Audio Distortion - How do I fix this?

[toomanyusernames]

This issue has been plaguing my computer for at least a year.

And now it's happening to my new build in a slightly different form.

Anything that can be done to fix/solve this problem would be amazing. <-- Emphasis on amazing.


First build: Windows 7 32 bit, e6600, 9800gtx+, 2gb ram
Audio Interface: Profire 610
Headphones: Sennheiser HD 650

This issue ONLY occurs on VLC.

Issue: When I would start playing an audio file on VLC I would hear a distortion in the treble. It sounded like a high pass filter affected by a sine wave oscillating every second.
The effect was not very loud, and it was easily fixed. I just had to hit stop, and hit start again and the effect went away (most of the time) The effect did not happen every time either. Mostly when I first started playing a list of music. I had to do the fix for music skipping at the beginning of an audio file. It helped with the smoothness to start a song but did not lower the incidences of distortion.

Second build: Windows 7 64 bit, i5 2500k, 9800gtx+, 8gb ram
Onboard Audio: Realtek ALC892
Headphones: Sennheiser HD 650

Issue: Audio clipping - Typical audio distortion. Fixed by starting/stopping the file being played 1-3 times.
Severity: Medium-High
Occurrence: Every time I play an audio file. ONLY occurs on VLC.


Theories:

#1 Many of my files were originally bought on itunes. Because they were only playable on iTunes I had them converted to be able to be played on every player. Maybe the conversion process effected the files so they play with distortion on VLC.
#2 My headphones may have a specific issue with VLC.
#3 VLC has a bug that I am encountering quite often.
#4 I did not set up VLC correctly.

Again, any ideas on how to fix this would be great.

Thank you.

EDIT: Before anyone asks, the audio isn't clipping/distorting from exceeding the headroom.

[Jean-Baptiste Kempf]

I would say the issue is #3 with synchronisation with your main clock. DId you over-clock? Did you try another audio output?

[toomanyusernames]

Before I posted I had not overclocked. I did overclock after I posted and the issue persisted. I did try another audio output, no change.

The issue doesn't happen every time I play an audio file anymore, only certain audio files now. And if I hit stop and restart it goes away.

Rarely it will occur while a song is already playing. Mostly the distortion starts with the audio.

I'd rate the occurrence as very low at the moment.

[toomanyusernames]

Maybe I can run some sort of audio capture tool or log capture tool that will show what the problem is?

It seems as though no one here knows what it is.

[VLC_help]

Tools -> Messages (set Verbosity to 2) will complain when errors happen.

[toomanyusernames]

I enabled the messages and did some testing. I discovered that on certain files the distortion starts at the beginning of the song. To remedy that I hit pause, and then hit play again.


Here's the log of my test: http://pastebin.com/eJYL3pM2


Here's what I think may be the part with the relevant information.

I hit play on the audio file and I get a stream of data and I get this warning:

main warning: PTS is out of range (-10000), dropping buffer
main warning: output date isn't PTS date, requesting resampling (42372)
main warning: buffer is 42371 late, triggering upsampling
main debug: control type=1


I hit pause, and then I hit play again and the audio fixes itself and this is this is the warning I get afterwards (Audio stops distorting, but still get another error message)

main debug: control type=1
main warning: computed PTS is out of range (510739), clearing out
main warning: timing screwed, stopping resampling
main warning: output PTS is out of range (515749), clearing out


EDIT: I did another test where I hit pause and play until there was an error and distortion (The last error messages are when the distortion started) LINK: http://pastebin.com/s5s4eph7

[VLC_help]

Those are just generic desync messages, so they confirm that the issue is software related, but they don't tell where it comes from.

[toomanyusernames]

What's the next step then?

[VLC_help]

If you have tried different video and audio output modules, and running VLC with some semi intensive background program, I don't think there really is anything that will give you guaranteed help. (there are just certain bugs in VLC core that cause problems like that in certain setups)

[tomaat]

Exactly the same problem here! I have almost get used to it. Maybe one year or so. Moderate distortion. Makes you think that this fiddling with controls (audio is almost everytime distorted if you don't re-start the file) is not necessary at all.

[loafmag]

Finally, I thought I was the only one with this problem!
I nearly sold my m-audio profire 610 some while ago, because I first started experiencing this after moving from Win XP to Win 7 64, and blamed M-Audio driver developers, but soon after found out that VLC is the only audio playback I experience this.

The distortion can be described as a sound similar to that when one's resampling audio down to a lower bitrate and/or sampling rate.
Kinda similar to that typical 12-bit sound of the late 1980/early 1990's hiphop and other sampled music where the E-MU SP-1200 sampler was the "industri standard" (12bit 22khz sampler).

Really weird, and pretty erratic behaviour aswell, sometimes it helps to restart VLC a few times, but after a while the problem returns.

[Jean-Baptiste Kempf]

I think VLC 1.2 will behave better on that regard.

[dmast]

I have the same problem. Even though this thread appears to be quite dead, I will add my data as well. I am running windows 7 sp1, and vlc version 1.1.11 which I downloaded just a couple of days ago to fix this problem. No joy. As the other authors mentioned, it comes and goes, and is fixed by pausing, or restarting the song affected. Unlike one of the authors, mine does not begin on the first song, but 10-15 minutes into playback. Also, once I get it to go away, it seems to stay gone (still testing on this point). I am playing back 192k/24bit files exclusively, btw. Other interesting data is that my MPC-HC player does the same thing except much worse, starting from the beginning of playback. Conversely, Audacity playback does not seem to do it, although I haven't tested it with 15 min of continuous playback.

Another bit of data is that when I am playing the VLC player, all of my unused 4GB of ram is converted from "free" to "cached" which does not seem to happen with other programs. Alas, the problem does NOT start when the "free" ram equals zero.

I checked levels everywhere in my system and they are all running midband, with no peaks exceeding maximum Tried reducing each of them, but it didn't impact the problem.

Its not the world's biggest issue in that it can be solved with one simple restart 15 minutes into playback. But why.........

[VLC_help]

dmast: did you try Waveout audio output module or VLC 2.0.0 nightly builds?
http://nightlies.videolan.org/build/win32/?C=M;O=D branches are 2.0.0

[dmast]

Thanks for the quick answer and suggestions to fix this vexing problem. I tried both, one at a time, and unfortunately, neither one solved the problem.

I do have some new insights to offer however:

1. The interfering sound this problem creates is relatively subtle. If the music is loud and complex, you can't hear this problem. It is only obvious on quieter pieces. I can most easily hear the problem on an album like "Oscar Peterson Plays The George Gershwin Songbook", which is mellow and at most has 4 instruments playing at a time, with the drums being very subdued. This may be why the issue hasn't been more widely reported.

2. The problem is happening more frequently than I knew, for the above reason. If I listen to the Peterson album end to end (24 tracks), the problem occurs about 6 - 10 times.

3. The problem will always go away simply by restarting the current track, although it sometimes takes two restarts to make in end.

4. The problem never seems to happen after a track is successfully launched. If it is going to happen, it happens right away in a track and persists.

5. VLC is clearly changing processes from track to track, either with a manual restart or a natural transition from track to track. I can see this by watching my Task Manager performance graphs and noting how all the cpu activity changes from one core to another on my Intel i5 quad core processor, and how virtually all of the VLC activity is confined to one single core at a time (at least with this current as of last night 2.0.0 nightly build). For all the above reasons, it would seem that VLC is doing something different at times with these track changes.

6. Once the problems starts, if I open a new folder on the desktop and scroll rapidly up and down the folder, the interfering sound goes up in quantity (not volume) dramatically. I can "hear" the scrolling. The added interference is directly related to how fast I scroll. This creates the exact same sound as the underlying problem, just much more of it. I hope this point in particular helps you.

7. Finally, probably totally unrelated. I had noticed that playing the VLC player causes an accelerated conversion of memory from "free" to "cached" until free memory reaches zero. Other programs don't seem to do this. Superfetch seems to do some of this then stop, with free memory not near zero. Now, to me, here is the interesting part. As I was listening to the Peterson set this morning with Task Manager on and visible, I noticed that there was no memory conversion for the first 10 tracks, then all of a sudden, it began. Out of curiosity, I stopped the playback (stopped not paused) and the memory conversion stopped also. It started back up again on resuming playback, and would reliably start and stop with starting and stopping the player. I can't imagine what VLC is doing in the background that would cause this in the first place, let alone do so with a 30 minute or so delay before starting?

Thanks for your attention. I really hope you can fix this. I am now playing all my blu rays videos of my htpc and with a solution to this problem, will also be exclusively play all my high end audio off the same pc. In the case of the audio, a nice reprieve from having to create and play optical discs. And, as often as this issue occurs, I can't quite do this.

Thanks again.....

[VLC_help]

6. Could you try with external sound device? (USB soundcard or headphones)

[dmast]

I don't have one but will try to borrow or buy an inexpensive one to try. Will update you.

[dmast]

I just put my USB d/a online today, and the audio distortion problem disappears. I played 10 straight tracks from my test folder with no problem. Upon restoring the original main bus d/a, the problem re-occurred on the second track and often after that.

So, where does that leave us? Is there anything you can do to the player, or that I can do to my pc to solve this problem?

Your help on this is greatly appreciated! Thank you....

[VLC_help]

It is either driver issue or grounding issue. Usually cheap power supplies pass forward unwanted noise which might cause problems for internal components (like for PCI soundcards).