/// <summary> /// This function is used to intialize a heuristics module. It must be implemented by all derived classes. /// </summary> /// <param name="manifestInfo">The manifest for the stream we are reading</param> /// <param name="playbackInfo">The playback info for the media element</param> /// <param name="adInsertPoints">Optional expected points for advertising. Can be null</param> public abstract void Initialize(ManifestInfo manifestInfo, PlaybackInfo playbackInfo, AdInsertionPoint[] adInsertPoints);
/// <summary>
/// Initializes a new instance of the AdaptiveStreamingSource class
/// </summary>
/// <param name="mediaElement">The media element that we are sending samples to. We use it internally to keep track of playback statistics</param>
/// <param name="url">The url of the manifest for the stream we are serving</param>
public AdaptiveStreamingSource(MediaElement mediaElement, Uri url)
{
// Make sure our Url is not null
if (null == url)
{
throw new ArgumentNullException("url", Errors.NullUrlOnMSSError);
}
// Also check the mediaElement parameter
if (null == mediaElement)
{
throw new ArgumentNullException("mediaElement", Errors.NullMediaElementOnMSSError);
}
// Remember the Url to the manifest we are streaming
m_manifestSourceUrl = url;
// Create our default manifest parser
ManifestParser = new ManifestParserImpl();
// Create our default chunk parser factory
ChunkParserFactory = new ChunkParserFactoryImpl();
// Create our default url generator
UrlGenerator = new UrlGeneratorImpl();
// Create a new queue for processing commands. All work is done on a background thread,
// which will shuttle events back to the UI thread in case something needs to be displayed.
m_workQueue = new WorkQueue();
// Create the thread that we are going to run background commands on
m_workQueueThread = new Thread(WorkerThread);
// Make sure we remember the Dispatcher class for the UI thread
UIDispatcher.Load();
// Playback info is a wrapper on around media element
m_playbackInfo = new PlaybackInfo(mediaElement);
// Hook our heuristics events
m_heuristics.ChunkReplacementSuggested += HeuristicsChunkReplacementSuggested;
}
/// <summary>
/// Handle a close command
/// </summary>
private void DoClose()
{
Tracer.Trace(TraceChannel.MSS, "Media closed");
if (m_heuristics != null)
{
m_heuristics.Shutdown();
}
if (m_manifestInfo != null)
{
m_manifestInfo.Shutdown();
}
m_workQueueThread = null;
m_isWorkQueueThreadStarted = false;
m_workQueue = null;
m_playbackInfo = null;
}
/// <summary>
/// Implements Heuristics.Initialize(). Called to initialize this heuristics module with
/// the given manifest file and optional adverting insertion points
/// </summary>
/// <param name="manifestInfo">The manifest of the stream we are using</param>
/// <param name="playbackInfo">The playback info for the media element</param>
/// <param name="adInsertPoints">Optional ad insertion points. Can be null</param>
public override void Initialize(ManifestInfo manifestInfo, PlaybackInfo playbackInfo, AdInsertionPoint[] adInsertPoints)
{
Tracer.Trace(TraceChannel.MSS, "MediaSource instance {0}, sessionID: {1}", InstanceId.ToString("B"), sm_sessionId.ToString("B"));
// Store our manifest info
m_manifestInfo = manifestInfo;
m_playbackInfo = playbackInfo;
// We only support 1 audio and 1 video stream right now, so let's throw an exception
// if someone tries to create us with more than that
int numStreams = m_manifestInfo.NumberOfStreams;
if (numStreams > 2)
{
throw new AdaptiveStreamingException("We only support 1 audio and 1 video stream at this time");
}
// Copy the add insertion points over
m_adInsertPoints = new AdInsertionPoints();
foreach (AdInsertionPoint ad in adInsertPoints)
{
m_adInsertPoints.Add(ad);
}
// Allocate some internal variables
m_heuristicsMode = new HeuristicsMode[numStreams];
m_fixedBitrateIndex = new int[numStreams];
m_mediaStreamTypes = new MediaStreamType[numStreams];
m_maxDownloadsPerStream = new int[numStreams];
m_numDownloadsInProgress = new int[numStreams];
m_nextChunkId = new int[numStreams];
// Go through each stream in our manifest and do per-stream configuration
int numVideoStreams = 0, numAudioStreams = 0;
for (int i = 0; i < numStreams; i++)
{
StreamInfo streamInfo = m_manifestInfo.GetStreamInfoForStream(i);
// Initialize some of the arrays we just created
m_mediaStreamTypes[i] = streamInfo.MediaType;
m_fixedBitrateIndex[i] = 0;
m_maxDownloadsPerStream[i] = GlobalMaxDownloadsPerStream;
m_numDownloadsInProgress[i] = 0;
m_nextChunkId[i] = 0;
// If we are a video stream, then we need to set our heuristics mode
// to Full
switch (streamInfo.MediaType)
{
case MediaStreamType.Audio:
m_heuristicsMode[i] = HeuristicsMode.FixedRate;
++numAudioStreams;
break;
case MediaStreamType.Video:
m_heuristicsMode[i] = HeuristicsMode.Full;
++numVideoStreams;
break;
default:
throw new AdaptiveStreamingException(Errors.NonVideoOrAudioStreamsNotSupportedError);
}
// Configure this stream
InitializeHeuristicsForStream(
streamInfo.StreamId,
(double)m_maxBufferSizeInMs / 1000,
m_manifestInfo.GetStreamInfoForStream(i).Bitrates.Count,
m_manifestInfo.GetStreamInfoForStream(i).GetBitrateArray());
}
// Make sure we found only 1 video and 1 audio stream
if (numVideoStreams != 1)
{
throw new AdaptiveStreamingException(Errors.IncorrectNumberOfVideoStreamsError);
}
// Start scheduling our downloads
ScheduleDownloads();
}