Can't get bitrate for mp3 with protectionEnabled bit set

[Tom Kleinpeter]

Hi folks,

I'm trying to understand why I can't get the bitRate for an mp3 one of
my users is having trouble with.  The track plays fine in several
players, but after constructing the File object like this:

TagLib::MPEG::File f( path, true, TagLib::AudioProperties::Fast);

when I step into f.audioProperties(), I see that it has detected the
number of channels (2) and the sample rate (11025), as well the
version (2.5).  However, the bitRate, length, and layer are all 0.  I
noticed that protectionEnabled bit is true, which is something that I
haven't seen before.

I don't know anything about the protectionEnabled flag -- could that
be related to the fact that I can't get the bitRate/length?

Thanks,
Tom