MP3 vs Wav bounce in PT 2020.11

[Neale Eckstein]

I have no idea if this is an old issue or something new in this version of PT, but I bounced a quick mix for a drummer to track to and also created a simultaneous MP3. Just to make sure the files were OK, I imported them both back into the session and was surprised the see the MP3 did not line up to the session. Here' a link to the session screen capture.

https://www.dropbox.com/s/ajyglc7yn6...20WAV.png?dl=0

[_JJ_]

In my experience (which isn't very deep) encoding to / from mp3 adds a sliver of time at the start of the file. I don't know the technical reason for that but it's why I always ask for some count-off clicks when dealing with mp3s in order to slip things back into sync later.

[albee1952]

Originally Posted by _JJ_

In my experience (which isn't very deep) encoding to / from mp3 adds a sliver of time at the start of the file. I don't know the technical reason for that but it's why I always ask for some count-off clicks when dealing with mp3s in order to slip things back into sync later.

I think you are correct. Plus, importing the mp3 into a session is going to up-sample, so that might cause some sample rounding issues.

[Wolfgang Eller]

Why does anybody care about mp3 anymore?

[_JJ_]

Originally Posted by Wolfgang Eller

Why does anybody care about mp3 anymore?

Agreed. Used to be a file size, mail attachment, upload/download problem. But now with Dropbox, WeTransfer, etc, it makes much more sense to stick with wav files - and keep it all in sync!

[frenchman]

Originally Posted by Neale Eckstein

...I imported them both back into the session and was surprised the see the MP3 did not line up to the session.....

A possible explanation :
- Wav files produced by Pro Tools have position metadata written into them, I doubt that this is the case of an mp3 file

Best regards
Mark

[daeron80]

That 40-some ms of silence at the start (and end?) is built into the mp3 spec. It has to do with the way the algorithm windows the audio. Anyone who ever wrote music for video games (which needs to loop seamlessly) back in the day knows that mp3 is the wrong tool for that job. Got to be OGG or ACC to loop.

[Rich Breen]

Yup - mp3s are completely unreliable from a timing standpoint - audio can start anywhere within the first data frame of an mp3 packet - usual deviations seem to be around 20msec. Never use an mp3 for overdubs unless you have the person recording include a snippet of the reference mp3 at start and end for sync reference - you cannot rely on file start time.

[DontLetMeDrown]

Originally Posted by Wolfgang Eller

Why does anybody care about mp3 anymore?

Because the majority of people who are not engineers/producers do not own desktop computers. Many people are streaming to their phone, so the file size of a wave file is generally not going to be convenient. Mp3s encoded at 320 offer a substantial reduction in file size over wav files and still sound good enough to identify mixing and balance issues.

[daeron80]

Originally Posted by DontLetMeDrown

Because the majority of people who are not engineers/producers do not own desktop computers. Many people are streaming to their phone, so the file size of a wave file is generally not going to be convenient. Mp3s encoded at 320 offer a substantial reduction in file size over wav files and still sound good enough to identify mixing and balance issues.

All true, but AAC and OGG sound even better at any given bit rate. Mp3's only advantage is that they were first, so everyone knows what it is and everything is compatible with it. Even now that it's no longer officially supported and thus technically obsolete. It's the VCR of audio.