cortex: org/capture-video.org comparison

comparison org/capture-video.org @ 42:ecafe87ffddc

updating capture video with new examples

author	Robert McIntyre <rlm@mit.edu>
date	Thu, 03 Nov 2011 16:01:14 -0700
parents	97703c7f020e
children	da4de661c5d9

comparison

equal deleted inserted replaced

-:cce471a4108a
+:ecafe87ffddc
 The easiest way to achieve this special timing is to create a new
 timer that always reports the same framerate to JME3 every time it is
 called.
-=./jme3/src/core/com/jme3/system/IsoTimer.java=
+=./src/com/aurellem/capture/IsoTimer.java=
-#+include ./jme3/src/core/com/jme3/system/IsoTimer.java src java
+#+include ../../jmeCapture/src/com/aurellem/capture/IsoTimer.java src java
 If an Application uses this =IsoTimer= instead of the normal one, we
 can be sure that every call to =simpleUpdate=, for example, corresponds
 to exactly $(\frac{1}{fps})$ seconds of game-time.
-In order to facilitate setting the =Timer= in user code, I added
-getter and setter methods to =Application.java=.
-In =./jme3/src/core/com/jme3/app/Application.java= I added:
-#+include ./jme3/src/core/com/jme3/app/Application.java src java :lines "340-356"
 * Encoding to Video
 Now that the issue of time is solved, we just need a function that
 writes each frame to a video.  We can put this function somewhere
 where it will be called exactly one per frame.
+The basic functions that a =VideoRecorder= should support are
+recording, starting, stopping, and possibly a final finishing step
+there it finilizes the recording (such as writing headers for a video
+file).
+An appropiate interface describing this behaviour could look like
+this:
+=./src/com/aurellem/capture/video/VideoRecorder.java=
+#+include ../../jmeCapture/src/com/aurellem/capture/video/VideoRecorder.java src java
 JME3 already provides exactly the class we need: the =SceneProcessor=
 class can be attached to any viewport and the methods defined therein
 will be called at the appropriate points in the rendering process.
+However, it is also important to properly close the video stream and
+write headers and such, and even though =SceneProcessor= has a
+=.cleanup()= method, it is only called when the =SceneProcessor= is
+removed from the =RenderManager=, not when the game is shutting down
+when the user pressed ESC, for example. To obtain reliable shutdown
+behaviour, we also have to implement =AppState=, which provides a
+=.cleanup()= method that /is/ called on shutdown.
+Here is an AbstractVideoRecorder class that takes care of the details
+of setup and teardown.
+=./src/com/aurellem/capture/video/AbstractVideoRecorder.java=
+#+include ../../jmeCapture/src/com/aurellem/capture/video/AbstractVideoRecorder.java src java
 If you want to generate video from Java, a great option is [[http://www.xuggle.com/][Xuggle]]. It
 takes care of everything related to video encoding and decoding and
 runs on Windows, Linux and Mac.  Out of all the video frameworks for
 Java I personally like this one the best.
-Here is a =SceneProcessor= that uses [[http://www.xuggle.com/][Xuggle]] to write each frame to a
+Here is a =VideoRecorder= that uses [[http://www.xuggle.com/][Xuggle]] to write each frame to a
 video file.
-=./jme3/src/core/com/jme3/app/VideoProcessor.java=
+=./src/com/aurellem/capture/video/XuggleVideoRecorder.java=
-#+include ./jme3/src/core/com/jme3/app/VideoProcessor.java src java
+#+include ../../jmeCapture/src/com/aurellem/capture/video/XuggleVideoRecorder.java src java
 With this, we are able to record video!
+However, it can be hard to properly install Xuggle. For those of you
+who would rather not use Xuggle, here is an alternate class that uses
+[[http://www.randelshofer.ch/blog/2008/08/writing-avi-videos-in-pure-java/][Werner Randelshofer's]] excellent pure Java AVI file writer.
+=./src/com/aurellem/capture/video/AVIVideoRecorder.java=
+#+include ../../jmeCapture/src/com/aurellem/capture/video/AVIVideoRecorder.java src java
+This =AVIVideoRecorder= is more limited than the
+=XuggleVideoRecorder=, but requires less external dependencies.
+Finally, for those of you who prefer to create the final video from a
+sequence of images, there is the =FileVideoRecorder=, which records
+each frame to a folder as a sequentially numbered image file. Note
+that you have to remember the FPS at which you recorded the video, as
+this information is lost when saving each frame to a file.
+=./src/com/aurellem/capture/video/FileVideoRecorder.java=
+#+include ../../jmeCapture/src/com/aurellem/capture/video/FileVideoRecorder.java src java
+* /Really/ Simple Video Recording
+The most common case for recording a video is probably to just capture
+whatever is on your screen exactly as you see it.  In this case, this
+method will do.
+#+begin_src java
+public static void captureVideo(final Application app,
+				final File file) throws IOException{
+final AbstractVideoRecorder videoRecorder;
+if (file.getCanonicalPath().endsWith(".avi")){
+	videoRecorder = new AVIVideoRecorder(file);}
+else if (file.isDirectory()){
+	videoRecorder = new FileVideoRecorder(file);}
+else { videoRecorder = new XuggleVideoRecorder(file);}
+Callable<Object> thunk = new Callable<Object>(){
+	public Object call(){
+	    ViewPort viewPort =
+	    app.getRenderManager()
+	    .createPostView("aurellem record", app.getCamera());
+	    viewPort.setClearFlags(false, false, false);
+	    // get GUI node stuff
+	    for (Spatial s : app.getGuiViewPort().getScenes()){
+		viewPort.attachScene(s);
+	    }
+	    app.getStateManager().attach(videoRecorder);
+	    viewPort.addProcessor(videoRecorder);
+	    return null;
+	}
+};
+app.enqueue(thunk);
+}
+#+end_src
+This will select the appropiate backend =VideoRecorder= class
+depending on the file name you specify, and insturment your
+application to record video to the file.  You should still set the
+game's timer to an =IsoTimer= with the desired fps.
+This example will record video from the ocean scene from the
+jMonkeyEngine test suite.
+#+begin_src java
+File video = File.createTempFile("JME-water-video", ".avi");
+captureVideo(app, video);
+app.start();
+System.out.println(video.getCanonicalPath());
+#+end_src
+I've added support for this under a class called
+=com.aurellem.capture.Capture=. You can get it [[http://hg.bortreb.com/jmeCapture/][here]].
 * Hello Video!
 I've taken [[http://code.google.com/p/jmonkeyengine/source/browse/trunk/engine/src/test/jme3test/helloworld/HelloLoop.java][=./jme3/src/test/jme3test/helloworld/HelloLoop.java=]] and
 augmented it with video output as follows:
-=./jme3/src/test/jme3test/helloworld/HelloVideo.java=
+=./src/com/aurellem/capture/examples/HelloVideo.java=
-#+include ./jme3/src/test/jme3test/helloworld/HelloVideo.java src java
+#+include ../../src/com/aurellem/capture/examples/HelloVideo.java src java
 The videos are created in the =hello-video= directory
-#+begin_src sh :results verbatim
+#+begin_src sh :results verbatim :exports both
 du -h hello-video/*
 #+end_src
 #+results:
 : 932K	hello-video/hello-video-moving.flv
 </iframe>
 #+END_HTML
 * Summary
 It's quite easy to augment your own application to record video,
 almost regardless of how complicated the actual application is.  You
 can also record from multiple ViewPorts as the above example shows.
 #+begin_src java :exports code
 this.setTimer(new IsoTimer(30));
 #+end_src
-Somewhere in the initialization of your Application.  Right now, you
+Somewhere in the initialization of your Application.
-will have to add the =setTimer= method to =Application=, but hopefully
-this method will be included soon by the JMonkeyEngine3 team.
-Then, you create a =VideoProcessor= object and attach it to the
-=ViewPort= from which you want to record.
 If you want to record from the game's main =ViewPort= to a file called
 =/home/r/record.flv=, then add:
 #+begin_src java :exports code
-viewPort.addProcessor(new VideoProcessor(new File("/home/r/record.flv")));
+Capture.captureVideo(app, new File("/home/r/record.flv"));
 #+end_src
-Do this for each =ViewPort= from which you want to record.  The more
+Before you call =app.start()=;
-ViewPorts from which you record, the slower the game will run, but
-this slowness will not affect the final video output.
 * More Examples
-** Hello Physics
+** COMMENT Hello Physics
 =HelloVideo= is boring. Let's add some video capturing to =HelloPhysics=
 and create something fun!
 This example is a modified version of =HelloPhysics= that creates four
 simultaneous views of the same scene of cannonballs careening into a
 Thats a terribly large size!
 Let's compress it:
-** Compressing the HelloPhysics Video
+** COMMENT Compressing the HelloPhysics Video
 First, we'll scale the video, then, we'll decrease it's bitrate. The
 end result will be perfect for upload to YouTube.
 #+begin_src sh :results silent
 cd youtube
 JME3 Xuggle Aurellem video capture
 * Sample Videos
 I encoded most of the original JME3 Hello demos for your viewing
-pleasure, all using the =VideoProcessor= and =IsoTimer= classes.
+pleasure, all using the =Capture= and =IsoTimer= classes.
 ** HelloTerrain
 [[http://youtu.be/5_4wyDFwrVQ][HelloTerrain.avi]]
 #+begin_html

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comparison org/capture-video.org @ 42:ecafe87ffddc