The Android platform offers built-in encoding/decoding for a variety of common media types, so that you can easily integrate audio, video, and images into your applications. Accessing the platform's media capabilities is fairly straightforward — you do so using the same intents and activities mechanism that the rest of Android uses.
Android lets you play audio and video from several types of data sources. You
can play audio or video from media files stored in the application's resources
(raw resources), from standalone files in the filesystem, or from a data stream
arriving over a network connection. To play audio or video from your
application, use the MediaPlayer
class.
The platform also lets you record audio and video, where supported by the
mobile device hardware. To record audio or video, use the MediaRecorder
class. Note that the emulator doesn't have hardware
to capture audio or video, but actual mobile devices are likely to provide these
capabilities, accessible through the MediaRecorder class.
For a list of media formats for which Android offers built-in support, see the Android Media Formats appendix.
Media can be played from anywhere: from a raw resource, from a file from the system, or from an available network (URL).
You can play back the audio data only to the standard output device; currently, that is the mobile device speaker or Bluetooth headset. You cannot play sound files in the conversation audio.
Perhaps the most common thing to want to do is play back media (notably sound) within your own applications. Doing this is easy:
res/raw
folder of your project, where the Eclipse plugin (or aapt) will find it and
make it into a resource that can be referenced from your R classMediaPlayer
, referencing that resource using
MediaPlayer.create
, and then call
start()
on the instance:MediaPlayer mp = MediaPlayer.create(context, R.raw.sound_file_1); mp.start();
To stop playback, call stop()
. If
you wish to later replay the media, then you must
reset()
and
prepare()
the MediaPlayer object
before calling start()
again.
(create()
calls prepare()
the first time.)
To pause playback, call pause()
.
Resume playback from where you paused with
start()
.
You can play back media files from the filesystem or a web URL:
MediaPlayer
using new
setDataSource()
with a String containing the path (local filesystem or URL)
to the file you want to playprepare()
then
start()
on the instance:MediaPlayer mp = new MediaPlayer(); mp.setDataSource(PATH_TO_FILE); mp.prepare(); mp.start();
stop()
and
pause()
work the same as discussed
above.
Note: It is possible that mp
could be
null, so good code should null
check after the new
.
Also, IllegalArgumentException
and IOException
either
need to be caught or passed on when using setDataSource()
, since
the file you are referencing may not exist.
Note: If you're passing a URL to an online media file, the file must be capable of progressive download.
The Android platform includes a JET engine that lets you add interactive playback of JET audio content in your applications. You can create JET content for interactive playback using the JetCreator authoring application that ships with the SDK. To play and manage JET content from your application, use the JetPlayer
class.
For a description of JET concepts and instructions on how to use the JetCreator authoring tool, see the JetCreator User Manual. The tool is available fully-featured on the OS X and Windows platforms and the Linux version supports all the content creation features, but not the auditioning of the imported assets.
Here's an example of how to set up JET playback from a .jet file stored on the SD card:
JetPlayer myJet = JetPlayer.getJetPlayer(); myJet.loadJetFile("/sdcard/level1.jet"); byte segmentId = 0; // queue segment 5, repeat once, use General MIDI, transpose by -1 octave myJet.queueJetSegment(5, -1, 1, -1, 0, segmentId++); // queue segment 2 myJet.queueJetSegment(2, -1, 0, 0, 0, segmentId++); myJet.play();
The SDK includes an example application — JetBoy — that shows how to use JetPlayer
to create an interactive music soundtrack in your game. It also illustrates how to use JET events to synchronize music and game logic. The application is located at <sdk>/platforms/android-1.5/samples/JetBoy
.
Audio capture from the device is a bit more complicated than audio/video playback, but still fairly simple:
android.media.MediaRecorder
using new
android.content.ContentValues
and put in some standard properties like
TITLE
, TIMESTAMP
, and the all important
MIME_TYPE
android.content.ContentResolver
to
create an entry in the Content database and get it to assign a path
automatically which you can then use)MediaRecorder.setAudioSource()
. You will probably want to use
MediaRecorder.AudioSource.MIC
MediaRecorder.setOutputFormat()
MediaRecorder.setAudioEncoder()
prepare()
on the MediaRecorder instance.start()
. stop()
.
release()
on it. The example below illustrates how to set up, then start audio capture.
recorder = new MediaRecorder(); ContentValues values = new ContentValues(3); values.put(MediaStore.MediaColumns.TITLE, SOME_NAME_HERE); values.put(MediaStore.MediaColumns.TIMESTAMP, System.currentTimeMillis()); values.put(MediaStore.MediaColumns.MIME_TYPE, recorder.getMimeContentType()); ContentResolver contentResolver = new ContentResolver(); Uri base = MediaStore.Audio.INTERNAL_CONTENT_URI; Uri newUri = contentResolver.insert(base, values); if (newUri == null) { // need to handle exception here - we were not able to create a new // content entry } String path = contentResolver.getDataFilePath(newUri); // could use setPreviewDisplay() to display a preview to suitable View here recorder.setAudioSource(MediaRecorder.AudioSource.MIC); recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); recorder.setOutputFile(path); recorder.prepare(); recorder.start();
Based on the example above, here's how you would stop audio capture.
recorder.stop(); recorder.release();