Issues when exporting M4A

[Gyugas]

Xubuntu 18.04 LTS
Audacity 2.2.1
Built in software manager


1. Every time i try to export a M4A file i get the error: "FFmpeg : ERROR - Couldn't write last audio frame to output file.". This happens just after the exporting finishes. This however doesn't seem to generate any problems when playing the file.

2. A problem with the quality setting when exporting. In windows (2.3.2), when i set the quality to 500 the files always export as 196kb/s which i find optimal for my needs. But no matter the quality i set in Xubuntu (2.2.1), the file always end up being 485kb/s.

[steve]

1. Every time i try to export a M4A file i get the error: "FFmpeg : ERROR - Couldn't write last audio frame to output file.". This happens just after the exporting finishes. This however doesn't seem to generate any problems when playing the file.

That's a bug that has since been fixed. As far as I'm aware it is "mostly harmless", though the M4A file is actually missing the last fraction of a second (usually around 0.03 s).

2. A problem with the quality setting when exporting. In windows (2.3.2), when i set the quality to 500 the files always export as 196kb/s which i find optimal for my needs. But no matter the quality i set in Xubuntu (2.2.1), the file always end up being 485kb/s.

This has also been fixed in later versions of Audacity, though there is a minor residual issue:
"that we have the same slider and setting for both mono and stereo. So we must accommodate the minimum mono (currently 98 kbps) and maximum stereo (which is 320 kbps). But mono doesn't use the top part of the range, and stereo does not use the bottom part."