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Channels

Split-stereo tracks, and why Pro Tools shows mono.

Two of the most common surprises in a timeline hand-off have the same root: stereo is not stored the same way twice. Two switches deal with both.

Short answer: A stereo pair delivered as two mono tracks is put back together by Combine split stereo tracks — with a review window so you confirm the pairs before anything is written. The opposite case, stereo that has to reach Pro Tools as one mono file per channel, is Separate combined channels.

Why the same stereo track has two shapes

Inside a timeline format, a stereo track can be stored in more than one way. It can be one file with two interleaved channels. It can be two mono files, one per channel, referenced by a track that still counts as stereo. Or it can genuinely be two separate mono tracks that a person intended as a pair — DaVinci Resolve, for instance, often delivers a stereo pair as Name_A01 and Name_A02.

Applications differ in which of those shapes they recombine on import. Pro Tools builds a stereo track from per-channel mono files that belong to one track; handed two unrelated mono tracks it leaves them mono. That is why a conversion can be technically correct and still look wrong when it opens.

The two switches, and when to use them

  1. Combine split stereo tracks — putting a pair back together

    Switch it on when the source hands you a pair as two mono tracks. The converter looks for the usual naming patterns, proposes the pairs it finds, and opens a review window before converting: the track list in file order, pairs grouped with L/R chips, single tracks marked M or ST. You confirm what it found, drop a pair it got wrong, or pair two tracks by hand. Nothing is written until you agree.

  2. Separate combined channels — one mono file per channel

    Switch it on when the AAF is going to Pro Tools. Every channel is written as its own mono file while the tracks stay stereo — the shape Pro Tools recombines. It does not turn stereo tracks into mono track pairs; the track layout is unchanged. The option applies to AAF only, because the other three formats have no equivalent.

  3. Leave both off when nothing is odd

    Both are off by default, and that is right for most files: if the source stereo is one interleaved file and the target reads it, there is nothing to fix. Use the report and, when in doubt, the demo — it converts unlimited files, just shorter.

How this shows up per format

Whatever the conversion does with channels ends up in the per-file report, including every pair that was combined and every track left alone.

FAQ

Resolve gave me _A01 and _A02 tracks. Is that broken?

No, that is simply how Resolve writes a split stereo pair. Switch on Combine split stereo tracks and confirm the pairing in the review window.

Will combining tracks change my mix?

No. The two mono tracks become the left and right channel of one stereo track; levels, fades and automation stay on the same material.

Why is the review window there at all?

Because naming conventions lie. Two tracks called Dial_A01 and Dial_A02 are usually a pair — but not always, and a wrong guess is worse than a question. You see what the converter thinks before it writes anything.

Does Separate combined channels split my stereo tracks into two mono tracks?

No. The track layout stays exactly as it is. Only the media is written per channel, which is the form Pro Tools recombines into stereo.

Try it on your own timeline first.

The demo is the complete app with unlimited conversions — each output covers the first 120 seconds with the full track layout. If your file converts the way you need, buy a license.

Download the free demo Buy — $79