Audio Resampler causes momentary speed/pitch shift for seconds

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userr2015
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Audio Resampler causes momentary speed/pitch shift for seconds

Postby userr2015 » 15 Nov 2021 01:03

When the standard audio resampler handles what's assumed to be a performance penalty, the audio will have a slight speedup or slowdown for several (approximately 7) seconds. This appears to be a very universal behavior that happens on VLC, regardless of platform, but not on any other media player.

This can be easily triggered by rapidly tapping/clicking the seek bar a few times. Other times this may happen occasionally just from simply loading another media file, or as the result of a random performance blip. I am far from being the only person who acknowledges this behavior.

On my Windows 8.1 PC, I have found that this happens when I leave the Audio Output module on Automatic, Windows Multimedia Device, or WaveOut. However, this appears to go away when I have it set to DirectX audio.

I would like to see a proper discussion over this, as I do believe this is improper, despite some other discussions hinting that this is normal Audio Resampler behavior. If this really is a bug, perhaps it should be acknowledged by the developers as one and get fixed.

Lotesdelere
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Re: Audio Resampler causes momentary speed/pitch shift for seconds

Postby Lotesdelere » 15 Nov 2021 14:29

Try to disable time stretching in the audio preferences in Menu Tools -> Preferences -> Audio
Use a faster resampler or no resampler at all.

After the changes save the preferences then exit and restart VLC.

userr2015
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Re: Audio Resampler causes momentary speed/pitch shift for seconds

Postby userr2015 » 15 Nov 2021 17:46

Try to disable time stretching in the audio preferences in Menu Tools -> Preferences -> Audio
Use a faster resampler or no resampler at all.

After the changes save the preferences then exit and restart VLC.
As I mentioned, I already don't experience this issue after I set the Audio Output to "DirectX audio". I've confirmed this also happens on another PC that's running Windows 10 My purpose is not to seek a remedy for my personal experience.

Setting the Audio Output back to Automatic, I've tested each of your suggested setting tweaks:
  • Time Stretching doesn't do anything about this
  • Most Audio Resampler options have the same identical pitch/speed inconsistency
  • One Audio Resampler does remedy this behavior; Speex resampler. This introduces a new but however, after rapidly seeking, the audio becomes severely stuttery, usually until the next non-rapid seek
  • Disabling the Audio Resampler also remedies this, but this brings the disadvantages of not having a resampler, including the inability to hear audio with a mismatched sample rate
Do note, none of these suggested tweaks are completely applicable to the Android version of VLC, as the settings are not available to the user, who is forcefully stuck with this.

Every other media player that is not VLC does not have this pitch/speed irregularity, yet it's universally known to be the default on VLC and I've seen this reported by many people, including on Reddit, several forum websites, and even a couple people I know personally who call this a bug. This isn't about rapidly seeking, it just so happens to be the easiest way to reproduce it, rather it's how Resampling is done in general. As this topic is on the official VideoLan Forums, I was hoping to initiate a proper dialogue about this at the software level, rather than having it brushed off as a personal or configuration problem.

Rémi Denis-Courmont
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Re: Audio Resampler causes momentary speed/pitch shift for seconds

Postby Rémi Denis-Courmont » 15 Nov 2021 17:50

This is a well known problem, that will take some more years to be fixed.
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LoganDark
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Re: Audio Resampler causes momentary speed/pitch shift for seconds

Postby LoganDark » 15 May 2024 15:22

This is a well known problem, that will take some more years to be fixed.
Can confirm it has been years and I'm still experiencing this issue.

I've been experiencing it on and off since 2.2.4 on macOS. It's now been happening for the past couple days on 3.0.19 Vetinari on Windows and I seriously cannot stand it. It completely ruins the audio. :(

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Re: Audio Resampler causes momentary speed/pitch shift for seconds

Postby Rémi Denis-Courmont » 15 May 2024 17:55

I meant that it would take at least a major release, and there hasn't been one since I wrote that.

Feel free to try VLC 4.0 preversions
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LoganDark
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Re: Audio Resampler causes momentary speed/pitch shift for seconds

Postby LoganDark » 15 May 2024 17:56

VLC 4.0 preversions
Those exist? I'll give them a try, thanks. (Also didn't realize you were a dev.)

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Re: Audio Resampler causes momentary speed/pitch shift for seconds

Postby LoganDark » 15 May 2024 18:14

I gave VLC 4.0 a try and I didn't get to the point of figuring out whether this is still a problem because I was too distracted by the playlist view. Is it impossible to get the playlist to take up the whole upper part of the window like it used to in prior versions? None of my audio has cover art and VLC won't let me resize or move the playlist panel to cover more than 50% of the window, so I'm losing the other 50% for no reason. Apologies if this is covered in a FAQ but I couldn't find a VLC 4.0 FAQ either. Additionally, the MSI installer deleted my existing version of VLC even though I told it to install into its own folder in Program Files, `C:\Program Files\VideoLAN\VLC4`. I was fine with it taking over the Start Menu entries since it didn't ask what Start Menu folder I wanted it in, but `C:\Program Files\VideoLAN\VLC\vlc.exe` simply no longer exists, and I did not expect that, or tell it to do that. I also tried to sign up for an account on the GitLab to file some tickets, but it says my username is in use, and no matter which email I put in, it's not sending me anything. Even if I put my old Trac email in, just in case those accounts were imported into GitLab, nothing happens.

LoganDark
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Re: Audio Resampler causes momentary speed/pitch shift for seconds

Postby LoganDark » 19 May 2024 14:39

oh well, after using 4.0 for a few days it seems like this specific issue is no longer present, but 4.0 has so many other issues that i'm going to have to downgrade again (lack of tooltips, scrub bar hitbox is too small, can't navigate playlist by arrow keys, can't set the playlist to full width, playlist items are too large / lack of real list view, no typeahead or search, stop button resets scroll position, windows audio mixer volume keeps resetting to 42% even though the music volume doesn't rely on the mixer anymore, etc.)

i can't report any of these issues due to being unable to make an account on your bug tracker / gitlab, so as long as i'm going to keep running into them, i'm going to go back to 3.0

-vicuna


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