public async Task <Tuple <MediaStreamSample, uint> > ParseSampleAsync(ShoutcastStreamProcessor processor, SocketWrapper socket, bool partial = false, byte[] partialBytes = null)
{
//http://www.mpgedit.org/mpgedit/mpeg_format/MP3Format.html
IBuffer buffer = null;
MediaStreamSample sample = null;
uint sampleLength = 0;
if (partial)
{
buffer = partialBytes.AsBuffer();
sampleLength = MP3Parser.mp3_sampleSize - (uint)partialBytes.Length;
//processor.byteOffset += sampleLength;
}
else
{
var read = await socket.LoadAsync(MP3Parser.mp3_sampleSize);
if (read == 0 || read < MP3Parser.mp3_sampleSize)
{
//disconnected.
throw new ShoutcastDisconnectionException();
}
buffer = await socket.ReadBufferAsync(MP3Parser.mp3_sampleSize);
//processor.byteOffset += MP3Parser.mp3_sampleSize;
sampleLength = MP3Parser.mp3_sampleSize;
}
sample = MediaStreamSample.CreateFromBuffer(buffer, processor.timeOffSet);
sample.Duration = MP3Parser.mp3_sampleDuration;
sample.KeyFrame = true;
processor.timeOffSet = processor.timeOffSet.Add(MP3Parser.mp3_sampleDuration);
return(new Tuple <MediaStreamSample, uint>(sample, sampleLength));
}
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);
}
