[Matroska-devel] Matroska v3

Steve Lhomme slhomme at matroska.org
Sat Feb 26 11:16:46 CET 2011

On Thu, Feb 24, 2011 at 8:17 AM, Joseph Ashwood <ashwood at msn.com> wrote:
> I'd like to see a few metadata changes for V3. Not having read the spec
> recently, and admittedly not having as much time to dedicate to this as I
> would like, some of this may already be included.
> I know of one company with an interest in adding some metadata to various
> elements. This metadata would be safely ignorable, so any parser that
> doesn't understand the metadata can and should ignore it with no detrimental
> effects, except the small increase in file size. As such I'd really like to
> see some clarity in the spec that this is acceptable, along with clarity
> that such additional metadata MUST be safely ignorable. How widespread the
> use of this will be is debatable, but the hope is that files from [sorry not
> giving out even that data yet, at least not publicly] will be widespread.

By ignorable, you mean not visible if not supported ? The best way to
do that would rather be to use proprietary EBML elements. Any Matroska
parser will skip such data if they don't know what they do. For
example DivX has some proprietary extensions and it doesn't create any

Tags on the other hand can be shown, since they have a user friendly name.

> The same company will be offering contributions on the tag discussion that
> was happening recently, but will happily work within whatever restrictions
> are finalized. The only problem I see with the proposals so far is that they
> don't cover that many videos and audios have different edits. Just off the
> top of my head, I know that Caligula had at least 6 different edits, ranging
> from a generally acceptable rating suggesting adult supervision, to one edit
> that is illegal throughout most of the world, not including the pre-release

There is a EditionUID target exacly for that. Although the specs
should be clearer on how mixing targets should work.

> edits. Add in releases that are language specific, the various "child-safe"
> editting services, and the others. It is actually quite easy for a
> particular movie to have over a dozen versions, and having worked on music
> significantly, there are often several final versions; one for radio, one
> for CD, one for online sales, one for radio-edit CD, one for etc. Having
> some way for the file to identify itself among these different versions
> would be useful.

Do you mean for the user or for archiving ? I know for music there is
ISRC that exactly defines exactly one recording that can't be
mismatched with any other. I don't know if there is something like
that for movies.

> The big problem is the naming, unlike software versions, very often the
> versions are simultaneous, and I'm open to suggestions.

This is more for human reading. Tags can be edited and users might
change it to the way they prefer. I'm not sure one set of naming rules
could ever apply. Artists will definitely use outside of any
boundaries for fun.

Steve Lhomme
Matroska association Chairman

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