Does change in buffer size really effect the rendered output

Discussion of music production, audio, equipment and any related topics, either with or without Ableton Live
Laura_Live
Posts: 167
Joined: Tue Nov 27, 2007 4:22 pm

Does change in buffer size really effect the rendered output

Post by Laura_Live » Sun Oct 24, 2010 8:28 pm

? ?

It seems it does..

fx23
Posts: 798
Joined: Wed Jul 08, 2009 3:23 pm

Re: Does change in buffer size really effect the rendered output

Post by fx23 » Sun Oct 24, 2010 8:29 pm

it shouldn't

Laura_Live
Posts: 167
Joined: Tue Nov 27, 2007 4:22 pm

Re: Does change in buffer size really effect the rendered output

Post by Laura_Live » Sun Oct 24, 2010 8:34 pm

fx23 wrote:it shouldn't
Well, automate panning in a mix and render it out at different buffersizes, then compare the files.. they won't match up..

Am I doing something wrong here ? ??

fx23
Posts: 798
Joined: Wed Jul 08, 2009 3:23 pm

Re: Does change in buffer size really effect the rendered output

Post by fx23 » Sun Oct 24, 2010 8:47 pm

well i think their is something really strange in your setup cause
i just rendered a 8 bar loop on wich i automated pans @ 2048, then 512, 128 and 64 samples
and they all return null results via a phase cancelation test, hopefully..

what differences do you see? is it a visible offset? maybe coming from a plugin that wouldn't readapt on
buffers changes? but since you speak about pans, i don't see what it could be at all...

Laura_Live
Posts: 167
Joined: Tue Nov 27, 2007 4:22 pm

Re: Does change in buffer size really effect the rendered output

Post by Laura_Live » Mon Oct 25, 2010 10:27 am

fx23 wrote:well i think their is something really strange in your setup cause
i just rendered a 8 bar loop on wich i automated pans @ 2048, then 512, 128 and 64 samples
and they all return null results via a phase cancelation test, hopefully..

what differences do you see? is it a visible offset? maybe coming from a plugin that wouldn't readapt on
buffers changes? but since you speak about pans, i don't see what it could be at all...
Please see attached image.

Sine tone is created in Alchemy, a panning envelope is drawn.

Output is rendered at buffersize 32 and 4096 and then put back in the arrangement.

Warping is disabled.

The files are different !!!!!!!

What is happening here ? ?? ? ????

I thought the rendering process would be independent from the choice of buffer size.

Clarification please, I am getting very anxious.

It probably means that Live is completely useless for mixing.

Image




Laura_Live
Posts: 167
Joined: Tue Nov 27, 2007 4:22 pm

Re: Does change in buffer size really effect the rendered output

Post by Laura_Live » Mon Oct 25, 2010 10:32 am

Could someone from Ableton please step in and clarify the issue.

Laura_Live
Posts: 167
Joined: Tue Nov 27, 2007 4:22 pm

Re: Does change in buffer size really effect the rendered output

Post by Laura_Live » Mon Oct 25, 2010 1:36 pm

OK, I have found a solution but this is a MAJOR BUG in Live. :cry: :cry: :cry:

The panning automation only renders correctly at all buffer sizes, meaning 'in time', as drawn to the grid, if the VSTi instrument is flattened before rendering.

Merely freezing the track containing the VSTi instrument with the automated panning envelope does not produce a consistent output at all buffer sizes

It is a repeatable bug.

Ableton, please comment

3phase
Posts: 4648
Joined: Fri Sep 26, 2003 3:29 am
Contact:

Re: Does change in buffer size really effect the rendered output

Post by 3phase » Mon Oct 25, 2010 1:41 pm

Laura_Live wrote:OK, I have found a solution but this is a MAJOR BUG in Live. :cry: :cry: :cry:

The panning automation only renders correctly at all buffer sizes, meaning 'in time', as drawn to the grid, if the VSTi instrument is flattened before rendering.

It is a repeatable bug.

Ableton, please comment
what you mean by flatened?
mac book 2,16 ghz 4(3)gb ram, Os 10.62, fireface 400,

Laura_Live
Posts: 167
Joined: Tue Nov 27, 2007 4:22 pm

Re: Does change in buffer size really effect the rendered output

Post by Laura_Live » Mon Oct 25, 2010 1:48 pm

3phase wrote:
Laura_Live wrote:OK, I have found a solution but this is a MAJOR BUG in Live. :cry: :cry: :cry:

The panning automation only renders correctly at all buffer sizes, meaning 'in time', as drawn to the grid, if the VSTi instrument is flattened before rendering.

It is a repeatable bug.

Ableton, please comment
what you mean by flatened?
right click on VSTi-track in question, click on 'freeze'

right click on frozen VSTi-track, click on 'flatten'

>> see its beautiful waveform

Ableton_David
Posts: 1766
Joined: Fri Aug 20, 2010 7:31 pm
Location: Ableton
Contact:

Re: Does change in buffer size really effect the rendered output

Post by Ableton_David » Mon Oct 25, 2010 2:41 pm

Hi, just a note that we aren't consistently involved in topics on this subforum. If you'd like to contact Ableton about an issue, then you're best bet is to get in touch with support: http://www.ableton.com/support

Laura_Live
Posts: 167
Joined: Tue Nov 27, 2007 4:22 pm

Re: Does change in buffer size really effect the rendered output

Post by Laura_Live » Mon Oct 25, 2010 2:51 pm

David Abravanel wrote:Hi, just a note that we aren't consistently involved in topics on this subforum. If you'd like to contact Ableton about an issue, then you're best bet is to get in touch with support: http://www.ableton.com/support
Thanks

Ableton_David
Posts: 1766
Joined: Fri Aug 20, 2010 7:31 pm
Location: Ableton
Contact:

Re: Does change in buffer size really effect the rendered output

Post by Ableton_David » Mon Oct 25, 2010 3:31 pm

No problem - I also responded to your question about this in Support Corner.

fx23
Posts: 798
Joined: Wed Jul 08, 2009 3:23 pm

Re: Does change in buffer size really effect the rendered output

Post by fx23 » Mon Oct 25, 2010 5:15 pm

woa, well spoted laura_live,
but you make me worry now, newer noticed that before since i generally use low buffers <512 so as david mention that's not a noticeable problem.
also my test were performed with raw audio, not generated vst, if Vsts latency compensation doesn't adapt thats indeed not cool at all when
working with big buffers. I spend time phasing stuff together, a simple 128 buffer offset would mean blow those efforts out.

did ya notice if that applies to every mixer events (volume/sends)
or only pans? if so that's indeed quite annoying..
..but im sooo surprised! was quite sure volume automations on Vsts would work with no offset at any buffer size. mmmmmm
when audio is runing live, automations are sync to VST whatever buffer size is, unless im going mad, so why it wouldn't at bounce?

Mean Vst aren't rendered BEFORE applying mixer automations by live when bouncing ?
that sound too crasy to not have been spoted before..
well think i have to performs a few checks..

kayhel
Posts: 52
Joined: Tue Oct 26, 2010 2:52 pm

Re: Does change in buffer size really effect the rendered output

Post by kayhel » Wed Oct 27, 2010 12:37 pm

Hi laura_live, hi ableton guys,

I know the reason:
Because you are using an external vst plugin as soundsource (your synth), it will create a delay. Question is how much? Well, it depends on your plugin settings. Check what you have selected in options > preferences > cpu
If it says "as audio buffer" thats the cause for the strange behaviour. So the plugin adds a delay equiv. to the audio buffer. and this plugin delay is also used during rendering (it has to). Changing buffers changes plugin delay. Try a fixed value here instead!

However this shouldn't happen, obviously, but that again is due to the fact that automation is _not_ plugin delay compensated.

See the other threads reg. this...

cheers
Kay
Bitwig 1.0, Live8 Suite Boxed, Studio One Professional, Melodyne Assistant
Komplete Ultimate, Sylenth, Ozone5

kayhel
Posts: 52
Joined: Tue Oct 26, 2010 2:52 pm

Re: Does change in buffer size really effect the rendered output

Post by kayhel » Thu Nov 28, 2013 11:31 pm

Hey folks, now its 2013 and we still have our pdc priblem. Ableton? Comments? Suggestions? Excuses? Please no more sw features and push like hw before fixing the basics. Please.
Bitwig 1.0, Live8 Suite Boxed, Studio One Professional, Melodyne Assistant
Komplete Ultimate, Sylenth, Ozone5

Post Reply