MediaRecorder test

public class

MediaRecorder

extends Object

java.lang.Object
↳	android.media.MediaRecorder

Class Overview

Used to record audio and video. The recording control is based on a simple state machine (see below).

A common case of using MediaRecorder to record audio works as follows:

MediaRecorder recorder = new MediaRecorder(); 
 recorder.setAudioSource(MediaRecorder.AudioSource.MIC); 
 recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); 
 recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); 
 recorder.setOutputFile(PATH_NAME); 
 recorder.prepare(); 
 recorder.start();   // Recording is now started 
 ... 
 recorder.stop(); 
 recorder.reset();   // You can reuse the object by going back to setAudioSource() step 
 recorder.release(); // Now the object cannot be reused 
 

Applications may want to register for informational and error events in order to be informed of some internal update and possible runtime errors during recording. Registration for such events is done by setting the appropriate listeners (via calls (to setOnInfoListener(OnInfoListener)setOnInfoListener and/or setOnErrorListener(OnErrorListener)setOnErrorListener). In order to receive the respective callback associated with these listeners, applications are required to create MediaRecorder objects on threads with a Looper running (the main UI thread by default already has a Looper running).

Note: Currently, MediaRecorder does not work on the emulator.

Developer Guides

For more information about how to use MediaRecorder for recording video, read the Camera developer guide. For more information about how to use MediaRecorder for recording sound, read the Audio Capture developer guide.

Summary

Nested Classes
class	MediaRecorder.AudioEncoder	Defines the audio encoding.
class	MediaRecorder.AudioSource	Defines the audio source.
interface	MediaRecorder.OnErrorListener	Interface definition for a callback to be invoked when an error occurs while recording.
interface	MediaRecorder.OnInfoListener	Interface definition for a callback to be invoked when an error occurs while recording.
class	MediaRecorder.OutputFormat	Defines the output format.
class	MediaRecorder.VideoEncoder	Defines the video encoding.
class	MediaRecorder.VideoSource	Defines the video source.

Constants
int	MEDIA_ERROR_SERVER_DIED	Media server died.
int	MEDIA_RECORDER_ERROR_UNKNOWN	Unspecified media recorder error.
int	MEDIA_RECORDER_INFO_MAX_DURATION_REACHED	A maximum duration had been setup and has now been reached.
int	MEDIA_RECORDER_INFO_MAX_FILESIZE_REACHED	A maximum filesize had been setup and has now been reached.
int	MEDIA_RECORDER_INFO_UNKNOWN	Unspecified media recorder error.

Public Constructors
	MediaRecorder() Default constructor.

Public Methods
final static int	getAudioSourceMax() Gets the maximum value for audio sources.
int	getMaxAmplitude() Returns the maximum absolute amplitude that was sampled since the last call to this method.
Surface	getSurface() Gets the surface to record from when using SURFACE video source.
void	prepare() Prepares the recorder to begin capturing and encoding data.
void	release() Releases resources associated with this MediaRecorder object.
void	reset() Restarts the MediaRecorder to its idle state.
void	setAudioChannels(int numChannels) Sets the number of audio channels for recording.
void	setAudioEncoder(int audio_encoder) Sets the audio encoder to be used for recording.
void	setAudioEncodingBitRate(int bitRate) Sets the audio encoding bit rate for recording.
void	setAudioSamplingRate(int samplingRate) Sets the audio sampling rate for recording.
void	setAudioSource(int audio_source) Sets the audio source to be used for recording.
void	setCamera( Camera c) Sets a Camera to use for recording.
void	setCaptureRate(double fps) Set video frame capture rate.
void	setLocation(float latitude, float longitude) Set and store the geodata (latitude and longitude) in the output file.
void	setMaxDuration(int max_duration_ms) Sets the maximum duration (in ms) of the recording session.
void	setMaxFileSize(long max_filesize_bytes) Sets the maximum filesize (in bytes) of the recording session.
void	setOnErrorListener( MediaRecorder.OnErrorListener l) Register a callback to be invoked when an error occurs while recording.
void	setOnInfoListener( MediaRecorder.OnInfoListener listener) Register a callback to be invoked when an informational event occurs while recording.
void	setOrientationHint(int degrees) Sets the orientation hint for output video playback.
void	setOutputFile( FileDescriptor fd) Pass in the file descriptor of the file to be written.
void	setOutputFile( String path) Sets the path of the output file to be produced.
void	setOutputFormat(int output_format) Sets the format of the output file produced during recording.
void	setPreviewDisplay( Surface sv) Sets a Surface to show a preview of recorded media (video).
void	setProfile( CamcorderProfile profile) Uses the settings from a CamcorderProfile object for recording.
void	setVideoEncoder(int video_encoder) Sets the video encoder to be used for recording.
void	setVideoEncodingBitRate(int bitRate) Sets the video encoding bit rate for recording.
void	setVideoFrameRate(int rate) Sets the frame rate of the video to be captured.
void	setVideoSize(int width, int height) Sets the width and height of the video to be captured.
void	setVideoSource(int video_source) Sets the video source to be used for recording.
void	start() Begins capturing and encoding data to the file specified with setOutputFile().
void	stop() Stops recording.

Protected Methods
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.

[Expand] Inherited Methods

From class java.lang.Object Object clone() Creates and returns a copy of this Object. boolean equals( Object o) Compares this instance with the specified object and indicates if they are equal. void finalize() Invoked when the garbage collector has detected that this instance is no longer reachable. final Class<?> getClass() Returns the unique instance of Class that represents this object's class. int hashCode() Returns an integer hash code for this object. final void notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up. final void notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up. String toString() Returns a string containing a concise, human-readable description of this object. final void wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object. final void wait(long millis, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires. final void wait(long millis) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.

Constants

public static final int MEDIA_ERROR_SERVER_DIED

Added in API level 17

Media server died. In this case, the application must release the MediaRecorder object and instantiate a new one.

See Also

• MediaRecorder.OnErrorListener

Constant Value: 100 (0x00000064)

public static final int MEDIA_RECORDER_ERROR_UNKNOWN

Added in API level 3

Unspecified media recorder error.

See Also

• MediaRecorder.OnErrorListener

Constant Value: 1 (0x00000001)

public static final int MEDIA_RECORDER_INFO_MAX_DURATION_REACHED

Added in API level 3

A maximum duration had been setup and has now been reached.

See Also

• MediaRecorder.OnInfoListener

Constant Value: 800 (0x00000320)

public static final int MEDIA_RECORDER_INFO_MAX_FILESIZE_REACHED

Added in API level 3

A maximum filesize had been setup and has now been reached.

See Also

• MediaRecorder.OnInfoListener

Constant Value: 801 (0x00000321)

public static final int MEDIA_RECORDER_INFO_UNKNOWN

Added in API level 3

Unspecified media recorder error.

See Also

• MediaRecorder.OnInfoListener

Constant Value: 1 (0x00000001)

Public Constructors

public MediaRecorder ()

Added in API level 1

Default constructor.

Public Methods

public static final int getAudioSourceMax ()

Added in API level 4

Gets the maximum value for audio sources.

See Also

• MediaRecorder.AudioSource

public int getMaxAmplitude ()

Added in API level 1

Returns the maximum absolute amplitude that was sampled since the last call to this method. Call this only after the setAudioSource().

Returns

• the maximum absolute amplitude measured since the last call, or 0 when called for the first time

Throws

IllegalStateException	if it is called before the audio source has been set.

public Surface getSurface ()

Gets the surface to record from when using SURFACE video source.

Should only be called after prepare(). Frames rendered before start() will be discarded.

Throws

IllegalStateException	if it is called before prepare(), after stop() or is called when VideoSource is not set to SURFACE.

See Also

• MediaRecorder.VideoSource

public void prepare ()

Added in API level 1

Prepares the recorder to begin capturing and encoding data. This method must be called after setting up the desired audio and video sources, encoders, file format, etc., but before start().

Throws

IllegalStateException	if it is called after start() or before setOutputFormat().
IOException	if prepare fails otherwise.

public void release ()

Added in API level 1

Releases resources associated with this MediaRecorder object. It is good practice to call this method when you're done using the MediaRecorder. In particular, whenever an Activity of an application is paused (its onPause() method is called), or stopped (its onStop() method is called), this method should be invoked to release the MediaRecorder object, unless the application has a special need to keep the object around. In addition to unnecessary resources (such as memory and instances of codecs) being held, failure to call this method immediately if a MediaRecorder object is no longer needed may also lead to continuous battery consumption for mobile devices, and recording failure for other applications if no multiple instances of the same codec are supported on a device. Even if multiple instances of the same codec are supported, some performance degradation may be expected when unnecessary multiple instances are used at the same time.

public void reset ()

Added in API level 1

Restarts the MediaRecorder to its idle state. After calling this method, you will have to configure it again as if it had just been constructed.

public void setAudioChannels (int numChannels)

Added in API level 8

Sets the number of audio channels for recording. Call this method before prepare(). Prepare() may perform additional checks on the parameter to make sure whether the specified number of audio channels are applicable.

Parameters

numChannels	the number of audio channels. Usually it is either 1 (mono) or 2 (stereo).

public void setAudioEncoder (int audio_encoder)

Added in API level 1

Sets the audio encoder to be used for recording. If this method is not called, the output file will not contain an audio track. Call this after setOutputFormat() but before prepare().

Parameters

audio_encoder	the audio encoder to use.

Throws

IllegalStateException	if it is called before setOutputFormat() or after prepare().

See Also

• MediaRecorder.AudioEncoder

public void setAudioEncodingBitRate (int bitRate)

Added in API level 8

Sets the audio encoding bit rate for recording. Call this method before prepare(). Prepare() may perform additional checks on the parameter to make sure whether the specified bit rate is applicable, and sometimes the passed bitRate will be clipped internally to ensure the audio recording can proceed smoothly based on the capabilities of the platform.

Parameters

bitRate	the audio encoding bit rate in bits per second.

public void setAudioSamplingRate (int samplingRate)

Added in API level 8

Sets the audio sampling rate for recording. Call this method before prepare(). Prepare() may perform additional checks on the parameter to make sure whether the specified audio sampling rate is applicable. The sampling rate really depends on the format for the audio recording, as well as the capabilities of the platform. For instance, the sampling rate supported by AAC audio coding standard ranges from 8 to 96 kHz, the sampling rate supported by AMRNB is 8kHz, and the sampling rate supported by AMRWB is 16kHz. Please consult with the related audio coding standard for the supported audio sampling rate.

Parameters

samplingRate	the sampling rate for audio in samples per second.

public void setAudioSource (int audio_source)

Added in API level 1

Sets the audio source to be used for recording. If this method is not called, the output file will not contain an audio track. The source needs to be specified before setting recording-parameters or encoders. Call this only before setOutputFormat().

Parameters

audio_source	the audio source to use

Throws

IllegalStateException	if it is called after setOutputFormat()

See Also

• MediaRecorder.AudioSource

public void setCamera (Camera c)

Added in API level 3

Sets a Camera to use for recording. Use this function to switch quickly between preview and capture mode without a teardown of the camera object. unlock() should be called before this. Must call before prepare().

Parameters

c	the Camera to use for recording

public void setCaptureRate (double fps)

Added in API level 11

Set video frame capture rate. This can be used to set a different video frame capture rate than the recorded video's playback rate. This method also sets the recording mode to time lapse. In time lapse video recording, only video is recorded. Audio related parameters are ignored when a time lapse recording session starts, if an application sets them.

Parameters

fps

Rate at which frames should be captured in frames per second. The fps can go as low as desired. However the fastest fps will be limited by the hardware. For resolutions that can be captured by the video camera, the fastest fps can be computed using getPreviewFpsRange(int[]). For higher resolutions the fastest fps may be more restrictive. Note that the recorder cannot guarantee that frames will be captured at the given rate due to camera/encoder limitations. However it tries to be as close as possible.

public void setLocation (float latitude, float longitude)

Added in API level 14

Set and store the geodata (latitude and longitude) in the output file. This method should be called before prepare(). The geodata is stored in udta box if the output format is OutputFormat.THREE_GPP or OutputFormat.MPEG_4, and is ignored for other output formats. The geodata is stored according to ISO-6709 standard.

Parameters

latitude	latitude in degrees. Its value must be in the range [-90, 90].
longitude	longitude in degrees. Its value must be in the range [-180, 180].

Throws

IllegalArgumentException	if the given latitude or longitude is out of range.

public void setMaxDuration (int max_duration_ms)

Added in API level 3

Sets the maximum duration (in ms) of the recording session. Call this after setOutFormat() but before prepare(). After recording reaches the specified duration, a notification will be sent to the MediaRecorder.OnInfoListener with a "what" code of MEDIA_RECORDER_INFO_MAX_DURATION_REACHED and recording will be stopped. Stopping happens asynchronously, there is no guarantee that the recorder will have stopped by the time the listener is notified.

Parameters

max_duration_ms	the maximum duration in ms (if zero or negative, disables the duration limit)

Throws

IllegalArgumentException

public void setMaxFileSize (long max_filesize_bytes)

Added in API level 3

Sets the maximum filesize (in bytes) of the recording session. Call this after setOutFormat() but before prepare(). After recording reaches the specified filesize, a notification will be sent to the MediaRecorder.OnInfoListener with a "what" code of MEDIA_RECORDER_INFO_MAX_FILESIZE_REACHED and recording will be stopped. Stopping happens asynchronously, there is no guarantee that the recorder will have stopped by the time the listener is notified.

Parameters

max_filesize_bytes	the maximum filesize in bytes (if zero or negative, disables the limit)

Throws

IllegalArgumentException

public void setOnErrorListener (MediaRecorder.OnErrorListener l)

Added in API level 3

Register a callback to be invoked when an error occurs while recording.

Parameters

l	the callback that will be run

public void setOnInfoListener (MediaRecorder.OnInfoListener listener)

Added in API level 3

Register a callback to be invoked when an informational event occurs while recording.

Parameters

listener	the callback that will be run

public void setOrientationHint (int degrees)

Added in API level 9

Sets the orientation hint for output video playback. This method should be called before prepare(). This method will not trigger the source video frame to rotate during video recording, but to add a composition matrix containing the rotation angle in the output video if the output format is OutputFormat.THREE_GPP or OutputFormat.MPEG_4 so that a video player can choose the proper orientation for playback. Note that some video players may choose to ignore the compostion matrix in a video during playback.

Parameters

degrees	the angle to be rotated clockwise in degrees. The supported angles are 0, 90, 180, and 270 degrees.

Throws

IllegalArgumentException	if the angle is not supported.

public void setOutputFile (FileDescriptor fd)

Added in API level 3

Pass in the file descriptor of the file to be written. Call this after setOutputFormat() but before prepare().

Parameters

fd	an open file descriptor to be written into.

Throws

IllegalStateException	if it is called before setOutputFormat() or after prepare()

public void setOutputFile (String path)

Added in API level 1

Sets the path of the output file to be produced. Call this after setOutputFormat() but before prepare().

Parameters

path	The pathname to use.

Throws

IllegalStateException	if it is called before setOutputFormat() or after prepare()

public void setOutputFormat (int output_format)

Added in API level 1

Sets the format of the output file produced during recording. Call this after setAudioSource()/setVideoSource() but before prepare().

It is recommended to always use 3GP format when using the H.263 video encoder and AMR audio encoder. Using an MPEG-4 container format may confuse some desktop players.

Parameters

output_format	the output format to use. The output format needs to be specified before setting recording-parameters or encoders.

Throws

IllegalStateException	if it is called after prepare() or before setAudioSource()/setVideoSource().

See Also

• MediaRecorder.OutputFormat

public void setPreviewDisplay (Surface sv)

Added in API level 1

Sets a Surface to show a preview of recorded media (video). Calls this before prepare() to make sure that the desirable preview display is set. If setCamera(Camera) is used and the surface has been already set to the camera, application do not need to call this. If this is called with non-null surface, the preview surface of the camera will be replaced by the new surface. If this method is called with null surface or not called at all, media recorder will not change the preview surface of the camera.

Parameters

sv	the Surface to use for the preview

See Also

• setPreviewDisplay(android.view.SurfaceHolder)

public void setProfile (CamcorderProfile profile)

Added in API level 8

Uses the settings from a CamcorderProfile object for recording. This method should be called after the video AND audio sources are set, and before setOutputFile(). If a time lapse CamcorderProfile is used, audio related source or recording parameters are ignored.

Parameters

profile	the CamcorderProfile to use

See Also

• CamcorderProfile

public void setVideoEncoder (int video_encoder)

Added in API level 3

Sets the video encoder to be used for recording. If this method is not called, the output file will not contain an video track. Call this after setOutputFormat() and before prepare().

Parameters

video_encoder	the video encoder to use.

Throws

IllegalStateException	if it is called before setOutputFormat() or after prepare()

See Also

• MediaRecorder.VideoEncoder

public void setVideoEncodingBitRate (int bitRate)

Added in API level 8

Sets the video encoding bit rate for recording. Call this method before prepare(). Prepare() may perform additional checks on the parameter to make sure whether the specified bit rate is applicable, and sometimes the passed bitRate will be clipped internally to ensure the video recording can proceed smoothly based on the capabilities of the platform.

Parameters

bitRate	the video encoding bit rate in bits per second.

public void setVideoFrameRate (int rate)

Added in API level 3

Sets the frame rate of the video to be captured. Must be called after setVideoSource(). Call this after setOutFormat() but before prepare().

Parameters

rate	the number of frames per second of video to capture

Throws

IllegalStateException	if it is called after prepare() or before setOutputFormat(). NOTE: On some devices that have auto-frame rate, this sets the maximum frame rate, not a constant frame rate. Actual frame rate will vary according to lighting conditions.

public void setVideoSize (int width, int height)

Added in API level 3

Sets the width and height of the video to be captured. Must be called after setVideoSource(). Call this after setOutFormat() but before prepare().

Parameters

width	the width of the video to be captured
height	the height of the video to be captured

Throws

IllegalStateException	if it is called after prepare() or before setOutputFormat()

public void setVideoSource (int video_source)

Added in API level 3

Sets the video source to be used for recording. If this method is not called, the output file will not contain an video track. The source needs to be specified before setting recording-parameters or encoders. Call this only before setOutputFormat().

Parameters

video_source	the video source to use

Throws

IllegalStateException	if it is called after setOutputFormat()

See Also

• MediaRecorder.VideoSource

public void start ()

Added in API level 1

Begins capturing and encoding data to the file specified with setOutputFile(). Call this after prepare().

Since API level 13, if applications set a camera via setCamera(Camera), the apps can use the camera after this method call. The apps do not need to lock the camera again. However, if this method fails, the apps should still lock the camera back. The apps should not start another recording session during recording.

Throws

IllegalStateException	if it is called before prepare().

public void stop ()

Added in API level 1

Stops recording. Call this after start(). Once recording is stopped, you will have to configure it again as if it has just been constructed. Note that a RuntimeException is intentionally thrown to the application, if no valid audio/video data has been received when stop() is called. This happens if stop() is called immediately after start(). The failure lets the application take action accordingly to clean up the output file (delete the output file, for instance), since the output file is not properly constructed when this happens.

Throws

IllegalStateException	if it is called before start()

Protected Methods

protected void finalize ()

Added in API level 1

Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.

Note that objects that override finalize are significantly more expensive than objects that don't. Finalizers may be run a long time after the object is no longer reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup. Note also that finalizers are run on a single VM-wide finalizer thread, so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary for a class that has a native peer and needs to call a native method to destroy that peer. Even then, it's better to provide an explicit close method (and implement Closeable), and insist that callers manually dispose of instances. This works well for something like files, but less well for something like a BigInteger where typical calling code would have to deal with lots of temporaries. Unfortunately, code that creates lots of temporaries is the worst kind of code from the point of view of the single finalizer thread.

If you must use finalizers, consider at least providing your own ReferenceQueue and having your own thread process that queue.

Unlike constructors, finalizers are not automatically chained. You are responsible for calling super.finalize() yourself.

Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.