I have a wav file recorded at 48 kHz. I want to render to mp3 using the factory presets.
As far as I can tell the sample rate is set to Match Input Stream in all of the presets so I would expect the resulting file to be 48 kHz, same as the source file. But some of them (pictured in red) change the sample rate to 44.1 kHz. Is this a bug or am I missing a setting somewhere?
The final mp3 sample rate is decided by the encoder. Usually, this is the same as the input, but it could be reduced. Indeed, remember that the mp3 process is to remove the most minor hearable frequencies to reduce the size of the file. The encoder might decide to remove the frequencies above 20 kHz hence switching from 48k to 44k.