Windows Phone中的麦克风和播放录音
问题描述:
我开发的应用程序的一部分允许用户使用麦克风录制任何内容。要从麦克风录音,我使用Microphone Code sample by Microsoft中给出的代码。我只是对代码进行了一些更改,以便将wav标头写入流,以便将记录作为波形文件存储在独立存储中。Windows Phone中的麦克风和播放录音
private void recordButton_Click(object sender, EventArgs e)
{
// Get audio data in 1/2 second chunks
microphone.BufferDuration = TimeSpan.FromMilliseconds(500);
// Allocate memory to hold the audio data
buffer = new byte[microphone.GetSampleSizeInBytes(microphone.BufferDuration)];
// Set the stream back to zero in case there is already something in it
stream.SetLength(0);
//Write wav header
WriteWavHeader(microphone.SampleRate);
// Start recording
microphone.Start();
SetButtonStates(false, false, true,false);
UserHelp.Text = "record";
StatusImage.Source = microphoneImage;
StatusImage.Visibility = System.Windows.Visibility.Visible;
}
public void WriteWavHeader(int sampleRate)
{
const int bitsPerSample = 16;
const int bytesPerSample = bitsPerSample/8;
var encoding = System.Text.Encoding.UTF8;
// ChunkID Contains the letters "RIFF" in ASCII form (0x52494646 big-endian form).
stream.Write(encoding.GetBytes("RIFF"), 0, 4);
// NOTE this will be filled in later
stream.Write(BitConverter.GetBytes(0), 0, 4);
// Format Contains the letters "WAVE"(0x57415645 big-endian form).
stream.Write(encoding.GetBytes("WAVE"), 0, 4);
// Subchunk1ID Contains the letters "fmt " (0x666d7420 big-endian form).
stream.Write(encoding.GetBytes("fmt "), 0, 4);
// Subchunk1Size 16 for PCM. This is the size of therest of the Subchunk which follows this number.
stream.Write(BitConverter.GetBytes(16), 0, 4);
// AudioFormat PCM = 1 (i.e. Linear quantization) Values other than 1 indicate some form of compression.
stream.Write(BitConverter.GetBytes((short)1), 0, 2);
// NumChannels Mono = 1, Stereo = 2, etc.
stream.Write(BitConverter.GetBytes((short)1), 0, 2);
// SampleRate 8000, 44100, etc.
stream.Write(BitConverter.GetBytes(sampleRate), 0, 4);
// ByteRate = SampleRate * NumChannels * BitsPerSample/8
stream.Write(BitConverter.GetBytes(sampleRate * bytesPerSample), 0, 4);
// BlockAlign NumChannels * BitsPerSample/8 The number of bytes for one sample including all channels.
stream.Write(BitConverter.GetBytes((short)(bytesPerSample)), 0, 2);
// BitsPerSample 8 bits = 8, 16 bits = 16, etc.
stream.Write(BitConverter.GetBytes((short)(bitsPerSample)), 0, 2);
// Subchunk2ID Contains the letters "data" (0x64617461 big-endian form).
stream.Write(encoding.GetBytes("data"), 0, 4);
// NOTE to be filled in later
stream.Write(BitConverter.GetBytes(0), 0, 4);
}
public void UpdateWavHeader()
{
//if (!stream.CanSeek) throw new Exception("Can't seek stream to update wav header");
var oldPos = stream.Position;
// ChunkSize 36 + SubChunk2Size
stream.Seek(4, SeekOrigin.Begin);
stream.Write(BitConverter.GetBytes((int)stream.Length - 8), 0, 4);
// Subchunk2Size == NumSamples * NumChannels * BitsPerSample/8 This is the number of bytes in the data.
stream.Seek(40, SeekOrigin.Begin);
stream.Write(BitConverter.GetBytes((int)stream.Length - 44), 0, 4);
stream.Seek(oldPos, SeekOrigin.Begin);
}
private void stopButton_Click(object sender, EventArgs e)
{
if (microphone.State == MicrophoneState.Started)
{
// In RECORD mode, user clicked the
// stop button to end recording
microphone.Stop();
UpdateWavHeader();
}
else if (soundInstance.State == SoundState.Playing)
{
// In PLAY mode, user clicked the
// stop button to end playing back
soundInstance.Stop();
}
SetButtonStates(true, true, false,true);
UserHelp.Text = "ready";
StatusImage.Source = blankImage;
}
之后,如果用户选择保存录制内容,我将它保存在独立存储器中。
应用程序中有各种页面,使用麦克风的页面就是其中之一。这个页面做导航是从另一个页面完成:
NavigationService.Navigate(new Uri("/Mic.xaml", UriKind.Relative));
现在,当Mic.xaml页面上,有或没有,如果用户点击硬件后退按钮他回到旧的一页记录任何东西。在此页面中,如果他再次导航到Mic.xaml页面,然后尝试录制内容,则录制的文件似乎无法正确录制。录音似乎有问题。
因此,当我们第一次导航到页面时,录制成功,但是当我们第二次或第四次导航时,它不会。
我在模拟器上
答
微软的样品不适合多页的场景进行测试,离开页面时,他们不清理资源。
首先,把DispatcherTimer在一个领域:
private DispatcherTimer dt;
然后,更改构造函数,而不是使用初始化一个新的DT这一领域:
this.dt = new DispatcherTimer();
最后,覆盖OnNavigateFrom方法检测用户何时离开页面,并清理资源:
protected override void OnNavigatedFrom(System.Windows.Navigation.NavigationEventArgs e)
{
base.OnNavigatedFrom(e);
dt.Stop();
microphone.BufferReady -= this.microphone_BufferReady;
}
感谢一吨:) It wo像魅力一样飞了过去 – Saurabh 2012-01-07 19:35:56