[vorbis] vorbiscomment question.

[xdfisl]

> There is no round-tripping problem with --raw regarding character
sets.
> The problem is with delimiting comments.  Vorbis comment names are
limited
> but the content can contain any characters, including =, line endings
and
> even zero charcodes (IIRC).

Okay, so --raw makes round-tripping okay for weird and non-standard
characters but the problem with line endings is still present regardless
of whether you specify --raw or not?

<p>Thanks for your reply,
Dani

> -----Original Message-----
> From: owner-vorbis at xiph.org [mailto:owner-vorbis at xiph.org] On Behalf
Of
> Beni Cherniavksy
> Sent: 22 August 2002 1026
> To: vorbis at xiph.org
> Subject: Re: [vorbis] vorbiscomment question.
> 
> On 2002-08-09, xdfisl wrote:
> 
> > Hello,
> >
> > I am writing a script which reads and writes vorbis comments using
the
> > vorbiscomment utility from vorbis-tools. I have just one question
> > regarding the --raw switch.
> >
> >    Raw mode (--raw, -R) will read and write comments in utf8,
> >    rather than converting to the user's character set. This is
> >    useful for using vorbiscomment in scripts. However, this is
> >    not sufficient for general round-tripping of comments in all
> >    cases.
> >
> > What is the "user's character set" likely to be on a Debian Linux
> > system?
> > By round-tripping I assume it is meant to read, modify, and write
back a
> > set of comments -- which is exactly what I am looking to do.
> > I assume not using --raw would only be appropriate if the comments
do
> > not contain any 'special' characters which are not supported by the
> > shell character set? But why would --raw not be sufficient in some
> > cases?
> >
> Sorry for answering so late, I understood the point just now ;-)
> 
> There is no round-tripping problem with --raw regarding character
sets.
> The problem is with delimiting comments.  Vorbis comment names are
limited
> but the content can contain any characters, including =, line endings
and
> even zero charcodes (IIRC).
> Currently vorbiscomment outputs one comment per line (and if it
contains
> line endings, it will take several lines) and expects to read one
comment
> per line.  So a multiline comment will be read back as just one line
> comment followed by some lines of garbage:
> 
> TITLE=first line of
> a 2-line comment
> 
> As long as these lines are not legal comments, one could attempt to
treat
> them as continuation lines but this is not reliable (a comment could
> contain a line `FOO=bar' that would make this ambiguous) and it
deproves
> vorbiscomment of almost all error checking.
> 
> However I do see a way to a syntax allowing multi-line comments:
> mandatorily start all continuation lines with a syntax that can't
start a
> comment, for example a single `=' (IIRC 0-length named comments are
not
> allowed; I can't find it v-comment.html now so can somebody
> confirm/disprove this?):
> 
> TITLE=first line of
> =a 2-line comment
> FOO=another comment
> 
> This has the draw back of more than one line per comment (bad e.g. for
> grepping on comment name, etc.) so maybe an option for escape
sequences
> for newlines putting all the comment on one lines could be better...
> 
> --
> Beni Cherniavsky <cben at tx.technion.ac.il>
> 
> Awake! Awake! Fear, Fire, Foes! Awake! Fire, Foes! Awake! [Tolkien,
LOTR]
> Fight software patents:  http://lpf.ai.mit.edu/
> If you know what's the situation in Israel concerning software patent,
> could you please enlighten me?
> 
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