MICROSOFT_PRESS_EBOOK_PROGRAMMING_WINDOWS_8_APPS_WITH_HTML_CSS_AND_JAVASCRIPT_PDF

Here’s how such apps generally work:
• Set up the necessary communication channels over the network, which could be a peer-to-peer
system or could involve a central service of some kind.
• Capture audio or video to a stream using the WinRT APIs we’ve seen (specifically
Media-Capture.startRecordToStreamAsync) or capturing to a custom sink.
• Do any additional processing to the stream data. Note, however, that effects are plugged into
the capture mechanism (MediaCapture.addEffectAsync) rather than something you do in
post-processing.
• Encode the stream for transmission however you need.
• Transmit the stream over the network channel.
• Receive transmissions from other connected apps.
• Decode transmitted streams and convert to a blob by using MSApp.createBlobFromRandom-
AccessStream.
• Use URL.createObjectURL to hook an audio or video element to the stream.
To see such features in action, check out the Real-time communications sample that implements
video chat in Scenario 2 and demonstrates working with different latency modes in Scenario 1. The
latter two steps in the list above are also shown in the PlayToReceiver sample that is set up to receive a
media stream from another source.
PlayTo
The final case of streaming is centered on the PlayTo capabilities that were introduced in Windows 7.
Simply said, PlayTo is a means through which an app can connect local playback/display for audio,
video, and img elements to a remote device.
The details happen through the Windows.Media.PlayTo APIs along with the extension methods
added to media elements. If, for example, you want to specifically start a process of streaming to a
PlayTo device, invoking the selection UI directly, you’d do the following:
• Windows.Media.PlayTo.PlayToManager:
o
o
o
getForCurrentView returns the object.
showPlayToUI invokes the flyout UI where the user selects a receiver.
sourceRequested event is fired when user selects a receiver.
• In sourceRequested
o
Get PlayToSource object from audio, video, or img element (msPlayToSource property) and
pass to e.setSource.
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