Midi not recording properly ... timing is off upon playback

[meech]

I've had this problem for a long time and I really want to get it fixed. When I record a midi passage it sounds great and in time, but when I play it back, it doesn't sound locked, it's noticeably out of time. This is with delay compensation off, with the Ivory plugin (with ADC on it reads as 10 samples of latency).


I did some testing at 96khz, 512 buffer size, ADC off. I record enabled the instrument track, bussed the track to an audio track, and recorded the audio as I recorded the midi (just some staccato notes with Ivory so I can see the waveforms clearly). Once I hit a couple notes, I stopped it, created a new playlist on the audio track, and bounced the instrument to audio again. Then I compared the two waveforms.
The first is definitely what I hear when recording midi, and the second is approx. 800 samples earlier, way out of time. Ivory is playing the same samples each take so I can measure exactly how much the midi is being shifted. BUT, not every note is off by the same amount. One note may be 12 ticks off, but another is 14, and another is 17. Because of this I can't simply shift my take a certain amount and have it be right! What on earth is going on? Why can't Pro Tools record what I play and play it right back for me?!

Does anyone have any solutions for this? Again, I did this all with delay compensation off. My specs are

Mac Pro 2.8 ghz 8 core intel xeon
6 gb ram
Mac OS 10.5.6
PT HD 2 accel 8.0cs2

I did a similar test in Logic Pro 8 and I had the same results (with delay comp off). I can't use logic very well so I haven't done exact measurements but the same thing happens! I also tested Logic on a iMac and the same thing happened.

Does anyone have any suggestions? Digidesign?

Thanks for the help

[EvilElfBoy]

Sounds like its a problem with the PI itself. Have you tried this same test with another VI and see if it locks?

Since you did the test on another platform, it's really pointing to the PI.

[meech]

I did the test also with Digidesign's Mini Grand and had the same results. What does PI stand for? Thank you for the help

[Audiofarm]

http://pi.ytmnd.com/

[meech]

bump... Can anyone give me any suggestions or does anyone know what PI stands for?

Thanks again :)

[Stig Eliassen]

Can anyone give me any suggestions or does anyone know what PI stands for?

Plug-In

[meech]

I've since tested this with multiple virtual instruments, and with all plugins moved to the unused folder except for stereo mixer.dpm and the mini-grand. It's definitely not a plugin issue.

[meech]

I've been in contact with Digi tech support and they don't have a solution yet but they suspect it has something to do with my computer buffering the midi or audio or something. They asked me to do tests with very high and low buffer sizes, they didn't change my results at all (except at really high buffer sizes there's too much latency to play). Does anyone have any insights into this? Thank you again

[suicune]

All I can say is you're not alone. I performed the test you described and got exactly the same results. The only way I could get it even remotely close without adjusting buffer sizes was to manually route the analog instrument output back to the audio track input (with a couple of old fashioned patch leads), with ADC switched on. This method produced latencies of around 300 samples at a 512 buffer size, which is at least tolerable compared to the 3000 I got by bussing it with ADC on.

I think the problem with bussing is that you are using an RTAS plugin then routing it to the TDM mixer, which has always induced massive problems with latency.

The real issue here is that ADC can't cope with recording in this situation, as turning ADC on causes MIDI to record out of time, and turning it off makes the audio playback out of time. Check out some other threads here:

http://duc.digidesign.com/showthread.php?t=245274
http://duc.digidesign.com/showthread.php?t=244162

And those are just the ones I've posted in. Do a search on ADC and MIDI and you'll find more.

[meech]

Yeah that is exactly what is happening to me to ... I'm not using Logic for midi but when I record something Pro Tools will push my midi back 800 to 1200 samples from where I played it at a 512 buffer size. And this is with ADC off! It's really horrible to work with, especially considering not every midi note gets shifted the same amount.

Digi you need to fix this~!