private async Task <AudioEncodingProperties> ParseEncodingFromMediaAsync()
{
//grab the first frame and strip it for information
AudioEncodingProperties obtainedProperties = null;
IBuffer buffer = null;
if (AudioInfo.AudioFormat == StreamAudioFormat.AAC)
{
//obtainedProperties = AudioEncodingProperties.CreateAac(0, 2, 0);
throw new Exception("Not supported.");
}
var provider = AudioProviderFactory.GetAudioProvider(AudioInfo.AudioFormat);
ServerAudioInfo firstFrame = await provider.GrabFrameInfoAsync(streamProcessor, AudioInfo).ConfigureAwait(false);
//loop until we receive a few "frames" with identical information.
while (true)
{
cancelTokenSource.Token.ThrowIfCancellationRequested();
ServerAudioInfo secondFrame = await provider.GrabFrameInfoAsync(streamProcessor, AudioInfo).ConfigureAwait(false);
if (firstFrame.BitRate == secondFrame.BitRate &&
firstFrame.SampleRate == secondFrame.SampleRate)
{
//both frames are identical, use one of them and escape the loop.
AudioInfo = firstFrame;
break;
}
else
{
//frames aren't identical, get rid of the first one using the second frame and loop back.
firstFrame = secondFrame;
continue;
}
}
cancelTokenSource.Token.ThrowIfCancellationRequested();
if (AudioInfo.AudioFormat == StreamAudioFormat.MP3)
{
//skip the entire first frame/sample to get back on track
await socket.LoadAsync(MP3Parser.mp3_sampleSize - MP3Parser.HeaderLength);
buffer = await socket.ReadBufferAsync(MP3Parser.mp3_sampleSize - MP3Parser.HeaderLength);
//streamProcessor.byteOffset += MP3Parser.mp3_sampleSize - MP3Parser.HeaderLength;
obtainedProperties = AudioEncodingProperties.CreateMp3((uint)AudioInfo.SampleRate, (uint)AudioInfo.ChannelCount, AudioInfo.BitRate);
}
else if (AudioInfo.AudioFormat == StreamAudioFormat.AAC_ADTS)
{
//skip the entire first frame/sample to get back on track
await socket.LoadAsync(AAC_ADTSParser.aac_adts_sampleSize - AAC_ADTSParser.HeaderLength);
buffer = await socket.ReadBufferAsync(AAC_ADTSParser.aac_adts_sampleSize - AAC_ADTSParser.HeaderLength);
//streamProcessor.byteOffset += AAC_ADTSParser.aac_adts_sampleSize - AAC_ADTSParser.HeaderLength;
obtainedProperties = AudioEncodingProperties.CreateAacAdts((uint)AudioInfo.SampleRate, (uint)AudioInfo.ChannelCount, AudioInfo.BitRate);
}
else
{
throw new Exception("Unsupported format.");
}
if (serverSettings.RequestSongMetdata)
{
streamProcessor.metadataPos += buffer.Length; //very important or it will throw everything off!
}
return(obtainedProperties);
}
internal async Task <MediaStreamSample> GetNextSampleAsync(CancellationToken cancelToken)
{
if (sampleProvider == null)
{
sampleProvider = AudioProviderFactory.GetAudioProvider(shoutcastStream.AudioInfo.AudioFormat);
}
//todo check for internet connection and socket connection as well
cancelToken.ThrowIfCancellationRequested();
MediaStreamSample sample = null;
uint sampleLength = 0;
//if metadataPos is less than sampleSize away from metadataInt
if (shoutcastStream.serverSettings.RequestSongMetdata && (shoutcastStream.metadataInt - metadataPos <= sampleProvider.GetSampleSize() &&
shoutcastStream.metadataInt - metadataPos > 0))
{
//parse part of the frame.
byte[] partialFrame = new byte[shoutcastStream.metadataInt - metadataPos];
var read = await socket.LoadAsync(shoutcastStream.metadataInt - metadataPos);
if (read == 0 || read < partialFrame.Length)
{
//disconnected.
throw new ShoutcastDisconnectionException();
}
await socket.ReadBytesAsync(partialFrame);
metadataPos += shoutcastStream.metadataInt - metadataPos;
Tuple <MediaStreamSample, uint> result = await sampleProvider.ParseSampleAsync(this, socket, partial : true, partialBytes : partialFrame).ConfigureAwait(false);
sample = result.Item1;
sampleLength = result.Item2;
cancelToken.ThrowIfCancellationRequested();
}
else
{
await HandleMetadataAsync(cancelToken);
Tuple <MediaStreamSample, uint> result = await sampleProvider.ParseSampleAsync(this, socket).ConfigureAwait(false);
sample = result.Item1;
sampleLength = result.Item2;
cancelToken.ThrowIfCancellationRequested();
if (sample == null || sampleLength == 0) //OLD bug: on RELEASE builds, sample.Buffer causes the app to die due to a possible .NET Native bug
{
//MediaStreamSource.NotifyError(MediaStreamSourceErrorStatus.DecodeError);
//deferral.Complete();
//return;
return(null);
}
else
{
if (shoutcastStream.serverSettings.RequestSongMetdata)
{
metadataPos += sampleLength;
}
}
}
return(sample);
}
