How do I export tracks in sync?

[kozikowski]

they will all line up correctly.

To each other, but not to your partner's song which started at the "real" zero and not zero plus the silent insert.

So managing that insert is important. You need a really small one, or you need to share the chosen duration value before you shoot files back and forth.

~~ Or ~~

6. The partner shears off all the silent inserts before they import your tracks. Is that a trim option?

6a. They put the same offset value into their tracks before they import your work.

Koz

[steve]

To each other, but not to your partner's song which started at the "real" zero and not zero plus the silent insert.

The common use case is that the Audacity project IS the song and the purpose of the exercise was to open the "project" in a third party DAW.
Also, standard practice in multi-track recording is to leave a couple of bars of "lead-in" (breathing space) at the start of the project.

Regardless of that. trimming off a couple of seconds from all tracks is trivial, but lining up 30 tracks with no common start time is not.
If working with others, I'd highly recommend inserting a whole number of seconds of silence (2 seconds is common), or if the music has strict tempo (electronic music), then an exact number of bars (2 bars is common).

In most cases there will be at least one track that started at time=0, so in practice it is usually pretty easy to work out how much "offset" (silent padding) has been added, even if the sender forgot to tell you.

6b) You add the amount of silence to match the offset that the recipient is using in their project.

The crucial thing is that all of the tracks that you send have a common start time.

[kozikowski]

This started out three documents. I refuse to condense the processes—I hate it when I have to juggle conditions inside instructions.

Koz





TITLE:
Track Sync Export


PURPOSE:
Export stand-alone sound files from a multi-track project in sync with each other.

If you use any of the time shift tools or processes, exported individual sound files can play out of sync with each other. This process guarantees all the tracks and exports from this show will match.

CAUTION:
Save your show as a uniquely-named Project safety backup before you take any action. Some portions of your show may be lost and Audacity Projects do not save UNDO. Once you close Audacity, you can't back up.


PROCESS — WINDOWS/LINUX:
==================================
Ctrl + A (select all)

Shift + Home (move start of the selection to "time=0")

Ctrl + T (trims off any sound outside of the selection — specifically, removes any audio that is before time=0)

Home (move cursor to start of project)

Generate > Silence (generates a predictable amount of silence at the beginning of all tracks)

Export stand-alone sound files as needed.


PROCESS — MAC DESKTOP:
==================================
Command + A (select all)

Shift + Home (move start of the selection to "time=0")

Command + T (trims off any sound outside of the selection — specifically, removes any audio that is before time=0)

Home (move cursor to start of project)

Generate > Silence (generates a predictable amount of silence at the beginning all tracks)

Export stand-alone sound files as needed.


PROCESS — MAC LAPTOP:
==================================
Command + A (select all)

Shift + fn + Left Arrow (move start of the selection to "time=0")

Command + T (trims off any sound outside of the selection — specifically, removes any audio that is before time=0)

fn + Left Arrow (move cursor to start of project)

Generate > Silence (generates a predictable amount of silence at the beginning all tracks)

Export stand-alone sound files as needed.



NOTES AND COMMENTS:
This suite of actions works from the regular I-Beam cursor not the Time Shift Tool (two sideways black arrows). If the last thing you did to the show was move tracks about, it's easy to have the wrong cursor.

The silence you insert at the beginning of each track changes the beginning of the show. If you share your files and tracks with others, they all should know that silent duration value.

You don't have to intentionally use Time Shift in your show to have a sync problem. If you use Musical Overdubbing, for example, some of your music tracks may export out of rhythm/sync with each other even though the project plays perfectly inside Audacity.

Production in WAV is recommended. MP3 files do not guarantee sound sync, even if you do everything right.



.

[steve]

Works for me

For completeness, the steps on Linux are identical to the steps on Windows.

[kozikowski]

That can be done.

What happens if you have a left-of-zero sound track with the Export-Selected Silent-Track method? you get too much sound, don't you? You always have to trim off the "early" sound.

Let me guess. Nobody thinks this is a problem.

Let me advance a radical idea. Export exports the timeline, no magic portions even though magic portions remain available for production. If you can play it, it exports.

Further, Export exports everything if you select all tracks or no tracks. If you select a track, Export automatically Exports Selected.

Hands? Everybody who's ever exported the whole show by accident? [forest of hands]

Koz

[NeilCake]

This is how I do it. The Mac version of the keyboard shortcuts are usually the same but with "Command" replacing "Ctrl".

1. Ctrl+A (select all)
2. Shift + Home (move start of the selection to "time=0")
3. Ctrl+T (trims off any sound outside of the selection - specifically, removes any audio that is before time=0)
4. Home {possibly "Fn+Left Cursor" on Mac} (move cursor to start of project
5. Generate menu -> Generate a small amount of silence

All tracks now start at exactly time=0, so when you Export Multiple, and import into another multi-track application, they will all line up correctly.

[@koz: this would be a good post to bookmark. Perhaps you could translate this into Mac shortcuts?]

This is really useful. Thanks very much - I just registered purely to tell you this. A question though; couldn't the latency correction function be adjusted such that it automatically deletes any portion of the track that is moved to the left of time zero? Or couldn't the export function be customised to only export data that occurs after time zero?

[steve]

This is really useful.

It's also obsolete.

With Audacity 2.4.2, all tracks should be automatically in sync by default.