@NYX @enguyen

Hi, this is in direct response to some queries on the posting on the "How to trace a memory leak?"  


I've recently made a bunch of updates to jmcvideo. Here is the source code for the various switchVideo methods:

Code:

  public void switchVideo(String filename)
  {
    mp.setSource(VideoUtils.toURI(new File(parent.dataPath(filename))));
    mp.play();
  }

  public void switchVideo(File file)
  {
    mp.setSource(VideoUtils.toURI(file));
    mp.play();
  }

  public void switchVideo(URL url)
  {
    mp.setSource(VideoUtils.toURI(url));
    mp.play();
  }

  public void switchVideo(URI uri)
  {
    mp.setSource(uri);
    mp.play();
  }
 

The "mp" variable stands for the current MediaProvider. Since creating a new MediaProvider uses native resources, it may be a better idea to reuse a single MediaProvider via the swtichVideo method when you want to start playing a second movie. The bug that didn't let you use the relative dataPath has been fixed. If you want to switch to a video that is not in the dataPath, simply create a File object that points to the video and use that version. You can also use the URL version for local files ("file://") and remote files ("http://").

For example, if you have two videos both stored in the sketch's data folder, you can call the first normally:

Code:

JMCMovie myMovie = new JMCMovie("movie1.mov");
myMovie.play();
 

And then at some other time you can switch to a new movie using the switchVideo method:

Code:

myMovie.switchVideo("movie2.mov");
 

Of course you can just make two separate JMCMovie objects as well.

I'll make sure that the "mp" variable is public in the next update so that you can create your own custom versions of switchVideo in Processing.

Also, I believe I have fixed the memory leak that was present in the last version of jmcvideo.

I'd appreciate any testing/feedback about this and any other issues. Thanks! -Angus

hello,

i'm using the JMC video library, attempting to playback a quicktime movie with a valid alpha channel and getting strange results: either the alpha channel is entirely ignored, or the video frames are like 'piling up' on each other - seems like the alpha channel is being recognized by JMC though the buffer is not getting cleared on every frame.

i've tried the trick of using the very same video file as a mask,

Code:

 image(myMovie, 0, 0);
   myMovie.mask(myMovie);
  

but no luck.

any clue how to get around this one?
does JMC supports playback of qt movies with an alpha channel?

thanks,
P.

Hi Eric, I'll look into it. I think that you can jump by time or by frame, and that on some platforms you only have resolution down to 1 second if you are seeking by time. What OS are you on? -Angus

spiraljetty wrote on May 23^rd, 2009, 11:49pm:


Thanks for your reply. I am on Mac OSX 10.5.7. I am able to jump down to millisecond with other video library, but none of them, in general, works as well as JMC in my sketch. BTW, if I can jump by frame would work to, but how can I do this

Thanks,
Eric

For some reason, the video refuses to loop in either the VideoLoop or the VideoLoopGL examples: it plays to the end and then stops. Is there any way I can troubleshoot this? I'm on OS X 10.5.7.

And thanks for a great library.

jonathan

Hi Angus, thanks for looking into the looping bug. I'm confused about something else now, which can all be summarized like this:

Code:

void videoFrameUpdated(JMCMovie jmcvideo) {
  println("This never seems to get called.");
}

void movieEvent(JMCMovie jmcvideo) 
{
  println("This never seems to get called either.");
  jmcvideo.read(); //doesn't seem to do anything at all, or at least it can be removed from every example I've seen
}
 

So, I'm trying to process each frame of video, but not in real time, and I'm thinking the program should go something like this:
Code:

read in a new frame of video & pause the video
process the video
when the processing's done
advance to the next frame and start over
 

but I'm having trouble because there doesn't seem to be any working callback after a new frame's read in.

Am I just missing something? Is there some way of using the callback function that I don't understand?

Thanks very much.
Jonathan

Hi,
great library.
I use JMC to play an introduction video. After it played once the draw method switch to draw everything but the video. My problem is that as soon i use the reference that contain the video (i.e. video.stop(), video.dispose() ) the video start again: I can hear the sound.

The other problem is a performance one: even after the video is finished the CPU still burn at 100%. There is a way to totally unload a video reference? I even used myVideo = null; with no success.

I am on Ubuntu 9.04 the video is a .mov file.

Thanks.

Edit:
Another question: what do I need to use JMC with a .mov under Windows XP? The code returns me "Unsupported format execption". Thanks again.