How get the screen share stream id not use chooseDesktopMedia?

[sean220]

The chooseDesktopMedia() callback streamId can be used only once and expires after a few seconds when it is not used. But in 0.12 the streamId can always be reused,
Is there any way get a streamId, not by calling chooseDesktopMedia()?

[sean220]

OK,I found the stream id can be get without GUI by Screen.DesktopCaptureMonitor.
But,unfortunately,The stream id obtained in this way is incorrect in 0.13beta7.
e.g. The primary screen stream Id get from chooseDesktopMedia looks like "5wAQj7o/czfAqRJs2uKUHQ==", and DesktopCaptureMonitor returns "screen:0"(like old one in version 0.12).

[rogerwang]

are you using the nw.Screen API? does chrome.desktopCapture work for you? https://developer.chrome.com/extensions/desktopCapture

[sean220]

Yes,I using nw.Screen.chooseDesktopMedia,And I test chrome.desktopCapture too, Both run the same results and the stream Id work fine with getUserMedia(),But I do not need to display the screen selection GUI Window,So the problem is the DesktopCaptureMonitor does not return the correct stream id.

[sean220]

Of course, if the stream Id is reusable like in version 0.12, can also solve the problem.
In 0.12 version, chooseDesktopMedia always returns "screen:0" for the primary screen,just like DesktopCaptureMonitor's 'added' event returns in version 0.13beta7.

[rogerwang]

Could you please provide a sample?

[sean220]

screenshare-demo.zip

[sean220]

I think reusable stream id like version 0.12 is more friendly for Desktop Application, After tests also found a temporary stream Id pass to other windows's getUserMedia() is not work。

[ghostoy]

In Chrome, the stream id used by getUserMedia() is limited to be one-time and only valid for 10s in the same frame that requesting it. These constrains must be for some reason, such as security concerns. So we'd better not to break it.

I'm proposing to add a new API Screen.DesktopCaptureMonitor.registerStream() to obtain the stream id used by getUserMedia(). The usage then should be slightly changed into following:

var dcm = nw.Screen.DesktopCaptureMonitor;
dcm.on("added",function(id, name, order, type, primary){
    // `id` is valid anywhere anytime and can be passed to any frame or window
    var conf = {
        mandatory: {
            chromeMediaSource: 'desktop',
            // register `id` to obtain a valid stream id before passing to `getUserMedia()`
            chromeMediaSourceId: dcm.registerStream(id),
            maxWidth: 1280,
            maxHeight: 720
        },
        optional: []
    };
    // ...
    navigator.webkitGetUserMedia(conf, callback);
});

Is the new API good for you? @sean220

[sean220]

Thanks for support,I have a few questions about the new API.
(1)Dose registerStream just translate id into the chrome's temporary stream id?
(2)Is the 'added' event return id reusable just like in version 0.12?
(3)Can I call this method directly outside the event callback function?

@ghostoy

[ghostoy]

1. Yes
2. Yes. The id returned by added can be used anywhere anytime as 0.12 until the source is removed.
3. Yes.

[sean220]

Sorry,I found the comments in the code now.
It's good enough for my case,Thanks.
Can I try this API from the last live build?

[ghostoy]

We are rebasing on CR49. I will let you know once it's available in live build.

[sean220]

OK,We are looking forward to the CR49 version.

[rogerwang]

@sean220 build available, pls test:

http://dl.nwjs.io/live-build/03-02-2016/12e5fb2-9285daa-3835621-8419c51/v0.13.0-rc1/

[sean220]

Well Done! It's works.
By the way,Is it possible to get rid of the 'Screen is sharing' prompt window?
@rogerwang

[rogerwang]

Sure, we'll see it. Please file another issue for that.