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Subject: Broken recordings

Broken recordings

From: Bluechip <csbluechip_at_gmail.com>
Date: 2005-11-06

Hi,

Couple of Q's if I may...

How long is one frame of MP3 Audio?

Given I have walked the file ...What is the algorithm to create a correct
Xing TOC?

Notes:

There seem to be a bunch of unrequired 0's on the start of each file
because afaict (and I am prepared to be proven wrong) the Xing tag is a
fixed length.
...this can be patched on old files by modifying the ID3v2 tag length - but
files with extra DAC-bits will need to be rewritten anyway.

Some files have a bunch of garbage on the front which looks like the
tail-end of an audio frame.
...this will need to be removed. Could move the Xing header so it touches
the first non-broken frame and stretch the id3v2 tag to fill the hole!?

I have only detected EXTRA 0's in files tested to date.
...in fact only one at a time. I have yet to require a shift of anything
other than 1 (although my code should happily accumulate all shifts found
in longer recordings)

Some files have a truncated audio frame at the end of the file.
...this will simply need to be removed - hence wanting to know how long (in
mS, I presume) a single MP3 Audio frame is.

BC

PS. For some reason unknown to me, I am not receiving copies of emails I
send to the group - so please forgive me if I repeat myself (hopefully now
fixed with a new filter on my email client - to save a copy of my outgoing mail)
Received on Sun Nov 6 09:05:47 2005


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