Please don't judge by duration, because DAWs tend to fill in some samples at the end of the file when exporting, how many depends on the DAW. Judge by sync to the original audio. Line up the processed audio with the sound of the sequence it's from, left aligned. Does the processed audio drift and if it does, in which direction (slower or faster than the original) and how much?
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Last Edit: 3 months, 1 week ago by hugly.

Re: Audio export weirdness 3 months, 1 week ago #191347

  • pulck
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Thanks. I now realise that I started a mixed frame project (not realising at the time that I would need to export/re-import audio) and the concerned footage is 30fps.

I solved it in the end by slowing the audio by a few percent in Audacity (trial and error method) but in future I'll make a note to myself to frame convert all footage to the the same standards before importing into Lightworks and then I'll stick to a non-mixed frame project.

Re: Audio export weirdness 3 months, 1 week ago #191352

  • hugly
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Even in mixed rates projects it shouldn't be a problem to export, process and re-import sound-only without trial and error to compensate for speed differences in the DAW. It should be possible to compensate for applied speed compensation by setting pre-ingest sync for audio-only media correctly. I haven't tested that intensively, but I will.

I assume that you've exported a video file for processing with Audacity. Please, can you tell, which frame rate exactly (including the decimals) did you select on export, what is the frame rate of your footage and what shows Pre-ingest-sync from context menu of Local Files?

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Re: Audio export weirdness 3 months, 1 week ago #191397

  • pulck
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hugly wrote:
I assume that you've exported a video file for processing with Audacity. Please, can you tell, which frame rate exactly (including the decimals) did you select on export, what is the frame rate of your footage and what shows Pre-ingest-sync from context menu of Local Files?


Thanks. I exported 30fps, the imported footage is 30fps, and Pre-ingest sync is set to "Picture @ 24fps".

Re: Audio export weirdness 3 months, 1 week ago #191403

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Currently I am working on a little project where the rushes audio is extremely quiet. If I put as much audio gain as is available on Lightworks, it is still too quiet and yet beginning to distort.
Doubling up the quiet tracks is often used to fix low level recording.

The following is a bit extreme but tells the story - the audio is 1000Hz_sine wave generated at -30dBFS playing without any gain or level lift in LW.
In normal use with a bit of level increase by LW it would be unusual to need more than one doubled track.

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Re: Audio export weirdness 3 months, 1 week ago #191408

  • hugly
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pulck wrote:
I exported 30fps, the imported footage is 30fps, and Pre-ingest sync is set to "Picture @ 24fps".

I'll try to reproduce the timing/speed issue you've encountered, later this day.
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Last Edit: 3 months, 1 week ago by hugly.

Re: Audio export weirdness 3 months, 1 week ago #191416

  • RWAV
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If bouncing via audacity seemed to create a problem then, as per my previous post, it is a redundant step.

The low levels can easily be dealt with in LW alone. As I understand it there was no sync problem with the original media in LW.

Solution dump the move to Audacity Make modest level/gain changes in LW and double tracks to increase levels.
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Re: Audio export weirdness 3 months ago #191423

  • hugly
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There might be other people who intend to process sound with external DAWs and re-import with the Pro and the Free version. In particular because compressor/limiter is missing and audio FX is quite limited, currently.

The available options of Pro and Free are different, but export and re-import of video/sound is assumed to keep the timing/speed with appropriate settings. If it doesn't, that's a bug of current release. *

*Edit: Or better, it would be a bug, because I still don't believe it.
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Last Edit: 3 months ago by hugly.

Re: Audio export weirdness 3 months ago #191443

  • RWAV
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The OP's major issue seemed to be about low levels on location recordings. It is common for recordists to retain very substantial headroom as protection against unexpected peaks and so hand in 'low level' tracks. LW is able to overcome that in the manner I described. The process is simple; once it is familiar it takes a matter of seconds and only a few minutes when learning.

There is no need to resort to any other software to overcome that issue.

As this is the LW forum and is about explaining and emphasising LW features and how to use them in practical situations.

LW does have what can be described as basic sound manipulation tools and of course some users will seek to enhance those by third party software. While that is best accomplished with LW Pro through the export of LW Audio tracks to a DAW and reimport of a finished mix but of course original tracks can also be processed.

Don't know much about Audacity but I do recall previous versions of ProTools where the user had to buy a software extension to allow work with moving image synchronisation.

I also recall that over time there have been very many threads detailing sync problems with Audacity processed sound. It would be facile to suppose LW is the source of all of those difficulties.

Perhaps issues with Audacity may be best refereed to a specialist Audacity forum and by all means results should be posted here.

Perhaps also LW users might look at alternative software DAW's, for example I think some LW users favour MixBus, and not assume Alacrity, with it's demonstrated failure rate, is the only option.
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Re: Audio export weirdness 3 months ago #191455

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pulck wrote:
I exported 30fps, the imported footage is 30fps, and Pre-ingest sync is set to "Picture @ 24fps".

Unfortunately, I did not have time to test that here, yet.

Whether the issue is caused by Audacity (or whatever DAW) or by Lightworks, can be easily determined just by re-importing the exported file, without processing in the DAW, and lining it up, left aligned, on tracks added to a copy of the generating sequence.

If audio speed matches, the third party software causes the drift, if it doesn't, Lightworks. In either case, the program itself or wrong settings/operations might be the cause.

@pulck,

Do you see a chance to test that with your material?
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Re: Audio export weirdness 3 months ago #191459

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The above may be a fine theory if LW Free were able to export isolated sound files. It cannot.

What needs to be checked is if the V/A muxed LW export is in sync with itself. As I recall the OP has said sync is fine in the LW edit with the original on-set recording - just some too-low-level matters to correct.

It may also be interesting if the OP were to take the Audacity generated .wav files - load them into WaveAgent and resample them to match the frame rate of the video. (Please be aware WaveAgent overwrites existing media so perhaps work with a copy)
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Re: Audio export weirdness 3 months ago #191462

  • hugly
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pulck has pointed out that they exported video and I know that Audacity doesn't change speed, so what's the cause?
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