『USB Camera』qml调用USB Camera失败，不能预览图像

cooper

大家好：
         小弟近日来在调试RK3288的USB Camera部分的内容遇到一些问题：
         设备环境为：lubuntu16.04 firefly官方提供。内核版本为4.4.194；
     

        下米是现象：

         当我通过guvcview应用打开USB Camera时能够预览到摄像头采集到的图像，但CPU占用率达到了90%-100%；不知原因，希望大家能够帮忙分析分析，需要哪些信息可以在评论区提供。
         当我使用qt编译出的qmlvideo应用程序，来打开摄像头时，出现了以下log：
# ./qmlvideo
QML debugging is enabled. Only use this in a safe environment.

** (qmlvideo:1499): CRITICAL **: gst_audio_format_from_string: assertion 'format != NULL' failed
Using mplane plugin for capture
[  284.950050] rkisp1: rkisp_enum_frameintervals Not active sensor
[  284.956124] rkisp1: rkisp_enum_frameintervals Not active sensor
[  284.962268] rkisp1: rkisp_enum_frameintervals Not active sensor
[  284.968301] rkisp1: rkisp_enum_frameintervals Not active sensor
[  284.974362] rkisp1: rkisp_enum_frameintervals Not active sensor
[  284.980370] rkisp1: rkisp_enum_frameintervals Not active sensor
[  284.986421] rkisp1: rkisp_enum_frameintervals Not active sensor
[  284.992425] rkisp1: rkisp_enum_frameintervals Not active sensor
[  284.998391] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.004390] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.010385] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.016394] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.022380] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.028336] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.034333] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.040404] rkisp1: rkisp_enum_frameintervals Not active sensor
Using mplane plugin for capture
Unable to query the parameter info: QCameraImageProcessingControl::WhiteBalancePreset : "Invalid argument"
Unable to query the parameter info: QCameraImageProcessingControl::ColorTemperature : "Invalid argument"
Unable to query the parameter info: QCameraImageProcessingControl::ContrastAdjustment : "Invalid argument"
Unable to query the parameter info: QCameraImageProcessingControl::SaturationAdjustment : "Invalid argument"
Unable to query the parameter info: QCameraImageProcessingControl::BrightnessAdjustment : "Invalid argument"
Unable to query the parameter info: QCameraImageProcessingControl::SharpeningAdjustment : "Invalid argument"
[  285.157594] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.165434] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.172210] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.178415] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.184680] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.190922] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.197067] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.203326] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.209365] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.215603] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.221849] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.227895] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.234134] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.240415] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.246545] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.252869] rkisp1: rkisp_enum_frameintervals Not active sensor
[  285.306591] rkisp1: update sensor info failed -19
CameraBin error: "Could not read from resource."
[  285.319061] rkisp1: update sensor info failed -19
qml: [qmlvideo] CameraItem.onError error function() { [native code] } errorString Could not read from resource.
qml: [qmlvideo] Content.onFatalError
Using mplane plugin for capture
.................................
CameraBin error: "Device '/dev/video0' is busy"
qml: [qmlvideo] CameraItem.onError error function() { [native code] } errorString Device '/dev/video0' is busy
qml: [qmlvideo] Content.onFatalError
Using mplane plugin for capture



在系统中我的/dev目录下video设备有：
# ls /dev/video*
/dev/video0  /dev/video2  /dev/video4  /dev/video6
/dev/video1  /dev/video3  /dev/video5



usb摄像头的接口是 /dev/video5


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vOv

插眼

灵犀鸟

检查一下设备树配置是否正常