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| java.lang.Object | |
| ↳ | android.media.MediaRecorder |
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.
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.
| Nested Classes | |||||||||||
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| MediaRecorder.AudioEncoder | Defines the audio encoding. | ||||||||||
| MediaRecorder.AudioSource | Defines the audio source. | ||||||||||
| MediaRecorder.OnErrorListener | Interface definition for a callback to be invoked when an error occurs while recording. | ||||||||||
| MediaRecorder.OnInfoListener | Interface definition for a callback to be invoked when an error occurs while recording. | ||||||||||
| MediaRecorder.OutputFormat | Defines the output format. | ||||||||||
| MediaRecorder.VideoEncoder | Defines the video encoding. | ||||||||||
| MediaRecorder.VideoSource | Defines the video source. | ||||||||||
| Constants | |||||||||||
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| 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 | |||||||||||
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Default constructor.
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| Public Methods | |||||||||||
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Gets the maximum value for audio sources.
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Returns the maximum absolute amplitude that was sampled since the last
call to this method.
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Gets the surface to record from when using SURFACE video source.
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Prepares the recorder to begin capturing and encoding data.
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Releases resources associated with this MediaRecorder object.
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Restarts the MediaRecorder to its idle state.
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Sets the number of audio channels for recording.
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Sets the audio encoder to be used for recording.
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Sets the audio encoding bit rate for recording.
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Sets the audio sampling rate for recording.
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Sets the audio source to be used for recording.
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Sets a Camera to use for recording.
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Set video frame capture rate.
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Set and store the geodata (latitude and longitude) in the output file.
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Sets the maximum duration (in ms) of the recording session.
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Sets the maximum filesize (in bytes) of the recording session.
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Register a callback to be invoked when an error occurs while
recording.
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Register a callback to be invoked when an informational event occurs while
recording.
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Sets the orientation hint for output video playback.
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Pass in the file descriptor of the file to be written.
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Sets the path of the output file to be produced.
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Sets the format of the output file produced during recording.
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Sets a Surface to show a preview of recorded media (video).
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Uses the settings from a CamcorderProfile object for recording.
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Sets the video encoder to be used for recording.
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Sets the video encoding bit rate for recording.
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Sets the frame rate of the video to be captured.
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Sets the width and height of the video to be captured.
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Sets the video source to be used for recording.
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Begins capturing and encoding data to the file specified with
setOutputFile().
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Stops recording.
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| Protected Methods | |||||||||||
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Invoked when the garbage collector has detected that this instance is no longer reachable.
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Inherited Methods | |||||||||||
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From class
java.lang.Object
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Media server died. In this case, the application must release the MediaRecorder object and instantiate a new one.
Unspecified media recorder error.
A maximum duration had been setup and has now been reached.
A maximum filesize had been setup and has now been reached.
Unspecified media recorder error.
Gets the maximum value for audio sources.
Returns the maximum absolute amplitude that was sampled since the last call to this method. Call this only after the setAudioSource().
| IllegalStateException | if it is called before the audio source has been set. |
|---|
Gets the surface to record from when using SURFACE video source.
Should only be called after prepare(). Frames rendered before start() will be discarded.
| IllegalStateException | if it is called before prepare(), after stop() or is called when VideoSource is not set to SURFACE. |
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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().
| IllegalStateException | if it is called after start() or before setOutputFormat(). |
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| IOException | if prepare fails otherwise. |
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.
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.
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.
| numChannels | the number of audio channels. Usually it is either 1 (mono) or 2 (stereo). |
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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().
| audio_encoder | the audio encoder to use. |
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| IllegalStateException | if it is called before setOutputFormat() or after prepare(). |
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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.
| bitRate | the audio encoding bit rate in bits per second. |
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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.
| samplingRate | the sampling rate for audio in samples per second. |
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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().
| audio_source | the audio source to use |
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| IllegalStateException | if it is called after setOutputFormat() |
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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().
| c | the Camera to use for recording |
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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.
| 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.
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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.
| latitude | latitude in degrees. Its value must be in the range [-90, 90]. |
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| longitude | longitude in degrees. Its value must be in the range [-180, 180]. |
| IllegalArgumentException | if the given latitude or longitude is out of range. |
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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.
| max_duration_ms | the maximum duration in ms (if zero or negative, disables the duration limit) |
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| IllegalArgumentException |
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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.
| max_filesize_bytes | the maximum filesize in bytes (if zero or negative, disables the limit) |
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| IllegalArgumentException |
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Register a callback to be invoked when an error occurs while recording.
| l | the callback that will be run |
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Register a callback to be invoked when an informational event occurs while recording.
| listener | the callback that will be run |
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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.
| degrees | the angle to be rotated clockwise in degrees. The supported angles are 0, 90, 180, and 270 degrees. |
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| IllegalArgumentException | if the angle is not supported. |
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Pass in the file descriptor of the file to be written. Call this after setOutputFormat() but before prepare().
| fd | an open file descriptor to be written into. |
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| IllegalStateException | if it is called before setOutputFormat() or after prepare() |
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Sets the path of the output file to be produced. Call this after setOutputFormat() but before prepare().
| path | The pathname to use. |
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| IllegalStateException | if it is called before setOutputFormat() or after prepare() |
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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.
| output_format | the output format to use. The output format needs to be specified before setting recording-parameters or encoders. |
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| IllegalStateException | if it is called after prepare() or before setAudioSource()/setVideoSource(). |
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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.
| sv | the Surface to use for the preview |
|---|
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.
| profile | the CamcorderProfile to use |
|---|
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().
| video_encoder | the video encoder to use. |
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| IllegalStateException | if it is called before setOutputFormat() or after prepare() |
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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.
| bitRate | the video encoding bit rate in bits per second. |
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Sets the frame rate of the video to be captured. Must be called after setVideoSource(). Call this after setOutFormat() but before prepare().
| rate | the number of frames per second of video to capture |
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| 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. |
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Sets the width and height of the video to be captured. Must be called after setVideoSource(). Call this after setOutFormat() but before prepare().
| width | the width of the video to be captured |
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| height | the height of the video to be captured |
| IllegalStateException | if it is called after prepare() or before setOutputFormat() |
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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().
| video_source | the video source to use |
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| IllegalStateException | if it is called after setOutputFormat() |
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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.
| IllegalStateException | if it is called before prepare(). |
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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.
| IllegalStateException | if it is called before start() |
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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.