Negative Midi Latency since Update 10.2.1

here are the release notes for 10.2.1.

 

https://support.apple.com/en-us/HT203718

 

I can see various references to some specific plugin meters being brought up to sync with the delay compensation. I do not see anywhere that is says in a general sense that all of video is being sent to the display in sync with PDC. I don't think you would want "all of video" to be sent to the display delayed with PDC either, that would result in some gross mouse click and key press delays while things are playing. No bueno.

 

It is reasonable that they are realizing that certain UI aspects have been incorrectly out of sync with the PDC delayed audio. This might include meters for example. Perhaps they fixed all of those...one can hope. The release notes only refers to some specific plugins.

 

However, the playhead is a completely different animal. Its not only a matter of whether it displays itself visually at the place on the timeline where you would expect it to be based on what you're hearing....but also that the clock would also match where the play head is..not only visually, but internally as well, so that if you are playing your midi keyboard, as you listen to PDC-delayed click and sound...the midi events you play on the keyboard go immediately to the correct place on the track based on the current playhead, both internally and visually, which should match the PDC-delayed point in time of the sound coming out.

 

It is very reasonable to assume that if there was some problem in the past where the playhead was running slightly ahead of the PDC-delayed sound..that they would have put some midi input correction into LPX a long time ago to make sure that the midi events end up where you would expect them to be. If they fixed this playhead positioning thing, but left that old code in place..then that is a very strong possibility for why suddenly now midi events are being recorded early for a lot of people.

 

Kind of just a theory, but....

I can see various references to some specific plugin meters being brought up to sync with the delay compensation. I do not see anywhere that is says in a general sense that all of video is being sent to the display in sync with PDC. I don't think you would want "all of video" to be sent to the display delayed with PDC either, that would result in some gross mouse click and key press delays while things are playing. No bueno.

 

They have not announced All video but The mixer meters and the Playhead and are compensated.

3rd party plug-ins are not at this point.

All of the video concerning the playback of data is delayed. So that if you have 1 second of latency induced by plug-ins and press play, you'll see the playhead flash for 1 second before it starts moving, so that when it passes over an event, you hear that event. Prior to 10.2.1, you would see the playhead pass over the event and hear the sound 1 second later.

the playback head flashing for 1 second before moving is not all of video. Just sayin'. David what you just described definitely sounds like in the past they just sort of allowed PDC to make all the audio late, but didn't synchronize the playhead with it, and now they are...which is definitely progress! But...there could definitely be some old legacy code lingering around about how incoming midi and audio is handled the old way which is now causing this problem.

 

I want to get a latency compensation plugin now and do some tests with really big induced PDC time...

 

Eric and David, where did you get information bout the playhead being compensated? I'm not disagreeing, I just want to read the announcements to understand it better. I'd also like to understand the implications for 3rd party plugins.

 

Which gets me back to my theory about why the people on this thread are having problems with midi events being recorded to the track early. Clearly there is something funny going on there and I'm suspicious they changed the playhead but didn't change the way incoming midi is stored to the track to match that change.

 

I know from my own perspective, I would rather know that when I hear a click, I am playing to that click. I don't care if there is a lot of PDC happening unless I'm trying to play into a software instrument, but either way, I want the midi event to end up on the timeline exactly where I played it relative to that audible PDC-corrected click, which should also be matching all the other PDC-corrected audio tracks that may have been playing back at that time as well.

 

But the other side of the coin is all the various modes of monitoring what you are singing or playing on midi, particularly if you need to play a software instrument or software monitor a vocal for example. If there is a lot of PDC, then it will be hard to record those because you will hear the software monitoring so late compared to what you're playing...so there are all these different options to temporarily reduce PDC or remove software monitoring altogether and monitor the source outside the box. That's all fine and good and useful, but at the end of the day, LPX should know what you are actually hearing...and it knows when it receives midi and audio data, and after you sing or play, the resulting midi or audio should end up on the time exactly in the right place to match what you were hearing when you recorded it.

 

That obviously isn't happening now, at least with midi. I can't speak for audio...but.... I'm suspicious to be honest. And my suspicion is that when they updated the playhead syncronization with PDC, they needed to go change the way some input stuff has been handled to ensure it ends up at the right place on the timeline after record. Previously it had to operate on the presumption that the playhead was always a bit ahead of what everyone was hearing. Now the playhead is synchronized, as it probably always should have been, so those corrective input adjustments should be removed.

It was announced here on this site:

 

Logic Pro X 10.2.1 is Out!!

that isn't really an official announcement I guess...just some more guys stating what they think is on there, unless I'm missing something?

 

Anyway, hopefully Apple will catch this bug and fix it soon. To me it seems pretty clear that when they updated whatever they updated to get the playhead in sync with PDC, they messed up the way live and possibly external midi is handled.

 

And since they have numerous combinations of latency oriented options that can be combined in various ways..there are numerous combinations that can lead to different results too, which only confuses the issue for everyone. It is downright difficult to know for sure if you are operating with everything in sync, both midi and audio. I am new to LPX...switching over from DP for a lot of reasons...but I do have to say..this aspect is disturbing.

that isn't really an official announcement I guess...just some more guys stating what they think is on there, unless I'm missing something?

You're missing something. It's not "just some guy stating what he thinks is there". It's someone in the know, stating what is there.

well since I'm not in the know, how would I know that some random poster on the internet is in the know? hehe. Great thanks for that! Edited March 5, 2016 by Dewdman42

All of the video concerning the playback of data is delayed. So that if you have 1 second of latency induced by plug-ins and press play, you'll see the playhead flash for 1 second before it starts moving, so that when it passes over an event, you hear that event. Prior to 10.2.1, you would see the playhead pass over the event and hear the sound 1 second later.

 

So I ran a quick test...I used Voxengo Latency Delay plugin (free) to create 60,000 samples of PDC delay on an instrument track.

 

 

what happens is that when I hit play..the playhead jumps BACK in time and starts rolling forward and when it hits the place where it was when I was stopped, the audio starts playing in sync with it.

Interesting. I tried with Logic's Adaptive Limiter and the playhead stays put but flashes while the playhead counter starts counting from back in time, then when the counter catches up to the playhead position, the playhead starts moving.

Yea its odd that mine is behaving differently then yours for sure!

 

That being said, I just tried to replicate this by creating a 1 second PDC delay and recording some live midi using another mac program as a keyboard controller, I don't have access to real midi gear at the moment...but...no...my theory is bunk..the incoming midi events were not recorded 1 second early as I would have expected from the above theory. So scratch that...

I just turned off audio pre roll in project prefs to see if that would replicate what you see with the flashing playhead. The playhead doesn't jump back and preroll anymore but it also doesn't stay in one place and flash like you reported, it just starts playing immediately but some audio from the period before PDC is not heard. Guess I will leave pre-roll on, the other way doesn't make sense...but the flashing playhead would be even better in some ways...not sure how to get that though.

You guys are trying different things.

David is nesting the Adaptive Limiter on an aux or output with causes the Video displacements in Logic Pro prior to 10.2.1.

 

Inserting latency inducing plug.ins on audio and instrument track is not the problem.

I guess the guys earlier on this thread are already working with apple engineers to figure this out, so hopefully that will come soon. It sorta seemed at first like it might just be related to old project file data being mis interpreted in some way, but then someone finally said they are having the problem with brand new projects too..so I dunno, they'll figure it out.

 

Regarding the flashing playhead...great point Eric..

 

very good point about AUX vs INST track.. my understanding of PDC is that in general, INST tracks are supposed to feed regions to the audio engine ahead of time so that they play on time. Audio Pre-roll enables them to do that fully...and in my case the playhead moves back as far as it needs to in order to feed a region to the audio engine ahead of time.

 

while AUX tracks handle PDC differently. They can't feed regions to the audio engine early because they don't have regions so AUX tracks with plugins cause all other tracks to be delayed by a certain amount to keep everyone in sync.

 

I just did a test with the voxengo plugin on AUX track and sure enough it flashes for a bit before starting to play. And if you combine both things... INST track with PDC and AUX track with delay, you actually get both... The playhead jumps back in order to preroll the INST track regios...but flashes there for the AUX track PDC time period.

 

makes perfect sense.

 

thanks Eric!

You're welcome!