FAQs


What formats does ExoPlayer support?

See the Supported formats page.

Why are some media files not seekable?

ExoPlayer does not support seeking in media where the only method for performing accurate seek operations is for the player to scan and index the entire file. ExoPlayer considers such files as unseekable. Most modern media container formats include metadata for seeking (e.g., a sample index), have a well defined seek algorithm (e.g., interpolated bisection search for Ogg), or indicate that their content is constant bitrate. Efficient seek operations are possible and supported by ExoPlayer in these cases.

If you require seeking but have unseekable media, we suggest converting your content to use a more appropriate container format. In the specific case of unseekable MP3 files, you can enable seeking under the assumption that the files have a constant bitrate using FLAG_ENABLE_CONSTANT_BITRATE_SEEKING. This can be set on a DefaultExtractorsFactory using setMp3ExtractorFlags.

Why do some MPEG-TS files fail to play?

Some MPEG-TS files do not contain access unit delimiters (AUDs). By default ExoPlayer relies on AUDs to cheaply detect frame boundaries. Similarly, some MPEG-TS files do not contain IDR keyframes. By default these are the only type of keyframes considered by ExoPlayer.

ExoPlayer will appear to be stuck in the buffering state when asked to play an MPEG-TS file that lacks AUDs or IDR keyframes. If you need to play such files, you can do so using FLAG_DETECT_ACCESS_UNITS and FLAG_ALLOW_NON_IDR_KEYFRAMES respectively. These flags can be set on a DefaultExtractorsFactory using setTsExtractorFlags. Use of FLAG_DETECT_ACCESS_UNITS has no side effects other than being computationally expensive relative to AUD based frame boundary detection. Use of FLAG_ALLOW_NON_IDR_KEYFRAMES may result in temporary visual corruption at the start of playback and immediately after seeks when playing some MPEG-TS files.

Why do some streams fail with HTTP response code 301 or 302?

HTTP response codes 301 and 302 both indicate redirection. Brief descriptions can be found on Wikipedia. When ExoPlayer makes a request and receives a response with status code 301 or 302, it will normally follow the redirect and start playback as normal. The one case where this does not happen by default is for cross-protocol redirects. A cross-protocol redirect is one that redirects from HTTPS to HTTP or vice-versa (or less commonly, between another pair of protocols). You can test whether a URL causes a cross-protocol redirect using the wget command line tool as follows:

wget "https://yourserver.com/test.mp3" 2>&1  | grep Location

The output should look something like this:

$ wget "https://yourserver.com/test.mp3" 2>&1  | grep Location
Location: https://second.com/test.mp3 [following]
Location: http://third.com/test.mp3 [following]

In this example there are two redirects. The first redirect is from https://yourserver.com/test.mp3 to https://second.com/test.mp3. Both are HTTPS, and so this is not a cross-protocol redirect. The second redirect is from https://second.com/test.mp3 to http://third.com/test.mp3. This redirects from HTTPS to HTTP and so is a cross-protocol redirect. ExoPlayer will not follow this redirect in its default configuration, meaning playback will fail.

If you need to, you can configure ExoPlayer to follow cross-protocol redirects when instantiating the HttpDataSource.Factory instances used by ExoPlayer in your application. [DefaultHttpDataSourceFactory][] has constructors that accept an allowCrossProtocolRedirects argument for this purpose, as do other HttpDataSource.Factory implementations. Set these arguments to true to enable cross-protocol redirects.

Why do some streams fail with UnrecognizedInputFormatException?

This question relates to playback failures of the form:

UnrecognizedInputFormatException: None of the available extractors
(MatroskaExtractor, FragmentedMp4Extractor, ...) could read the stream.

There are two possible causes of this failure. The most common cause is that you’re trying to play DASH (mpd), HLS (m3u8) or SmoothStreaming (ism, isml) content using ExtractorMediaSource. To play such streams you must use the correct MediaSource implementations, which are DashMediaSource, HlsMediaSource and SsMediaSource respectively. If you don’t know the type of the media then Util.inferContentType can often be used, as demonstrated by PlayerActivity in the ExoPlayer demo app.

The second, less common cause, is that ExoPlayer does not support the container format of the media that you’re trying to play. In this case the failure is working as intended, however feel free to submit a feature request to our issue tracker, including details of the container format and a test stream. Please search for an existing feature request before submitting a new one.

How can I query whether the stream being played is a live stream?

You can query ExoPlayer’s isCurrentWindowDynamic method. A dynamic window implies that the stream being played is a live stream.

How do I keep audio playing when my app is backgrounded?

There are a few steps that you need to take to ensure continued playback of audio when your app is in the background:

  1. You need to have a running foreground service. This prevents the system from killing your process to free up resources.
  2. You need to hold a WifiLock and a WakeLock. These ensure that the system keeps the WiFi radio and CPU awake.

It’s important that you stop the service and release the locks as soon as audio is no longer being played.

How do I get smooth animation/scrolling of video?

SurfaceView rendering wasn’t properly synchronized with view animations until Android N. On earlier releases this could result in unwanted effects when a SurfaceView was placed into scrolling container, or when it was subjected to animation. Such effects included the SurfaceView’s contents appearing to lag slightly behind where it should be displayed, and the view turning black when subjected to animation.

To achieve smooth animation or scrolling of video prior to Android N, it’s therefore necessary to use TextureView rather than SurfaceView. If smooth animation or scrolling is not required then SurfaceView should be preferred (see Should I use SurfaceView or TextureView?).

Should I use SurfaceView or TextureView?

SurfaceView has a number of benefits over TextureView for video playback:

  • Significantly lower power consumption on many devices.
  • More accurate frame timing, resulting in smoother video playback.
  • Support for secure output when playing DRM protected content.

SurfaceView should therefore be preferred over TextureView where possible. TextureView should be used only if SurfaceView does not meet your needs. One example is where smooth animations or scrolling of the video surface is required prior to Android N (see How do I get smooth animation/scrolling of video?). For this case, it’s preferable to use TextureView only when SDK_INT is less than 24 (Android N) and SurfaceView otherwise.

Does ExoPlayer support emulators?

If you’re seeing ExoPlayer fail when using an emulator, this is usually because the emulator does not properly implement components of Android’s media stack. This is an issue with the emulator, not with ExoPlayer. Android’s official emulator (“Virtual Devices” in Android Studio) supports ExoPlayer provided the system image has an API level of at least 23. System images with earlier API levels do not support ExoPlayer. The level of support provided by third party emulators varies. If you find a third party emulator on which ExoPlayer fails, you should report this to the developer of the emulator rather than to the ExoPlayer team. Where possible, we recommend testing media applications on physical devices rather than emulators.