LAME MP3 frequency as source defaults to 32KHz

[cornishman]

It appears that the dBpoweramp 17.0 batch conversion for LAME constant bit rate fails to honour the input bit rate when required. It generates 32KHz when fed with 44.1KHz and 48KHz files. This has been an issue for a long while and yes it's easy to work around but would be nice to have fixed.

[Spoon]

Re: LAME MP3 frequency as source defaults to 32KHz

It is lame which decides this, unless you force a frequency that is how lame is designed. Note this is only for lower bit rates, if you encode 320kbps CBR then you get 44KHz with the frequency set [as source]

[cornishman]

Re: LAME MP3 frequency as source defaults to 32KHz

Thanks Spoon.
So you are saying that when the MP3 encoder has the output frequency selected as "[as source]", then Lame decides on what the output rate should be based on the chosen quality?
The lame CLI lists the "-resample <selected frequency>" for forced output frequency which is dropped when the "[as source]" option is chosen so this sounds correct. I would expect that a 44.1KHz input sample rate file would be generated with a 44.1KHz sample rate, but it sounds like there is more optimisations going on in the algorithm that alter the sample rates too.

[Spoon]

Re: LAME MP3 frequency as source defaults to 32KHz

Yes the encoder chooses based on various calculations, as decided by the designers of the lame codec.