Latency Compensation bug in 5.2

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poshook
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Latency Compensation bug in 5.2

Post by poshook » Tue Aug 29, 2006 10:07 am

Latency Compensation is ON.
I play any VSTi via my midi keyboard with almost no latency (ASIO - 8ms).
Then I insert some instances (try f.e. eight) of any VST on master track (it does not matter, if they are bypassed or not). From this point I notice increased latency while I playing on keyboard.

Native Live's plugins do not cause this problem.
There is also no problem, when Latency Compensation is OFF.

Waht is wrong?

thnx for advices

Nod
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Re: Latency Compensation bug in 5.2

Post by Nod » Wed Aug 30, 2006 6:48 pm

poshook wrote:Latency Compensation is ON.
I play any VSTi via my midi keyboard with almost no latency (ASIO - 8ms).
Then I insert some instances (try f.e. eight) of any VST on master track (it does not matter, if they are bypassed or not). From this point I notice increased latency while I playing on keyboard. Native Live's plugins do not cause this problem. There is also no problem, when Latency Compensation is OFF. Waht is wrong? thnx for advices
Also looking for a solution Poshook & I've posted in a coupla threads about this:

http://www.ableton.com/forum/viewtopic. ... highlight=
http://www.ableton.com/forum/viewtopic. ... highlight=
http://www.ableton.com/forum/viewtopic. ... highlight=

I can load any synth in v4 and play it with almost no percievable latency - load the same thing in v5 and immediately there is a noticable delay in response which increases as per the project load.

Feel free to point out if this is a stupid question but are ALL tracks with monitoring 'in' also subject to latency compensation? If so would it be possible to turn this off whilst actually playing in parts before resuming the function after the part was accurately recorded?

poshook
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Re: Latency Compensation bug in 5.2

Post by poshook » Thu Aug 31, 2006 5:44 am

Nod wrote:
poshook wrote:Latency Compensation is ON.
I play any VSTi via my midi keyboard with almost no latency (ASIO - 8ms).
Then I insert some instances (try f.e. eight) of any VST on master track (it does not matter, if they are bypassed or not). From this point I notice increased latency while I playing on keyboard. Native Live's plugins do not cause this problem. There is also no problem, when Latency Compensation is OFF. Waht is wrong? thnx for advices
Also looking for a solution Poshook & I've posted in a coupla threads about this:

http://www.ableton.com/forum/viewtopic. ... highlight=
http://www.ableton.com/forum/viewtopic. ... highlight=
http://www.ableton.com/forum/viewtopic. ... highlight=

I can load any synth in v4 and play it with almost no percievable latency - load the same thing in v5 and immediately there is a noticable delay in response which increases as per the project load.

Feel free to point out if this is a stupid question but are ALL tracks with monitoring 'in' also subject to latency compensation? If so would it be possible to turn this off whilst actually playing in parts before resuming the function after the part was accurately recorded?
I have only one track with one VSTi (no other midi or audio tracks in the project) and one master track with those VSTs, which can be bypassed. CPU usage is 3% and latency is there...

Synthbuilder
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Post by Synthbuilder » Thu Aug 31, 2006 7:52 am

This sounds like standard behaviour for any host. Any plug in will introduce some latency. Latency in this case should be defined as a through delay when used to process live audio.

PDC [plug in delay compensation] will only work when Live is playing back audio or midi data. It cannot work on real time audio or midi.

Latency compensation only applies to recorded audio.

Live's native plugins are actually very fast and have a small buffer hence any delay they cause is pretty small. A more complex VST plug in will usually have a bigger buffer requirement and therefore the sound is delayed more.

Its probably best to monitor your playing through no plug ins and then once recorded, add your plugs. If you need to play your synths live through a heap of plug in then your options are either choose a faster PC, smaller soundcard buffers, higher sample rate or less complex plug-ins.

Or even try a hardware FX box.

Tony

poshook
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Post by poshook » Thu Aug 31, 2006 10:49 am

Synthbuilder wrote:This sounds like standard behaviour for any host. Any plug in will introduce some latency. Latency in this case should be defined as a through delay when used to process live audio.

PDC [plug in delay compensation] will only work when Live is playing back audio or midi data. It cannot work on real time audio or midi.

Latency compensation only applies to recorded audio.

Live's native plugins are actually very fast and have a small buffer hence any delay they cause is pretty small. A more complex VST plug in will usually have a bigger buffer requirement and therefore the sound is delayed more.

Its probably best to monitor your playing through no plug ins and then once recorded, add your plugs. If you need to play your synths live through a heap of plug in then your options are either choose a faster PC, smaller soundcard buffers, higher sample rate or less complex plug-ins.

Or even try a hardware FX box.

Tony
try doing the same as me (mentioned in first post). I wilfully used VST plugins with NO internal latency:

1. Make One MIDI track with any VSTi (or Live's native instrument|
2. Select sound and play via midi keyboard (notice almost no latency)
3. Insert some instances (more is better) of VST plugin with no internal latency (see the plugin's manual about this) on this MIDI track (or Master Track, or any other track you want)
4. Turn the PDC ON (if is not)
5. Try playing on that MIDI track and feel the difference...


No other DAW with PDC make this!!!! (I was checking Cubase, FL Studio)

Do you have the impression that I have slow PC (look at my system below)

Alex
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Post by Alex » Thu Aug 31, 2006 12:56 pm

What you experience is not related to the delay compensation or to the speed of your computer.

It is related due the fact that Live's engine processes sample by sample but Plug-ins processes a bunch of samples (buffers). Most other other audio software applications (Cubase, Logic,...) also operate internally with buffers which allows them to feed the plug-ins with these buffers too. This again makes it possible for them to process all data within the time of one buffer (which mostly is equal to the audio buffer size).

In Live you can setup the plug-in buffer size between values from 32 to 8192 samples. If you do your test with these values you should get a big difference concerning the delay, depending on the numbers of inserted plug-ins.
Note: When you you change the plug-in buffer size within Live you should quit and restart Live to get the new value working.

Maybe I will come up with a more detailed explanation because it's a bit complex to explain this issue.


Regards,
/Alex

poshook
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Post by poshook » Thu Aug 31, 2006 1:47 pm

thnx for answer Alex.

But it is definitely difference if PDC is ON (bigger latency) and OFF (smaller latency).
And also when I turn PDC ON and then OFF, latency stay unchanged (stay bigger latency).
And finaly, if PDC is ON, it does not matter if those VST plugins are bypassed or running (still the same bigger latency)

Synthbuilder
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Post by Synthbuilder » Fri Sep 01, 2006 8:09 am

Hi Poshook,

Sorry mate, I misunderstood your level of experience. :oops:
poshook wrote:
try doing the same as me (mentioned in first post). I wilfully used VST plugins with NO internal latency..
Understood.

Although, Alex's reply raises some interesting questions.

Alex's answer talks about buffer sizes. But surely the speed of the PC sets the minimum size the plug in buffer can be set to without incurring clicks and drop-outs. Setting this buffer size too small will result in a higher CPU load.

I have also discovered this unusual problem with PDC, but not in this contact. Once a device is activated the PDC is always in operation even when the device is later deactivated. Only by removing it from the audio chain can you get rid of its delay compensation.

BTW Poshook your PC will do far better than mine in this test.

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