The capabilities used to choose the output of the Track's elements.
Internally, this is used to select output streams when several may be available, by determining whether its Pad
is compatible (see NleObject:capss for nlecomposition). As such, this is used as a weaker indication of
the desired output type of the track, **before** the restriction_caps is
applied. Therefore, this should be set to a *generic* superset of the
restriction_caps, such as "video/x-raw(ANY)". In addition, it should match with the track's
track_type.
Note that when you set this property, the CapsFeatures of all its Structure-s will
be automatically set to GST_CAPS_FEATURES_ANY.
Once a track has been added to a Timeline, you should not change this.
Default value: GST_CAPS_ANY.