RE: Excess URI schemes considered harmful

On Tue, 25 Sep 2001, Harald Tveit Alvestrand wrote:
> I have trouble imagining the case where you would want to use [a URI
>representation of a media type]

In SMIL 2.0, one can use the "systemComponent" attribute to query a media
player for a particular capability.  systemComponent takes a URI as a

An example use:
  <seq systemComponent="ContentType:image/png">
    <img src="slide1.png" dur="5s"/>
    <img src="slide2.png" dur="5s"/>
    <img src="slide3.png" dur="5s"/>
    <img src="slide4.png" dur="5s"/>
  <img src="sorry.jpg"/>

More details can be found in the specification:

If the "image/png" media type is supported, the sequence of images should
be played.  Otherwise, the "sorry.jpg" image should be played.

In hindsight, we probably should have created a special "systemMediaType"
test attribute (which would take the native media type string), but we
thought that the mapping between URIs and Media Types was a rote exercise.
"systemMediaType" is on the wishlist for SMIL 3.0, presuming we get around
to doing that.


Received on Wednesday, 26 September 2001 03:18:32 UTC