Add ProRes encode and decode support to @mediabunny/server

src/encode.ts

@@ -251,8 +251,9 @@ export type VideoEncodingAdditionalOptions = {
 	 * What to do with alpha data contained in the video samples.
 	 *
 	 * - `'discard'` (default): Only the samples' color data is kept; the video is opaque.
-	 * - `'keep'`: The samples' alpha data is also encoded as side data. Make sure to pair this mode with a container
-	 * format that supports transparency (such as WebM or Matroska).
+	 * - `'keep'`: The samples' alpha data is also encoded. Depending on the codec, the alpha may be emitted as packet
+	 * side data or in-band alongside the main packet. For codecs that emit alpha side data, such as VP9, make sure to
+	 * pair this mode with a container format that supports transparency (such as WebM or Matroska).
 	 */
 	alpha?: 'discard' | 'keep';
 	/** Configures the bitrate mode; defaults to `'variable'`. */
@@ -344,6 +345,7 @@ export const buildVideoEncoderConfig = (options: {
 			options.width,
 			options.height,
 			resolvedBitrate,
+			options.alpha === 'keep',
 		),
 		width: options.width,
 		height: options.height,