- From: Lachlan Hunt <lachlan.hunt@lachy.id.au>
- Date: Mon, 14 Mar 2011 17:59:00 +0100
Hi, There are a few issues with the recently added media streaming API. The IDL for GeneratedStream should indicate that it inherits from the Stream interface. The API includes both readystatechange event, as well as independent events for play, paused and ended. This redundancy is unnecessary. This is also inconsistent with the design of the HTMLMediaElement API, which does not include a readystatechange event in favour on separate events only. The API does not provide any way for the author to indicate a preferred camera. Some devices include multiple cameras, particularly phones with front and rear facing cameras, and some use cases are better suited to one or the other. For example, an augmented reality application that takes advantage of geolocation and device orientation in order to overlay the video stream with things (e.g. push pins to identify points of interest, like on Google Street View). Such an application would be better suited for working with the rear facing camera. But with a video conferencing application, the front facing camera would be more suitable. It might therefore be useful for the author to provide a hint to this effect, which would allow the UA to more intelligently select the default camera for the user. There are some use cases for which it would be useful to know the precise orientation of the camera, such as augmented reality applications. The camera orientation may be independent of the device's orientation, and so the existing device orientation API may not be sufficient. In the simple case, the front and rear cameras face in opposite directions, and so if an augmented reality application was built assuming it was using the rear camera, but the user instead granted access to the front camera, the calculations would be 180? out. Some devices may also provide cameras that may allow the camera to be rotated independently of the device itself, and so camera orientation information would need to allow for this. I don't know the best way to provide this, and there likely to be issues about whether the camera orientation should be relative to the device itself, or relative to fixed Earth coordinates (North, East, Up), like the existing device orientation API. -- Lachlan Hunt - Opera Software http://lachy.id.au/ http://www.opera.com/
Received on Monday, 14 March 2011 09:59:00 UTC