SOUND ON SOUND

[Dr Huge Longjohns]

Exported four bar audio loop from Logic Pro X, sent to friend as MP4. He opened it in Reaper at the same bpm and sample rate etc and it wouldn't sync properly, the audio seemed to have an extra bit at the beginning. Tried mp3, same thing.

He imported it into Garageband on his Mac. Worked perfectly. Imported into Wavelab, same problem as with Reaper.

Sent him a WAV instead, worked perfectly in Reaper with none of the strange 'corruption' of the file we had with the MP4 of the same file.

Anyone have any idea what's going on here? Cheers

[desmond]

You can't guarantee a length with compressed files like mp3. Use uncompressed WAV's/etc if length accuracy is important.

[Dr Huge Longjohns]

Had no idea this was a thing. But why should the compressed ones work fine in GarageBand if their length was compromised?

[desmond]

Logic writes in proprietary metadata, project tempo, transients and other stuff to the audio files, so likely GB was reading that and it let it place the audio in the project correctly.

[The Bunk]

Not sure if this is the same sort of issue but I was doing an "on-line" collaborative effort with someone a few years ago, and they would send me their parts for me to slot into Reaper; I can't remember now what format was used though. Anyway, I kept on noticing that his parts were heavily out of sync after maybe 5-10 secs. It really baffled me until I went into the item's properties window in Reaper and noticed that the playback rate was something like 1.008546. Naturally I put it back to 1.0000 and all was fine. But why would that happen in the first place?

[Dr Huge Longjohns]

Logic writes in proprietary metadata, project tempo, transients and other stuff to the audio files, so likely GB was reading that and it let it place the audio in the project correctly.

Ahh, really interesting, thanks Desmond. Nice to know that it wasn't just me being a total incompetent (for a change), just ignorant!

[CS70]

Good to know. I've had sometimes odd synch issues with importing tracks that my drummer had exported in Logic or Garageband (not sure) and this could be the reason.

Is there a way to export from Logic that doesn't write anything else than the audio data? Especially starting from zero one would expect no alignment issues..

[desmond]

It’s nothing to do with Logic, it’s about using compressed formats like mp3, due to the encoding process.

Regular audio files like wavs and aiffs etc are fine...

[CS70]

Alright, thx!