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There isn't a means to disable the video track. The motivation for the ability to disable of video is in case the application wants to simply have audio track playing but no video. It may be possible to hide the video but it unclear if the associated resources are released or not. Making an explicit method makes for a clear behavior by the browser and easier for developers to create webpages that may need the additional resources. This may be required when developing web pages that overlay or cover the fullscreen while playing a live broadcast. If the video is HD quality and uses a large amount of processing power a the web page that may be overlayed termporarily it may require addition graphics or cpu power. The audio may continue to be played in order for the user to be able to track the live broadcast. An example is if live broadcast is being rendered during commercials the end-user may want to play a game but listen to the commercials in order to know when to turn off the game. With this approach more advanced web pages may be supported on terminals with a reduced capacity. The proposal is to have a similar option as text track to disable the video track. Note-This proposed changed is based in discussions in W3C webTV IG - media piping task force.
Are you asking specifically for a way for a *user* to disable the video channel while keeping the audio channel running, or some way for an *author* to deliver a video and only present the audio channel? The latter can theoretically be handled by just using the video file in <audio>. The former can probably just be done as a UA-specific UI option; do you need the author to have scripted access to the functionality?
(In reply to comment #1) > Are you asking specifically for a way for a *user* to disable the video channel > while keeping the audio channel running, or some way for an *author* to deliver > a video and only present the audio channel? > > The latter can theoretically be handled by just using the video file in > <audio>. Not really if you want to switch back and forth. Reloading the file in <audio> is not only a costly operation, it disrupts playback. > The former can probably just be done as a UA-specific UI option; do > you need the author to have scripted access to the functionality?
(In reply to comment #1) > Are you asking specifically for a way for a *user* to disable the video channel > while keeping the audio channel running, or some way for an *author* to deliver > a video and only present the audio channel? > I assume by *author* you mean the application (web) developer. In this case the *author* shall have the control in order to give the *user* a better user experience. > The latter can theoretically be handled by just using the video file in > <audio>. The former can probably just be done as a UA-specific UI option; do > you need the author to have scripted access to the functionality? The live broadcast is a single encapsulated stream, MPEG2-TS, so there aren't seperate files that can be loaded and unloaded. The URL for the MPEG2-TS source it applies for video/audio/subtitles/etc. The UA may optimize and notice that something is covering the video and release the video decoder resources but that is unpredicatable. Having an explicit control then the *author* can have a clear behaviour form the UA across platforms.
EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document: http://dev.w3.org/html5/decision-policy/decision-policy.html Status: Accepted Change Description: no spec change Rationale: You can do this already. Just set the "selected" attribute of the active track to "false".
You got ahead of me. I had not seen it in earlier versions and I missed it. When I look at the latest version of video tag I found a attribute called videoTracks.select(index). I am not clear in the text associated to the attribute, copy below. "The select(index) must select the track with index index, if there is one, unselecting whichever track was previously selected. If there is no track with index index, it must instead throw an INDEX_SIZE_ERR exception." How does one turn off the track? There is no statement that setting false will cause the video track to be disabled.