Basic Audio and Video

1. Basic Audio and Video

2. Audio

3. Audio • Primary components • Audio file • stored in ‘raw’ folder within ‘res’ folder • ‘raw’ directory must be created • while many formats supported, .mp3 is most stable across devices • Instance of MediaPlayer • android.media.MediaPlayer • key methods • create • static convenience method for instantiation and preparation • start

4. Sample code - MediaPlayer MediaPlayeraudioPlayer; audioPlayer = MediaPlayer.create(this, R.raw.audio_file_name); //no extension on file name audioPlayer.setAudioStream(AudioManager.STREAM_MUSIC); audioPlayer.start();

5. MediaPlayer – coding issues • Other information • audioPlayer.stop(), pause(), and resume() • audio does not automatically stop if activity pauses • only if application stops • audioPlayer.release() should be called when done • MediaPlayers can be expensive • frees resources • Can use a BroadcastReceiver to allow hardware control (e.g. play, pause, skip, etc. on headset) • Can use Service to continue playback when App stops

6. MediaPlayer – coding issues • One of the prepare() methods must be called • prepare() method • called automatically by create() method • OK if using a file • prepareAsync () method • cannot use create() convenience method • starts MediaPlayer in a new thread • better for streaming audio • app does not ‘hang’ if waiting for buffered data

7. Video

8. Video • Primary components • Video file • .3gp file • new standard supported by 3G phones • can be stored in res/raw folder • don’t supply extension in call • can be stored within device’s file system (i.e. SD card) • VideoView widget • typical widget in xml layout file • key methods • setVideoPath (full path and file name with extension) • start

9. Sample code - VideoView //Video stored on SD Card VideoView vv = (VideoView)findViewById(R.id.vvVideo); vv.setVideoPath("/sdcard/filename.3gp"); vv.start(); or: //Video stored in raw directory VideoViewvv = (VideoView)findViewById(R.id.vvVideo); vv.setVideoPath("android.resource://edu.csci153/raw/filename"); vv.start();

10. Internal file system Emulator or attached device

11. Internal file system • Display files within eclipse • Window…Show View…Other…File Explorer • avoid ‘data’ directory • emulator allows access • system directory – restricted access on an actual device • Copy files to/from device within eclipse • icons in File Explorer • copy to: ‘Push a file onto the device’ icon • copy from: ‘Pull a file from the device’ icon • delete from device: ‘Delete the selection’ icon