Old 10-05-2019, 12:25 AM   #1
tdc
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Default Source of Audio Glitch when stopping playback?

Hi folks,

I have been researching potentially moving from PT HD Ultimate to Reaper as the call of scripting and creating our own control and console solutions is too great. So far, most of our workflow seems to be able to be replicated within Reaper with some adjustments, however I have hit a problem that I am unable to resolve.

When I press stop, the audio that is playing has a dropout glitch then continues for a few hundred milliseconds before stopping. This might sound like a small issue but really begins to annoy artists as well as the engineer over the course of a session.

Seems to be related to Plugins. I have created an example Project to illustrate this. It has two tracks, one with a sine wave and no FX plugins, and the second track with the same sine wave, but with a ReaEQ installed. If you stop playback when track one is playing back the audio stops as you would expect. But if you stop playback whilst the second track is playing (that has the ReaEQ instantiated) then the glitch is heard.

I have played with the various "Run FX" settings to stop this, but then all tails of reverb tracks are choked on stop which is also not good.

Any thoughts on how to resolve this?

Many thanks,

tdc

[Running Reaper on various new Mac's, mostly with RME interfaces or CoreAudio builtin devices. All at standard default settings and either 48/96k sessions)
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File Type: zip Gitch Test Project.zip (11.2 KB, 13 views)
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Old 10-05-2019, 05:42 AM   #2
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"Anticipative FX processing" might be the culprit. But I would not recommend to disable it.
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Old 10-05-2019, 06:53 AM   #3
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Thanks. Yes, tried that but it didn’t remedy the situation.
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Old 10-05-2019, 10:58 AM   #4
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Quote:
Originally Posted by tdc View Post
<snip>

Seems to be related to Plugins. I have created an example Project to illustrate this. It has two tracks, one with a sine wave and no FX plugins, and the second track with the same sine wave, but with a ReaEQ installed. If you stop playback when track one is playing back the audio stops as you would expect. But if you stop playback whilst the second track is playing (that has the ReaEQ instantiated) then the glitch is heard.

<snip>
I cannot replicate that here. For both tracks, when I hit space, the audio stops immediately. I can hear no difference between playing and stopping Track 1 compared to Track 2.

I have "Anticipative FX processing" turned on and set to the default 200 ms. Maybe you have it turned off for tracks with no FX (there is a switch for that, mine is on) and that makes the difference for you. Just guessing...
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Old 10-05-2019, 12:38 PM   #5
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I remember having this problem and the setting that fixed it was counter-intuitive. Try searching "flush" in preferences and play with those settings. I can check find out for sure when I get home if you don't find it by then.
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Old 10-05-2019, 08:09 PM   #6
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Thanks Fabian and Dstruct for your advice. I have done further testing based on your suggestions. Still no proper solution but I have some more observations.

It appears to be related to a channel when its playing back and stopping and feels like an error when the channel is moving from play to stop, just like a tape machine does when changing from Play to input mode (repro).

Here is a screen shot of the resultant waveform. I have played out of Reaper, via SoundFlower to another DAW to capture the audio. Each Item is the result from starting and stopping Reaper. You can clearly see the appended region of audio on the second file. Interestingly this additional content is 9500 samples in length. (My PDC is at 0)




With further testing, I found that if I put the channel into Record, whilst in "Record: Disable (input monitoring only) then ti don't get this bug. Also If I add the same ReaEQ to the Item as Item FX instead of Channel FX, I also don't get this bug.

I have also created a brand new install, portable, and replicated this bug with the default settings.

Are there any Dev's who could advise me whether this is a known symptom of the audio engine design, or whether this is an anomaly of my use or systems?

Thanks,

tdc

Last edited by tdc; 10-05-2019 at 11:34 PM. Reason: updating details
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Old 10-06-2019, 12:12 AM   #7
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Quote:
Originally Posted by tdc View Post
Thanks Fabian and Dstruct for your advice. I have done further testing based on your suggestions. Still no proper solution but I have some more observations.

It appears to be related to a channel when its playing back and stopping and feels like an error when the channel is moving from play to stop, just like a tape machine does when changing from Play to input mode (repro).

Here is a screen shot of the resultant waveform. I have played out of Reaper, via SoundFlower to another DAW to capture the audio. Each Item is the result from starting and stopping Reaper. You can clearly see the appended region of audio on the second file. Interestingly this additional content is 9500 samples in length. (My PDC is at 0)




With further testing, I found that if I put the channel into Record, whilst in "Record: Disable (input monitoring only) then ti don't get this bug. Also If I add the same ReaEQ to the Item as Item FX instead of Channel FX, I also don't get this bug.

I have also created a brand new install, portable, and replicated this bug with the default settings.

Are there any Dev's who could advise me whether this is a known symptom of the audio engine design, or whether this is an anomaly of my use or systems?

Thanks,

tdc
Try disabling "tiny fade at play and stop" in Audio prefs.
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Old 10-06-2019, 12:50 AM   #8
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Try disabling "tiny fade at play and stop" in Audio prefs.
Hi Magnus, thanks for that. That has indeed made it better by stoping the fadeout and fadein happening at the expense of sharp ends when pressing stop (Red Section in Image) But the extended buffer that is played back if there are FX's instantiated on a channel is still there (Blue section in image)

Green line is where I press stop on the transport.

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Old 10-06-2019, 01:46 AM   #9
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Hmm, "pre-zero output buffers" in Device setting makes a diff?

Dont know what youve done but sounds like you should play more with the "flush settings" in the Playback prefs section.
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Old 10-06-2019, 02:15 AM   #10
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Quote:
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Hmm, "pre-zero output buffers" in Device setting makes a diff?.
Sadly no.

Quote:
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Dont know what youve done but sounds like you should play more with the "flush settings" in the Playback prefs section.
Not sure I have "done" anything, as this is a completely new install, new prefs etc. Out of the box this is the behaviour on every studio Mac we have. Are you running on Mac Magnus? Does the test project I created exhibit this?
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Old 10-06-2019, 02:37 AM   #11
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Not sure I have "done" anything, as this is a completely new install, new prefs etc. Out of the box this is the behaviour on every studio Mac we have. Are you running on Mac Magnus? Does the test project I created exhibit this?
No, and No! Its not normal for sure. Try different setting in the playback section.
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Old 10-06-2019, 03:22 AM   #12
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No, and No! Its not normal for sure. Try different setting in the playback section.
Right thanks for your help. Sounds like its a MacOS version of reaper issue perhaps.

My systems are:
MacOS 10.14.3
Reaper 5.983/64

Various machines are MBP 2015, and Mac Pro 2013's.
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Old 10-14-2019, 06:07 AM   #13
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I recommend you send this bug report (or a link to it) together with your Reaper.ini and system specs to support@cockos.com . This needs to be resolved in the interest of any new MacOS user.
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Old 10-14-2019, 04:14 PM   #14
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Thanks - Shall do. As I mentioned in the post, this behaviour is with a fresh install so thats a clean .ini file, and occurs on all macs I have access to.

Cheers, tdc
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Old 10-14-2019, 04:30 PM   #15
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With your test project I don't have that glitch here (on Windows).


Maybe the "Close audio device" options help?
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Old 10-14-2019, 04:32 PM   #16
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Thanks Dstruct - yes, it appears to be a MacOS issue.
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Old 10-14-2019, 08:04 PM   #17
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Update: Justin has kindly had a look at the issue, and got me to turn off the

Preferences/Buffering "Anticipative FX Processing"

@ Dstruct, why do you advise against it?
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Old 10-14-2019, 08:11 PM   #18
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Because it will decrease performance. Try with lower "Render-ahead" size instead (50ms).
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Old 10-15-2019, 06:51 PM   #19
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Right. I wonder how much of a Processing hit that will incur. I will try and do some quantitive tests later this week.

Trying a 50ms setting just makes the glitch at the end of pressing stop just shorter :-)
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Old 10-15-2019, 06:55 PM   #20
Dstruct
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Here on Windows I don't have that glitch with 200ms render-ahead size either. Audio is stopping smooth without any glitch here.
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Old 10-16-2019, 07:14 AM   #21
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Quote:
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Here on Windows I don't have that glitch with 200ms render-ahead size either. Audio is stopping smooth without any glitch here.
Do you have "flush fx on stop" enabled? That eliminates it but also obviously kills reverb tails.

Are you testing it with synthetic content that makes it obvious (e.g. sinewave)? With most real world stuff it's really not noticeable IMO.
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Old 10-16-2019, 07:17 AM   #22
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Do you have "flush fx on stop" enabled? That eliminates it but also obviously kills reverb tails.
Yeah, that's it. I guess I had it enabled because of that glitch (I "hate" such things).
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Old 10-16-2019, 05:38 PM   #23
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Hi Justin,

The audio glitch occurs on all source material, and is fatiguing due to the fact that as an engineer you are always on alert for issues.

On MacOS, as you suggested, turning off Prefs/Buffering/Anticipative FX Processing does indeed stop this stuttering.
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