[FFmpeg-user] When encoding mp3 at low bitrate FFmpeg gives error report.

[bat guano]

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> ...The sample rate 22050 is not part of the MPEG-1
> audio layer III spec (but is part of the MPEG-2 audio layer III spec).
> ffmpeg is only trying to write a MPEG-1 spec header, so it fails, and
> you see the error message.
>
>
> Cheers
>
> Tom

Thanks Tom, that explains it. ;-)

I can confirm FFmpeg gives the error message when using other MPEG-2 layer III settings.

eg
ffmpeg -i foo.flac -c:a libmp3lame -b:a 64k -ar 22050 -ac 1 foo.mp3

and also with MPEG-2.5 layer III settings.

eg
ffmpeg -i foo.flac -c:a libmp3lame -b:a 64k -ar 11025 -ac 1 foo.mp3

But when I use lame like this:-
lame -b 16 --resample 22050 foo.wav foo.mp3
or this:-
lame -b 16 --resample 11025 foo.wav foo.mp3

It converts OK, without showing an error.

Shouldn't FFmpeg, when using libmp3lame, be able to convert to MPEG-2 and MPEG-2.5 without showing errors too?