Consistent audio glitches

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tlegvold

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Consistent audio glitches

PostWed Apr 22, 2020 4:15 am

Hi,

I've been spending time learning Resolve, especially Fairlight as applies to post-production sound. However, it seems that the app runs worse and worse with each update. The last few days I've been trying to do some simple adjustments and sweetening to a few sets of stereo tracks. They are all on the same channel, all 44.1k, there is no video, and currently no plugins. I.e. one stereo track routed to one master bus for stereo output.

What I'm experiencing is audio glitches and stutters every 2-3 seconds consistently. When I was working through some of the tutorials to learn the system under version 15 and the first releases of 16, I didn't really discover any serious issues, but now I don't seem to be able to even play back a simple audio-only timeline with a simple set of stereo files.

I've also tried as a new user on a fresh account, same problem. I was originally running the audio files off of an external SSD drive via USB 3, moving the audio to the internal SSD I thought might help, but the stuttering and glitching is still there.

Any ideas what this might be, and how I can alleviate it? I really want to learn to use Resolve and integrate it into our post workflow, but as it is I'm not confident we can do so. Currently running Nuendo 10 along with some niche mastering software.

The system is Resolve 16.2.1, MacBookPro 15" Retina (late 2013 - 11,3) quad i7 2.3GHz, 16GB RAM, NVIDIA GeForce GT 750M 2 GB and Intel Iris Pro 1536 MB, 1TB SSD running OS X Mojave 10.14.6. Audio IO is a MetricHalo ULN-8 connected via MHLink (ethernet).

I realize the computer is getting long in the tooth, but the fact that Resolve has been running flawlessly previously, I've been able to open all the tutorials and work with them without any problems, along with the utter minimalism of my timeline leads me to think it's not the computer.

Thanks.
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Shrinivas Ramani

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Re: Consistent audio glitches

PostWed Apr 22, 2020 5:21 am

To rule out issues with the MetricHalo, could you check if disconnecting it and playing back the timeline using the system audio shows the same behavior?
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tlegvold

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Re: Consistent audio glitches

PostThu Apr 23, 2020 1:30 am

That's actually a great point.

I just disconnected the MetricHalo and ran on the BuiltInAudio, it played back fine with no stuttering, and with multiple plugins present on the main bus.

Who should I report a bug to? Is this BMD, or MH, or both that need to look into what's going on?

Thanks!
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Shrinivas Ramani

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Re: Consistent audio glitches

PostThu Apr 23, 2020 2:14 am

Since I don't have an equivalent device around, I have to be non-specific.

Resolve has been tested and works well with a range of audio devices, so it might be worth narrowing down the issue a bit more. Checking for 48K 24-bit output configuration, tweaking settings under Resolve's Preferences (various System / Video & Audio I/O settings, audio processing block size, and checking the monitoring settings etc may yield possible solutions.

It may help to check with the device manufacturer to check if they have Resolve specific advice.

Thanks
Shrinivas
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tlegvold

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Re: Consistent audio glitches

PostFri Apr 24, 2020 12:52 am

Hi Shrinivas,

we use a range of audio software here with the Metric Halo, it's all rock solid except for Resolve. I've done some digging and found some interesting things.

I found one thing in particular a bit bizarre.

Resolve takes *less* resources when running under my regular user name with Firefox, Mail, Preview and a bunch of other cr*p running in the background than it does under a clean user with no extra bells and whistles, only the handful of audio apps needed (and nothing else running except MIOConsole). It pegs the meters under that system and stutters away.

On my regular user account it uses about 1 CPU (there’s an effect on the first clip I forgot to remove, but it works). No stutter or glitching, 96% CPU:

Screenshot 2020-04-22 at 22.31.04.png
Resolve under "audio" (minimal) user with nothing running in the background, MHLink Audio IO, 96kHz
Screenshot 2020-04-22 at 22.31.04.png (328.24 KiB) Viewed 290 times


Under a fresh user account, nothing else running, and me logged out of the other account, it gets *worse*

Running @ 96k in the Timeline gives 115% CPU, and glitches (source files are 44.1):

Screenshot 2020-04-22 at 22.13.01.png
Screenshot 2020-04-22 at 22.13.01.png (318.35 KiB) Viewed 290 times


Recreating the session to run @ 48k maxes out all 4 cores, glitches:

Screenshot 2020-04-22 at 22.37.32.png
Screenshot 2020-04-22 at 22.37.32.png (351.31 KiB) Viewed 290 times


It also looks like ReportCrash is busy, but I'm not sure what's crashing, or where to look. It isn't an app, there's no panel popping up reporting a crash, so I think it must be a driver, plugin, or some module of an app (perhaps within Resolve itself).

The MHLink IO runs via ethernet, I have a TB -> EN adapter from Apple to connect.

I ran a new test today, about the same results, still glitching on playback, one track audio, no plugins, nothing else running on the machine.


I do not see these loads with the other audio DAWs I'm accustomed to using. And the disparity between a "clean" minimal system with no added software running the background vs a "home office" user full of running apps and flashing lights is curious.

Do you have any idea what kind of numbers I should be expecting, and what else I can check to see what's causing the poor performance?

Thanks.
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Peter Chamberlain

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Re: Consistent audio glitches

PostFri Apr 24, 2020 2:46 am

Did you re-install Resolve under the 'clean user'?
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Shrinivas Ramani

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Re: Consistent audio glitches

PostFri Apr 24, 2020 3:12 am

Thor

Can I check if you tried any of the suggestions below? Specifically, increasing the audio processing block size?
Shrinivas Ramani wrote:Checking for 48K 24-bit output configuration, tweaking settings under Resolve's Preferences (various System / Video & Audio I/O settings, audio processing block size, and checking the monitoring settings etc may yield possible solutions.


Thanks
Shrinivas
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tlegvold

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Re: Consistent audio glitches

PostFri Apr 24, 2020 3:55 am

Peter Chamberlain wrote:Did you re-install Resolve under the 'clean user'?


Peter,

as a matter of fact, yes I did. The new 16.2.1 release came just as I was getting ready for a new project that I wanted to try doing all in Resolve, so I installed it while running as the "audio only" user.

Shrinivas, I will up the buffer size as you suggest and report back. Due to a looming deadline, I need to move back to Nuendo to get this project delivered on time.

Thanks again for the suggestions!
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Will Howard

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Re: Consistent audio glitches

PostFri Apr 24, 2020 5:35 am

Have you tried running the ULN-8 through the USB connection? Not to have you change your whole setup if you’re integrating other MH devices but just as a temporary test? Also are you on the latest 3D driver release? They’re refining the MHLink protocol with each release I believe. Regardless it definitely shouldn’t perform differently with Resolve than any other program. Especially on MacOS, Resolve audio is much better sorted there than on Windows or Linux.
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tlegvold

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Re: Consistent audio glitches

PostFri Apr 24, 2020 2:53 pm

Hi Will, I have not, no, but thanks for the suggestion. I'm working against a deadline and will have to circle back to this issue when I've delivered the project.

I have had a closer look, the MHLink driver is using minimal resources and pretty highly optimized, I am indeed on the latest version of both the MIOConsole, firmware and driver.

One thing that stands out is the number of threads and wake-up calls Resolve is using. 187 threads seems like an awful lot, as does 11550 idle wakeups. Perhaps there is some sort of resource leak in Resolve? Or BMD is testing on hugely powerful machines and ignoring "real world" kind of computers Resolve is used on, basically just throwing CPU/GPU at the problem and adding features without optimizing their code?

When I load the same tracks into Nuendo 10, same user, same everything, I get a much more sane 40% CPU, 68 open threads and 577 idle wakeups.

Will Howard wrote:Have you tried running the ULN-8 through the USB connection? Not to have you change your whole setup if you’re integrating other MH devices but just as a temporary test? Also are you on the latest 3D driver release? They’re refining the MHLink protocol with each release I believe. Regardless it definitely shouldn’t perform differently with Resolve than any other program. Especially on MacOS, Resolve audio is much better sorted there than on Windows or Linux.
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Will Howard

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Re: Consistent audio glitches

PostFri Apr 24, 2020 6:16 pm

It very well could come down to your machine. I've never run Resolve on a MacBook but it generally does need both a beefy CPU and at least a mid-range GPU. I know Pro Tools is still pretty capable on that era MacBook as it sounds like Nuendo is.
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tlegvold

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Re: Consistent audio glitches

PostFri Apr 24, 2020 9:20 pm

Well the thing that got me curious was that it appears to work fine with the BIA. It may be an issue of channel count, as BIA is stereo I/O only, while the MH driver allows a choice of between 8-128 channels.

Once I get this current project delivered I plan on doing some more testing to see what I can find.

Thanks.

Will Howard wrote:It very well could come down to your machine. I've never run Resolve on a MacBook but it generally does need both a beefy CPU and at least a mid-range GPU. I know Pro Tools is still pretty capable on that era MacBook as it sounds like Nuendo is.
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tlegvold

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Re: Consistent audio glitches

PostSat May 23, 2020 7:09 pm

Now that the project has been delivered, of course I have more coming in. Still, a few days in between to check things out.

I've upgraded to the latest 16.2.2 version, which seems to have been optimized somewhat, I see significantly less system resources being used when opening the same project that was causing headaches before. Based on feedback here, I've also set the GPU acceleration to Metal instead of Auto, and selected the GPU card specifically in preferences. I also reduced my audio I/O to 8 channels instead of 32, which also seemed to reduce the load somewhat. Here is a sample with all plugins on the clip while playing back, before the glitching started. It never went over 100% CPU, which is a major improvement from only a few weeks ago.

Currently it shows as about 50% of one CPU when playing a stereo 44.1kHz track, no video, with a few simple plugins (a metering plugin that sends an audio stream over a socket to a standalone metering app and Quartet DynPEQ). Adding a few more (an EQ, a Weiss Limiter) works well up to a point, and then the system starts playing back the audio slower than real time. If I stop and start playback it plays fine for 30-45 seconds before starting to glitch again.

Screenshot 2020-05-23 at 00.29.16.png
Screenshot 2020-05-23 at 00.29.16.png (155.89 KiB) Viewed 63 times


While it's much better than what I was seeing before, it's still relatively unusable for serious audio production. This is a single stereo track, no video, nothing fancy. 4 plugins on the audio clip (song), one in the master bus (metering).

I have yet to test with BIA to see how the load and responsiveness changes, but plan to soon. Also will test with my I/O (Metric Halo ULN-8) connected via USB rather than MHLink (ethernet).

One last question here. I'm using a late 2013 15" Retina MBP with 2.3GHz Quad i7, 16GB Ram, GT 750M 2GB RAM, 1TB SSD. It runs Mojave.

With my current machine, would an external CC2 card or an eGPU make the biggest difference for audio-only work? I keep hearing that a better GPU will make Resolve run so much better, but I'm not doing any video work (currently), only audio (perhaps some sound for picture, but only 1080p HD reference tracks). Does an eGPU affect the GUI, or audio processing in any way, or is it primarily related to editing and grading functions?

While I'm tempted to get a new laptop, one audio app I am dependent upon will not run under Catalina (Sonic Studio soundBlade), and I'm not able to do much of my work without it. New machines will not boot under older OS's. Thus my interest in going as far as I can with my current machine.

My audio I/O has MADI, so I would be able to connect the CC2 to it for further processing, monitoring, and DA conversion.

Thanks for any suggestions or info you can provide.
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tlegvold

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Re: Consistent audio glitches

PostMon May 25, 2020 8:59 pm

Tested now to compare MHLink (8 active channels) with BIA, there is no discernible difference in CPU load or performance.

This seems to have changed between 16.1 and 16.2. Additionally, the advice to manually set Metal and choose the graphics card made a big difference. I'm not sure why "Auto" didn't work, but I now have video and one stereo audio track, 5-6 plugins, and the system is responsive and smooth. I can see in Activity Monitor and iStat Menus that the CPU rarely ever goes above 100% (of 4 cores in total - 400% max), and that the graphics card memory is completely used as is the GPU, running at max capacity.

Very nice. Things are improving. Although it looks like I might want to consider a new(er) computer if I'm going to get the most out of Resolve moving forwards.

Thanks again for the help and suggestions.

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