Multitrack export from selected clip adds 160ms of blank audio at the end of the file

[franksantermans]

Check this out. (not funny)

I have a audio file of 10 seconds in the multitrack. The file is selected. The result after "File > Multitrack Midown > Selected Clips" is a file that is 10 seconds and 160ms! The extra audio is just silence. Why is this? I would expect the files to have the same lenght?

On the other hand when you first select the audio around the selected clip, the mixdown "File > Multitrack Midown > Time Selection" will be exactly 10s, as expected.

Files that are created via a Selected Clips export commando should have the same lenght as the selected clips.

Kind regards,

Frank

[SteveG_AudioMasters_]

I just tested your scenario here, and I don't get the same result at all - the mixdown file of the selected clip is exactly 10 seconds. But the file below doesn't look identical to the one above, so clearly you've done something else to it as well - what is that?

[franksantermans]

Hi Steve,

Tnx for simulating this issue.

The workflow is used by journalists for editing news quotes while in the background there are indeed some track effects processing the audio. 

With no processing inserted on a audio track there is no issue. That is the result you got I presume. 

If you insert an untouched parametric EQ for example, the "selected clips"-export has the same length, no problem there. 

Then, if you change any gain parameter in that EQ ( for example, boost the high band by 1dB) the resulting export audio file is extended by about 160ms. So once any real time DSP is added the file is prolonged by a constant amount of silence. The only time the extention changes is by inserting a reverb where the whole length of the reverb tale is included. 

I can work around this issue by selecting the time around the selected clips and exporting the "multitrack mixdown > time selection" instead of the "selected clips". Selecting the time around the selected clips however is an extra manual commando that is slowing down the workflow. 

This might be a feature where some extra time is included at the end of the file when track effects are used. I call it a bug. I prefer not to use clip effects or Essential Sound because that also is an extra manual action to add. 

I am using EQ, Compression, some De-noising and Limiting as track effects. This should not alter the file lenght while exporting the selected clips.

Kind regards,

frank

[SteveG_AudioMasters_]

Well, you have confirmed what I suspected - which is that it isn't Audition itself, but a consequence of using effects that in theory shouldn't add any time. I tried this with Parametric EQ, and can confirm that exactly 185ms gets added to the resultant mixdown of a 10 second clip of tone, with a parameter changed.

Is it a bug? Probably, but I don't know yet what the developers would have to say about it. Personally I agree with you - it is. I'll log it with reference to this thread and we'll see...

*Update: bug report submitted.

[franksantermans]

tnx for submitting.

Would it be possible to follow the bug reporting Tool?

[SteveG_AudioMasters_]

No, I'm afraid not. Even I don't have access to that!

[kevinc42687134]

I found the solution for me.

Kevin here with Prog Radio.  I had this same problem and it was driving me nuts.  In radio, you want very clean and tight edits.  I finally figured out what what causing the mystry space to be added to a track when saved.  It was the Reverb effect I had on the track.  When doing the mix down, there is the decay from the reverb that adds the "silence" at the end.  (It's not really silence, it's the decay from the reverb effect.). This can happen with any effect you have that carries over past the end of the track (reverb, echo, delay, etc.).

There are a few ways to fix this:

1. Remove or adjust any effect that could spill over when the track ends (Reverb, Delay, etc.).  The problem with this option, is you may still want the effect on the rest of the track.

2. Mix down the track, reload the exported audio file back into Audacity, cut the ending off that was added, and mixdown again, only this time without the reverb.  Since the reverb was added on the first mixdown, this keeps the reverb effect on the entire track other than the bit you snipped off at the end.  This option works, but is an extra few steps, so a bit of a hassle, especially if going lots of tracks.

3. Use automation on the effect.  This is the one I use.  In the multitrack editor, show the envilope for the effect, and simply drop it off a second or two before the track ends.  (See screenshot.). This will put the effect on the entire track, other than the last second or so, so you don't get the mystry silence spilling over past the end of the track.  

Hope that helps.