HarmonyOS 鸿蒙Next外接装置USB线连接手机

HarmonyOS 鸿蒙Next外接装置USB线连接手机 【问题描述】：现在卡在了使用UVC相机这块上面，我们的应用有部分重要功能需要手机通过OTG连接外设通过UVC协议获取图像，但是目前我们所了解到的，在鸿蒙5.0+上没有合适的库来实现，目前有个 https://ohpm.openharmony.cn/#/cn/detail/uvc_camera 但是只适配了openharmony

【问题现象】：如果需要完全要从底层驱动和协议开始开发，目前确实成本有点高，系统层面或者内部有没有相关SDK

【版本信息】：NA

【复现代码】：NA

【尝试解决方案】：NA


更多关于HarmonyOS 鸿蒙Next外接装置USB线连接手机的实战教程也可以访问 https://www.itying.com/category-93-b0.html

6 回复

【解决方案】

开发者你好，USB外接相机的能力现已支持，接口参考：getSupportedCameras，选择ConnectionType为CAMERA_CONNECTION_USB_PLUGIN的相机即可，使用方式与正常系统相机使用方式一致，可参考相机管理和开发相机应用文档。

更多关于HarmonyOS 鸿蒙Next外接装置USB线连接手机的实战系列教程也可以访问 https://www.itying.com/category-93-b0.html


尝试结论

getSupportedCameras 获取不到 ConnectionType 为 CAMERA_CONNECTION_USB_PLUGIN（USB 连接的相机）的相机；仅能获取到 ConnectionType 为 CAMERA_CONNECTION_BUILT_IN（内置相机）。

API版本

5.0.5（17）

getSupportedCameras返回

[
    {
        "cameraId": "device/0",
        "hostDeviceType": 0,
        "cameraType": 0,
        "connectionType": 0,
        "cameraPosition": 1,
        "hostDeviceName": "",
        "cameraOrientation": 90
    },
    {
        "cameraId": "device/1",
        "hostDeviceType": 0,
        "cameraType": 0,
        "connectionType": 0,
        "cameraPosition": 2,
        "hostDeviceName": "",
        "cameraOrientation": 270
    }
]

usbManager.getDevices可获取usb相机

{"name":"2-2","serial":"","manufacturerName":"Generic","productName":"USB Camera","version":"0200","vendorId":3034,"productId":22624,"clazz":239,"subClass":2,"protocol":1,"devAddress":2,"busNum":2,"configs":[{"id":1,"attributes":128,"isRemoteWakeup":false,"isSelfPowered":true,"maxPower":1000,"name":"USB Camera","interfaces":[{"id":0,"protocol":0,"clazz":14,"subClass":1,"alternateSetting":0,"name":"USB Camera","endpoints":[{"address":131,"attributes":3,"interval":6,"maxPacketSize":32,"direction":128,"number":3,"type":3,"interfaceId":0}]},{"id":1,"protocol":0,"clazz":14,"subClass":2,"alternateSetting":0,"name":" ","endpoints":[]},{"id":1,"protocol":0,"clazz":14,"subClass":2,"alternateSetting":1,"name":" ","endpoints":[{"address":129,"attributes":5,"interval":1,"maxPacketSize":128,"direction":128,"number":1,"type":1,"interfaceId":1}]},{"id":1,"protocol":0,"clazz":14,"subClass":2,"alternateSetting":2,"name":" ","endpoints":[{"address":129,"attributes":5,"interval":1,"maxPacketSize":512,"direction":128,"number":1,"type":1,"interfaceId":1}]},{"id":1,"protocol":0,"clazz":14,"subClass":2,"alternateSetting":3,"name":" ","endpoints":[{"address":129,"attributes":5,"interval":1,"maxPacketSize":1024,"direction":128,"number":1,"type":1,"interfaceId":1}]},{"id":1,"protocol":0,"clazz":14,"subClass":2,"alternateSetting":4,"name":" ","endpoints":[{"address":129,"attributes":5,"interval":1,"maxPacketSize":2816,"direction":128,"number":1,"type":1,"interfaceId":1}]},{"id":1,"protocol":0,"clazz":14,"subClass":2,"alternateSetting":5,"name":" ","endpoints":[{"address":129,"attributes":5,"interval":1,"maxPacketSize":3072,"direction":128,"number":1,"type":1,"interfaceId":1}]},{"id":1,"protocol":0,"clazz":14,"subClass":2,"alternateSetting":6,"name":" ","endpoints":[{"address":129,"attributes":5,"interval":1,"maxPacketSize":4992,"direction":128,"number":1,"type":1,"interfaceId":1}]},{"id":1,"protocol":0,"clazz":14,"subClass":2,"alternateSetting":7,"name":" ","endpoints":[{"address":129,"attributes":5,"interval":1,"maxPacketSize":5120,"direction":128,"number":1,"type":1,"interfaceId":1}]}]}]}

开发者您好，请升级手机系统至6.0.1（21）版本测试一下是否可以获取到USB连接的相机，

开发者您好，您测试使用的手机不支持USB相机，您可以根据getSupportedCameras接口去查寻，找到里面类型为USB的相机设备，如果能查到就说明手机支持USB相机，如果查不到就说明USB相机不可用。

HarmonyOS Next支持USB外接设备连接手机，需使用OTG转接线。连接后可在通知栏查看USB设备状态，通过文件管理器访问存储设备内容。部分USB设备需安装对应驱动或应用才能正常使用。

针对您在HarmonyOS Next上通过USB OTG连接UVC相机的问题，目前确实存在挑战。

核心情况是：HarmonyOS Next（即您提到的鸿蒙5.0+）与OpenHarmony在架构和API层面已明确区分。 您找到的uvc_camera三方库（ohpm链接）是为OpenHarmony社区版本设计的，其底层依赖的驱动框架、HDF（硬件驱动框架）接口以及@ohos.driver等相关API，与HarmonyOS Next的商用系统不兼容，因此无法直接使用。

关于系统支持，截至当前信息，HarmonyOS Next的公开SDK中尚未提供直接面向应用层、开箱即用的UVC协议或USB Video Class标准API。这意味着，实现此类功能通常需要涉及系统底层能力，而这部分能力目前并未开放给普通应用开发者。

对于您“从底层驱动开始开发成本高”的顾虑，这是完全合理的。目前可行的路径非常有限：

  1. 关注官方动态：此类涉及核心外设连接的功能，最可行的方式是等待华为官方在未来版本的HarmonyOS Next SDK中，提供相应的硬件访问或USB视频类支持。这是解决该问题的根本途径。
  2. 评估备选方案：如果项目周期紧急，需要评估是否可采用其他图像获取方案作为临时替代。

总结来说，在HarmonyOS Next的当前公开能力范围内，尚无直接支持应用层调用UVC相机的标准方案。建议将开发计划与官方SDK的更新路线图进行对齐。

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