Reducing audio file length

[claudius06]

Hello Bernd,
Is there a way in PF to reasonably reduce the length of a file automatically using a specific command?
With a feature like those found in Adobe Audition or Logic Pro?
I have files that are supposed to be 14 minutes long but actually last 14:15, 14:30, and sometimes up to 16:00.
Thank you,
Claude.

[radio42]

I don’t know the feature of Logic or Adobe.
But in ProppFrexx you can automatically cut any silence at the beginning or end of the audio. This is called Automatic Cue Point Detection (ACPD) - using various features, even for different media types.
Else, there is no such function. ACPD is however even enabled by default.

[claudius06]

Thank you for your reply.
I'm very familiar with the ACPD - I use it all the time. It's a very effective feature when properly configured. Unfortunately, that's not what I'm looking for. What I need is time compression, but I don't think that's included in ProppFrexx, despite the countless great features of this software. Maybe it could be added in future versions - it would be very useful.

[radio42]

What is Timecompression?
Can you explain that feature? As I don’t know or understand it.

You can set the tempo of a track in ProppFrexx (either with or without pitch shifting - aka master tempo), so that it plays faster. Is that what you are looking for?
Else please describe the feature you are looking for.

[claudius06]

I'm sure you know what I mean, but maybe I didn't use the right words. Actually, I'm talking about time-stretch. For example, you have an audio file that's 62 minutes long, but you only have a 60-minute slot. With the Time-Stretch function, you open your 62-minute file and enter the value 60 minutes. The system will remove parts of the audio without distorting it, to achieve a result of exactly 60 minutes, without the listener noticing any change.

Of course, if the file is much shorter (e.g 35 seconds and you want it to be 30 seconds), then the change might be noticeable. It's widely used, often exaggerated, for legal disclaimers in radio spots. But when used properly, it's very handy for adjusting audio files to an exact duration.

[radio42]

I did not know what you ment before, as you didn’t explained it before or even mentioned the term.

And as said. This is possible in ProppFrexx already. You can set the initial Tempo of a track - ie. to play it faster and perform time-stretching. Eg. see the TAG Editors Track Data tab. The field is called Initial Tempo.

[claudius06]

OK! Good news but I tried "Initial track tempo" but when I change the % (for example 20%) the sound is not stretched, it's accelerated and therefore distorted (like a 33rmp to 45). Perhaps i haven't found the right command?

[radio42]

Sorry, it is called "Initial Pitch" in the TAG Editor:

In the PFL Player you can also right-click on the Tempo Slider and select "Set as Initial Track Tempo" - it is the same:

By default Master Tempo is not enabled, i.e. changing the Pitch/Tempo would also change the Key - this is like changing the sample rate or playing the track faster/slower.
If you like to preserve the Key while changing the Pitch/Tempo you need to enable Master Tempo and also set the DJ Players to MasterTempo mode (MT). These two settings needs to be applied for that. Note, that these changes are non-destructive to the audio track (ie. they are applied in real-tme and consume more CPU, depending on your system probably not really noticable):

[claudius06]

As you said, I have enabled Master Tempo and set the DJ players to MasterTempo, but the key is still changed. Do I have to restart PF after made these changes?

[radio42]

No. But you have to open a new playlist window…