[vorbis-dev] Chapter titles and metadata

[Anthony Arcieri]

On Sat, 9 Jun 2001 10:54:43 +0100, Alan Swanson <swanson at uklinux.net>
wrote:

>Useful for long files, eg from live recordings, interviews, stories,
>plays and so on. I was thinking something along the lines of;
>
>comment[x]="CHAPTER=00:12:13 Third chapter"
>comment[x+1]="CHAPTER=00:13:56 Fourth chapter"

This is another case where a non-time specific block of metadata would be
useful.  While multiple chained streams can be used for delineating the
physical beginnings and endings of "chapters," it seems
reasonable to assume that one would want chapter-specific metadata.

As far as metadata goes, I think the following assumptions are reasonable:

Storage of non-time specific metadata will be contiguous within the file
or at least interleaved in such a way that is advantageous to whatever
parsing engine is being used, not interleaved in some quasi-random
fashion where we have to worry about the data being unparsable.

Furthermore, extraction of the non-time specific metadata for the purposes
of streaming is trivial.  The streaming server can extract this data
on-the-fly, strip the unnecessary metadata, and reinterleave it into the
stream in such a way that it remains parsable.  This avoids problems of
finding a way to interleave non-time specific metadata in such a way that
a "dumb" streaming server can be used.

If someone insists upon using a "dumb" streaming server which pays no
attention to the metadata whatsoever, then it really isn't that big of a
loss if the metadata arrives (initially) in an unparsable state since it
should become parsable later in the stream.

As far as time specific metadata goes, it's really up for grabs.  I think
it depends a great deal upon how much data we're talking about.  If it's
just lyrics/subtitles, that can just as easily be stored with offsets
along with the rest of the metadata rather than worrying about finding
another format.

I have no objections to using XML.  Any problems with parsability can be
solved by using reasonably intelligent utilities to manipulate the
metadata.  Any comments/ideas?

Tony Arcieri

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