[Matroska-devel] Matroska v3

Steve Lhomme slhomme at matroska.org
Sat Feb 26 11:08:02 CET 2011

On Thu, Feb 24, 2011 at 7:51 AM, Joseph Ashwood <ashwood at msn.com> wrote:
> Since we seem to be moving decidedly towards a V3, this seems to be a good
> time to discuss adding significant features. I've seen some interest from
> manufacturers to implement haptics in video moving forward.

That sounds interresting.

> The devices for doing this are so varied that a single standard really isn't
> possible yet. The devices themself vary from a subwoofer-like device
> attached to the bottom of the seat to certain devices of an adult nature.

Sounds like different track types would be needed to do that. And
corresponding "codecs" to define the effects to use with their

> Right now, haptic devices are extremely rare, but I've seen either market
> ready or working prototypes for roughly a dozen such devices. Its also worth
> noting that multiple devices may be used at the same time (e.g. one seat
> shifter, one wind simulator).
> In terms of how to implement, I think the appropriate path is 0 or more
> separate streams, of which 0 or more streams may be active, each stream
> dedicated to one device (although some devices may be compound). Many of the
> streams will be very similar to subtitle tracks, although as implemented
> right now many of them include DRM. I'm in favor of it simply being their
> problem to make that work, most of them don't seem to mind that. The other
> option that seems to be used is an audio track, again I think its up to them
> to make it work, even though this on is easier (heavily compressed audio and
> a low pass filter).
> So what is the view on including a new type of stream for haptics devices?

As said above it's probably good to have a separate track for that (or
more than one). In the end the audio and video streams should work
just like they do now. It would be possible to use BlockAddition for
an extra sub-woofer track using the same audio codec. But most audio
codec have some kind of high pass filter to remove everything under 20
Hz. (I think the CD format too). So a special codec may be needed for
that as well.

It would be good to have a list of possible types of haptics to know
how we can handle them. For example the sub-woofer may not say it's an
audio track but a sub-woofer track, so that players that don't have
such capabilities skip it. For the other streams they may just be an
extra "haptic" track type and the codec would define what it does ? So
that leaves freedom on what features a "codec" can provide.

Steve Lhomme
Matroska association Chairman

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