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Old 11-26-2016, 04:37 PM   #1
MRMJP
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Default Latency bug with Item FX blend (NOT FIXED)

I'm not sure if this is a REAPER bug or a Goodhertz plugin bug but I found a case where sometimes on play/record there is a latency issue that is noticeable when the plugin blend is set below 100% and over 0% of course, and most noticeable when set to 50%.

Check this video:
https://dl.dropboxusercontent.com/u/...GHz_PDC_V1.mov

Excuse the poor audio quality but Quicktime only captures mono audio and this is already at a loud/mastered level so the recorded video audio is distorted and bad. But, you can hear that when I change the blend to 50% that there is a some bad latency/flanging/flamming etc.

I can't reproduce on every record/playback but it happens often. I hope this isn't happening on all item FX that are set below 100% and only most noticeable on this one because it has a very high latency.

Here is my current REAPER config:
https://www.dropbox.com/s/16qxej6kiq...ConfigZip?dl=0

Here is the session sans audio so you can see what I'm doing:
https://www.dropbox.com/s/pyurc8bl8g...pture.RPP?dl=0

I'm basally sending a track with items and item FX out to two hardware stereo outs and capturing back in on a new track.

This has been working well for awhile but maybe I've never blended the Goodhertz Tone Control plugin before using the native REAPER FX blend.

I will contact Goodhertz too but wanted to post here incase it's a REAPER issue as I've seen a very similar issue occur when trying to use the plugin pins to duplicate a stereo feed to another hardware output. When FX are blended below 100% I would sometimes get this issue.
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Last edited by MRMJP; 03-18-2017 at 06:36 AM.
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Old 11-26-2016, 05:54 PM   #2
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Thanks for the post, Justin.

What does REAPER report for you for Tone Control's latency in HQ mode? It definitely seems like REAPER is not accounting for the latency with its built-in blend. One other possibility: the latency of Tone Control changes when the HQ mode is activated, so it's possible that REAPER isn't picking up on this latency change. That said, I know it works properly in other hosts.

Aside from the bug, is there any specific reason you're not using Tone Control's built-in master mix control? It should act similarly but is guaranteed to be phase coherent.
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Old 11-26-2016, 06:28 PM   #3
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Quote:
Originally Posted by goodhertz View Post
Thanks for the post, Justin.

What does REAPER report for you for Tone Control's latency in HQ mode? It definitely seems like REAPER is not accounting for the latency with its built-in blend. One other possibility: the latency of Tone Control changes when the HQ mode is activated, so it's possible that REAPER isn't picking up on this latency change. That said, I know it works properly in other hosts.

Aside from the bug, is there any specific reason you're not using Tone Control's built-in master mix control? It should act similarly but is guaranteed to be phase coherent.
Thanks Devin. I'm getting 4096 samples of reported latency @ 96k from Tone Control in HQ mode. You're right that I should have been using the built-in mix control of the plugin but honestly, I forget it had that option as I'm so used to used the native REAPER FX blend which is one of the great features of REAPER in my opinion.

Anyway, I mostly want to get to the bottom of why this happens incase it also affects other plugins in a way that is harder to detect. Maybe being at or near the end of the item FX chain, this was the plugin that pushed REAPER over the edge of item FX latency support.

What's weird is that it only seems to happen on SOME playbacks but not all the time. I didn't notice this when I was working and stopping and starting the transport in the middle of items.

BUT, when I went to play the entire session through from start to end in one pass and print it to the new track, this is when problems occurred.

I wonder if there is an issue initializing PDC on items when playing the entire session through as opposed to a hard start and stop within an item? I seem to get random results when I play from the start vs. starting in the middle of an item that contains item FX.

As I said, I had a VERY similar issue to this when I was trying to use plugin pin connectors on the first inserted item FX to mirror the stereo feed to another hardware output. It worked great EXCEPT when I started using the item FX blend knobs. Then I would start to get these kinds of issues so I stopped doing that.

I'm hoping Justin or somebody from REAPER can take a very close look at this to see where the problem lies.
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Old 11-29-2016, 08:58 AM   #4
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I can't duplicate this with 5.29, using TC2X on both item and tracks, with HQ mode (2048 samples latency at 48khz), REAPER's wet/dry at around 65%.

I have the gains at +0dB, then I compare the output of that track to an unprocessed track, and they null every time. If you have a way to duplicate I'd be happy to take a look.
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Old 11-29-2016, 09:01 AM   #5
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Quote:
Originally Posted by Justin View Post
I can't duplicate this with 5.29, using TC2X on both item and tracks, with HQ mode (2048 samples latency at 48khz), REAPER's wet/dry at around 65%.

I have the gains at +0dB, then I compare the output of that track to an unprocessed track, and they null every time. If you have a way to duplicate I'd be happy to take a look.
Thanks Justin,

I'll try to find a reproducible way later today. Did you check my actual session I linked to? A few of the items have TC2X inserted. I wonder if it's just high latency in general that causes this. I may not be related to this plugin but just general hight latency.

Like I said, it wasn't every playback but it happened often. Most noticeably when playing from well before the item starts. It seems there is a problem with the PDC engaging properly when the FX blend knob is used as a new item starts.
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Old 11-29-2016, 09:07 AM   #6
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Quote:
Originally Posted by Justin View Post
I can't duplicate this with 5.29, using TC2X on both item and tracks, with HQ mode (2048 samples latency at 48khz), REAPER's wet/dry at around 65%.

I have the gains at +0dB, then I compare the output of that track to an unprocessed track, and they null every time. If you have a way to duplicate I'd be happy to take a look.
I also wonder if having another track in the session in record arm mode has any influence on this behavior. With my workflow, I always have a track armed so I can monitor the analog input, and then of course I record it. So, perhaps record arm/monitor or actual recording has an influence?
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Old 11-29-2016, 04:21 PM   #7
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Quote:
Originally Posted by Justin View Post
I can't duplicate this with 5.29, using TC2X on both item and tracks, with HQ mode (2048 samples latency at 48khz), REAPER's wet/dry at around 65%.

I have the gains at +0dB, then I compare the output of that track to an unprocessed track, and they null every time. If you have a way to duplicate I'd be happy to take a look.
@Justin,

I tried recreating this issue in a more simple session but I could not. It would mean a lot and put my mind at ease if you were able to check out the session I posted and also confirm you see/hear the issue in my video clip.

I really need to be sure this isn't happening to a less noticeable degree in any future session.
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Old 11-29-2016, 05:01 PM   #8
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Quote:
Originally Posted by Justin View Post
I can't duplicate this with 5.29, using TC2X on both item and tracks, with HQ mode (2048 samples latency at 48khz), REAPER's wet/dry at around 65%.

I have the gains at +0dB, then I compare the output of that track to an unprocessed track, and they null every time. If you have a way to duplicate I'd be happy to take a look.
What I've found as I dig deeper is that @ 96k, the Tone Control plugin has a reported latency of 4096 samples when the HQ mode in the plugin is engaged.

What I can report is that sometimes even with HQ mode engaged, REAPER thinks there are 0 samples of latency and that's why there is an issue when the blend knob is used.

It doesn't always happen, but sometimes what happens is when I start playback from before the item, the reported latency is wrong once the item is being played.

Is this a REAPER issue or plugin issue?

I have a video capture of it but don't want to share it publicly because it contains a client's music. I can share privately if interested.
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Old 11-29-2016, 08:16 PM   #9
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Another thing I notice is that with something like Zero Crossing Maximizer plugin, when you change the buffer size during playback, REAPER is pretty quick to recover and recalculate the latency on the fly and adjust so everything is in sync again when the FX blend knob is used.

With Goodhertz Tone Control, if you turn the HQ setting on or off during playback, the reported latency isn't updated until playback stopped and started again.

I'm guessing this is related to the issue I'm seeing but the question is why it's only on some playback instances that the latency is incorrectly reported and then there is this issue when the FX blend knob is used.

The short term solution is to simply use the blend knob within the plugin but I want to be certain this isn't happening with other plugins that may have a much less obvious latency that is more of a comb filter as opposed to the slapback sound you get with longer latencies.
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