[Matroska-devel] Re: Re: Tag names

Age Bosma agebosma at home.nl
Mon Mar 15 16:51:14 CET 2004

Paul Bryson wrote:

>>Is the Matroska page I refered to the most up to date information
>>available? You said you changed it but where is it changed?
> I updated it on my harddrive, but hadn't committed to CVS yet.  Its committed
> now.

Ok, cool, please keep me informed of any other changes being made to 
your file later on.

>>The green area's: You seem to be using BITSPS (bits per second) but
>>aren't bits per minute a more widely used unit? 
> Perhaps you are thinking of "Beats per minute" as I have never heard of "Bits
> per minute".  Bits per second refers to the bitrate, or the rate of data
> transfer.  Beats per minute is an audio term refering to (I'm not even sure how
> to define this).  I'm pretty sure that Matroska is supposed to have a Beats Per
> Minute tag.  Is there a common one that fb2k currently stores?

Yeah, you're right, my mistake, unmarked it now.
I don't know about a foobar field being used for this. Let's hope more 
people will respond in the forum thread. Maybe we should notify peter 
about the thread?

>>You refer to the id3 CONTENTTYPE for the genre but according the the ID3
>>list GENREID should be used, shouldn't it? GENRE is the actual used
>>field name instead of GENREID though... Also, is there realy a need to
>>use two different tags to refer to the audio and video genre? Imo it
>>should be judged by the used context if it refers to audio or video.
> If a tag is set for a Chapter instead of a Track, then it becomes important to
> know which you are refering to because it will refer to both a video and audio
> track.  Is it a music video or a movie?


>>And finally SET_PART, the current description is "the total number of
>>tracks on a disc" but judging by the field name itself it's refering to
>>a single part instead of the total. If the current description is
>>incorrect, the field would be the same as the id3 PARTINSET field.
> This is another case of a missing tag.  There are supposed to be two tags to
> hold the data that might be held in the TRCK tag.  One holds the total number of
> parts.  The other holds the part that this item refers to.  Unfortunately I am
> not sure which exactly SET_PART refers to.  Can you think of more descriptive
> names for this.  Maybe TOTAL_PARTS and PART?

I think SET_PART is self descriptive enough as it is refering to 
PARTINSET in id3. This can be used for the TRACKNUM info as well because 
it's basically the same.
Maybe TOTAL_SET_PARTS should be added for the total information.

>>The blue area's: Isn't there a tracknumber field included in the
>>Matroska tag fields? Shouldn't there be? 
> Yes, there should be.  See above with the SET_PART.  I don't want to use
> TRACKNUMBER however as that creates confusion with the Matroska meaning of the
> word "track".

You got a point. See SET_PART comment again.

>>Also the COMMENT field, this one appears to be left out in Matroska as
>>well. Imo a comment field should be included. E.g. what if you want to
>>mark a track being a bonus track of a disc? Or what if the track is
>>featuring a different artist?
> There is already a tag labelled "COMMENTS".  If a track features a different
> artist, then that track should be labelled with that artist.  That information
> shouldn't need to go in the COMMENTS tag.

In the current specs it's listed under Image Specific which it shouldn't 
if it can be used outside of image info as well, that's why I didn't 
include it in the first place.
As for the featuring of an artist, I must partially disagree, suppose 
you have the latest Norah Jones album, the artist of that complete album 
is Norah Jones but on one track ("number 07 - Creepen' in" to be more 
specific) Dolly Parton is singing together with her as well. Because 
Norah Jones is the main artist of that album Dolly Parton shouldn't be 
included in the main artist label just for that one song imo.
On the other hand Dolly Parton could be included in the INVOLVED_PERSON 
label for that one track but I'm not realy sure if this would be the 
best place for it. What I do know is that introducing a new label for 
this kind of information would be overkill.

> Do you want to some how indicate items that would be nested tags in Matroska,
> such as WWWARTIST?

Sure, although I don't know for sure which field should all be marked. 
I'll dig in the excel file a bit more to see what I can do.

> I want to make some specific examples of how to use certain tags.  For instance,
> take a movie, and say where to store each piece of data for that movie.  Then
> take a CD, and say where to store each piece of data for that CD.  Preferably
> they would each be part of a large, multi-volume set, containing all of the
> different levels of titles that could be used.  Do you have any ideas of what to
> use for this?

At the moment no. At least not Matroska specific.
I'll dig into that a bit more as well and try to find out how the 
Matroska tags should be set up exactly. If we work out a good system for 
Matroska this will be very useable for xml output as well and not just 
limited to Matroska. The reason why I started all this in the first 
place ;-)
If a "standard" xml output can be developed introducing a new namespace 
for it and maybe combine it with rdf and the dublincore we would have a 
very powerfull format which can be used on a very large scale. (I'll 
just keep on dreaming for now ;-) )

One final thing I would like to get off my chest. I was amazed to see 
how many tags where included in Matroska. I never expected to see an 
attempt to combine all current tags into one system.
Like mentioned in the thread you pointed to earlier the whole tag field 
stuff should be cleaned up a some stage although I agree in being 
compatible with other tag fields as well. As a step in the right 
direction we could created 2 specs. Something like "Matroska" and 
"Matroska lite" where the first one includes all the tag fields like now 
and the lite version only includes the more usefull and necessary 
fields. In the Matroska specs people will be pointed to the lite version 
as much as possible and if realy realy realy needed people can use the 
complete spec of tag fields. What's your opinion about this?



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