<http://alph.io/interfaces/fragment>
Ver. PA5
Sending an HTTP GET request to an Alph server resource with the "fragment" query parameter returns the specified fragment of that resource.
FORM
?fragment=valid_selector
A 'valid_selector' is going to be a string representing a Simple Selector, which you can read more about here: <http://alph.io/selectors>. These are numeric fragment selectors for text, images, and audio/video streams.
The returned media fragment SHOULD always be the same media type as the full resource.
ERRORS
If the requested fragment selector is invalid (out-of-bounds, or of an inappropriate/unsupported form for the media type), the server SHOULD return an HTTP 400 error response with some text describing the issue with the selector.
NEAR-ENOUGH
In some cases, the server may not be able to return a perfectly accurate fragment as specified in the request. An example of this would be when a fragment of an AVC video is requested: in order to get a frame-accurate fragment of this type of video, the server may need to re-encode the video stream as the requested fragment is unlikely to fall precisely between a pair of I-frames; however, the current server implementation does not do this. Instead, it returns a fragment of the video resource between the two nearest I-frames that fully enclose the requested fragment. In cases where something like this is happening, the server SHOULD return an HTTP 302 response with the "Location" header set to the URL of the resource with the ?fragment query parameter changed to match exactly the content that's being returned.
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