Media transcoding and editing, transform and roll out!

// Create a TransformationRequest and set the output format to H.265
val transformationRequest = TransformationRequest.Builder().setVideoMimeType(MimeTypes.VIDEO_H265).build()
// Create a Transformer
val transformer = Transformer.Builder(context)
    .setTransformationRequest(transformationRequest) // Pass in TransformationRequest
    .setRemoveAudio(true) // Remove audio track
    .addListener(transformerListener) // transformerListener is an implementation of Transformer.Listener
    .build()
// Start the transformation
val inputMediaItem = MediaItem.fromUri("path_to_input_file")
transformer.startTransformation(inputMediaItem, outputPath)

Transformer.Builder(context)
    .setVideoEffects(listOf(Presentation.createForHeight(480)))
    .build()

You can also chain multiple effects to create more complex results. This example converts the input video to grayscale and rotates it by 30 degrees:

Transformer.Builder(context)
    .setVideoEffects(listOf(
        RgbFilter.createGrayscaleFilter(),
        ScaleToFitTransformation.Builder()
            .setRotationDegrees(30f)
            .build()))
    .build()

It's also possible to extend Transformer’s functionality by implementing custom effects that build on existing ones. Here is an example of subclassing MatrixTransformation, where we start zoomed in by 2 times, then zoom out gradually as the frame presentation time increases:

val zoomOutEffect = MatrixTransformation { presentationTimeUs ->
  val transformationMatrix = Matrix()
  val scale = 2 - min(1f, presentationTimeUs / 1_000_000f) // Video will zoom from 2x to 1x in the first second
  transformationMatrix.postScale(/* sx= */ scale, /* sy= */ scale)
  transformationMatrix // The calculated transformations will be applied each frame in turn
}
Transformer.Builder(context)
    .setVideoEffects(listOf(zoomOutEffect))
    .build()

Here's a screen recording that shows this effect being applied in the Transformer demo app:

For even more advanced use cases, you can wrap your own OpenGL code or other processing libraries in a custom GL texture processor and plug those into Transformer as custom effects. See the demo app for some examples of custom effects. The README also has instructions for trying a demo of MediaPipe integration with Transformer.

Coming soon

Transformer is actively under development but ready to use, so please give it a try and share your feedback! The Media3 development branch includes a sneak peek into several new features building on the 1.0 release described here, including support for tone-mapping HDR videos to SDR using OpenGL, previewing video effects using ExoPlayer.setVideoEffects, and custom audio processing. We are also working on support for editing multiple videos in more flexible compositions, with export from Transformer and playback through ExoPlayer, making Media3 an end-to-end solution for transforming media.

We hope you'll find Transformer an easy-to-use and powerful tool for implementing fantastic media editing experiences on Android! You can send us feature requests and bug reports in the Media3 GitHub issue tracker, and follow this blog to get updates on new features. Stay tuned for our upcoming talk “High quality Android media experiences” at Google I/O.