FLAC clicks/pops during foobar playback

Anyone else have this problem? I've hooked up a netbook to my DAC using optical, and it sounds good except for the clicks. Since I've backed up all my discs to FLAC using EAC, I'd much rather use my PC than media for convenience. The clicking is driving me crazy though. Is it because my CPU is underpowered and can't decompress FLAC in real time?

The netbook has an Intel Atom processor running at 1.6 ghz with 2 gigs of RAM. Not exactly robust. But FLAC isn't that complicated, is it? Could it be something else?

 

It is surely something else, try to set your soundcard with a ASIO driver and avoid doing any kind of resample.
BTW, which SC are you using to get the optical out?

 

which playback software? try another

 

Run LatencyMon and/or DPC Latency Checker. Both are free utilities that check OS latency that blocks the CPU from processing the audio. It's one cause of clicks and glitches. The web pages for each utility explain the problem and how to fix it.

 

I am running an Acer nettop with an Atom processor (1.8GHz) playing FLAC's with foobar and experience no clicks and pops. Windows 7 WASAPI exclusive mode.

I am also using the SoX plugin in foobar to upsample to 24/96 as well so I don't think the Atom processor being under powered is at the heart of your problem.

 

I am using an Atom PC and foobar2000 with no problem whatsoever (even with 192/24 stereo FLACs or 96/24 multichannel FLACs) so the problem is definitely somewhere else.... try adjusting the buffer length in the foobar settings and see if it helps... but I doubt.... perhaps you can try another optical cable?
Also check if your antivirus is performing some heavy scan or if you have other resource-intensive programs running....

 

My audio computer is old, 1.6Ghz with only 500MB RAM -- and that is the maximum it will take. I use foobar, Audacity, others, with no problems. But maybe your computer is running other programs that are massively hogging resources.

 

Hah. Mine runs fine, mostly.

800MHz, 384Mb. Music runs fine. Don't mention video (most sites are good but occasionally there's a land-grab for huge resources especially TV channel sites) Local download and DVD no problem.

 

agree

 

Thanks for all the suggestions. I'll check out the latency tests when I get home tonight. I know it's not the optical cable because the clicks occur during analog out as well. Resampling isn't the issue either; cliclicks are still audible regardless if my DAC has 96k or 44.1k input. The sound board in the netbook is an onboard VIA chipset, I believe. The SPDIF shares a miniplug jack with the analog headphones out.

 

I had troubles playing hi-res flac files on my computer with pops every now and then, but disabling Intel SpeedStep in the bios fixed it. I don't know why CPU throttling does that, but that's what worked for me.

 

SpeedStep? Never heard of it. But I'll check the BIOS. If it's there, I'll disable it. Thanks.

 

SpeedStep and similar technologies lower the clock speed of the CPU and the power the CPU uses. It does it dynamically based on what the needs are at that instant. So the CPU could be at 25% speed one instant, bump up to 75% speed then full speed then back to 25% speed all from second to second. The lowest power levels can interrupt audio due to the switching, lower processing level, and other power saving tricks.

You don't necessarily want to completely disable the speed changing on a laptop. That decreases battery life and causes the laptop to run hotter. An alternative is to go into the Power Options in Control Panel and decrease how much the OS allows the CPU to throttle itself. Drill down to the Advanced settings for your power plan. Scroll down to "Processor power management" and set the minimum processor state to something like 40%. Experiment and see how low you can go without affecting the audio. If you want to disable the CPU speed changing the set the minimum level to 100%.

There are utilities that let you see the current CPU speed and see how it dynamically changes as you do different things on the computer. One is CPU-Z. But it only shows the speed of one core. There are others that show the speed for all cores, but their names escape me at the moment.

Wireless network drivers and even mouse (trackpad) drivers can be a source of glitches due to the drivers causing DPC latency. The latency checking utilities will let you know if that's a problem.

 

In addition to disabling SpeedStep in the BIOS, in Windows Task Manager, right-click on foobar.exe in the Processes tab and change Set Priority from Normal to Realtime, which you'll have to remember to do everytime you open foobar2000.

 

Not necessarily a good idea to do that. When you bump the entire foobar process to realtime priority you bump every thread in that process to realtime priority, not just the audio processing thread. Apps like Foobar are multithreaded. They'll have multiple threads each for a different purpose. Some high priority audio processing threads, some less critical UI updating threads, and some very low priority general monitoring threads.

If you bump every thread in the app to realtime priority level then every thread in the foobar app gets set to realtime priority. That destroys any benefit of having different priority levels within the app. The developers of apps like Foobar know what they are doing and have taken very special care to make sure the app uses resources and thread priorities efficiently and effectively. If you bump the app to realtime priority you destroy all that. If everything is realtime priority, who is second priority? It's like wanting everyone in a store to be first in line at the only cash register. It can't be done and destroys any concept of scheduling or priority.

Here's what MSDN has to say about general practices for thread priority:

Playing around with setting realtime priority on a complex app like Foobar (or any other audio player) is not wise and comes with a price and consequences that few people who are not software developers will understand. Not a tweak that should be taken casually.

 

Are the files on the computer or are you playing from anything external using USB?

Have seen this problem numerous times when people are playing files through USB.

 

Perhaps. Perhaps not.

I was getting pops and clicks playing SACD ISO files using the new plugin http://sourceforge.net/projects/sacddecoder/files/
but changing Priority to Realtime alleviated that.

I also had long ago set Threads to 7 in foobar's Preferences Advanced section.

 

Files are stored on the primary SATA hard disk. Originally I tried playing thru WIFI using my Windows 7 HomeGroup since my PC in the basement has a 2TB drive where all my FLACs are archived. That seemed to cause another set of hangups, however. I know it's the netbook causing problems and not my router - I can watch Netflix through Nintendo Wii at maximum quality (~1GB/hr), without any bottlenecks. And video is much more demanding than audio. Perhaps I'll try tweaking my wifi adapter drivers too.

 

I've started by adjusting advanced power settings for the minimum CPU usage and wireless performance. I'll see if this eliminates the problem first before running tests or changing BIOS settings.

 

Ok, so I set minimum CPU power to 40%, and increased the buffer in foobar to 4000ms. The clicking has stopped, however I still can't stream FLAC wirelessly over my home network...any ideas??

 

I should note that I even tested FLAC playback on a USB drive and it doesn't click or pop now.

 

Progress!
If you disable the wireless (disabled so the wireless is fully disabled, not just not being used) and use a wired connection will it work?

Wireless network drivers can be pigs. They have a lot of computing they need to do that wired networks don't need to do. Sometimes updating to the latest version for the wireless driver can help.

 

I've lowered the network buffer in foobar to the minimum (16), and went into the Control Panel Device Manager & set the buffer receive on my wifi adapter to the same. The hangups are less frequent but still happening.

 

I wish I could do a wired connection, but my place is too old. I'd have cables running all over the place if I went wired. It would look like a recording studio! Lol.

 

I don't understand why this is happening. I can play maximum quality netflix movies on the wii over wireless without any dropouts & yet I can't even watch a youtube clip on my netbook without it choking up...