File properties

While I was thinking about this RTP thing (I'm glad a nice solution seem to be
appearing) I was thinking about what have been previously said : the person at
the other side of the transmission should be able to put the MCF data in a file
without much problem. And the file will be a valid MCF file.

Let's take the example of a live radio. You hear different chained track with an
different artist and title for this song. And for each track you use a different
Vorbis codebook (let's say you use Vorbis). For the codebook you have the choice
of putting it in the TrackEntry (in the RTP mode it would go in the Info
"channel") or alternatively attached to the first data Block of the Track (in
the data "channel"). But the codebook could also be changed during the same song.
The title and artist goes in the Info element (Info "channel").

Now the problem is that you have a resulting file like this :
(song1[Info][Data][Info{new codebook}][Data])(song2[Info][Data][info{new
codebook}][Data])

It appears that the Info relates to the following data in the stream.
But a basic MCF file could also have this kind of informations at the end (to
avoid rewriting the whole file when changing, a large comment for example). And
it would correspond to the data _before_ these informations.

So it appears that the artist and track name should be "global" to the Segment.
And in the resulting file of the RTP stream, each song would correspond to a
Segment. But what if the streaming server send this information many times
during the same song (since UDP is not reliable and this kind of info doesn't
require protection) ? There should be a way for the RTP stream to notify a
"change of Segment". Probably another channel for the level-0 element Segment.

It also means that in the spec there should be a field for each element, to say
if they are unique to a Segment or not. The "Multi" attribute is something
different. It means that an element can have multiple values for the same
Segment (like 3 different AuthorURL).


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