What is media playback Android?

Media playback refers to the ability to play audio and video files on Android devices. This includes features like playing local media files, streaming audio and video over the internet, and using built-in media apps like music and video players.

Media playback is a core feature of the Android platform. It enables users to consume entertainment and multimedia content directly on their phones and tablets. Several key Android APIs and components like MediaPlayer, AudioManager, and MediaCodec support media playback capabilities.

Smooth media playback provides an enhanced user experience and allows Android devices to compete with platforms like iOS. It is an essential part of Android’s value proposition as a multimedia and entertainment platform.

Native Media Playback Support

Android provides native support for audio and video playback through the MediaPlayer and MediaCodec classes. The MediaPlayer class provides an easy-to-use interface for playing common media types like audio, video and images 1. Under the hood, it uses MediaCodec APIs for hardware-accelerated decoding and rendering.

The Android multimedia framework and Stagefright media playback engine include built-in software codecs that support popular media formats like MP3, AAC, MP4, H.264, VP8, VP9, and more 2. This allows apps to easily play media files and streams without needing external libraries or codecs.

Overall, Android’s native media support provides a powerful and optimized foundation for audio/video playback in apps. The MediaPlayer simplifies development while MediaCodec handles efficient decoding and rendering.

ExoPlayer

ExoPlayer is an open source media player library developed by Google for Android applications. It provides an alternative to Android’s built-in MediaPlayer API for playing audio and video both locally and over the network. ExoPlayer was designed to be extensible, easy to customize, and feature rich.

Some key benefits of using ExoPlayer over MediaPlayer include:

  • ExoPlayer supports advanced streaming capabilities like DASH and HLS adaptive bitrate streaming.
  • It provides abstractions for media tracks, subtitles, and adaptive playlists.
  • ExoPlayer makes it easier to customize the UI, controls, and behavior of the player.
  • It offers improved stability and debugging capabilities.

Some of the main features of ExoPlayer include:

  • Adaptive bitrate streaming support for DASH, HLS, and SmoothStreaming.
  • Customizable UI components.
  • Support for DRM protected content.
  • Automatic buffer management.
  • Media track selection and adaptive track switching.
  • Custom rendering capabilities.

Overall, ExoPlayer provides a full-featured, flexible, and robust media playback solution for Android apps. Its modular design makes it easy to build customized players.

Other Media Playback Libraries

In addition to ExoPlayer, there are other third-party media playback libraries available for Android development. Some popular options include:

  • Vitamio – A full-featured media player library that supports many formats and codecs out of the box. Vitamio can play H.264, MKV, MP4, MOV, TS, RM, FLV and other video formats as well as MP3, AAC, WMA and WAV audio files (Vitamio website).
  • ffmpeg – A popular open source multimedia framework that can decode, encode, transcode, mux, demux, stream, filter and play pretty much anything. ffmpeg for Android provides native API access to ffmpeg features (ffmpeg-android-java).

Compared to ExoPlayer, these libraries provide more out-of-the-box support for playing various media codecs and containers. However, they may not be as flexible or customizable as ExoPlayer. They also aren’t officially supported by Google. ExoPlayer has better optimization for Android, integration with MediaSession, and focus on advanced streaming capabilities. For most use cases, ExoPlayer is recommended over third-party options unless specific format support is needed.

Media Codecs

Media codecs play a critical role in media playback on Android. They are responsible for encoding and decoding audio and video into compressed or uncompressed formats that can be processed and rendered on Android devices. Android supports hardware accelerated decoding and encoding using the MediaCodec API and codec implementations.

Android supports a wide range of popular media codecs including:

  • H.264 AVC (Baseline, Main and High profiles)
  • H.265 HEVC (Main profile)
  • MPEG-4 SP
  • VP8
  • VP9 (decoder only)
  • AAC, AAC+, eAAC+
  • MP3
  • AMR-NB, AMR-WB
  • FLAC
  • Opus
  • Vorbis

Hardware acceleration allows supported codecs to be decoded efficiently using dedicated media processing capabilities on the device’s SoC. This avoids taxing the CPU and improves battery life during media playback. The supported formats depend on the Android version and device SoC capabilities.

DRM Support

Digital rights management (DRM) allows media publishers to control access to copyrighted content. On Android, there are two main DRM systems used for securing media playback – Widevine DRM and PlayReady DRM.

Widevine DRM provides content protection for Android devices and is developed by Google. It supports the Common Encryption (CENC) protection scheme and uses the Encrypted Media Extensions (EME) API available in Chrome and other modern web browsers (1). Widevine has three security levels that determine the level of protection – L1 provides hardware-based security only available on certified devices like phones and tablets, L3 provides software-only security on all devices, and L2 is a hybrid approach.

PlayReady DRM was developed by Microsoft and is also supported on Android for securing media. It uses the same CENC protection scheme as Widevine. Apps can enable PlayReady DRM by integrating the PlayReady client SDK. This allows playback of content encrypted with PlayReady DRM (2).

To enable DRM-protected playback in Android apps, the app needs to check if the required DRM is supported and obtain the necessary licenses. The ExoPlayer on Android makes it easy to add DRM support with modular components for Widevine and PlayReady (3). Supporting DRM is important for premium media content playback in Android apps.

<1> https://developer.android.com/media/media3/drm
<2> https://source.android.com/docs/core/media/drm
<3> https://docs.jwplayer.com/players/docs/android-play-drm-protected-content

Audio Playback

Android provides several classes for handling audio playback, the most commonly used being the MediaPlayer class.

MediaPlayer provides functionality for playing audio from various sources including raw resources, standalone files, and streams. It handles loading and decoding audio, manages callbacks and state changes, and applies audio effects and equalizer settings.

MediaPlayer supports key audio playback features like gapless playback for smooth transitions between tracks, audio focus for managing multiple audio streams, and looping. It also allows handling callbacks for events like completion, errors, and buffering.

For simpler audio playback needs, the SoundPool class can be used which loads audio samples into memory for low latency playback.

There are also other libraries like ExoPlayer which build on top of MediaPlayer with additional capabilities like DASH/HLS streaming support.

Video Playback

Android provides native support for video playback through various classes like MediaPlayer, ExoPlayer, and SurfaceView. These classes utilize audio and video decoders to play various media formats like MP4, MKV, and streaming protocols like HLS and DASH.

MediaPlayer is the primary API for playing videos in Android. It handles decoding and rendering of the media frames. ExoPlayer builds on top of MediaPlayer and provides more advanced features like adaptive bitrate streaming support.

For hardware acceleration, Android uses codecs like MediaCodec for audio/video decoding and OpenGL ES for rendering graphics. This offloads intensive media processing to dedicated hardware like DSPs and GPU for efficient video playback. Android also supports features like subtitles, multi-audio tracks, and DRM through MediaPlayer and ExoPlayer.

Media Browsers

Media browsing apps on Android allow users to browse and play music, videos, and other media files. Some key APIs used for building media browser apps include:

The MediaBrowser API provides the client-side support for connecting to a media browsing service and accessing the media library. The client can subscribe to media items and be notified when the library is updated.

The MediaBrowserService API provides the server-side implementation for exposing the media library to clients. It allows managing client connections and publishing updates to the library.

The MediaController class is used in conjunction with MediaBrowser to control media playback and receive playback updates from the MediaBrowserService.

These APIs enable building rich media browsing experiences where clients can efficiently discover, subscribe to, and play media content exposed by the server-side media provider app.

Conclusion

Media playback is a core feature on Android devices, enabled through native APIs like MediaPlayer and ExoPlayer as well as third-party libraries. Android supports most common media formats and codecs out of the box, with abilities like adaptive streaming, DRM, and gapless playback. Both audio and video playback are robust on Android, allowing users to enjoy music, videos, podcasts and more. The platform offers developers powerful tools to build immersive media apps and experiences.

Looking ahead, we can expect continued improvements to media APIs, wider codec and format support, and better performance optimizations on Android. Playback capabilities will likely expand, with more advanced interactive, social, and augmented reality features. As media consumption grows on mobile, Android will adapt to user demands for more seamless, integrated experiences across devices and platforms. Overall, the future is bright for rich media applications on Android.

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