The [`MetadataRetriever`](https://developer.android.com/reference/androidx/media3/inspector/MetadataRetriever.md.txt) retrieves information (such as duration, video
resolution, codecs, available tracks, and sampling rates) from a [`MediaItem`](https://developer.android.com/reference/androidx/media3/common/MediaItem.md.txt)
without playback.

> [!NOTE]
> **Note:** `MetadataRetriever` is intended for extracting metadata from media formats supported by Media3 players, such as ExoPlayer, for playback. It is not designed to be a general-purpose metadata extractor for non-playback formats, such as standalone images. To extract properties like height, width, and rotation from images, use [`ExifInterface`](https://developer.android.com/reference/androidx/exifinterface/media/ExifInterface.md.txt).

Common use cases include:

- **[Retrieving motion photo metadata](https://developer.android.com/media/media3/exoplayer/retrieving-metadata.md.txt#motion-photos)**: including the offsets and lengths of the image and video parts of the file.
- **Building a media library** : Populating a [`MediaLibraryService`](https://developer.android.com/reference/androidx/media3/session/MediaLibraryService.md.txt) with rich [`MediaItem`](https://developer.android.com/reference/androidx/media3/common/MediaItem.md.txt) details (like duration and title) to serve a full media catalog to clients like Android Auto.
- **Prefetching UI details**: Fetching information like video resolution or duration to prepare the UI before playback begins.
- **Validating media files**: Checking if a file contains the required audio or video tracks or specific metadata before processing it.

## Overview

Using `MetadataRetriever` is a two-step process:

1. **Build the retriever** : Create an instance using `MetadataRetriever.Builder`. Pass a `Context` and the `MediaItem` that you want to inspect to the builder. For advanced use cases, such as custom networking or caching, you can also supply a custom [`MediaSource.Factory`](https://developer.android.com/reference/androidx/media3/exoplayer/source/MediaSource.Factory.md.txt).
2. **Retrieve metadata** : Call methods like [`retrieveDurationUs()`](https://developer.android.com/reference/androidx/media3/inspector/MetadataRetriever.md.txt#retrieveDurationUs()), [`retrieveTimeline()`](https://developer.android.com/reference/androidx/media3/inspector/MetadataRetriever.md.txt#retrieveTimeline()), or [`retrieveTrackGroups()`](https://developer.android.com/reference/androidx/media3/inspector/MetadataRetriever.md.txt#retrieveTrackGroups()) to fetch the required information. These methods are **asynchronous** , returning a `ListenableFuture` so that network or I/O operations don't block the main thread.


### Kotlin

```kotlin
suspend fun retrieveMetadata(context: Context, mediaItem: MediaItem) {
  try {
    // 1. Build the retriever.
    // `MetadataRetriever` implements `AutoCloseable`, so wrap it in
    // a Kotlin `.use` block, which calls `close()` automatically.
    MetadataRetriever.Builder(context, mediaItem).build().use { retriever ->
      // 2. Retrieve metadata asynchronously.
      val trackGroups = retriever.retrieveTrackGroups().await()
      val timeline = retriever.retrieveTimeline().await()
      val durationUs = retriever.retrieveDurationUs().await()
      handleMetadata(trackGroups, timeline, durationUs)
    }
  } catch (e: Exception) {
    handleFailure(e)
  }
}
```

### Java

```java
public void retrieveMetadata(Context context, MediaItem mediaItem) {
  // 1. Build the retriever.
  // `MetadataRetriever` implements `AutoCloseable`, so use try-with-resources
  // so that the resources are automatically released.
  try (MetadataRetriever retriever = new MetadataRetriever.Builder(context, mediaItem).build()) {
    // 2. Retrieve metadata asynchronously.
    ListenableFuture<TrackGroupArray> trackGroupsFuture = retriever.retrieveTrackGroups();
    ListenableFuture<Timeline> timelineFuture = retriever.retrieveTimeline();
    ListenableFuture<Long> durationUsFuture = retriever.retrieveDurationUs();

    ListenableFuture<List<Object>> allFutures =
        Futures.allAsList(trackGroupsFuture, timelineFuture, durationUsFuture);
    Futures.addCallback(
        allFutures,
        new FutureCallback<List<Object>>() {
          @Override
          public void onSuccess(List<Object> result) {
            handleMetadata(
                Futures.getUnchecked(trackGroupsFuture),
                Futures.getUnchecked(timelineFuture),
                Futures.getUnchecked(durationUsFuture));
          }

          @Override
          public void onFailure(Throwable t) {
            handleFailure(t);
          }
        },
        directExecutor());
  }
}
```

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