Which of the following classes comes with the Android platform to play audio and video files?

ByJael Lawler

Android is a popular mobile operating system developed by Google. It has built-in support for playing a variety of media file formats including audio, video, and images. The Android multimedia framework includes APIs and classes to handle tasks like media playback, editing, recording and more.

Android supports common audio formats like MP3, AAC, OGG, MIDI, FLAC, WAV. For video, Android supports MP4, M4V, 3GP, WebM, MKV and more. With the right classes and APIs, developers can easily integrate media capabilities into their Android apps.

Some of the key Android classes for working with media include MediaPlayer for audio/video playback, MediaRecorder for recording, SoundPool for audio samples and streams, ExoPlayer for advanced playback, and MediaMetadataRetriever for reading media metadata.

This article explores the main Android classes used to play audio and video files in Android apps. It provides an overview of each class along with examples demonstrating their usage.

MediaPlayer Class

The MediaPlayer class can be used to control audio/video playback in Android. It provides capabilities for controlling playback, managing audio focus, adjusting volume, seeking to different positions in the media source, and monitoring playback state changes.

Some key features of the MediaPlayer class include:

  • Playing local and network audio/video files
  • Streaming media over HTTP and RTSP
  • Controlling playback speed and seeking to arbitrary positions
  • Retrieving metadata like duration, dimensions, tracks
  • Handling interrupts and errors gracefully
  • Managing audio focus to pause/resume based on other playing media
  • Adjusting audio volume even during playback
  • Monitoring playback state changes through listeners

Overall, MediaPlayer provides a full-featured API for playing audio and video in Android apps. It is one of the core media classes included in the Android platform.

Audio Attributes

Android uses audio attributes to define properties for audio streams and how they should be handled by the system. Audio attributes allow developers to specify things like the usage or content type of an audio stream, its relative importance compared to other streams, and whether it should play over a device’s speakers or Bluetooth.

There are several system-defined audio attributes for common use cases, like music playback, alarms, notifications, etc. Developers can also create custom audio attributes for advanced audio use cases. The audio attributes are passed to methods like setAudioAttributes() on classes like MediaPlayer to tell the Android system how the audio stream should be handled.

Setting the correct audio attributes is important for Android to determine the priority and behavior of an audio stream. For example, a navigation app may set attributes signaling that its voice guidance is relatively high importance, so music streams will duck in volume while it plays. Media streams that set attributes incorrectly may not play as intended on Android devices.

ExoPlayer

ExoPlayer is a media player library developed by Google that is designed to be easy to customize and extend. It is an alternative to Android’s built-in MediaPlayer API. Some key benefits and usage of ExoPlayer include:

– Supports features not currently supported by Android’s MediaPlayer like DASH and SmoothStreaming adaptive streaming. According to the Android documentation, ExoPlayer supports HLS and DASH formats on Android devices running KitKat (4.4) and higher.

– ExoPlayer is easy to customize and extend by inheriting base classes. For example, you can create customized renderers and track selectors.

– ExoPlayer supports advanced features like multi-track audio and captions.

– Works consistently across a wide range of Android devices as noted in the ExoPlayer Supported Devices page.

– Large active community behind ExoPlayer with many code samples and sources available.

SoundPool

The SoundPool class is useful for playing short audio files and sound effects in Android apps. It allows you to load multiple small audio files into memory and play them with low latency. Some key features of SoundPool include:

– Loading and playing short audio clips, like sound effects or UI sounds (http://www.pepinonline.com/courses/mobileos/30/soundpool/).

– Managing audio resources and controlling playback, including setting volume, loop count, playback rate, etc.

– Playing multiple audio sounds at the same time with priority and looping options.

– Low latency playback suitable for games and interactive apps.

So in summary, SoundPool is the recommended class for efficiently playing short sound clips on Android, like game sound effects, background music, or UI sounds. It’s not suitable for long audio files like songs or podcasts.

VideoView

The VideoView class in Android is used to display and control playback of video files. It can load videos from various sources like resources, content providers, local or remote paths, and URIs. VideoView makes it simple to play videos in your Android app.

To use VideoView, add it in your app’s layout XML file. Set the location of the video file with setVideoURI() or setVideoPath(). Use methods like start(), pause() and resume() to control playback. You can also display playback controls using the MediaController class.

Some key capabilities of VideoView include:

  • Plays local video files as well as videos from internet URLs
  • Provides playback controls such as play, pause, fast forward, rewind
  • Adjusts itself when screen orientation changes
  • Can be integrated with MediaController for playback toolbar

Overall, VideoView greatly simplifies displaying videos in your Android app. With just a few lines of code, you can add video playback functionality using this built-in class.

MediaMetadataRetriever

The MediaMetadataRetriever class provides a unified interface for retrieving frame and meta data from an input media file.

This class can be used to extract metadata from audio and video files. Some of the metadata that can be retrieved includes:

  • Title
  • Artist
  • Album
  • Author
  • Composer
  • Date
  • Genre
  • Duration
  • Video width and height
  • Video rotation
  • Frame rate
  • Bit rate
  • Codec information

To extract metadata, create a MediaMetadataRetriever object, set the data source, and then call one of the extract metadata methods like getEmbeddedPicture(), extractMetadata(), or getText(). The metadata can be retrieved as raw data or formatted strings.

This allows developers to easily get metadata from media files without having to fully decode or play the file. It provides efficient access to information like title, artist, resolution etc. that can be displayed in media library applications.

MediaRecorder

The MediaRecorder class is used to record audio and video in Android. It allows access to the device’s audio and video sources like microphones and cameras to capture the media. To use MediaRecorder, first create an instance of it:

MediaRecorder mr = new MediaRecorder();

Then set the audio and video sources using setAudioEncoder() and setVideoEncoder(). Specify the output format and output file path. Finally, call prepare() and start() to start recording.

To stop recording, call mr.stop() and mr.release() to properly release the resources.

MediaController

The MediaController class allows you to control media playback in your Android app. It contains UI elements like play/pause, rewind, fast forward buttons and a progress bar to indicate playback progress. The MediaController works with classes like VideoView and MediaPlayer to control video and audio playback.

To use MediaController, you need to instantiate it by passing a Context and a Token that binds it to the playback instance. For example:


MediaController mediaController = new MediaController(this, videoView.getSessionToken());

You can then customize the controls shown and attach the controller to your playback view to display it on screen. The MediaController allows easy integration of standard media controls in your app.

Conclusion

Android provides a rich set of classes and APIs for audio and video playback, recording, and manipulation. The MediaPlayer class is the primary API for playing audio and video files. For more advanced use cases, ExoPlayer provides added capabilities like adaptive bitrate streaming. The AudioAttributes and SoundPool classes allow fine-grained audio configuration and sound effect playback. VideoView makes it easy to display video files, while MediaRecorder enables capturing audio and video. Classes like MediaMetadataRetriever provide additional media inspection capabilities.

When developing audio/video apps, it’s important to follow best practices like properly managing audio focus, maintaining high quality for sharing, and optimizing for performance. Features like scoped storage require adjusting how files are accessed. Overall, Android’s media APIs provide powerful building blocks for all types of audio, video, and multimedia applications.

Leave a Reply

Your email address will not be published. Required fields are marked *