Audio file reading produces drop-outs

[PierreG]

"I use the W7 Resource Monitor to examine disk I/O, which reveals that the issue can present itself with T audio buffering happening, or not."

I don't think I understand what you mean by this. How can you tell whether T audio buffering is happening from Resource Monitor?

The Resource Monitor shows detailed real time disk activity, where you can clearly see when T is accessing audio files and when the page file is being accessed.

I don't have any answers to this really, but I'd probably get some disk utility and run it to check the read and write and random access speeds for the disks you use, and check you can actually read and write the kind of iops you're trying to achieve at the samplerate you're using

I'd also maybe check whether all the audio (recorded tracks and any samples, or audio sounds used in plugins) are at the same samplerate and bit depth you're using in your soundcard. Just because I'd want to rule out some kind of resampling taking place in either the app or by the audio driver, to play back everything in the edit. As in, if you're using 16bit 44khz samples on one track, but recording audio at 88khz, and the card is running at 88khz, does the sample get converted on the fly, when the audio first gets played? I dunno, but if you're looking for things to rule out, maybe that's an idea...

I'm also curious about mixed sample rate performance in T. This includes how things like convolution reverb impulses that are of a different sample rate than the audio files being processed in T are dealt with. I've made comment in this thread regarding issues I'm having with SIR2 running 44.1 impulses against my 88.2 audio. If SIR is in a rack, the live mix sounds great, yet the render has the verb wrong. Removing SIR from the rack fixes the render.

I also wonder if the implementation of the new Elastique Pro engine in T has issues to work out. I typically record in 88.2 / 24 and use the Elastique pitch correction and time stretching quite a bit.

Did you look for DPC issues yet? I spent ages chasing them on an old laptop that finally died a death, but they seemed to be causing me grief, at one point...

I've most certainly spent an great amount of time with DPC, which smoked out driver issues and such. Latency Monitor was also used for tuning. My system checks out very well with these various tools. While we're on the topic of system tuning, I will say that one gotcha app that I found to really mess with T is the Cubby cloud backup process. I was not aiming that app at any audio space, thus it wasn't that sort of sharing conflict, yet when I disabled it, the Tracktion.exe process CPU consumption was cut by more than 50%. Another issue I just posted to this thread concerns SpeedStep issues with my laptop overheating without knowing it was occurring. That was my most niggly discovery, which happily resolved my T CPU clock throttling issue. Search for it and read if you care to.

[valley]

'king hell, valley' s back...

I've been lurking for a little while. I found some free time, and figured I should dust off my gear before my hearing buggers off for good.

Hope you're well sir

I am. How are you doing? It's been a while! I've seen a few names I remember, but far more that I don't.

[PierreG]

Just remembered something about DPC. Turning wifi off (disabling the wireless interface in control panel, and using any available hardware button to disable wifi) really helped.

Can't remember if disabling Bluetooth too made a difference or not. Suspect it would. Might mean plugging a USB wired mouse in, instead of using a Bluetooth or wifi one, but it's an easy enough thing to try

Been there! Wireless can be a problem for sure. On my Dell D630, the DVD player has to be disabled. If not, DPC shows massive periodic red spikes, which I assume are when the device is being interrogated by the driver. AutoPlay perhaps?

[PierreG]

Totally stupid question here, but are you using a laptop? If so, do you have *all* hard-drive idling disabled[1]? I only ask, because it occurred to me I might be thinking about this problem back to front. The drive may not be delivering data because it is *too* busy, rather it might not be busy *enough*. With a decent cache on the drive, and in Tracktion, it's possible that practically all activity is being performed via cache, so short of much to occupy itself, the drive spins down. The next time data is needed the drive will spin up, but might not do so fast enough. This would certainly look like insufficient throughput.

If any of this seems like it might be applicable, one easy test would simply be to stress the drive *more*. Try playing an large and long audio file (perhaps a mix-down of another song) on a muted track so the drive has no choice but to keep streaming data.

Just a thought.

[1] Note, WD Green Series drives will sleep regardless, so all bets are off here.

I'm currently using an oldish Dell D630 laptop. Great question and description of a very likely issue! This totally makes sense, which at first is counter intuitive.

Here's my silly question - Where does one turn off hard drive idling? It's been a while, yet I think I explored a power saving option on my Hitachi Travelstar drive.

[PierreG]

The old T4 manual used to say this:

"Cache size: You can adjust how much of your computer’s main memory (RAM) is used to cache audio files. Caching helps audio tracks play back without glitches or drop-outs, but reduces the amount of memory available to other applications and plug-ins. Making this value too large will also be counter-productive because computers become greatly less efficient once main memory is depleted. The default setting of 64MB is usually fine, but you may want to increase it if you have lots of RAM installed on your computer."

That sounds like my writing from the T2 / T3 manuals. Things are a bit more complicated these days.

Good to meet one of the legacy T manual authors!

Even in the XP era, Windows would go off and make itself a swap file regardless of how much system space was free. I'm simplifying greatly here, but the old theory on swap files was early and often. The idea being that running out of RAM is messy, so an OS would strive to commit as little RAM as actually possible at any given time. I know some people liked to run Windows with the swap file disabled on their DAW if they had two or more gigs of RAM installed.

Modern OSes now tend to work in the opposite direction. Unused RAM is wasted RAM. A lot of this is being driven by the move to mobile, where disk accesses are expensive in watts. However some of it is performance too. Personally, today I'd probably bump the buffer size as a matter of course. RAM is cheap and drives are fast. That said, the hard drive probably already has a buffer equal to this size, and at a certain point, buffers only delay the inevitable. If a system is emptying the buffer faster than it can be filled, no amount of buffer is going to completely solve the problem.

In this case though instinct tells me the buffers are a red herring.

Excellent description of the evolution of cache buffering, thanks.

Again, this behavior of audio dropouts when first running through the edit, seems like T needs to load the cache buffers, which takes a while, thus the dropouts happen until the buffers are loaded. Yet I also will get the dropouts after mixing for a while, which suggests that there's more cache management happening and causing the dropouts again. Then once cache is reloaded, all is good again. As Chaos points out, why is the cache buffer limit so small? Perhaps going larger actually causes other issues. Maybe my hard drive is too slow for 88.2 audio...

I'm assuming 24bit stereo? Two tracks is only about a megabyte a second. A typical desktop hard drive should handle sustained throughput of around 100MB. (Note though that 'typical' here is a *wide* net. If yours is an energy efficient drive, such as the WD green series, you might see much lower numbers). Also note, we're talking sustained throughput here; multiple tracks playing at the same time will obviously perform significantly less well, as more time is spent seeking data, rather than reading it.

If you haven't already, I'd run a performance test over the drive but look for signs of uneven throughput. 100MBs per second isn't quite so great if the drive likes to deliver that data in bursts.

What performance test would you recommend I use? And do you think disabling the page file is worth trying under Windows 7?

[PierreG]

Sysinternals have some handy utilities that might help to pinpoint what is happening behind Windows and Tracktion. I'd start ProcExp (Process Explorer), make something happen with Tracktion, and then look at spikes in the graphs in ProcExp. You can put the mouse pointer over the graph for clues to what was running when your problems happened.

ProcExp is indeed a good tool, which I've used from time to time, yet not lately. The Windows Resource Monitor is great in that it shows CPU utilization for both processes and services, as well as the detailed happenings of hard drive I/O.

[chico.co.uk]

The Resource Monitor shows detailed real time disk activity, where you can clearly see when T is accessing audio files and when the page file is being accessed.

I'm familiar with Resource Monitor. I can't think of a way to get it to show me when Tracktion is accessing audio files. Can you walk me through that?

[chico.co.uk]

You're not thinking of procmon, are you? Rather than resource monitor?

[chico.co.uk]

'king hell, valley' s back...

I've been lurking for a little while. I found some free time, and figured I should dust off my gear before my hearing buggers off for good.

Hope you're well sir

I am. How are you doing? It's been a while! I've seen a few names I remember, but far more that I don't.

Good mate, all bobbing along. We've got three wee ones to keep me from making poor quality noises on computers these days, which is a bit different from when I started messing with T1... still manage to squeeze in a bit of noise making, but it's more infrequent. Still as low quality as ever though, i'm proud to report.

[PierreG]

You're not thinking of procmon, are you? Rather than resource monitor?

Are you using Windows 7 or above? If so, just type in Resource Monitor into your app search. If I recall, XP = no go.

[chico.co.uk]

You're not thinking of procmon, are you? Rather than resource monitor?

Are you using Windows 7 or above? If so, just type in Resource Monitor into your app search. If I recall, XP = no go.

You misunderstand me. I know exactly what Resource Monitor is, how to open it, and use it. I don't know how to use it to get it to show me when Tracktion is accessing audio files. How did you manage that?

[PierreG]

You're not thinking of procmon, are you? Rather than resource monitor?

Are you using Windows 7 or above? If so, just type in Resource Monitor into your app search. If I recall, XP = no go.

You misunderstand me. I know exactly what Resource Monitor is, how to open it, and use it. I don't know how to use it to get it to show me when Tracktion is accessing audio files. How did you manage that?

Resource Monitor - Disk tab - You will see all hard drive activity in real time. Look for Tracktion.exe disk activity under the Image column.

[chico.co.uk]

You're not thinking of procmon, are you? Rather than resource monitor?

Are you using Windows 7 or above? If so, just type in Resource Monitor into your app search. If I recall, XP = no go.

You misunderstand me. I know exactly what Resource Monitor is, how to open it, and use it. I don't know how to use it to get it to show me when Tracktion is accessing audio files. How did you manage that?

Resource Monitor - Disk tab - You will see all hard drive activity in real time. Look for Tracktion.exe disk activity under the Image column.

Yup. That doesn't actually tell me Tracktion is accessing audio files though, does it? It just shows me disk reads and writes at that exact moment in time. Which isn't the same thing. Thought I must be missing something

[PierreG]

You're not thinking of procmon, are you? Rather than resource monitor?

Are you using Windows 7 or above? If so, just type in Resource Monitor into your app search. If I recall, XP = no go.

You misunderstand me. I know exactly what Resource Monitor is, how to open it, and use it. I don't know how to use it to get it to show me when Tracktion is accessing audio files. How did you manage that?

Resource Monitor - Disk tab - You will see all hard drive activity in real time. Look for Tracktion.exe disk activity under the Image column.

Yup. That doesn't actually tell me Tracktion is accessing audio files though, does it? It just shows me disk reads and writes at that exact moment in time. Which isn't the same thing. Thought I must be missing something

Guess I'm the one missing something, "same thing" as what exactly? This utility shows the exact files that are being accessed by the Tracktion process, all of them, not just audio. You can view exactly what's happening when T is grabbing files to load into cache. At least this is how I understand the process.

Example: I run a T loop, I see T accessing the audio files and loading them into the cache buffers (I assume). Then as the buffers are filled, the T disk I/O goes away. I stop looping and let the playback run out towards the end, I see T grabbing (buffering) the new sections of the audio files for playback.

What am I missing here?

[chico.co.uk]

You're not thinking of procmon, are you? Rather than resource monitor?

Are you using Windows 7 or above? If so, just type in Resource Monitor into your app search. If I recall, XP = no go.

You misunderstand me. I know exactly what Resource Monitor is, how to open it, and use it. I don't know how to use it to get it to show me when Tracktion is accessing audio files. How did you manage that?

Resource Monitor - Disk tab - You will see all hard drive activity in real time. Look for Tracktion.exe disk activity under the Image column.

Yup. That doesn't actually tell me Tracktion is accessing audio files though, does it? It just shows me disk reads and writes at that exact moment in time. Which isn't the same thing. Thought I must be missing something

Guess I'm the one missing something, "same thing" as what exactly? This utility shows the exact files that are being accessed by the Tracktion process, all of them, not just audio. You can view exactly what's happening when T is grabbing files to load into cache. At least this is how I understand the process.

Example: I run a T loop, I see T accessing the audio files and loading them into the cache buffers (I assume). Then as the buffers are filled, the T disk I/O goes away. I stop looping and let the playback run out towards the end, I see T grabbing (buffering) the new sections of the audio files for playback.

What am I missing here?

No, this is me mate, I've got the wrong end of the stick. More accurately, looking on the wrong tab.

I've managed to somehow never tick boxes for individual processes on that disk tab, and see the "disk activity" window change to show what that process is accessing. I've more usually used filemon or procmon for that kind of thing, which has its own benefits, but this is a cool wee feature I wasn't aware of.

Cheers, my bad, but kind of glad I asked, because that's handy.

(oddly, I do use the network tab in a similar way, to check network activity for individual processes, instead of using tcpview, or wireshark, so you'd think I'd have noticed how the disk tab stuff works. But apparently not)