Report the bitrate of VBR-encoded files as the average bitrate

[MichaelZer0]

mp3.js appears to report the bitrate of a VBR-encoded file as just 128 (maybe the bitrate of the first frame it encounters?) The average of all frames would be more useful, perhaps also with a flag to tell that the file is VBR if the average just so happens to be an integer.

[devongovett]

You're right, it is from the first frame in the file. In order to get the actual average bitrate though, we'd need to read the entire file first I would think. This isn't currently possible since the entire file isn't loaded at the time the format info is emitted.