Use CameraX with VideoCapture use case as input

[aloz77]

I'm wondering if there a good way to use the CameraX to get the video stream without using a preview?

Sandeep Raghuraman described an interesting approach to use VideoCapture use case to get the video stream at https://medium.com/@sandeepraghuraman/video-streaming-with-camerax-8549a0c86d21

Is it somehow possible to use a Surface drawn up by VideoCapture in RootEncoder ? I can't see a way to access videoEncoder.getInputSurface() and to prevent glInterface.start() unfortunately.

[pedroSG94]

Hello,

Using GenericStream you can totally avoid use startPreview and it will works.

[aloz77]

I still can't find the way to get a reference to the inputSurface of the videoEncoder

[pedroSG94]

Hello,

That surface is used by glInterface directly. You set that surface to glInterface here:
https://github.com/pedroSG94/RootEncoder/blob/master/library/src/main/java/com/pedro/library/view/GlStreamInterface.kt#L149

Now, you draw in that surface using the surfaceManagerEncoder that reference to that surface. It is done in the draw method of the class.
The flush is like this:

• VideoEncoder create input surface
• VideoEncoder set that surface to glInterface
• glInterface create a gl surface
• glInterface send that gl surface to video sources
• video sources render gl surface provided by glInterface
• gl interface receive this render and copy it to video encoder input surface using draw method
• video encoder detect that the input surface is renderer by glInterface and encode the frame.

[aloz77]

Do we have to use the glInterface at all? My assumption was that VideoCapture can draw directly to the inputSurface of the videoEncoder because we don't have a preview, we don't have OnFrameAvailable events.

[pedroSG94]

You don't need use it at all but without it you can't modify the input to rotate or add filters. You already have a way it use it without glInterface using this library. For example you have Camera1Base with SurfaceView or TextureView.
In old versions you also could use Camera2Base the same way than I told you with Camera1Base but since it is really limited I removed it and now, only Camera1Base can do it to support Android API 16 and 17.