Incredibly slow import in 2.3.0


An 8m:40s long .opus file takes 4 seconds to import in 2.2.2 and 37 seconds to import in 2.3.0.

This is unacceptable. What is going on here?

Windows 10 Pro x64 1803

We had a report like this recently that was caused by their antivirus app scanning the project files before allowing the project to open. Perhaps the same in your case. If this is the problem, the white-listing “.au” files may fix it.

I’ve noticed that import through FFMmpeg (e.g. AAC/M4A files) is noticably slower after upgrading to Audacity 2.3.0. Disabling my Antivirus (Avast) does (as expected) not fix this.

Is that “a bit slower” or “incredibly slow”? The original post is about a 900% slowdown. Are you writing about the same thing?

Import of 3 minute song (tested with .ogg through FFmpeg):

Audacity 2.2.2: approx. 2 seconds
Audacity 2.3.0: approx. 25 seconds


How are you doing that, and why are you doing that?

I tested this with importing a one hour AAC (M4A) audio file - and although my results are not as extreme as normann1974 reports, I can confirm that 2.3.0 is indeed slower at that import than 2.3.0. But the good news is that the upcoming 2.3.1 appears to have fixed this and is now even faster than 2.2.2.

2.2.2 15 seconds
2.3.0 82 seconds (5.55 times slower 0 normann1974’s is 21.5 times slower)
2.3.1 alpha 9 seconds

I don’t recall us ever logging this as a big on our Bugzilla tracker nor doing anything to fix it. The one bug that we did have and have fixed for the upcoming 2.3.1 was that Nyquist effects ran slower in 2,3,0 compared to 2.2.2 and earlier Audacity versions. See:

Since this appears to be already fixed I don’t propose to log it on Bugzilla (as an already fixed P1 bug) - unless you, Steve, think that I should for completeness.

@normann1974: we should be building Release Candidates for 2.3.1 sometime in January - would you be interested in testing your use case on that?


Audacity is doing that. Preferences → Libraries → FFMPEG Import/Export Library.

I just tried the latest alpha as well. Import of the same file I tested with earlier takes 3 seconds, slightly slower than 2.2.2, but remarkably faster than 2.3.0.

Yes, I could do that if needed. Could someone write the announcement of the RC here or send me an e-mail when I need to do something?


By default, Audacity uses “liboggvorbis” (not FFmpeg) to import OGG files, though it is possible (but not recommended) to import OGG files with FFmpeg.

To check to see which importer Audacity is using:

  1. Launch Audacity (or close and restart Audacity)
  2. “Help menu > Diagnostics > Show Log” (
  3. Clear the log.
  4. Import an OGG file.

The log will show something like:

14:03:57: Opening with liboggvorbis
14:03:57: Open(...../untitled.ogg) succeeded

2 or 3 seconds seems close enough considering that there are many other variables. If possible, could you do a comparison of Audacity 2.2.2 vs 2.3.0 with a much larger file? (20 seconds vs 21 seconds is insignificant, but 20 seconds vs 30 seconds may be something the developers want to fix).

For comparison I tested the same one hour AAC file on my Macbook Pro running Mojave 10.14.2
Here I find that 2.3.0 and 32-bit 2.3.1 are actually a bit quicker than 2.2.2 - I can’t trest yet on 64-bit 2.3.1 64-bit for Mac as we haven’t yet got the 64-bit FFmpeg library compiled and installed for testing.

2.2.2 33 seconds
2.3.0 25 seconds
2.3.1 alpha 32-bit 25 seconds

I don’t understand why the Mac version is so much slower than Windows for this test - theye are both hi-spec machines with fast non-rotating SSD drives …


There are many platform specific optimization that can be made when writing and building applications. For example, SBSMS time stretching is significantly faster on 64-bit Linux than on 32-bit Windows or Mac, because of ONE optimisation switch when compiling SBSMS (I don’t know if Paul has applied this optimisation for 64-bit Mac builds).

Overall, Windows, Mac and Linux are likely to run applications at about the same speed on similar hardware, but there are often differences in speed with specific task due to different optimisations. Linux can often appear quicker because it tends to use far less horsepower doing background tasks.

13:09:59: Mime type is *
13:09:59: Opening with liboggvorbis
13:09:59: Opening with libav

I haven’t configured anything but add the FFMPEG library so that Audacity can read all the formats it needs to.


Incredibly slow audio file import

problem still happening a long way down the road
in my case 2023 on Ubuntu 22.04 with version 3.3.3 Audacity AFTER an update from 2.4.2

going to Preferences/Libraries and locating seems to fix it [here it was /usr/lib/x86_64-linux-gnu/]. It goes from 2.30mn to 28s to load a 35mn file

annoying tho but it seems in this case the update did not locate the and therefore loads REAAAAAAAAAALLLL slow

Thought i would share as it may help others too