It should be very rare that MP3s contain frames of different sample rates. It is usually a sign someone has tried to concatenate parts of two completely different MP3 files/
I think this is not rarly as you think. VBR file is totally common in use, such as "Sleep away.mp3" in Windows 7. And i have this problem files many times
Would u support this feature one day?
When you want to read info about an MPEG file, it is usually enough to find the first frame, read its header and assume that the other frames are the same. But this may not be always the case. Variable bitrate MPEG files
may use so called bitrate switching, which means that bitrate changes according to the content of each frame.