'Automatic latency compensation' TRULY sucks!

Parametex · Post by **Parametex** » Wed Sep 10, 2008 6:32 pm

The problem in a nutshell is that Live is able to compensate latency introduced by the built in plugins but is only part time able to determine if a third party plugin is introducing latency that should be compensated. Also changing the rendering sample frequency will fuck everything up, more on this a bit more below.

This leaves the user guessing if latency is actually reported by the 3rd party plugin and compensated by Live. And this fucking paranoid guessing is for me THE ABSOLUTE worst 'feature' in Live.

When making music with Live I use a lots and lots of plugins. As much as a quad core workstation can coupe. That means hundreds of instances. And always at some point when the project has grown quite complex (routing, bussing, summing back and forth) these highly annoying latency issues are starting to manifest themselves.

As an example Ozone 3 multi purpose plugins latency depends on what of the features are being used at every given time. So when making music you are constantly paranoid if you clicked something or inserted a 'rogue' plugin which is starting to insert latency of few milliseconds. Couple of Milliseconds you say ... ok, but when you are working with huge projects then these milliseconds add up and suddenly the groove of the song is lost somewhere and it's pretty impossible to find a single plugin offender that could be removed to cure everything.

So ABLETON cure it:
1) Report the plugin to the user which is not reporting it's latency to Live so users don't need to guess. (Check Nuendo etc)
2) If a plugin is changing it's latency by itself then there needs to be some Live follows

Also I think all these latency problemos might have something to do with extensive bussing (Routing to bus to send to bus again etc). BUT the point is that it shouldn't!

AND theres more!

When I compose a song and think that it is ready and get ready to bounce the whole shit, I have sometimes changed the sample rate to double what it has been so the render quality would be better (lets not argue here is it or true or not!) then Live fucks up all the latency compensations and all the timing of the song is absolutely out of place. That is so unbelievably annoying!!!!!

AND EVEN MORE !!!!!

When you are dealing with these god awful issues that really bleed you dry of any artistic inspiration you get the final kick below the waste : Because of the Vst delay compensation BS the fucking automation curves are not in sync with you musics graphical data anymore!!! So the user has to go thru all the hundreds of automation curves manually and nudge them forward while listening with ear when it is where it's supposed to be.

ABLETON FIX YOUR SHIT !!! PLEASE !!!

Grappadura · Post by **Grappadura** » Wed Sep 10, 2008 6:46 pm

some good points.

abletoff · Post by **abletoff** » Thu Sep 11, 2008 12:19 am

There should be, in the browser area, a window with all the plugs currently in the project sorted by track, with an on-off button and whatever else. Clicking on them could open the track or the automation lanes or both.
I have problems with latency compensation and liquidmix hardware. On some projects it just goes all crazy.

ethios4 · Post by **ethios4** » Thu Sep 11, 2008 12:23 am

+1
I have an electroboner just thinking about these issues being resolved!

NorthernMonkey · Post by **NorthernMonkey** » Thu Sep 11, 2008 12:34 am

I understand your issues, but purely out of interest, if a third-party plugin doesn't report its latency, and you are aware of that, how would you go about adding in the compensation manually? Would you just have a stab at it until it sounded ok?

timothyallan · Post by **timothyallan** » Thu Sep 11, 2008 12:45 am

My copy crashes every time I change the buffer settings when I have many plugins. I reported it with my crash logs etc but Ableton said there was nothing they could do.

If you really want PDC grief, try having lots of plugins and try to do some parallel compression using Sends, or have complex routing between audio tracks! Kaboom!

ethios4 · Post by **ethios4** » Thu Sep 11, 2008 1:03 am

timothyallan wrote:If you really want PDC grief, try having lots of plugins and try to do some parallel compression using Sends, or have complex routing between audio tracks! Kaboom!

Exactly!

Khazul · Post by **Khazul** » Thu Sep 11, 2008 12:32 pm

I havnt been getting any *unexpected* problems with latency compensation with the plugins I use - that is ableton plugins, Access virus control, various plgins from camel space, fabfilter, and UAudio (DSP card).

The said, I do regularly run into latency compensation problem of my own making associated with sends, deliberate feedback loops, and non feedback loops that still cause calculation cycle deferrals which is wher the typical latency comp problem come from.

The problem is with potential feedback loops. In an analog system the feedback signal is near instant - speed of electrons in a cable etc.

in a digital system however there is a finite time offset between a signal entering a processing chain and a feedback loop of that signal re-enterign at the same point - in dedicate standalone hardware this can be as little as the time it takes to process a single sample. In ableton live it is the time it take to process an entire audio buffer - which by default is the output latency of the audio card unless you have set you plugin buffers to be different.

In general if there are no feedback loops, then Live appears to work with single buffers in calculation cycles. If all the plugins in the chain and on sends etc can all calculate their buffer immediately, then all is good.

If you introduce a calculation feedback loop (doesnt actually have to be real audio feedback, just the possibility of it), for example Audio 1 -> master + send A, Return A -> Audio Track 2 on input monitor mode -> Master, both Track 1 and Track still have Send A + B enabled (as thats the default), then this causes a calculation cycle deferral. That is the audio buffer calculated on the Track 2 -> Send A will be held for the next calculation cycle (as far as I can tell fro observation).

The way to fix this is to ensure that all non-essential send are disabled in cases where you route the output of a send back to a normal track. You may find that was you go through disabling non-required sends you find one that dratically changes the relative timing of part of the mixed audio when you disable it - this was the feedback defferral you just switched out along with a whole heap of attempted latency compensation to go with it.

I think part of the problem is that the whole process of PDC isnt quite as simple as Ive outlined above and in fact Live does try to be a little mroe clever with some potential feedback loops. Either way, I have often seen time when switching off an unessary send has made a drastic difference to overall latency.

Now when you latter change the sample rate, you are also reduce the time it take to process each audio buffer (for eg 44.1->96K means just under half the time per buffer) and that will cause a significant timing shift if you have potential feedback loops.

Note - there is pretty much bugger all ableton can do about feedback loops without consuming alot of CPU due to calculating many audio path several times in a single buffer cycle.

I have also found that atttempting to decouple the plugin delay times from the audio out latency (by changing the plugin buffer size in prefernces to a much smaller value) seems to cause a whol heap of other odd problems with some plugins, so I seem to get best performance by leave it at its default.

So what you can do to live with it:

1. As mentioned above - disable all sends and only re-enable those that you actually need at some point in your project. Dont enable aned disbale them at different times - that only causes timing trouble.

2. Take a note of the example audio card latency setting you used when making a track - do not change it during the making of that track as it will impact timing in feedback loops and perhaps poorly behaved plugins.

3. If you really need perfection with zero offsets around feedback loops, multi-path signal etc - bounce all the revelent parts of the multi-path signal and manually re-align them - its a pain but its the only fix in any DAW when feedback loops are present.

Ableton Live at least lets you do this kind of abuse - for that alone it stands out as my favourite DAW.

Live does have some problems with latency compensation, most notably that when you have a long processing chain on your master (for eg external bug compressor, DSP card plugin etc) the the song poition marker can be a long way ahead of what you are hearing which makes it really hard to ties heard problems with a specific music-time point.

abletoff · Post by **abletoff** » Thu Sep 11, 2008 1:12 pm

Khazul wrote:everything

that was enlightening

I mostly work with sends as a busses for drums, keys, guitars, vox, with liquidmix instances all over the place, on a dual daw setup (identical pcs, different audio boards (rme ff800/m-audio 1814). Your explanation makes sense of the troubles I'm encountering. Thanks

Parametex · Post by **Parametex** » Thu Sep 11, 2008 6:31 pm

Hey thank for the proper anwser Khazul!

Actually in my search of remedy for the latency issues I have already deleted all the sends from my template project...

And I actually have noticed that playing with feedback loops can bring the machine on it's knees suprisingly fast.

But alas I don't really use track 2 aux 2 track 2 aux kind of routings.

My problem is plain and simple. Lots and lots of plugins with Live. And using less plugins is not the anwser I tell you that much ,)

What really eats me is the fact that when I'm really trying to concentrate to the actual composing suddenly I wake up from my musical bliss and notice that things (latencies) are not as they should be and I have no idea what routing or plugin is the one that snapped the audio camel back...

Cheers

leedsquietman · Post by **leedsquietman** » Fri Sep 12, 2008 2:21 am

I personally have not encountered issues using 3rd party plugins and Live. I think it depends widely upon which plugins you use. Liquid Mix usually imparts 2,048 samples of latency according to the review in Electronic Musician. A lot of the issue is 3rd party plugins not disclosing their true latency and where this occurs, it doesn't matter which DAW you have, you will have to manually compensate.

Anyway, if you think Live is bad, try PTLE/M-Powered where you have to manually enter every single effing latency value, and trust that the vendor wasn't lying about their latency value. Although as I own Cubase, I do like the plugin screen which gives you all the details, even if this is an arbitrary figure supplied by the vendor.

Tone Deft · Post by **Tone Deft** » Fri Sep 12, 2008 2:29 am

abletoff wrote:
Khazul wrote:everything

that was enlightening

no doubt, stickied it for future reference.

http://www.ableton.com/forum/viewtopic. ... 075#751075

Parametex · Post by **Parametex** » Fri Sep 12, 2008 9:53 am

Yeah I'd wish there was some possibility to make Live recalculate plugin instances latency when the user would so demand. Heres just an idea ... If there would be a small icon next to the preset circle icon in the plugins conrner and when clicking it ableton would immediately measure/calculate and store that plugins latency settings.

Even that would help shitloads!

Cheers

Khazul · Post by **Khazul** » Fri Sep 12, 2008 11:23 am

Parametex wrote:Yeah I'd wish there was some possibility to make Live recalculate plugin instances latency when the user would so demand. Heres just an idea ... If there would be a small icon next to the preset circle icon in the plugins conrner and when clicking it ableton would immediately measure/calculate and store that plugins latency settings.

Even that would help shitloads!

Cheers

That shouldnt be needed. Plugins do report their standard latency compensation requirement (I beleive they can update it dynamically if the DAW supports that, otherwise of course they shouldnt) - if they dont get it correct then its a bug in the plugin - at least for VST plugins, and I assume its the same for ableton native plugins which do appear to be able to update their latency dynamically

This is how cubase manages to list default plugin latency information in its plugins list. There is no mearuring of latency on the part of the DAW.

What is additional and different between DAWs however is how auudi data is buffer between between plugins and whether thhe DAW ends up having to add additional compensation for such buffers. I get the impression that with cubase it stick quite rigidly to calculation cycles where it calculates a standard buffer size worth fo datta for all plugins.

With ableton live, I am not entirely sure it allways does that hence my comment in the above post about Live possibly doing something a bit more clever than the simple version I gave). Certainly under some cicumstances I have seen evidence of specific plugins cause a far greater delay than I would have expected or can observe with cubase.

Indeed there are very difinately circumstance where Live gets its timing very badly wrong (for eg with external midi clocks, external instrument and fx plugins, looping portions of a track etc, possiblyy be trying to be too clever and as a result not getting it right).

Sadly for us hardware dinosaurs Ableton dont seem hugely interested in investigating/resolving them, but then Steinberg seem to have lost interest in supporting hardware synth and fx users too as similar bugs there also get treated as very low priority.

leedsquietman · Post by **leedsquietman** » Fri Sep 12, 2008 11:43 am

not every plugin manufacturer declares the correct latency because if it is high, some don't declare it at all, they just enter '0'. they are afraid people won't use it. Ditto audio and MIDI interfaces, they often sneak extra buffers in which they don't declare.

I'm not having any problems as yet with Live's auto latency. i have a whole bunch of 3rd party softsynths from Korg, NI and Arturia and UHE. I have various fx plugins. I have Cubase too and don't notice any extra adjustment needed for Live with what I've got so far.