同时录制音频和播放声音 - C＃ - Windows Phone 8.1

Question

我正在尝试录制音频并直接播放它（我想在耳机中听到我的声音而不保存它），但是MediaElement和MediaCapture似乎不是同时工作。 我初始化我MediaCapture这样：

_mediaCaptureManager = new MediaCapture(); 
    var settings = new MediaCaptureInitializationSettings(); 
    settings.StreamingCaptureMode = StreamingCaptureMode.Audio; 
    settings.MediaCategory = MediaCategory.Other; 
    settings.AudioProcessing = AudioProcessing.Default; 
    await _mediaCaptureManager.InitializeAsync(settings); 

但是我真的不知道如何着手;我wonderign如果这些方法之一可以工作（我tryied实现它们没有成功，我还没有发现的例子）：

1. 是否有使用StartPreviewAsync（）录制音频，办法或它仅适用于视频？我注意到，我得到以下错误：“指定的对象或值不存在”，而设置我的CaptureElement来源;它只发生，如果我写“settings.StreamingCaptureMode = StreamingCaptureMode.Audio;”而每一个作品的视频。
2. 如何使用StartRecordToStreamAsync（）记录流;我的意思是，我如何初始化IRandomAccessStream并从中读取？我是否可以在上写而我保持为呢？

3. 我读到将MediaElement的AudioCathegory和MediaCapture的MediaCathegory更改为Communication可能有效。但是，虽然我的代码与以前的设置一起工作（它只需记录并保存在文件中），但如果我编写“settings.MediaCategory = MediaCategory.Communication;”，则不起作用。而不是“settings.MediaCategory = MediaCategory.Other;”。你能告诉我为什么吗？ 这是我目前的计划，只是记录，保存和播放：

   private async void CaptureAudio() 
   { 
       try 
       { 
        _recordStorageFile = await KnownFolders.VideosLibrary.CreateFileAsync(fileName, CreationCollisionOption.GenerateUniqueName);      
        MediaEncodingProfile recordProfile = MediaEncodingProfile.CreateWav(AudioEncodingQuality.Auto); 
        await _mediaCaptureManager.StartRecordToStorageFileAsync(recordProfile, this._recordStorageFile); 
        _recording = true; 
       } 
       catch (Exception e) 
       { 
        Debug.WriteLine("Failed to capture audio:"+e.Message); 
       } 
   } 
   
   private async void StopCapture() 
   { 
       if (_recording) 
       { 
        await _mediaCaptureManager.StopRecordAsync(); 
        _recording = false; 
       } 
   } 
   
   private async void PlayRecordedCapture() 
   { 
       if (!_recording) 
       { 
        var stream = await _recordStorageFile.OpenAsync(FileAccessMode.Read); 
        playbackElement1.AutoPlay = true; 
        playbackElement1.SetSource(stream, _recordStorageFile.FileType); 
        playbackElement1.Play(); 
       } 
   } 
   

如果您有任何建议，我会gratefull。 祝您有美好的一天。

Answer 1

您会考虑将目标锁定为Windows 10吗？新的AudioGraph API可以让你做到这一点，并且Scenario 2 (Device Capture) in the SDK sample很好地演示了它。

首先，将样品填充所有输出设备到一个列表：

private async Task PopulateDeviceList() 
{ 
    outputDevicesListBox.Items.Clear(); 
    outputDevices = await DeviceInformation.FindAllAsync(MediaDevice.GetAudioRenderSelector()); 
    outputDevicesListBox.Items.Add("-- Pick output device --"); 
    foreach (var device in outputDevices) 
    { 
     outputDevicesListBox.Items.Add(device.Name); 
    } 
} 

然后获取打造AudioGraph：

AudioGraphSettings settings = new AudioGraphSettings(AudioRenderCategory.Media); 
settings.QuantumSizeSelectionMode = QuantumSizeSelectionMode.LowestLatency; 

// Use the selected device from the outputDevicesListBox to preview the recording 
settings.PrimaryRenderDevice = outputDevices[outputDevicesListBox.SelectedIndex - 1]; 

CreateAudioGraphResult result = await AudioGraph.CreateAsync(settings); 

if (result.Status != AudioGraphCreationStatus.Success) 
{ 
    // TODO: Cannot create graph, propagate error message 
    return; 
} 

AudioGraph graph = result.Graph; 

// Create a device output node 
CreateAudioDeviceOutputNodeResult deviceOutputNodeResult = await graph.CreateDeviceOutputNodeAsync(); 
if (deviceOutputNodeResult.Status != AudioDeviceNodeCreationStatus.Success) 
{ 
    // TODO: Cannot create device output node, propagate error message 
    return; 
} 

deviceOutputNode = deviceOutputNodeResult.DeviceOutputNode; 

// Create a device input node using the default audio input device 
CreateAudioDeviceInputNodeResult deviceInputNodeResult = await graph.CreateDeviceInputNodeAsync(MediaCategory.Other); 

if (deviceInputNodeResult.Status != AudioDeviceNodeCreationStatus.Success) 
{ 
    // TODO: Cannot create device input node, propagate error message 
    return; 
} 

deviceInputNode = deviceInputNodeResult.DeviceInputNode; 

// Because we are using lowest latency setting, we need to handle device disconnection errors 
graph.UnrecoverableErrorOccurred += Graph_UnrecoverableErrorOccurred; 

// Start setting up the output file 
FileSavePicker saveFilePicker = new FileSavePicker(); 
saveFilePicker.FileTypeChoices.Add("Pulse Code Modulation", new List<string>() { ".wav" }); 
saveFilePicker.FileTypeChoices.Add("Windows Media Audio", new List<string>() { ".wma" }); 
saveFilePicker.FileTypeChoices.Add("MPEG Audio Layer-3", new List<string>() { ".mp3" }); 
saveFilePicker.SuggestedFileName = "New Audio Track"; 
StorageFile file = await saveFilePicker.PickSaveFileAsync(); 

// File can be null if cancel is hit in the file picker 
if (file == null) 
{ 
    return; 
} 

MediaEncodingProfile fileProfile = CreateMediaEncodingProfile(file); 

// Operate node at the graph format, but save file at the specified format 
CreateAudioFileOutputNodeResult fileOutputNodeResult = await graph.CreateFileOutputNodeAsync(file, fileProfile); 

if (fileOutputNodeResult.Status != AudioFileNodeCreationStatus.Success) 
{ 
    // TODO: FileOutputNode creation failed, propagate error message 
    return; 
} 

fileOutputNode = fileOutputNodeResult.FileOutputNode; 

// Connect the input node to both output nodes 
deviceInputNode.AddOutgoingConnection(fileOutputNode); 
deviceInputNode.AddOutgoingConnection(deviceOutputNode); 

一旦所有做到这一点，你可以录制文件，同时播放录制的音频，如下所示：

private async Task ToggleRecordStop() 
{ 
    if (recordStopButton.Content.Equals("Record")) 
    { 
     graph.Start(); 
     recordStopButton.Content = "Stop"; 
    } 
    else if (recordStopButton.Content.Equals("Stop")) 
    { 
     // Good idea to stop the graph to avoid data loss 
     graph.Stop(); 
     TranscodeFailureReason finalizeResult = await fileOutputNode.FinalizeAsync(); 
     if (finalizeResult != TranscodeFailureReason.None) 
     { 
      // TODO: Finalization of file failed. Check result code to see why, propagate error message 
      return; 
     } 

     recordStopButton.Content = "Record"; 
    } 
}