Audacity 2.3.3 on ubuntu 16.04 libavformat.so.55

I had a working v2.3.1 version of Audacity, on ubuntu 16.04.06 (x64).

The ubuntu software-updater updated it to version v2.3.3 and it now cannot find working ffmpeg library.
Audacity now reports “FFmpeg library not found:”
"Audacity needs the file ‘libavformat.so.55’ to import and export audio via FFmpeg. Location of ‘libavformat.so.55’.

Looking for advice on how to fix or workaround the error.

This file libavformat.so.55 is not on my filesystem.

But I do have these libraries: libavformat.so.57 (for Google Earth, and gimp(snap) and also /usr/lib/x86_64-linux-gnu/libavformat.so.57.83.100'

I saw on the documentation page

"“Navigate to the folder that contains FFmpeg and select the file libavformat.so.55 or other appropriate libavformat version.”

I tried to use

 /usr/lib/x86_64-linux-gnu/libavformat.so.57.83.100

for audacity, but the diagnostics > show log has:

08:35:25: Actual avformat path /usr/lib/x86_64-linux-gnu/libavformat.so.57.83.100
08:35:25: Importing symbols...
08:35:25: Retrieving FFmpeg library version numbers:
08:35:25:    AVCodec version 0x396b64 - 57.107.100 (built against 0x373466 - 55.52.102)
08:35:25:    AVFormat version 0x395364 - 57.83.100 (built against 0x372164 - 55.33.100)
08:35:25:    AVUtil version 0x374e64 - 55.78.100 (built against 0x344264 - 52.66.100)
08:35:25: Error: AVCodec version mismatch = 2
08:35:25: Error: AVFormat version mismatch = 2
08:35:25: Error: AVUtil version mismatch = 3
08:35:25: Error: Version mismatch. FFmpeg libraries are unusable.

I have these ffmpeg packages installed:

ffmpeg/now 7:3.4.4-1~16.04.york0 amd64 [installed,local]
ffmpeg-dbg/xenial-updates,xenial-security 7:2.8.17-0ubuntu0.1 amd64
ffmpeg-doc/xenial-updates,xenial-updates,xenial-security,xenial-security 7:2.8.17-0ubuntu0.1 all
ffmpeg2theora/xenial 0.30-1 amd64
ffmpegthumbnailer/xenial 2.0.10-0.1 amd64
ffmpegthumbnailer-dbg/xenial 2.0.10-0.1 amd64
ffmpegthumbs/xenial 4:15.12.3-0ubuntu1 amd64

I guess that you must have got that from a PPA.
Look on the web page of that PPA to see if they still offer the 2.3.1 version for download. If they do, then:

  1. Uninstall Audacity
  2. Remove the PPA from your sources
  3. Manually install the 2.3.1 version.

If they don’t offer the 2.3.1 version, then you will either need to revert to the official Ubuntu 16.04 version, or build Audacity from the source code.
To revert to the official Ubuntu version:

  1. Uninstall Audacity
  2. Remove the PPA from your sources
  3. Reload the package list
  4. Install Audacity.