| Subject: | Digest calculation should ignore Xing frame |
I know this is my own module, but I'd like to show to interested parties
how I feel about this issue.
Xing frames look like audio frames, but they contain no sound, they are
silent; instead, they are like tags, containing meta info. They can be
changed on existing mp3 files, for example with VBRFix, without changing
the audio, and therefore the digest value should not change if you let a
program change this frame. In short: the Xing frame should be ignored
(skipped) for the digest calculation.
Other, similar empty frames are for example the "Lame" frame.
I'm working on the issue, but there is very little info on the internet
on how to easily recognize empty frames. It seems to me that Xing, the
company who designed it, simply went for the assumption that the
presence of the word "Xing" at a particular position in a normal mp3
frame is close to impossible.
To me, if I can help it, that assumption is simply not good enough.