Re: [PATCH] tracker: use "nfo" ontologies for media

[Jussi Kukkonen <jku linux intel com>]

On 02/03/2011 12:38 PM, Juan A. Suárez Romero wrote:
> On Thu, 2011-02-03 at 11:53 +0200, Jussi Kukkonen wrote:
>> The ontologies are a bit weird/incomplete here: nmm:Video is a
>> superclass of both nfo:Video and nfo:Audio. This makes some sense on
>> it's own but is fairly inconsistent with the lack of nmm:Audio --
>> there's no way to define non-music audio (say a podcast) in the
>> multimedia namespace so the only way to do that is with nfo:Audio
>> which
>> then gets tangled up with video...
>>
>> Practical alternatives include
>>   A) more complex matching (grilo "audio" would mean something that is
>> "nfo:Audio" but is _not_ "nfo:Video").
>>   B) pretend all audio is music: IOW match only "nmm:MusicPiece". I'd
>> still continue using nfo-namespace for other media.
>>
>> Option B is what most people seem to be doing at the moment -- the
>> downside of this is that if anyone later tries to do the right thing,
>> their data will appear broken in other apps (this is how I found the
>> problem in he first place -- a tracker miner doesn't necessarily know
>> if
>> an audio item is music so I thought nfo:Audio made perfect sense in
>> that
>> situation). Any opinions? 
> 
> 
> I do not have a deep understanding about how miners works. I guess that
> miners crawling a video file mark it as nfo:Video & nfo:Audio just
> because it is a video file, and then inspect the tags to mark them as
> nmm:Video.

Well, there probably are no video files that aren't nmm:Video? Otherwise
that's my understanding as well.

> I guess the same happens for audio files: they are nfo:Audio and, if
> they have tags, then are marked as nmm:MusicPiece[1].
> 
> The point is that I think miners can't distinguish between a music piece
> and other kind of audios, like podcasts. That is why nmm:Audio probably
> doesn't make too much sense.


I wasn't explaining myself fully: I meant that if there was a
"intermediate" class this could be avoided:
     nmm:MusicPiece  is a  nmm:Audio  is a  nfo:Audio
but there isn't so we have to make a non-optimal choice. I'll add this
to the tracker bug.

> So regarding the alternatives, so far I was following the (b) approach.
> But I'm not sure if *all* audio will be tagged as nmm:MusicPiece by
> tracker. What happens with a file with no tags at all? If actually all
> miners tag audio files as nmm:MusicPiece then I would go with this
> option.
>
> Else, I would go with option (a). In fact, I would go with (a) right now
> if nmm:MusicPiece were a nfo:Audio, but it isnt.


I _think_ all miners tag audio files as MusicPiece _and_ nfo:Audio, but
I agree it's probably safer to go with MusicPiece for now. It may make
sense to change to defining audio as "nfo:Audio and not nfo:Video" when
we can trust that to do the right thing... because only then can the
miners start doing the correct classification.

I'll send a new patch.

 - Jussi