[Bug 13333] audio, video (and source) elements require param children or equivalent

http://www.w3.org/Bugs/Public/show_bug.cgi?id=13333

--- Comment #44 from Glenn Adams <glenn@skynav.com> 2011-07-29 18:40:39 UTC ---
(In reply to comment #43)
> Examples of such specifications are CEA-2014-{A,B}
> (CE-HTML) [1], DLNA Guidelines 2009 [2]
> 
> [1] http://www.ce.org/standards/listings.asp
> [2] http://www.dlna.org/

To provide further documentation, consider the following language found in
CEA-2014-A, Section 5.7.1, which is normatively referenced by DLNA Guidelines:

"[Req. 5.7.1.a] The Remote UI Client SHALL support the control of audio and
video content
through the use of <object>-elements (see [5] and Annex G for a definition of
the <object>-
element), whereby:

1) The “type” attribute SHALL be included to define the MIME-type used for
the audio or
video profile that matches the content referred to by the value of the
“data” attribute.

2) An <object>-element SHOULD contain a <param>-element dlna_res_attr which
SHALL
contain the media properties attributes associated with the content resource
that is
referred to by the value of the data attribute. These media properties SHALL be
an XML
escaped string containing the space-separated list of attributes of one single
“res”-
element, of which the format and possible values have been defined by the DLNA
guidelines [2] related to a UPnP Content Directory Service (CDS). Employing
UPnP A/V
standards for the playback and control of A/V is OPTIONAL, not required.

3) An <object>-element of type video (as defined by [Req 5.7.1.b]) SHOULD
contain a
<param>-element to set the aspect ratio parameter of this object. This is an
initial aspect
ratio of the video content."

and

"This is an example of an <object>-tag used for including an object of type
video:

<object type="video/mpeg" id="vid1"
data="http://www.avsource.com/video/test.mpg">
  <param name=”dlna_res_attr“
   
value=”protocolInfo=&quot;http-get:*:video/mpeg:DLNA.ORG_PN=MPEG_PS_NTSC&quot;duration=&quot;1:25:34&quot;”/>
  <param name=”aspectratio“ value=”1.33”/>
</object>

Note: a Remote UI Client SHOULD provide native support for these
<object>-elements, and
is not required to support downloading of a plug-in to support these
<object>-elements."

In CEA-2014-B , this is expanded as follows

"[Req. 5.7.1.f0] The Remote UI Client SHALL support the following
<param>-elements as childelement
of the <object>-element used for instantiating the A/V control scripting
object:

a. <param name=”aspectratio” value=”…”/> - sets the preferred aspect
ratio of this
object. This is an initial aspect ratio of the video content. The value of this
parameter
SHALL equal the width divided by height, rounded to a float value with two
decimals, e.g.
1.78 to indicate 16:9 and 1.33 to indicate 4:3. Recommended to include this
parameter as
child of the <object>-element used for A/V control scripting object.

b. <param name=”loop” value=”…”/> - sets the number of times the A/V
content SHALL
be played. A/V playback SHALL be automatically restarted if the end of content
is reached
and the content has not been played the number of times indicated by the loop
parameter.
The value of this parameter SHALL be either:

  i. the number of times (> 0) that the content SHALL be played, OR

  ii. “infinite” if the content SHALL be looped continuously.
  If the AV Player is reinitialized (i.e. the data or type attribute has
changed as per [Req.
  5.7.1.l]), the indicated loop count SHALL be automatically re-applied by the
Remote UI
  Client. If the AV player is stopped or paused, and subsequently restarted,
the current
  pending loop count SHALL remain in effect. If missing, the default value of
the loop
  parameter SHALL be 1.

c. <param name=”autostart” value”…”/> - used for indicating whether
or not the A/V
Player scripting object SHALL behave as if an initial play(1) method call was
automatically issued. If the A/V Player scripting object is reinitialized (i.e.
the data or
type attribute has changed as per [Req. 5.7.1.l]), then the behavior indicated
by the value
of the autostart parameter SHALL be automatically re-applied by the Remote UI
Client.
The value of this parameter SHALL be “true” or “false”. If missing, the
default value of the
autostart parameter SHALL be “false”.

d. <param name=”avControlMode” value=”…”/> - This parameter is used
to set the
playback control mode of the A/V control scripting object. The following values
SHALL be
supported:

  i. “ruicontrol”: the A/V control scripting object provides an audio/video
playback
  window without any additional user-interface controls. See [Req 5.7.1.i] for
more
  details.

  ii. “localcontrol”: the A/V control scripting object provides an
audio/video playback 
  window which includes user-interface controls. See [Req 5.7.1.i] for more
details.
  The default mode of operation (i.e. if the server did not include a
“avControlMode”
  <param>-element) SHALL be “ruicontrol”.

[Req. 5.7.1.f1] The Remote UI Client MAY support the following <param>-elements
as childelement
of the <object>-element used for instantiating the A/V control scripting
object:

a. <param name=”dlna_res_attr” value=”…”/> - used to convey media
properties that are
useful for playback and control of A/V in a DLNA/UPnP environment. The value of
this
parameter SHALL contain the media properties associated with the content
resource that
is referred to by the value of the “data” attribute. These media properties
SHALL be an
XML escaped string containing the space-separated list of attributes of one
single “res”-
element, of which the format and possible values have been defined by the DLNA
guidelines [2] related to a UPnP Content Directory Service (CDS). Employing
UPnP A/V
standards for the playback and control of A/V is OPTIONAL, not required."

As can be seen, the set of "standardized" param names/values increases/changes
over time in such a manner as to preclude an a priori definition of new
attributes.

Again, these are NOT vendor-specific or proprietary uses of param.

G.

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Received on Friday, 29 July 2011 18:40:41 UTC