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Play or Capture Audio Sound. Send and Receive as Multicast (RTP)

By , 12 Apr 2014
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Download Exe_3.zip

Download WinSoundServer.zip

Introduction

It is not comfortable to use the Sound API in .NET, because there is no support by the class library itself. So I decided to write my own small Audio Assembly WinSound.dll by using PInvoke and the native WMM API (Windows Multi Media). With help of this library you can play or capture audio sound in an easy way. In addition i wrote some Network Assemblies, to stream and play Audio Data over Network by Multicast.

Optional C++

In addition i implemented a similar C++ Version of this project as a COM Server with name WinSoundServer. In the project is also included a little WinSoundServerTester.sln for VisualStudio 2012 that shows the recording and playing methods in an example. I did not intend to publish that, but maybe anybody will find it useful anyway. You must first compile the WinSoundServer project, so that the vc100.tlb and the WinSoundServer.dll will be created. Before starting the test app you have to register the COM Server with help of the reg.bat file including in the project directory. This will register the WinSoundServer.dll. After that the test application must refers to the typelibrary by an import statement, so you have access to all interfaces and classes (like adding a reference in C#)

#import "WinSoundServer\\vc100.tlb" no_namespace

Background

The WaveOut and WaveIn functions of WMM are very tricky, because you have to know some special features of how to work with the internal buffers and handles. For example you can not stop a recording, without waiting for all buffers to finish. You are not allowed to stay too long in the Callback functions. You have to swap from managed to unmanaged code. The Repeater is the most sensitive one, because you have to balance the recording and playing buffers all the time.

Using the code

The assemblies which are to be used as DLLs are

For common sound operations

  • WinSound.dll

For network operations

  • TCPClient.dll
  • TCPServer.dll
  • MulticastReceiver.dll
  • MulticastSender.dll

Example Projects are

  • MulticastPlayer (Plays a RTP-Multicast to Soundcard)
  • MulticastStreamer (Sends a RTP-Multicast from Soundcard)
  • Player Tester (Plays or records a wav-File)
  • RepeaterTester (Plays from Soundcard to Soundcard)

The heart of all this is WinSound.dll. All example projects need this DLL (add as reference).

Using the Sound Recorder

Note that buffersize and buffercount must be optimized to your Sounddevice and used SamplesPerSecond.

//Create a Recorder
WinSound.Recorder recorder = new WinSound.Recorder();
//Add DataRecording and RecordingStopped Event Functions
recorder.DataRecorded += new WinSound.Recorder.DelegateDataRecorded(OnDataRecorded);
recorder.RecordingStopped += new WinSound.Recorder.DelegateStopped(OnRecordingStopped);
//Start capturing (44100 SamplesPerSecond, 16 BitsPerSample, 2 Channels, 8 * 4096 Byte Buffers)
recorder.Start("Line 1 (Virtual Audio Cable)", 44100, 16, 2, 8, 4096);
//Check if started
bool isStarted = recorder.Started;
//Stop recording
recorder.Stop();


//Called, when datas are incoming
private void OnDataRecorded(Byte[] data)
{
    
}

//Called, when recording has stopped
private void OnRecordingStopped()
{
    
}

Using the Sound Player

Note that buffercount must be optimized to your Sounddevice and used SamplesPerSecond.

//Create a SoundPlayer
WinSound.Player player = new WinSound.Player();
//Add Player Stopped and Player Closed Events
player.PlayerStopped += new WinSound.Player.DelegateStopped(OnPlayerStopped);
player.PlayerClosed += new WinSound.Player.DelegateStopped(OnPlayerClosed);
//Open a SoundDevice (44100 SamplesPerSecond, 16 BitsPerSample, 2 Channels, 8 Buffers)
player.Open("Realtek", 44100, 16, 2, 8);
//Check if open
bool isOpen = player.Opened;          
//Get Sound Datas as linear bytes (maybe from Wav-File)
Byte[] data = GetDatas();
//Play linear datas to SoundDevice
player.PlayData(data, false);
//Check if playing
bool isPlaying = player.Playing
//Start pause
player.StartPause();
//Check if paused
bool isPaused = player.Paused;
//End pause
player.EndPause();
//Stop Playing
player.Stop();
//Close Player
player.Stop();
                    
//Called, when player is stopped 
private void OnPlayerStopped()
{

}

//Called, when player is closed (WaveOut closed)
private void OnPlayerClosed()
{

}  

Linear Bytes

The linear data bytes you write or read from soundcard, are depending on BitsPerSample and Channel Count. Each "Data Packet" is to interpret as this picture shows.

The Player (Recorder) Tester

This example uses WinSound.dll to play or record a Wav-file. SamplesPerSecond, BitsPerSample and Channels are only used in record mode.

//Create a SoundPlayer
WinSound.Player playerOne = new WinSound.Player();
//Add callback functions for stop and close events (optional)
playerOne.PlayerClosed += new WinSound.Player.DelegateStopped(OnPlayerClosed);
playerOne.PlayerStopped += new WinSound.Player.DelegateStopped(OnPlayerStopped);
//Play a Wav File on a specific Sounddevice
playerOne.PlayFile(@"C:\Record.wav", "Realtek");   
//Close the player
bool hr = playerOne.Close(); 

//Read Wave-Header and payload data from Wav-File
WinSound.WaveFileHeader header = WinSound.WaveFile.Read(@"C:\Record.wav");
//Get the payload data size
uint dataSize = header.DATASize;
//Get the payload data
Byte[] data = header.Payload;

//Write payload data in a new Wav-File 
WinSound.WaveFile.Create(@"C:\Record.wav", 44100, 16, 2, data);
//Add payload data in an existing Wav-File (Append)
WinSound.WaveFile.AppendData(@"C:\Record.wav", data);  

The Repeater Tester

This example is recording Sound-Data from one sound device (WaveIn) to another (WaveOut). Every sound device has its special features, so you have to change the BufferCount and BufferSize for optimal performance. It also differs from operating System Windows-XP, Vista or Windows 7.

394890/2.png

//Create the Repeater
WinSound.Repeater repeaterOne = new WinSound.Repeater(); 
//Start the Repeater
repeaterOne.Start("Line 6", "Realtek", samplesPerSecond, bitsPerSample, channels, bufferCount, bufferSize);
//Stop the Repeater 
repeaterOne.Stop();

The Multicast Streamer

This example Streams ULAW RTP-Multicast data from a sound device or a Wav-File. When using sound device streaming, it is possible to synchronise it with the "Time Sync" checkbox. Buffer Count is the amout of buffers, that are used by capturing from sound-device (Use 8 as standard). You can use the Multicast Player to play this Multicast. Also you can use the VLC Media Player for testing (Use Samples Per Second = 8000 and BitsPerSample = 16 with VLC).

//Create a  Multicast Sender and a Sound-Device Recorder
NF.MulticastSender m_MulticastSender = new NF.MulticastSender(Address, Port, TTL);
WinSound.Recorder m_Recorder = new WinSound.Recorder();
//Define a callback function for reveiving datas from soundcard
m_Recorder.DataRecorded += new WinSound.Recorder.DelegateDataRecorded(OnDataReceivedFromSoundcard);
//Start Recorder 
m_Recorder.Start(SoundDeviceName, SamplesPerSecond, BitsPerSample, ChannelCount, BufferCount, BufferSize) 
//In callback function, get the linear datas from soundcard and translate to MuLaw
Byte[] mulawData = WinSound.Utils.LinearToMulaw(linearData, Config.BitsPerSample, Config.Channels);
//Create the RTP Header 
Byte[] rtpBytes = RTPHeader.ToBytes();
//Combine RTP Header and mulawData
Byte[] bytes = new Byte[mulawData.Length + WinSound.RTPPacket.MinHeaderLength];
Array.Copy(rtpBytes, 0, bytes, 0, WinSound.RTPPacket.MinHeaderLength);
Array.Copy(mulawData, 0, bytes, WinSound.RTPPacket.MinHeaderLength, mulawData.Length);
//Send Bytes to Multicast
m_MulticastSender.SendBytes(bytes);
 

The Multicast Player

This example plays a ULAW RTP-Multicast stream to a sound device. You can use the Multicast Streamer for this purpose. Note, the packet size of the Multicast Player must be greater or equal than the packet size of the multicast streamer (Use 16000 Bytes as standard) . A Jitter Buffer is used, when entering a minimum value of "2" as jitter count. Jitter count means the amount of RTP-Packets that will be queued as maximum. Values of "0" or "1" means, there is no Jitter Buffer in use. (Use 20 as standard)

//Create a Multicast Receiver and a SoundPlayer 
NF.MulticastReceiver m_Receiver = new NF.MulticastReceiver(PacketSize);
WinSound.Player m_Player = new WinSound.Player(); 
//Define a callback function for receiving datas from multicast
m_Receiver.DataReceived += new NF.MulticastReceiver.DelegateDataReceived(OnDataReceived);
//Connect the Multicast and open the Player
m_Receiver.Connect(MulticasAddress, MulticastPort); 
m_Player.Open(SoundDeviceName, SamplesPerSecond, BitsPerSample, Channels, BufferCount); 
//In the callback function get the rtp header of the multicast packet
WinSound.RTPPacket rtp = new WinSound.RTPPacket(bytes);
//Translate MuLaw to linear
Byte[] linearBytes = WinSound.Utils.MuLawToLinear(rtp.Data, Config.BitsPerSample, Config.Channels);
//Play the linear datas to soundcard
m_Player.PlayData(linearBytes, false);
//Close the Player and the Receiver
m_Receiver.Disconnect();
m_Player.Close(); 

History

  • 31.05.2012 - Added.
  • 30.06.2012 - Updated. Using the CSRC Count Information in RTP Header for Multicast Player.
  • 08.07.2012 - Updated. Wav-File Read/Write operations for Player Tester.
  • 11.08.2012 - Updated. Error resolved, when calling Player.PlayData in blocking mode = true
  • 21.08.2012 - Updated. Error resolved. Garbage Collection caused Application crash.
  • 07.09.2012 - Updated. Error resolved. Reading Wave-Files in different formats.
  • 09.09.2012 - Updated. Better performance when playing wav files.
  • 19.10.2012 - Updated. Added Jitter buffer. Added streaming wav-files directly.
  • 22.10.2013 - Updated. Drawing the linear datas as curve
  • 12.04.2014 - Added Source. WinSound implementation written in C++ as a COM Server (Optional)

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Banjoo
Software Developer Telecommunication
Germany Germany
No Biography provided

Comments and Discussions

 
QuestionGood work bro! PinpremiumVolynsky Alex13-Apr-14 10:09 
AnswerRe: Good work bro! PinpremiumBanjoo13-Apr-14 15:34 
GeneralRe: Good work bro! PinpremiumVolynsky Alex13-Apr-14 21:33 
GeneralMy vote of 5 PinpremiumVolynsky Alex12-Apr-14 21:37 
BugStability issues on long run PinmemberZejulioZ11-Apr-14 7:45 
GeneralRe: Stability issues on long run PinpremiumBanjoo11-Apr-14 13:17 
GeneralRe: Stability issues on long run PinmemberZejulioZ11-Apr-14 23:11 
GeneralRe: Stability issues on long run [modified] PinpremiumBanjoo12-Apr-14 14:12 
GeneralRe: Stability issues on long run [modified] PinmemberZejulioZ14-Apr-14 3:02 
GeneralRe: Stability issues on long run PinpremiumBanjoo14-Apr-14 7:47 
GeneralRe: Stability issues on long run PinmemberZejulioZ15-Apr-14 0:39 
GeneralRe: Stability issues on long run PinpremiumBanjoo15-Apr-14 7:01 
GeneralRe: Stability issues on long run PinmemberZejulioZ15-Apr-14 9:10 
QuestionSample rates Pinmemberhagver7426-Feb-14 0:19 
AnswerRe: Sample rates [modified] PinmemberBanjoo26-Feb-14 9:56 
GeneralRe: Sample rates Pinmemberhagver7427-Feb-14 0:40 
QuestionStart on execute PinmemberMember 1060982619-Feb-14 8:30 
AnswerRe: Start on execute PinmemberBanjoo19-Feb-14 12:36 
QuestionPacket size, Buffer count, etc. and Sound Card Pinmembersisifo3-Dec-13 2:06 
AnswerRe: Packet size, Buffer count, etc. and Sound Card PinmemberBanjoo3-Dec-13 2:42 
GeneralRe: Packet size, Buffer count, etc. and Sound Card Pinmembersisifo3-Dec-13 3:39 
SuggestionSupport for Multiple Channel Audio data and *.wav files Pinmemberbrissdo2-Dec-13 21:34 
Suggestiondeal with packets repeat, loss and out of order Pinmemberbrissdo14-Nov-13 0:12 
GeneralRe: deal with packets repeat, loss and out of order PinmemberBanjoo15-Nov-13 3:19 
GeneralRe: deal with packets repeat, loss and out of order Pinmemberbrissdo16-Nov-13 17:31 

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