How to create a consitent output buffer/delay?

[RAR]

I'm looking to use reaper for live mixing of bands for the purpose of livestreaming, and would like to implement a consistent processing delay no matter the track count or fx used so that the video will always line up. Is there a particular setting I should look at to make that happen? E.g. No matter if 2 tracks or 32, and 4 or 10 instances of Ozone modules etc, can I have a constant 3000mS buffer?

[mschnell]

Welcome to the Forums and to Reaper used for Live playing.

If thinking about latency, you need to very clearly define latency between which events you are considering.

For live playing it often is very critical to reduce latency as much as possible. This needs decent hardware and some tweaking of the OS.Regarding "consistent latency" this in many cases is worse than "as low as possible".

For this you might want to switch off PDC for the plugins.

You might want to skim the sticky thread here for more information.

-Michael

[RAR]

Thanks for your reply! I'm hoping instead of minimizing latency, to standardize it for all of our sessions, which may have two tracks or thirty-two (depending on the band). So that the processing needed eats into the "buffer-time" but is consistently X-ms for every session. I may be thinking about it wrong, and there may be a simple solution... but consistent processing delay each session would be immensly helpful so that we don't have to calculate the compensation for the video each time. 1 second or 5... doesn't matter as long as it is always exactly the same no matter the track or fx count.

[mschnell]

You still did not state the latency between exactly which and what should be "consistent", and why it is not.

-Michael

[RAR]

Maybe the assumptions I have about DAW's and processing are incorrect and an impediment to the conversation, so with your patience I'll start again.

We are taking between 1 and 32 xlr lines per session and performing real-time processing using reaper. We send the stereo master mix of those tracks onward to a video/stream computer.

Signal flow looks like this: 1-32 XLR lines > X32 Rack > Sum/Master to 2ch. on PC with Reaper via USB > X32 Rack > 2 XLR lines to Video Computer.

I guess the first question should have been: Does increasing/decreasing the number of tracks and FX increase/decrease the time it takes for everything to be processed and sent back to the X32 Rack?

[mschnell]

In Computer audio, the performance required (e. g. # of inputs) never should affect the latency. The latency is defined by the user by appropriate parameters. (Hence it is "consistent" by design)

If the CPU performance is not enough to cope with the latency you set, you will get crackles, stuttering audio etc, but not (automatically) enlarged latency.

-Michael

[RAR]

I have a better way to frame the question now.

I'm building live mixes for livestreams; the mix gets sent over dante to our video streaming pc. We would like to set the audio output latency to an arbitrary amount such that adding or removing plugins will not affect the alignment of the audio to our live video that we are syncing to.

For example, on the master bus I've three plugins totaling 7168 samples. If I take one away or add another, it will change. I'm hoping to set the delay to always be something like 100,000, so that adding plugins just eats into that global delay and the audio will always remain synced to the video.

The # of plugins will change during the session and between sessions, so it is important to always have the same amount of delay at all times, no matter the plugin count. Assume there is plenty of processing and memory headroom.

Does this make sense? Is this possible to do?

[mschnell]

I don't know if there is a more straight way, but you can use use a plugin with definable PDC (such as ReaPack +/- delay with negative delay) in a track that is mixed to the Master with zero volume. Same should defined the minimum global PDC.
-Michael