为何三星自适应亮度调用摄像头？CameraX日志异常技术问询

问题背景 #

开发带摄像头功能的Android应用时，在三星设备上发现开启自适应亮度后，即使退出摄像头功能停留在应用内，仍会持续生成大量CameraManagerGlobal日志，且所有CameraX版本都存在这个问题，疑似三星设备特有。

日志示例 #

2023-08-07 10:44:16.722 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_OPEN for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:16.735 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_ACTIVE for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:17.713 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_IDLE for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:17.777 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_CLOSED for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:22.844 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_OPEN for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:22.855 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_ACTIVE for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:23.839 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_IDLE for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:23.897 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_CLOSED for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:28.967 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_OPEN for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:28.988 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_ACTIVE for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:29.953 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_IDLE for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:30.006 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_CLOSED for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:35.056 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_OPEN for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:35.068 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_ACTIVE for client com.samsung.adaptivebrightnessgo API Level 2User Id 0
2023-08-07 10:44:36.040 17070-19345 CameraManagerGlobal     com.example.cam.sam            I  Camera 3 facing CAMERA_FACING_FRONT state now CAMERA_STATE_IDLE for client com.samsung.adaptivebrightnessgo API Level 2User Id 0

问题解答 #

1. 三星将摄像头与自适应亮度关联的原因 #

三星的自适应亮度系统（com.samsung.adaptivebrightnessgo）调用前置摄像头是为了优化亮度检测：

• 手机顶部的传统光线传感器容易被遮挡（比如用户手握手机、侧躺），前置摄像头可以补充采集用户周围的光线数据，让亮度调节更精准。
• 日志里的周期性启停（约5秒一次）是系统为了持续监测环境光变化，保证屏幕亮度能实时适配当前场景，属于三星定制系统的优化逻辑。

2. 其他开发者是否遇到类似问题 #

是的，不少使用CameraX的开发者在三星设备上碰到过这个问题。这是三星系统层面的行为，和CameraX版本无关——不管用哪个CameraX版本，只要三星设备开启自适应亮度，就会触发这个周期性的摄像头调用日志。相关反馈在开发者社区里很常见，比如国内的技术社区以及Google的CameraX issue tracker上都有讨论。

内容的提问来源于stack exchange，提问作者Deepu George Jacob