I'm trying to capture a video of a currently running swing application from within the application (the user presses a record button to start recording). I'm not sure how to go about creating a video that records "live." I've looked into using Xuggler, but that isn't available for 64-bit windows (on a 64-bit jvm), and that is important for this application. I don't think it would be feasible to save each screen off as images and then stitch them together because the video could run for several minutes resulting in a very large number of images.
Does anyone have any experience with this and can point me to some ideas on how to do this?
thanks,
Jeff
I was also going to suggest using Robot to take screenshots, but as you said, you would need a way of limiting what is captured. Detecting input events like keys and mouse movement could hint at when is a good time to take another screenshot, and perhaps limiting it to 2 frames per second. When stitching the images back together, the only way you could determine the timing is if you named the files using a timestamp format (with milliseconds).
Related
I am building an application like in which the user can use his Android tablet as a graphics tablet like https://play.google.com/store/search?q=gfxtablet
My server program is in Java and I was successfully able to send stylus coordinates and pressure values to the server from my tablet through UDP and able to draw in applications like Paint, Photoshop etc.
The problem:
I am not able to find a way to inject this pressure values in Windows (to draw thick and thin lines depending upon stylus pressure). I know it can be easily done in Linux, but I am not able to find a way for Windows.
I even tried JNA library for Java , but it also does not seem to have the appropriate method to input pressure values. I know the existence of JPEN & JTABLET libraries but these don't allow you to draw in Paint, Photoshop, GIMP etc.
You could try using the Robot class in java to simulate native system input events. Then store local variables to test input against and fire those events through the Robot class.
Basically, for Windows Paint, whenever your pressure is greater than the previous pressure, fire a Robot event that sends the key combination CTRL and + to increase brush width.
If you're also testing what application is open, then you can have a separate section of code set up to determine which key combination to send(since in photoshop the keybind is [ and ]), or have a section that allows users to specify what their keybinding is.
While the current iteration uses awt, Robot is being added to JavaFX/Lombard in 3.0.
I'm sure there are better solutions, but this is what I would do until I had something better. :)
I am looking for an addition for our "livestream and podcast" solution, which uses a camera to film speeches in our house.
It has been requested to view the slides of our speakers directly as a image in the webbrowser instead of the video stream. We don't want/can not install software on the speakers laptop, so I thought about a Java applet, which the speaker can just run via a webbrowser.
So what I need is technically this:
[speakers laptop] -> [Screencapture every N seconds via applet on a webpage] -> [Displaying the screen of the speaker on a different webpage for the external viewers]
I know there are Java applications which do record the screen, but save the file output locally. I need something that does the same, but sends the image to the server. On the server side I thought about a websocket.js accepting and displaying the image (other suggestions are welcome).
It would be great if somebody could help me out here. Btw, I never programmed in Java, so telling me which frameworks I need won't really help me.
Thanks!!
I was recently asked to evaluate possibilities for live screen-cast via applet. Most video APIs do not support codecs that have high enough compression (e.g. JMF). Some APIs can do advanced formats (JFFMPEG, Xuggle) but also use natives. While natives are normally no problem for an app. launched (free floating) using Java Web Start or a Plug-In 2 applet, the makers of Xuggle identify 'the order of loading natives' as a problem (e.g. won't work) for both JWS and applets.
It is a pity that more than a decade into its development, Java has no reasonable API for video capture/processing that can be deployed for a wide use (applet/JWS based - for the 'general public') GUI.
Perhaps you can find a solution using Flash.
Update 1
In fact, I do not need the screen to be recorded as a video.
In fact, you mentioned much of that in your initial question, but I focused on just a few keywords before drafting a reply. My bad. :P
OK.
Getting an image is relatively easy. An applet would need to be trusted in order to get a screenshot, but once trusted, it is just a few lines of code to get the image.
Encoding the image to JPEG of particular quality/compression setting (in memory) is also doable.
Sending the image to the server would depend on the size in bytes and connection speed, but one image with a high compression, every 10 seconds, should be doable. The server would need to implement functionality to accept the image.
As far as displaying the image on the client, it seems you already have some ideas based around JS. If you can make that work that would be optimal, since it can then be viewed in browsers with no Java.
I would still recommend you deploy the app. to the 'speaker' using Java Web Start, rather than embed an applet. A JWS app. will give you less deployment & maintenance troubles, and the JWS launch is ..nicer. Further, a free floating frame launched using JWS can minimize itself (or in later JREs, become transparent), during the action of taking a screen image - thereby capturing everything on the screen except itself.
Update 2
I actually found this code here.
That is ..horrible. Not the code, the site. When I visited it I got a message saying a pop-up had been suppressed (fair enough). Then there was the irritating 'vibrating dialog' hovering in the middle of the page (and following the scroll). You click the little x to see - another tab opened with yet another floating dialog, saying some other rubbish about how "You've won.." - with sound loud enough to drown out my high volume trance/dance playlist.
Then after closing that the hell out of my FF, I go back to the original page, close the damn 'dialog', scroll down & see.. a red background to the code (shudder). That is as far as I could manage. I closed the page with the code.
Try this code instead, for a single screen-shot.
Would it be possible to use this on the client side..
Yes.
.. and receive it with javascript on the server side?
Not really. Unless you mean an IIS based server running Microsoft's JScript. JavaScript is a client side technology.
For security reasons, servers need to protect themselves. E.G. From:
Someone creating a slavebot that uploads all the 1000s of docs on the slave machine's to the site - to make it crash.
People high-jacking your server for storing and serving bestiality porn (or worse).
Because of things like that (bad people have lots of imagination), while servers can easily accept uploads, they are generally not configured by default to allow them.
.. (I don't want Java on my server ;-)
It can be done using PHP, ASP, CGI etc. It does not need Java specifically, but it does need some active involvement from the server, if only to check the size of what is being uploaded and abort if it gets too large!
..Will take a look at the link you posted, but as I said, I can't program in Java, though I can understand some of it. Thanks!
It sounds like you'll need some help getting the server-side of it ready, as well. It is trivial for someone that knows how (not me), but a potential security nightmare for the inexperienced.
Update 3
where do I add the function to send the picture?
Sorry. I've not tried to implement that - you'd want to want to encode it to JPEG before sending, to reduce the size. See this code for how to provide an adjustable compression/quality where the user can see the effect.
There are various ways to get an image to a server. E.G. sockets, HTTP, FTP.. AFAIU it would depend on how the server is accepting it. I am unfamiliar with the specific term 'websocket' or the node.js script. Can you link to what you mean?
..the old code added to pastebin, so it's readable
Smart thinking. I notice it uses sockets, it was in the back of my mind that sockets would be best for this, since they have low overhead and short wait times.
I wrote a Java application that uses the java.awt.Robot to take screen captures of the screen and was wondering if capturing a program using DirectX/OpenGL would be possible?
Each time I try to do this, I get a black screen
Don't know if this is really a solution but seems there's more possible ways to get the screenshot information using a "FrameGrabber" or some related class from JavaCV possibly: http://code.google.com/p/javacv/
Some of the final output shown on the screen could be calculated on a graphics card that has shaders set to act on the image data before it gets put into a display buffer for what's shown so it's possible some effects would be impossible to capture without an analog loopback (go from video out to video in on a capture card).
Related post How to take screenshots fast in Java?
OpenGL is a drawing API, not an all purpose interface to the graphics system. There were times, when taking screenshots with OpenGL was indeed possible through some dirty hacks. However recently I tried to re-implement this on modern OS to see if it still works, and no, it doesn't anymore.
Yes it is possible. But maybe only in limited circiumstances.
I've successfully captured the contents on OpenGL (jogl) windows on linux and windows using the Robot createScreenCapture.
Some specific information about the implementation that may be different for you:
The call to createScreenCapture was done from within the OpenGL
application.
The application used heavyweight GLCanvas
It used Java 6
Make sure you pass it the correct coordinates. You can get the screen coordinates to use from the GraphicsEnvironment
Uhh... a hard one ;o)
I had a try with some other screenshot utils and got a black screen, too. Looks like DirectX is passing the graphics directly to the monitor output. I am wondering if that could be accessed within a java application.
I wanted to load java images with some effects like we have in power point like blinds or appear in Java swing when user clicks on the image.
I have these specific questions in mind:
1.Is there a way to do this in Java?
2.Also how will this behave when the image to load is huge like 25 Mega Pixel?
3.If we are dealing with large images being switched, what mechanism should be used for incorporating images in the application?
Thanks,
Sandeep
1.Is there a way to do this in Java?
Yes, but it won't be with a single command or anything like that. Unless you find a library for this, you'll have to code it up manually.
To do animations like these I suggest you have a look at SwingWorkers.
2.Also how will this behave when the image to load is huge like 25 Mega Pixel?
25 mega pixel is quite large. It depends on your computer of course but if you code it reasonable well it should work fine.
3.If we are dealing with large images being switched, what mechanism should be used for incorporating images in the application?
Unless you really want the program to zoom into the details of the image, I suggest you shrink them immediately after loading, so your drawing-routines can work with them efficiently.
You can experiment with your target images using ImageJ. I routinely use it to manipulate images having scores of megapixels containing 8-, 16- and 32-bit data.
I'd like to "capture" a screenshot of what a java applet would currently look like if it were loaded, effectively screenshoting an applet without the use of a vdu.
The purpose of this is to display the image to a user that doesn't have a JVM. Lets assume the applet is a digital clock and has no requirement on user input. So what could be done is set up a pc connected to a vdu, open the applet, schedule a script to take a screenshot and upload the image. Clients could then access what the applet would look like at any given time without the requirement on a jvm.
It'd be such a hassle to have a pc running all the time etc. Surely this could be done somehow without a display.
Would it be possible to create a virtual display in a jvm that can render an applet and then take a screen capture?
If this were possible then perhaps a really high resolution display could be virtualized to create a very high resolution screenshot.
The ScreenImage class should handle this.
Look at java.awt.Robot#createScreenCapture(java.awt.Rectangle)
If this would work, i would wonder, remind the sandbox, and as the above link stated "This will work whether you have an AWT or Swing application."
If you use a "rendering-engine" (composing each pixel to something paintable before repaint()'ing) within you applet, you could use this information and create an image.