On Sun, 1 Oct 2000, Michael Mutschler wrote:
> MT> It only needed so the decoder can compute the correct playing
> MT> time (and how to seek within the file) of mp3's encoded with
> MT> VBR. Hardware players may just ignore it.
>
> Not only for this, but to give information about the whole mp3-file
> when it is encoded with VBR.
>
> The usual way to get the information about a mp3-file is to look at
> the bitrate first MP3-Frame(s) and then calculate the playing time
> from filesize/bitrate. This works good as long as you don't have a VBR
> encoded file. Usually these files start with a low bitrate frames
> (~32kb) and the information is totally wrong then. The Xing-Header is
> encoded as a (invalid I think) MP3-frame, and stores information about
> the mp3-data.
Isn't that what MarkT said? :)
> Since my program displays icons for the mp3-files according to the
> bitrate, this gives wrong information on VBR-MP3-files without the
> Xing header.
Your program displays the icon with the bitrate equivalent or greater than
average? Would be nice if you could have 289 icons for all the possible
variable bitrates. i.e. 167v, 192, 192v, 205v etc.
Also, I noticed some times when your code would not display the full
id3v2 track name. I'll send you example file headers later.
NB MarkT I assumed LAME was causing these, due to it's Xing tag
problems. However, this is not the case. Sorry for any confusion.
> btw, how about a "--id3v2PaddingSize" option, where you can specify
> the padding size of the ID3-tag, so the editing of the mp3-files can be
> faster? No long copying of the complete MP3-data will be necessary on
> small changes then.
Good idea, for some. Although I don't think I'd ever use it. I rarely
modify v2 tags and if I do modify them, I correct them. I'd rather the
files were as small as possible.
Cheers.
Mark Powell - UNIX System Administrator - The University of Salford
Academic Information Services, Clifford Whitworth Building,
Salford University, Manchester, M5 4WT, UK.
Tel: +44 161 295 5936 Fax: +44 161 295 5888 www.pgp.com for PGP key
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