Features:
Stream
Task
-based APIsAudioPlayer
includedPlatform | Supported | Version | Notes |
---|---|---|---|
Xamarin.iOS | Yes | iOS 7+ | |
Xamarin.Android | Yes | API 16+ | Project should target Android framework 8.1+ |
Windows UWP | Yes | 10.0 | Build 15063 and up |
Notes:
The following permissions/capabilities are required to be configured on each platform:
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
Additionally, on OS versions Marshmallow and above, you may need to perform a runtime check to ask the user to access their microphone.
Example:
Do this in your main activity or at the point you'll be needing access to record audio:
if (ContextCompat.CheckSelfPermission (this, Manifest.Permission.RecordAudio) != Permission.Granted)
{
ActivityCompat.RequestPermissions (this, new String [] { Manifest.Permission.RecordAudio }, 1);
}
For iOS 10 and above, you must set the NSMicrophoneUsageDescription
in your Info.plist:
<key>NSMicrophoneUsageDescription</key>
<string>The [app name] wants to use your microphone to record audio.</string>
You must check the Internet
and Microphone
capabilities in your app's Package.appxmanifest
file.
In a controller/activity/page, initialize a new AudioRecorderService
.
Example:
recorder = new AudioRecorderService
{
StopRecordingOnSilence = true, //will stop recording after 2 seconds (default)
StopRecordingAfterTimeout = true, //stop recording after a max timeout (defined below)
TotalAudioTimeout = TimeSpan.FromSeconds (15) //audio will stop recording after 15 seconds
};
More settings and properties are defined below
To begin recording, use the StartRecording ()
and StopRecording ()
methods as shown:
async void RecordButton_Click (object sender, EventArgs e)
{
await RecordAudio ();
}
async Task RecordAudio ()
{
try
{
if (!recorder.IsRecording)
{
await recorder.StartRecording ();
}
else
{
await recorder.StopRecording ();
}
}
catch (Exception ex)
{
...
}
}
In lieu of calling StopRecording ()
, you can also make use of the StopRecordingAfterTimeout
and/or StopRecordingOnSilence
settings, which are explained below.
Once recording has begun, there are two different ways to determine when recording has finished:
To use the Task-based API, you can grab the returned Task
from the call to StartRecording ()
. This allows you to await the result of the Task
, which will complete when recording is complete and return the path to the recorded audio file.
Example:
var recordTask = await recorder.StartRecording ();
... maybe do some other things like toggle your 'mic' button off while recording
//await the returned Task... this will complete once recording has been stopped
var audioFile = await recordTask;
if (audioFile != null) //non-null audioFile indicates audio was successfully recorded
{
//do something with the file
}
The AudioInputReceived
is raised when recording is complete, and the full filepath of the recorded audio file is passed along.
Example:
recorder.AudioInputReceived += Recorder_AudioInputReceived;
...
await recorder.StartRecording ();
...
private async void Recorder_AudioInputReceived(object sender, string audioFile)
{
//do something with the file
}
NOTE: This event is raised on a background thread to allow for further file processing as needed. If the audioFile
is null or empty, no audio was recorded.
--
There are also multiple ways to use the recorded (or recording) audio data:
There are multiple ways to access the recorded audio file path:
Task
can be awaited or use standard Task
continuation APIs.audioFile
parameter of the AudioInputReceived
event handler.GetAudioFilePath ()
method on the AudioRecorderService
class will return the recorded audio file path.These will all return null
in the case that no audio has been recorded yet or no audio was recorded/detected in the last recording session.
Once you have the path to the recorded audio file, you can use standard file operations (for native/.NET Standard) and/or a cross platform file system abstraction like PCLStorage to get a stream to the file data.
It's also possible to get a stream to the recording audio data as it's being recorded, once StartRecording ()
has been called.
To access this readonly stream of audio data, you may call the GetAudioFileStream ()
method. This is useful in the case you want to immediately begin streaming the audio data to a server or other consumer.
NOTE: Since the WAV header is written after recording, once the audio length is known, the provided Stream
data will contain the PCM audio data only and will not contain a WAV header. If your use case requires a WAV header, you can call AudioFunctions.WriteWaveHeader (Stream stream, int channelCount, int sampleRate, int bitsPerSample)
, which will write a WAV header to the stream with an unknown length.
Since GetAudioFileStream ()
will return a Stream
that is also being populated concurrently, it can be useful to know when the recording is complete - the Stream
will continue to grow! This can be accomplished with either the Event-based API or the Task-based API (which is often more useful).
An example of the Task-based API and concurrent writing and reading of the audio data is shown in the sample accompanying the Xamarin.Cognitive.Speech library. This speech client will stream audio data to the server until the AudioRecordTask
completes, signaling that the recording is finished.
IsRecording
bool IsRecording
Returns a value indicating if the AudioRecorderService is currently recording audio.
StopRecordingAfterTimeout / TotalAudioTimeout
bool StopRecordingAfterTimeout
Gets/sets a value indicating if the AudioRecorderService should stop recording after a certain amount of time. Default is true
.
TimeSpan TotalAudioTimeout
If StopRecordingAfterTimeout
is set to true
, this TimeSpan
indicates the total amount of time to record audio for before recording is stopped. Defaults to 30 seconds.
StopRecordingOnSilence / AudioSilenceTimeout
bool StopRecordingOnSilence
Gets/sets a value indicating if the AudioRecorderService should stop recording after silence (low audio signal) is detected. Default is true
.
TimeSpan AudioSilenceTimeout
If StopRecordingOnSilence
is set to true
, this TimeSpan
indicates the amount of 'silent' time is required before recording is stopped. Defaults to 2 seconds.
SilenceThreshold
float SilenceThreshold
Gets/sets a value indicating the signal threshold that determines silence. If the recorder is being over or under aggressive when detecting silence for your use case, you can alter this value to achieve different results. Defaults to .15. Value should be between 0 and 1.
FilePath
string FilePath
Gets/sets the desired file path. If null it will be set automatically to a temporary file.
ConfigureAVAudioSession (iOS only)
static bool ConfigureAVAudioSession
Gets/sets whether the AudioRecorderService
should attempt to control the shared AVAudioSession
category. This can be set from the AppDelegate
(example) or other iOS-specific class. When set to true
, the AudioRecorderService
will attempt to set the category to Record
before recording, and restore the category to its previous value after recording is complete. This can help this plugin coexist with other media plugins that try to unilaterally set the category. Defaults to false
.
Complete samples demonstrating audio recording (AudioRecorderService
) and playback (AudioPlayer
) of the recorded file are available in the /Samples folder:
Contributions are welcome. Feel free to file issues and pull requests on the repo and they'll be reviewed as time permits.
This solution requires the following environment/config:
NuGet.Build.Packaging
The easiest way to debug this library is to clone this repo and copy the shared library + platform project (of the platform you're debugging with) into your solution folder, then include the projects in your solution and reference them directly, rather than referencing the NuGet package.
Licensed under the MIT License (MIT). See LICENSE for details.