Please note: This post is "reprinted" from the "Managing Windows Store Developer Solutions" blog with permission from the author (just so happens to be me). 

Original post found here:

http://blogs.msdn.com/b/wsdevsol/archive/2013/03/08/mixed-media-audio-amp-video-windows-store-vs-windows-phone-8.aspx

 

As everyone knows, with the release of Windows 8 and Windows Phone 8 we have brought the two platforms closer together than ever before. The keyword here is “closer”. There are still some fairly major implementation and terminology differences between the two platforms particularly when working with digital audio and video. Hopefully this article will help you map and understand the media technologies between the two platforms. In this article I’m assuming that you are familiar with the media technologies on one platform or the other and just need some hints how to migrate your code to the other platform.

 

Audio / Video Playback Technologies

 

Audio / Video Playback – Technology Map

Windows Store

Windows Phone 8

MediaElement (XAML)

 

MediaElement (XAML)

IMFMediaEngine (C++ only)

IMFMediaEngine (C++ only) (Subset)

 

WASAPI (C++ only)

WASAPI (C++ only) (Subset)

 

XAudio2 (C++ only)

XAudio2 (C++ only)

 

 

The MediaElement will likely be your “go to” control on both platforms for playing audio and video. There are a few differences though. You can’t add audio or video effects (plug-ins) to the MediaElement on the phone. The DRM implementation is also quite different between the two platforms. If you are not doing anything “fancy” you should be able to port your MediaElement implementation with no problem.


The MediaEngine (different from the MediaElement discussed above) is new for both platforms in version 8. On both platforms the MediaEngine can only be used from C++ and is not currently supported from managed code. The phone also has slightly reduced functionality. On the phone the MediaEngine only supports frame-server mode. Also keep in mind that on the phone hardware acceleration will always be used.

 

WASAPI and XAudio2 are also supported on both platforms. Unfortunately at this time these audio only technologies can only be called from C++. They are not currently supported from managed code. While the full XAudio2 functionality is supported on both platforms keep in mind that XAudio2 only supports uncompressed PCM audio on the phone. It is extremely difficult to use XAudio2 with compressed media formats on the phone at this time. The phone also only supports a subset of the WASAPI Core Audio APIs as well.

 

References

Windows Store app

Windows Phone 8 app

Win32 and COM for Windows Store apps (multimedia)

Native audio APIs for Windows Phone 8 

 

IMFMediaEngine interface (Windows)

Supported Microsoft Media Foundation APIs for Windows Phone 8

 

MediaElement class (Windows)

MediaElement Class

         

 

Background Audio

 

Background Audio – Technology Map

Windows Store (XAML / HTML5)

Windows Phone 8 (XAML)

MediaElement / Audio tag

 

BackgroundAudioPlayer

msAudioCategory="BackgroundCapableMedia"

AudioPlayerAgent

 

Windows.Media.MediaControl

Universal Volume Control (UVC)

 

Media Foundation Source (C++ only)

MediaStreamSource

 

 

The big difference playing background audio in a Windows Store app vs. Windows Phone 8 app is the use of the BackgroundAudioPlayer on the Phone and the MediaElement / Audio tag for Windows Store apps. The BackgroundAudioPlayer is a static class that can be used without needing instantiation. The MediaElement and Audio tags must be defined in markup before they can be used.

 

For your Windows Store app you must set MsAudioCategory=”BackgroundCapableMedia”. For your phone app you need to create an AudioPlayerAgent that will run in the background when your app gets swapped out.  

 

The final thing to note is that on both platforms you need to handle user input from the lock screen media controls. On the phone we call these controls the “Universal Volume Control” (UVC) and in your Store app we call them the “media controls”. Different terms but the same basic functionality.

 
 

References

Windows Store app

Windows Phone 8 app

How to play audio in the background (Windows Store apps using JavaScript and HTML)

Background audio overview for Windows Phone

 

 

Sharing Media

 

Sharing Media – Technology Map

Windows Store (XAML / HTML5)

Windows Phone 8 (XAML)

DataTransferManager class

ShareMediaTask Class

 

 

The big difference here is that with Windows Store apps the user initiates the sharing process using the “share charm”. On the phone your app will need to invoke the ShareMediaTask directly from within your code.

 

In both cases you will likely never get confirmation that your data was successfully shared. In essence it’s a “fire and forget” operation.

 

Keep in mind that on the phone your app will be swapped out and may get shut down when the app you are sharing with takes up the full screen. Because of this you may need to save state.

 

References

Windows Store app

Windows Phone 8 app

Sharing and receiving content (Windows Store apps using JavaScript and HTML) (Windows)

How to use the share media task for Windows Phone

 

 

 

Follow us on Twitter @wsdevsol.