Extract video frames

The FrameExtractor class provides an efficient way to extract decoded frames from a MediaItem.

Common use cases include:

  • Generating thumbnails: Creating high-quality thumbnails for a video gallery or seek bar.
  • Video editing previews: Displaying precise frame previews in an editor timeline, allowing users to seek through the content and visualize frames accurately.
  • Applying transformations like scaling, cropping, or rotation directly during extraction, avoiding a separate post-processing step.
  • Content analysis: Extracting frames at intervals to send to an analysis pipeline for tasks like scene detection, object recognition, or quality control.

Overview

Using FrameExtractor is a two-step process:

  1. Build the extractor: Create an instance using FrameExtractor.Builder. Pass a Context and the MediaItem that you want to inspect to the builder. You can also chain configuration methods on the Builder for advanced settings.
  2. Extract frames: Call getFrame() to extract a frame at a specific timestamp or getThumbnail() to request a representative thumbnail. These methods are asynchronous and return a ListenableFuture. Hence, the complex decoding work doesn't block the main thread.

Kotlin

suspend fun extractFrame(context: Context, mediaItem: MediaItem) {
    try {
        // 1. Build the frame extractor.
        // `FrameExtractor` implements `AutoCloseable`, so wrap it in
        // a Kotlin `.use` block, which calls `close()` automatically.
        FrameExtractor.Builder(context, mediaItem).build().use { extractor ->
            // 2. Extract frames asynchronously.
            val frame = extractor.getFrame(5000L).await()
            val thumbnail = extractor.thumbnail.await()
            handleFrame(frame, thumbnail)
        }
    } catch (e: Exception) {
        Log.e(TAG, "Exception: $e")
    }
}

Java

public void extractFrame(Context context, MediaItem mediaItem) {
    // 1. Build the frame extractor.
    // `FrameExtractor` implements `AutoCloseable`, so use try-with-resources
    // so that the resources are automatically released.
    try (FrameExtractor frameExtractor = new FrameExtractor.Builder(context, mediaItem).build()) {
        // 2. Extract frames asynchronously.
        ListenableFuture<FrameExtractor.Frame> frameFuture = frameExtractor.getFrame(5000L);
        ListenableFuture<FrameExtractor.Frame> thumbnailFuture = frameExtractor.getThumbnail();

        ListenableFuture<List<Object>> allFutures = Futures.allAsList(frameFuture, thumbnailFuture);
        Futures.addCallback(allFutures, new FutureCallback<>() {
            @Override
            public void onSuccess(List<Object> result) {
                handleFrame(Futures.getUnchecked(frameFuture), Futures.getUnchecked(thumbnailFuture));
            }

            @Override
            public void onFailure(@NonNull Throwable t) {
                handleFailure(t);
            }
        }, MoreExecutors.directExecutor());
    }
}