No way to mimic AVAssetWriterInput in Android

Using CameraX 1.1.0-alpha02, there is not way to minic what iOS does with respect to taking the video buffer, modifying it with CISourceOverCompositing and then use the result to feed AVAssetWriterInput (save the video output). That allows them to easily do things like add overlays to video. We have no way to do that to this day on Android.

Given that we can pass frames to ImageAnalysis, the same mechanism should be able to be done where the final output feed is generated in Android's equivalent of CISourceOverCompositing (sample code available for that many places). It looks like two of the three components already exist then. Android can pull the frame and modify it. We just need a way to use the modified frame as the replacement for the original one in the stream.

So, outputFileOptions needs to be extended to take a frame/bitmap produced by a function (overlay function...the equivalent of CISourceOverCompositing), and then use that in videoCapture.startRecording

Esamina l’API VideoCapture di CameraX 1.1.0-alpha02, in particolare outputFileOptions e videoCapture.startRecording, insieme al meccanismo ImageAnalysis esistente. Determina il design dell’API necessario per accettare fotogrammi video modificati e verifica che uno stream elaborato con un overlay possa essere salvato come output video.

Scritto dal modello di indicizzazione a partire dal testo della issue.