Fixing broken links

Author: drewbatgit

hub/apps/develop/media-playback/media-playback-with-mediasource.md

@@ -133,7 +133,7 @@ In the handler for the [**TimedTextSource.Resolved**](/uwp/api/windows.media.cor
 
 :::code language="csharp" source="~/../snippets-windows/winappsdk/audio-video-camera/media-source-winui/cs/MediaSourceWinUI/MainWindow.xaml.cs" id="SnippetTimedTextSourceResolved":::
 
-For a list of the timed text formats that are supported on Windows, see [Supported codecs](supported-codecs.md).
+For a list of the timed text formats that are supported on Windows, see [Supported codecs](/windows/uwp/audio-video-camera/supported-codecs).
 
 ## Add additional metadata tracks
 
@@ -230,7 +230,8 @@ Starting with Windows 10, version 1703, you can supply an [**AdaptiveMediaSource
 
 
 ## Related topics
+
 * [Media playback](media-playback.md)
 * [Play audio and video with MediaPlayer](play-audio-and-video-with-mediaplayer.md)
 * [Integrate with the System Media Transport Controls](integrate-with-systemmediatransportcontrols.md)
-* [Play media in the background](background-audio.md)
+

hub/apps/develop/media-playback/play-audio-and-video-with-mediaplayer.md

@@ -271,4 +271,3 @@ The user may decide that they want to pause or continue playback, even if the au
 * [Media items, playlists, and tracks](media-playback-with-mediasource.md)
 * [Integrate with the System Media Transport Controls](integrate-with-systemmediatransportcontrols.md)
 * [Create, schedule, and manage media breaks](create-schedule-and-manage-media-breaks.md)
-* [Play media in the background](background-audio.md)

hub/apps/develop/media-playback/system-media-transport-controls.md

@@ -103,9 +103,10 @@ If you are not using the automatic SMTC integration provided by **MediaPlayer**
 
 Apps that use the new one-process model for background audio should get an instance of the [**SystemMediaTransportControls**](/uwp/api/Windows.Media.SystemMediaTransportControls) by calling [**GetForCurrentView**](/uwp/api/windows.media.systemmediatransportcontrols.getforcurrentview). Apps that use the legacy two-process model for background audio must use [**BackgroundMediaPlayer.Current.SystemMediaTransportControls**](/uwp/api/windows.media.playback.mediaplayer.systemmediatransportcontrols) to get access to the SMTC from their background process.
 
-For more information on playing audio in the background, see [Play media in the background](background-audio.md).
+
 
 ## Related topics
+
 * [Media playback](media-playback.md)
 * [Integrate with the System Media Transport Controls](integrate-with-systemmediatransportcontrols.md) 
 * [System Media Transport sample](https://github.com/Microsoft/Windows-universal-samples/tree/dev/Samples/SystemMediaTransportControls)