mp3s Being Encoded at the Wrong Sample Rate

[pfo]

I have a client who requires 22.050 kHz 24kbit/s mono mp3s.

I ran into an issue a couple years ago, where it turned out that Pro Tools was encoding mp3s at 16 kHz despite my having selected 22.050 khz. After much experimentation, I finally found that selecting the "Faster" encoding speed instead of the "Highest Quality" option produced mp3s at the proper sample rate.

Then, with PT9, this bug seemed to be fixed, because I was now able to use the "Highest Quality" setting again and get the sample rate I'd selected.

Unfortunately, I've just now realized that this bug appears to have returned with PT10. The behavior is exactly the same -- it encodes at 22.050 kHz just fine, as long as I don't select "Highest Quality." If I do, it creates 16 kHz files.

Could it be a setting I'm not aware of? For what it's worth, I never changed anything between 8 and 9, when it started working properly. Nor did I change anything between 9 and 10 when it stopped again.

Can anybody else reproduce this behavior?

Anybody have any ideas?