用android Camera2连续拍摄静态照片 [英] Continuously take still photo with android Camera2

问题描述

在 Camera2Basic 示例中，我修改了代码以使程序连续拍摄每张照片2秒它运行正常，但过一会儿进入了相同的状态回调条件，并且不再拍照:

From Camera2Basic example, I modified the code to make the program continuously takes still photo every 2 seconds. It runs fine but after a while it enters the same statecallback condition and does not take picture anymore:

case STATE_WAITING_PRECAPTURE: {
                // CONTROL_AE_STATE can be null on some devices
                Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
                if (aeState == null ||
                        aeState == CaptureResult.CONTROL_AE_STATE_PRECAPTURE ||
                        aeState == CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED) {
                    mState = STATE_WAITING_NON_PRECAPTURE;
                }
                else
                {
                    Log.e(TAG,"aeState = " + aeState);
                }
                break;
            }

日志继续打印aeState = 2，即CONTROL_AE_STATE_CONVERGED.我的问题是，为什么在AE收敛时代码不执行任何操作?为什么不将状态更改为STATE_WAITING_NON_PRECAPTURE?

The log keeps printing aeState = 2, which is CONTROL_AE_STATE_CONVERGED. My question is why the code does nothing when the AE is converged? Why not change state to STATE_WAITING_NON_PRECAPTURE?

我的意思是为什么不这样做呢?

I mean why not doing this instead?

case STATE_WAITING_PRECAPTURE: {
            // CONTROL_AE_STATE can be null on some devices
            Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
            if (aeState == null ||
                    aeState == CaptureResult.CONTROL_AE_STATE_CONVERGED ||
                    aeState == CaptureResult.CONTROL_AE_STATE_PRECAPTURE ||
                    aeState == CaptureRequest.CONTROL_AE_STATE_FLASH_REQUIRED) {
                mState = STATE_WAITING_NON_PRECAPTURE;
            }
            else
            {
                Log.e(TAG,"aeState = " + aeState);
            }
            break;
        }

ps:如果我想每2秒拍照一次，应该在哪里调用takePicture()?目前，我在CaptureCallback中调用了它，但是看起来有些竞争情况，因为CaptureCallback在后台线程中.

ps: Where should I call takePicture() if I want to take photo every 2 seconds? Currently I call it in the CaptureCallback, but look like there some race condition because the CaptureCallback is in the background thread.

谢谢.

推荐答案

代码应在此之前将AE_PRECAPTURE_TRIGGER设置为START；然后等待看到至少一个结果与AE_PRECAPTURE的AE_STATE一起出现，以了解触​​发器已激活并且预捕获已开始.然后它将等待第一个非PRECAPTURE AE_STATE知道预捕获已完成.

The code should be setting the AE_PRECAPTURE_TRIGGER to START right before this; it's then waiting to see at least one result come in with AE_STATE of AE_PRECAPTURE to know the trigger has activated and precapture has started. It'll then wait for the first non-PRECAPTURE AE_STATE to know that precapture has completed.

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