- From: Silvia Pfeiffer <silviapfeiffer1@gmail.com>
- Date: Wed, 1 Dec 2010 22:05:12 +1100
- To: Media Fragment <public-media-fragment@w3.org>
Hi all, I started putting some thought together as to what browser vendors would need to implement to support media fragments. It's at https://wiki.mozilla.org/Accessibility/Video_Media_Fragments . The required additions to HTML5 can be extracted from there as below. Please have a thorough read so we can figure out if we have missed something. Cheers, Silvia. (1) Temporal Media Fragments As per: http://www.w3.org/TR/media-frags/#naming-time Relevant to: audio & video Recommended approach to support temporal media fragments: byte range requests, see http://www.w3.org/TR/media-frags/#URIfragment-user-agent Two uses: 1. URL in address bar When a media fragment URL is pasted into a Web browser address bar and the browser is able to decode the media resource, the user should see a video or audio file that starts playing from the fragment start time and stops at end time. Also, since the browser will display controls, we need to introduce markers on the controls for the fragment, see http://www.youtube.com/watch?v=LfRRYp6mnu0 for an example implementation. The means towards interpreting the fragment should be by starting to download the resource, then, as it is confirmed that it is a media resource, download will stop and byte range requests will be applied. Note further that for any video or audio that is playing in this way, it makes sense to update the URL bar when pausing and to include the fragment offset, such that users can cut and paste the new URL for sharing. Also, it might make sense to add the new URL to the browser history when pausing, allowing the user to jump back and forth between pause points through navigating the browser history. 2. URL in @src attribute of video/audio element When a media fragment URL is used in a video/audio element, the user will similarly expect the media resource to start playing from fragment start time and stops at end time. If no @controls attribute is given, this equates to playing back a media fragment without context and may be useful for video editing applications or playlists of media snippets (so-called mash-ups). If the @controls attribute is given, there is a need to introduce markers for the fragment, see e.g. http://www.youtube.com/watch?v=LfRRYp6mnu0 for an example implementation. Note that if the @loop attribute is given, the fragment will loop and not the resource. (2) Spatial Media Fragments As per: http://www.w3.org/TR/media-frags/#naming-space Relevant to: images & video Recommended approach to support spatial media fragments: CSS-like, i.e. hide unwanted pixels A spatial media fragment URI can be used in the URL address bar or in the @src attribute of video/img element. The user will expect a cropped (spliced) image/video display of the resource. (3) Track Fragments As per: http://www.w3.org/TR/media-frags/#naming-track Relevant to: audio & video Recommended approach to support track fragments: hide unwanted tracks A track media fragment URI can be used in the URL address bar or in @src attribute of video/img element. One example use case has been shown at https://labs.ericsson.com/developer-community/blog/beyond-html5-conversational-voice-and-video-implemented-webkit-gtk . The user will expect that only the enumerated tracks (audio, video etc) will be displayed.
Received on Wednesday, 1 December 2010 11:06:07 UTC