Sampling Rounding Bug and Workarounds - Pro Tools 2020.3

[Evermore]

The issue/bug: When copying/pasting and/or moving clips in the timeline can cause audio and midi clips to shift away from the grid line and become unaligned.
This causes phase issues between audio and a big mess with midi clips and notes.

(Sampling Rounding Issue)
https://www.dropbox.com/s/la3z2e05ep...20bug.mov?dl=0

Things to know:

• Bug has been around since 2015 for Midi with the introduction of Pro Tools 12 but many years longer for audio according to some forum users.
• It is Sample Rate depended and only affects certain Tempos.
• There are Tempos where this bug does not exist.
• Causes Audio and Midi clips to not align to the grid.
• It affects both Audio and MIDI clips randomly adding or cutting length by 1 sample either at the start or end of a clip.
• The grabber Tool activates this bug when used to option+drag copy/paste or when moving a clip on the timeline to the Grid.
• Users who use Grid Type are the ones greatly affected.


Finding the Tempos that work for you:

First thing I recommend anyone to do is to determine which Tempos are not affected for the Sample Rate you use.
This will be a bit of a time consumer but totally worth it in the end.

1. Create a new clean project and select your Sample Rate.
2. Change both the Grid and Nudge Value to 1 Bar
3. Add 1 Audio clip to the Timeline and align it to a Bar.
4. Change the Tempo to the lowest bpm you know you will use in any project. e.g. I hardly go under 60bpm so I would start there.
5. Zoom in all the way to the start of the clip.
6. Now you can begin testing.

Note: We can refer to the Tempos that work as (Confirmed Tempos) and (Unconfirmed Tempos) for the ones affected.
You will only want to write down the working (Confirmed Tempos) for your records.
Also, open the Undo History window and keep it right under your clip, this way you can undo by jumping back to the beginning quickly.

Use the + key command to start nudging your audio clip.
A minimum of 15 key presses is good but I recommend 20 to be safe. Some Tempos will let you know immediately with just a few nudges.
If the Tempo you have selected is affected by the bug, you will see the start of the clip becomes detached from the grid. Basically it will not remain aligned to the bar.
At this point you can say this Tempo is unconfirmed and is affected by the bug and should be ignored.
Undo all of that to get back to where your audio clip becomes aligned again.
Next step is to change the Tempo by 1 increment in the Tempo box. e.g. 60,61,62,63,64,65 etc…
You will eventually find a Confirmed Tempo because you will notice that is stays aligned to the bar regardless of how much nudging you do.
Write it down in your notes as a Confirmed Tempo then continue your journey…

These were the Tempos that I confirmed in my testings @96k Sample Rate:

60, 64, 72, 75, 80, 90, 96, 100, 120, 125, 128, 144, 150, 160, 180, 200bpm

I can work with these worry-free and never have to think about this nasty bug affecting any clips in my projects.

Tip: I placed these in the Get Info… and saved it with my main template for quick access.(File->Get Info…).

(A Confirmed Tempo)
https://www.dropbox.com/s/msm0dhzv78...Tempo.mov?dl=0

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Suggestions and workarounds for Unconfirmed Tempos

Things to know:

• Using the Grabber Tool(option+drag) to move or paste an individual or multiple audio/midi clips on the timeline, will activated the bug for those clips.
• Nudging +&- key commands should not be used at all.
• Editing clips with the Trimmer Tool also activates the bug.
• Certain key commands(see below) work fine in Unconfirmed Tempos until you edit audio or midi clips/notes using the Grabber Tool.

These commands work before using the Grabber Tools:

• Duplicating (option+D)
• Repeating (option+R)
• Shift… (option+H)
• copying then pasting with the timeline insertion using C and V key commands.

In order to make the above commands become unaffected, one must quantize the clips.
Quantizing somehow temporarily removes the bug from the above commands for both Audio and Midi clips.


Tips:

Quantize the clips before or after you have moved or pasted using the Grabber Tool(option+drag) and Trim Tool.
Use Shift…(option+H) instead of nudge.
Use A & S key commands to trim a clip instead of the Trimmer Tool.
Alternatively, you can also change the Tempo to a Confirmed Tempo if moving clips around. You can change it back to the original tempo and your audio and Midi clips will remain on the grid.

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MIDI

All of the above suggestions and workarounds are true for Midi clips and should be followed. There is however a dangerous underlying bug/issue.

Note: There is a different bug that shifts all or some notes by 1 sample either earlier or later to the grid when copy/pasting, moving or barely touching the clip with the Grabber Tool. It also adds 1 sample in length to the end of the clip.
The dangerous part about this bug is that it affects all Tempos, even the Confirmed Tempos. Combine this bug with the regular Sampling Rounding issue and you have catastrophic mess you will never recover from.

(1 Sample Shift Bug)
https://www.dropbox.com/s/4cpskz4zyw...20Bug.mov?dl=0

Fortunately I have discovered a few ways on how to avoid it.

Things to know:

• Making any kind of editing to midi notes activates this bug, even drawing in midi notes into a midi clip.
• Quantizing(option+0) your midi notes will activate this bug.
• Quantizing Midi clips with Real-Time Properties avoids this bug and the rounding issue completely.
• Copying, pasting, duplicating or any command used on Midi clips will be affected.
• You have to be zoomed in all the way to notice the shifted notes.

In order to avoid it before copying, pasting, moving or duplicating in any Tempo, you must do the following:

Timebase Trick

1. Switch your Instrument track from Ticks to Samples.
2. Use the Grabber Tool and click+hold the Midi clip.
3. Make the slightest movement from side to side and release it in its original place.
4. Switch back to Ticks on the Instrument track.
5. You can then make any copying or pasting etc… commands without being affected.

(Timebase Trick Workaround)
https://www.dropbox.com/s/ahamxylckf...20Fix.mov?dl=0

Remember that once you edit/adjust or move midi notes around in any form for that clip, the bug will re-activate.

Editing properties that activate this bug:

• Quantize
• Duration
• Velocity
• Transposing
• Split Notes

Note: It is best to keep away from having to edit midi notes as much as possible. You will save a lot of time and trouble If you can record a great midi performance that does not require editing mdi notes.

Tips:

Use Real-Time Properties to keep midi notes quantized and work worry-free in any Tempo.
The Timebase Trick is the only way to avoid the 1 sample shift in midi notes.

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Final words:

Having worked with so many DAWs throughout the years, I can honestly say that my workflow has never been as hindered by such bug. Losing focus or workflow momentum can be a major bummer due to having to stop and worry whether or not normal editing functions are working correctly. My intentions are not to bash Avid here but instead, hope that this thread can help and bring light to this unpleasant bug/s.

I would really appreciate any confirmations by as many users as possible, even If you are unaffected by this because you don’t use Midi, solely mix songs or work with Time based projects.

I would want to make it as easy as possible for Avid to see and gather information for a speedy solution.

A confirmation would be very helpful.

Example:

+1 bug confirmed

Pro Tools 2019.x, 2020.x
Mac/WindowOS
System Info

Thanks in Advance!
Ever

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Update: Automation

Going further deep into the abyss of this bug, I have noticed that it also affects Automaiton when copying/pasting and duplicating sections. Below are 2 vids demonstrating what happens when duplicating a section, one showing how automation points are being added unnoticeably unless you zoom in. The second one shows what can happen after moving a clip with "Automation follows Edit" is on and used with a Unconfirmed Tempo. It is very random with automation making it that more dangerous.

(Automation being affected)
https://www.dropbox.com/s/igt4jpojzb...ected.mov?dl=0

(Moving Clips around)
https://www.dropbox.com/s/shtknj5c0l...Clips.mov?dl=0

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Update 6/12/2020: Midi Zoom toggle Workaround

Would like to share yet another workaround which has turned out to be the best one yet. This one will avoid both the midi clips and midi notes from shifting. Requires a few extra steps but can become a quick workflow. You will have to use "waveforms/notes" in the Track view option in order to make this work. Here are the steps on how to do this one.

1. Highlight/select the midi clip you want to duplicate and hit the E (Zoom Toggle) to zoom toggle.
2. Re-highlight just the area within the midi clip then duplicate.
3. Now separate the midi to the original length using B (separate at selection).
4. You should have every single Midi clip/notes in their original length and positions.

Here is a vid demonstrating how this works.
https://www.dropbox.com/s/gvx670chpd...round.mp4?dl=0

This should ease you from this problematic issue pretty well until Avid is able to fix this.

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Other Threads worth checking out regarding the same topic:

http://duc.avid.com/showthread.php?t...ghlight=sample

[innesireinar]

Great work. I hope this will help Avid for fixing this.
I would like to specify that since PT 12 this bug showed up on midi clips as well. But on audio it also happened before. I will do some tests on 2020.3 soon

[foxes]

Evermore, absolutely fantastic detailed post about this longstanding incredibly frustrating bug that is ONLY prevalent in Pro Tools. How is the so called "industry standard" DAW the only one that cannot fix or totally ignore this bug?

Crazy!!!

[Evermore]

Thanks guys!

I have updated a few things and will continue to update the thread as needed. If you know of any other threads besides the one Foxes created, please pm me the links from here or other sites so that I can add them to the thread.

[innesireinar]

I have noticed that sometimes some sessions get some weird pref that doesn't allow PT to rename audio clips that have fades directly in the playlist by double clicking. However it is still possible to rename them by scrolling local menu (by pressing right button) or in the clip list. At the same time in those sessions the layered editing doesn't work. I am checking if this could be related to the rounding error. I'm rebuilding the sessions that have this bug by create new ones and by importing sessions data from original sessions.

[kuldeepnc]

I just change the track to tick based when duplicating audio. Bam problem-kinda-solved.

[innesireinar]

Originally Posted by kuldeepnc

I just change the track to tick based when duplicating audio. Bam problem-kinda-solved.

Maybe you are talking about a different problem. The sample rounding error happens on tracks in tick bsse as well. However we are focusing on midi clips that sometimes lose notes at clip start when copied or moved by dragging.

[kuldeepnc]

Originally Posted by innesireinar

Maybe you are talking about a different problem. The sample rounding error happens on tracks in tick bsse as well. However we are focusing on midi clips that sometimes lose notes at clip start when copied or moved by dragging.

Ah yes I see. Tick based solves the issue 100% of the time for me with audio tracks (It leaves tiny gaps in the timeline but they are negligible). But I don't use MIDI notes in PT so i have no experience with that. I use Ableton for that! Just disregard my post.

[Evermore]

Originally Posted by innesireinar

I have noticed that sometimes some sessions get some weird pref that doesn't allow PT to rename audio clips that have fades directly in the playlist by double clicking. However it is still possible to rename them by scrolling local menu (by pressing right button) or in the clip list. At the same time in those sessions the layered editing doesn't work. I am checking if this could be related to the rounding error. I'm rebuilding the sessions that have this bug by create new ones and by importing sessions data from original sessions.

Interesting. I'm curious to see how many things this bug actually affects inside Pro Tools.

[take77]

Thank you for taking the time to provide detailed insights into the matter.
Really appreciate it.

Right now all I'm trying to do is change a few section tempos and cut/insert a few sections.

This shouldn't have took long.
Instead, I've spent my entire session coming upon MIDI clips that have been altered in the process and readjusting 75% of my arrangement on every track.
Quantizing as a whole just quantizes some patterns out of time (in accord with the outta time notes) so I have to do everything manually. Have had to go through this countless times during this project.
Sometimes just half of a section has been altered. So I have to scroll through every single clip of my arrangement on every track.

This may not affect everyone because some of my patterns have a variance of tempo on some of the accents. (e.g.,120bpm for the overall pattern then 119 for the accents & back to 120).
But that shouldn't be a problem with MIDI in tick mode.
I even imported everything into a new 48kHz session to see if it would help.

I guess I could install PT11 on my laptop and get the best of both worlds that way. Yeah, gonna have to.

Thanks again for the informative post.