From Bjoern Hassler

This section develops the idea of the yahoo media group alternatives scheme, that was introduced in the previous chapter Media rss media group element.

Contents 1 Overview 2 Aim 1 2.1 Example 1: Adding the scheme to media:content elements 2.2 Example 2 3 Aim 2

[edit] 1 Overview

• Aim 1: Use standard media:rss elements to specify the nature of the media alternatives in the media:category
• Aim 2: Use standard media:rss elements to specify the nature of other synchronised materials

The formal definition of the scheme is here W:Media rss media group alternatives scheme.

[edit] 2 Aim 1

Suppose you have several media:content items, e.g.

<media:content url="http://www.foo.com/movie.mov"/>
<media:content url="http://www.foo.com/movie.wmv"/>
<media:content url="http://www.foo.com/movie.m4v"/>
<media:content url="http://www.foo.com/movie.mp4"/>
<media:content url="http://www.foo.com/movie.pdf"/>
<media:content url="http://www.foo.com/movie.txt"/>

How do these relate to eachother?

Within the media group there isn't an attribute with associated scheme that describes what these additional media:content items are. Somehow they are all the same thing (because they are in the same media group), but what distinguishes them? The <media:category> tag can help. It can be a sub-element of channel, item, media:group and media:content.

Essentially the page w:media rss media group alternatives specifies a scheme for distinguishing various media:content elements within a media group. The idea is to introduce a scheme that describes media:content items further:

<media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="slides">slides</media:category>

[edit] 2.1 Example 1: Adding the scheme to media:content elements

This would give (version 1):

<media:group>

  <media:content url="http://www.foo.com/movie.mov" fileSize="3054080"
    type="video/quicktime" medium="video" isDefault="true"
    expression="full" bitrate="128" duration="185" height="200" width="300" lang="en" />

  <media:content url="http://www.foo.com/movie.avi" fileSize="30540800"
    type="video/msvideo" medium="video" isDefault="true"
    expression="full" bitrate="128" duration="1850" height="400" width="600" lang="en" />

  <media:content url="http://www.foo.com/movie.mp3" fileSize="12216320"
    type="video/quicktime" medium="audio" isDefault="false"
    expression="full" bitrate="32" duration="185" lang="en">
    <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="audio track">audio track</media:category>
  </media:content>

  <media:content url="http://www.foo.com/movie_slides.pdf" fileSize="522163"
    type="application/pdf" medium="document" isDefault="false"
    expression="full" lang="en">
    <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="slides">slides</media:category>
  </media:content>
 
  <media:content url="http://www.foo.com/movie_transcript.txt" fileSize="251564"
    type="text/plain" medium="document" isDefault="false"
    expression="full" lang="en">
    <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="transcript">transcript</media:category>
   </media:content>

<media:group>

[edit] 2.2 Example 2

You might also consider the content items to below to different media:groups, in which case you could e.g. take out the slides into a separate group ('version 2'):

We start with the main content:

<media:group>
  <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="main">main</media:category>

  <media:content url="http://www.foo.com/movie.mov" fileSize="3054080"
    type="video/quicktime" medium="video" isDefault="true"
    expression="full" bitrate="128" duration="185" height="200" width="300" lang="en" />

  <media:content url="http://www.foo.com/movie.avi" fileSize="30540800"
    type="video/msvideo" medium="video" isDefault="true"
    expression="full" bitrate="128" duration="1850" height="400" width="600" lang="en" /> 
<media:group>

Followed by supplementary materials:

 <media:group>
  <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="supplementary materials">supplementary</media:category>

  <media:content url="http://www.foo.com/movie_slides.pdf" fileSize="522163"
    type="application/pdf" medium="document" isDefault="false"
    expression="full" lang="en">
    <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="slides">slides</media:category>
  </media:content>

  <media:content url="http://www.foo.com/movie_commentary.pdf" fileSize="522163"
    type="application/pdf" medium="document" isDefault="false"
    expression="full" lang="en">
    <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="commentary">commentary</media:category>
  </media:content>
 
</media:group>

Followed by materials to enable access:

<media:group>
  <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="access">access</media:category>

  <media:content url="http://www.foo.com/movie.mp3" fileSize="12216320"
    type="video/quicktime" medium="audio" isDefault="false"
    expression="full" bitrate="32" duration="185" lang="en">
    <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="audio track">audio track</media:category>
  </media:content>

  <media:content url="http://www.foo.com/movie.mp3" fileSize="12216320"
    type="video/quicktime" medium="audio" isDefault="false"
    expression="full" bitrate="32" duration="185" lang="en">
    <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="audio description">audio description</media:category>
  </media:content>
 
  <media:content url="http://www.foo.com/movie_transcript.txt" fileSize="251564"
    type="text/plain" medium="document" isDefault="false"
    expression="full" lang="en">
    <media:category scheme="http://www.sciencemedianetwork.org/mrmgas" label="transcript">transcript</media:category>
   </media:content>

</media:group>

Please have a look at the scheme on w:media rss media group alternatives, because the details may vary from what is suggested above.

[edit] 3 Aim 2

A similar issue to specify basic synchronised materials. The narrower question is what do do with <media:thumbnail>. A wider question would be to think about general synchronised events. However, for that the media rss shoudl point at an application, or specify a <media:player>.

However, the narrower question is providing more details on what content provided by <media:thumbnail> is. It could be

• stills from the movie (with timing) (the original intent)
• a set of slides to be synchronised with audio
• a set of slides to be synchronised with video
• generic images, that may not necessarily appear in the video, but might be
  • a representative image for the video
  • a representative image for a series (such as cover art for an album)

It may also be an image that is embedded in some of the media, e.g. as album art in an mp3.

More soon.