尽管是adapter.js，GetUserMedia - facingMode仍然无法识别 [英] GetUserMedia - facingMode not recognized despite adapter.js

问题描述

我想在离子应用程序中获取后置摄像头的视频流。
为此，我使用可正常用于前置摄像头的getUserMedia。

I want to get the video stream of my rear camera in an Ionic Application. For this, I use getUserMedia that work correctly for the front camera.

当我将面向模式更改为环境时，我收到此错误：

When I change the facing mode to 'environment' I got this error :

名为facingMode的未知约束被拒绝
ConstraintNotSatisfiedError

在我的Ionic应用程序中，我已经安装了npm软件包webrtc-adapter。

In my Ionic application I have already installed the npm package "webrtc-adapter".

这是我从后置摄像头获取流的代码：

Here is my code to get the stream from the rear camera :

this.constraints = { audio: true, video: {mandatory: { facingMode: 'environment'}}};
        cordova.plugins.diagnostic.requestRuntimePermission( (status) => {
            if (cordova.plugins.diagnostic.permissionStatus.GRANTED){

                navigator.getUserMedia(this.constraints, (stream) => {
                    let video = <HTMLVideoElement>document.getElementById('localVideo');
                    video.srcObject =  stream;
                }, function(err){
                    console.log("Error get stream: ", err.name);
                });
            }
        }, (error) => {
            console.error("Error during runtime permission :", error);
        }, cordova.plugins.diagnostic.permission.CAMERA);

我认为这是兼容性问题。有人可以帮帮我吗？

I think that is a compatibility issue. Anyone can help me ?

谢谢。

推荐答案

你'重新使用过时的非标准约束语法。 adapter.js 会填充规范，因此要从中受益，您必须关注规范。
例如而不是：

You're using an outdated non-standard constraints syntax. adapter.js polyfills the spec, so to benefit from it you have to follow the spec. E.g. instead of:

{audio: true, video: {mandatory: {facingMode: 'environment'}}};

使用

{audio: true, video: {facingMode: {exact: 'environment'}}};

我已经这是一个有效的例子的回答。它应该适用于Chrome。不确定这是否适用于离子。如果它不起作用，请告诉我。

I already have an answer with a working example of this. It should work with Chrome. Not sure if this will work with ionic or not. Let me know if it doesn't work.

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