[camera] Camera Timeout on some devices

[Tomucha]

I have trouble with camera plugin (0.7.0+2) - the second time I try to:

  XFile file = await controller.takePicture();
  return file;

... the call ends up with "timeout". The first time I take a photo everything works fine, but all subsequent calls fail. It all happens with example application too:

https://github.com/flutter/plugins/tree/master/packages/camera/camera/example

I/flutter ( 4707): Error: captureTimeout
I/flutter ( 4707): Error Message: Picture capture request timed out
W/System  ( 4707): A resource failed to call release. 

It works on some low-level phone I have here (myPhone Hammer Iron 2).

---

tomucha@tomucha-mx:~$ flutter --version
Flutter 1.22.6 • channel stable • https://github.com/flutter/flutter.git
Framework • revision 9b2d32b605 (4 weeks ago) • 2021-01-22 14:36:39 -0800
Engine • revision 2f0af37152
Tools • Dart 2.10.5

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel stable, 1.22.6, on Linux, locale en_US.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.2)
[✓] Android Studio (version 3.5)
[✓] IntelliJ IDEA Ultimate Edition (version 2019.3)
[✓] VS Code (version 1.52.1)
[✓] Connected device (1 available)

[TahaTesser]

Hi @Tomucha
I see there's an open issue addressing the case you described. #74645
Please follow up on that issue, I'm closing the current one as a duplicate.
If you disagree, please write in the comments and I will reopen it.
Thank you

[Tomucha]

Hi, @TahaTesser sorry, I don't think so, please re-open :-(

#74645 is supposedly fixed by commit flutter/plugins@361567b so I applied the changes from that commit to local clone of camera 0.7.0+2 (because I cannot use non-null version). But problem is still there.

I can take the first photo, but all subsequent attempts fail. I can destroy camera controller and initialize it again, and I'm at the beginning: I can take the first photo but that's it.

I added some logging to the Camera.java and I see that "processCapture" method gets called many times and the last (hundred) calls are "case preCapture" with "aeState == 1", until it dies with CameraException(captureTimeout, Picture capture request timed out). At the beginning it goes through "case focusing" several times.

I can change whatever I want - flash mode, autofocus mode ... first photo is fine, all others fail.

//cc @mvanbeusekom

[Tomucha]

To ride the "cargo cult" wave a little bit longer, when I change:

            case preCapture:
              // Some devices might return null here, in which case we will also continue.
              if (aeState == null
                  || aeState == CaptureRequest.CONTROL_AE_STATE_PRECAPTURE
                  || aeState == CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED
                  || aeState == CaptureRequest.CONTROL_AE_STATE_CONVERGED) {
                pictureCaptureRequest.setState(State.waitingPreCaptureReady);
                setPreCaptureStartTime();
              }
              break;

to

            case preCapture:
              // Some devices might return null here, in which case we will also continue.
              if (aeState == null || aeState == 1
                  || aeState == CaptureRequest.CONTROL_AE_STATE_PRECAPTURE
                  || aeState == CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED
                  || aeState == CaptureRequest.CONTROL_AE_STATE_CONVERGED) {
                pictureCaptureRequest.setState(State.waitingPreCaptureReady);
                setPreCaptureStartTime();
              }
              break;

(aeState == 1) ... it seems to be working just fine.

Needless to say - I have no idea what that means :-)

[mvanbeusekom]

Thanks for the feedback @Tomucha, we will look into this. I quickly looked up what aeState == 1 means and it seems to be CONTROL_AE_STATE_SEARCHING (see here).

Now I am not yet sure how we should handle this and if simply advancing to the waitingPreCaptureReady state will solve all problems but will definitely look into it further.