Streaming Data from a WAV File

Artikel
09/29/2011

This section demonstrates how to stream audio from a wave (.wav) file utilizing dynamic sound.

Loading Audio Content

The code in this topic describes how to stream an audio file using DynamicSoundEffectInstance. You can download a complete code sample for this topic, including full source code and any additional supporting files required by the sample.

Complete Sample

The code in this topic shows you the technique. You can download a complete code sample for this topic, including full source code and any additional supporting files required by the sample.

Download StreamFromFileSample

To open a wave file for streaming

Create global variables to hold the DynamicSoundEffectInstance, position, count, and data.
```
DynamicSoundEffectInstance dynamicSound;
int position;
int count;
byte[] byteArray;
```
In the Game.LoadContent method of your game, open the audio data using TitleContainer.OpenStream.
```
System.IO.Stream waveFileStream = TitleContainer.OpenStream(@"Content\48K16BSLoop.wav");
```

Create a new binary reader to read from the audio stream.

BinaryReader reader = new BinaryReader(waveFileStream);

Read the wave file header from the buffer.

int chunkID = reader.ReadInt32();
int fileSize = reader.ReadInt32();
int riffType = reader.ReadInt32();
int fmtID = reader.ReadInt32();
int fmtSize = reader.ReadInt32();
int fmtCode = reader.ReadInt16();
int channels = reader.ReadInt16();
int sampleRate = reader.ReadInt32();
int fmtAvgBPS = reader.ReadInt32();
int fmtBlockAlign = reader.ReadInt16();
int bitDepth = reader.ReadInt16();

if (fmtSize == 18)
{
    // Read any extra values
    int fmtExtraSize = reader.ReadInt16();
    reader.ReadBytes(fmtExtraSize);
}

int dataID = reader.ReadInt32();
int dataSize = reader.ReadInt32();

Store the audio data of the wave file to a byte array.
```
byteArray = reader.ReadBytes(dataSize);
```
Create the new dynamic sound effect instance using the sample rate and channel information extracted from the sound file.
```
dynamicSound = new DynamicSoundEffectInstance(sampleRate, (AudioChannels)channels);
```
Store the size of the audio buffer that is needed in the count variable. Submit data in 100 ms chunks.
```
count = dynamicSound.GetSampleSizeInBytes(TimeSpan.FromMilliseconds(100));
```
Set up the dynamic sound effect's buffer needed event handler so audio data can be read when it needs more data.
```
dynamicSound.BufferNeeded += new EventHandler<EventArgs>(DynamicSound_BufferNeeded);
```

Implement the buffer needed event handler.

void DynamicSound_BufferNeeded(object sender, EventArgs e)
{
    dynamicSound.SubmitBuffer(byteArray, position, count / 2);
    dynamicSound.SubmitBuffer(byteArray, position + count / 2, count / 2);

    position += count;
    if (position + count > byteArray.Length)
    {
        position = 0;
    }
}

Use the controller buttons to play and stop the sound stream.

protected override void Update(GameTime gameTime)
{
    GamePadState gamePadState = GamePad.GetState(PlayerIndex.One);
    if (lastGamePadState != gamePadState)
    {
        if (gamePadState.Buttons.A == ButtonState.Pressed)
        {
            dynamicSound.Play();
        }
        if (gamePadState.Buttons.B == ButtonState.Pressed)
        {
            dynamicSound.Stop();
        }
        lastGamePadState = gamePadState;
    }

    base.Update(gameTime);
}

Concepts

Playing a Sound
Demonstrates how to play a simple sound by using SoundEffect.

Reference

DynamicSoundEffectInstance
Provides properties, methods, and events for play back of the audio buffer.
BufferNeeded
Event that occurs when the number of audio capture buffers awaiting playback is less than or equal to two.
OpenStream
Returns a stream to an existing file in the default title storage location.

Bagikan melalui