Camera 2 Video Recording - Auto Flash Does Not Work

Question

I have implemented a custom camera that records video using the camera2 API. It is possible to set the flash to “On”, “off” and “Auto”. Setting the flash to “Auto” does not work , while other settings work fine.

Here is the code:

private void updateFlash() { Log.e(TAG, "Flash = " + currentFlash); switch (currentFlash) { case Constants.FLASH_OFF: previewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF); break; case Constants.FLASH_ON: previewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_TORCH); break; case Constants.FLASH_TORCH: previewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_TORCH); break; case Constants.FLASH_AUTO: previewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH); break; } cameraCaptureSession.setRepeatingRequest(previewRequestBuilder.build(), null, null); } 

I have a lot of googled and almost all answers on stackoverflow for automatic flash, but no one worked.

Please, help. I do not understand what the problem is.