Constrained Variable bit rate is not constraining

[mmynsted]

When using dBpoweramp Music Converter to convert audio files from Flac (also produced by dBpoweramp), the constrained variable bit rate setting is not transcoding the audio file to new file that is constrained to the upper bound defined.

I know this at least two ways. First because an audio player that does not accept files above 256kbps rejects the files and second because I can see the rate in playback, and watch it exceed the defined bounds.

- dBpoweramp Music Converter Release 2025-12-04 (1)
- macOS 26.2 (25C56) on Apple silicon

1. See target is set to `Constrained Variable Bit Rate`
2. Bit Rate is set to 256 kbps








Is there a fix for this?

[PeterP]

I'm sorry but there's no easy fix.

dBpoweramp passes arguments to Apple encoder (afconvert), asking for VBR file with constrained bitrate of 256000 bits per second ( -s 2 -b 256000 ).

It doesn't seem like Apple encoder restricts the bitrate enough for your use case.

To satisfy quirks of specific player, you might have to fall back to constant bit rate, or lower the bitrate enough to mitigate this.

What exact player has such AAC bitrate restrictions if I may ask? Maybe there's some other workaround for this.