Develop Reference

Building a music player for both android and Desktop at the same time

I'm going to build a music player working on both Android and Desktops. It won't be anything special, I'm doing it more to training myself and know more or less what problems I might encounter if I want to do a real app/program one day. Therefore, since I'm already rather decent at web technologies, I'll try to use something else: Java.
My app / program with have to
be able to read music files and play them (I'm planning on reading the files myself, meaning that I only need to be able to read "raw" sound, WAV or such)
be able to write to music files (to change tags)
be able to communicate with another instance of the program on another device that's on the same network (I want to be able to use my phone as a remote control and my pc as a remote control for my phone)
If possible, show some play/pause buttons on the screen even if it's locked (probably just on android)
And this is where I need your help: What you I do to write as little "device specific" code as possible?
It's obvious I can reuse classes used to encode/decode some music types. Finding the files, reading them, writing them, playing raw sound and connection to the network will be easy to abstract if needed.
But then there is the UI and it looks like if I don't plan carefully, I'll have to do it twice... I've seen libGDX but they kinda insist a lot on the fact it's for games...
All I need is some way to build a simple UI (a few buttons, the cover of the albums) that'd work for both the desktop and the phone.
Should I use libGDX, the "normal" libs (*WT, Swing, neither of which seem to be "compatible" with Android) or something else?
I'd also like to request as few permissions as possible. Meaning that I'd like to have a base music player that only request access to the sd card, and then features requiring additional permissions would be added as other apps/programs or addons.
From what I understood, the only way to achieve this is to create a second app and make the user install it. I think I'll manage to make the two apps communicate (with Intent?) but is it really the only solution?
Thank you in advance for your answers.

Maybe you could consider building the app with something such as Phonegap: http://phonegap.com/ This would let you use your web technologies strength and write a very slim layer of device specific code if any at all!
As for getting a phonegap app to run on the desktop....you could use something like :http://ripple.incubator.apache.org/ to have it run on the desktop. I know this is slightly different and you wanted to tackle writing something in Java - however this is the way mobile development is moving so you may want to get started like this!

Video - sound - sensor capture in Java

I would like to develop an application which would be able to capture video from a webcam, capture sound from a mic and capture movement if a proximity sensor is available.
Initially I want it to run on windows but if able I might want to make it work on android later on.
I'm looking for something pretty straight forward and easy to understand.
My research has led me to Java Media Framework but it is too old and abandoned.
FMJ seems also old.
JavaCV appears to have poor documentation available.
My goal is to make a home detection app which uses the camera imagery, mic sound and sensors to detect and analyze home invasion.
I might take a leap and do it in .NET or other object oriented programming languages if
easier solutions present themselves.
How should I approach this, what are your suggestions?

One Solution is use JavaCV. So you can develop your desktop application using java and later can be ported in to android with fewer changes. As you said JavaCV haven't rich documentation. But JavaCV is just a wrapper to a OpenCV. So you can read OpenCV documentaion and find the relevant method(function) names. The methods in JavaCV has almost same names as OpenCV. So you can try those methods in JavaCV.
Next solution is use .NET to develop the system. There you can use
AForge.NET a rich library for .NET or Emgu CV .NET wrapper
for OpenCV. But you will be facing a problem when creating the
android app. Because you have to build it from scratch.

Which Java library to use for record a video from a connected camera?

You would have thought that tere is a simple solution to this but there isn't :(
My application needs to capture a stream from a USB/firewire (or whatever is the connection) connected camera (result would be a file like output.flv). I would prefer that I can detect all connected cameras and choose which one to use (one or more at the same time --> one or more output files). Application has to be cross platform.
Found libraries:
Xuggle - not very good camera support. Good for manipulating over images and video.
JMF - an old API but if I can use it, I will. I don't see a MAC OS X link on downloads page.
FMJ - looks like a better version of JMF but a can't find a way of installing it.
LTI-CIVIL - FMJ uses it. It looks like it only captures images from camera (not video). I could use Xuggle to create a video from images taken from LTI-CIVIL. And like FMJ, it is difficult to install.
What are your suggestions on this one?

I'd recommend VLCj for this - it should be able to stream from webcams onto a Java canvas without any difficulties. It uses native code so you need to provide libvlc.so / dll but from there on it should work on all the major platforms (Windows, Mac, Linux).
You may need to look at out of process players for complete reliability which is a bit more complex (see here for my efforts so far) but once you've got that in place it should work fine.

There really is no good camera support for Java. You will have to use native code, tailored for each platform, through JNI to get video capture for your project.
There's a related question here. Basically they're suggesting OpenCV wrapped with JNI.

Video playback in Java ( JMF, Fobs4JMF, Xuggler, FMJ )

I need simple video playback in Java.
Here are my requirements:
PRODUCTION QUALITY
Open and decode video files whose video and audio codecs can be chosen by me. I.E I can pick well behaving codecs.
Be able to play, pause, seekToFrame OR seekToTime and stop playback. Essentially I wish to be able to play segments of a single video file in a non linear fashion. For example I may want to play the segment 20.3sec to 25.6sec, pause for 10 seconds and then play the segment 340.3sec to 350.5sec, etc.
During playback, video and audio must be in sync.
The video must be displayed in a Swing JComponent.
Must be able to use in a commercial product without having to be open source (I.E. LGPL or Comercial is good)
My research has led me to the following solutions:
Use Java Media Framework + Fobs4JMF
http://fobs.sourceforge.net/f4jmf_first.html
I have implemented a quick prototype and this seems to do what I need. I can play a segment of video using:
player.setStopTime(new Time(end));
player.setMediaTime(new Time(start));
player.start();
While Fobs4JMF seems to work, I feel the quality of the code is poor and the project is no longer active. Does anyone know of any products which use Fobs4JMF?
Write a Flash application which plays a video and use JFlashPlayer to bring it into my Java Swing application
Unlike Java, Flash is brilliant at playing video. I could write a small Flash application with the methods:
open(String videoFile),
play(),
pause(),
seek(int duration),
stop()
Then bring it into Java using JFlashPlayer which can call Flash functions from Java.
What I like about this solution is that video playback in Flash should be rock solid. Has anyone used JFlashPlayer to play video in Java?
Write a simple media player on top of Xuggler
Xuggler is an FFMpeg wrapper for Java which seems to be a quite active and high quality project. However, implementing the simple video playback described in the requirements is not trivial (Seeking in particular) but some of the work has been done in the MediaTools MediaViewer which would be the base upon which to build from.
Use FMJ
I have tried to get FMJ to work but have had no sucess so far.
I would appreciate your opinions on my problem.

Can a brother get a shout out for Xuggler?

In my mind, VLCJ is the way forward for this type of thing. I love Xuggler for encoding / transcoding work, but unfortunately it's just so complicated to do simple playback and solve all the sync issues and suchlike - and it does very much feel like reinventing the wheel doing so.
The only thing with VLCJ is that to get it to work reliably with multiple players I've had to resort to out of process players. The framework wasn't the simplest thing in the world to get in place, but when it's there it works beautifully. I'm currently running 3 out of process players in my app side by side with no problems whatsoever.
The other caveat is that the embedded media player won't work with a swing component, just a heavyweight canvas - but that hasn't proven a problem for me at all. If it does, then you can use the direct media player to get a bufferedimage and display that on whatever you choose, but it will eat into your CPU a bit more (though no more than other players that take this approach.)

JavaFX has a number of working video and audio codecs builtin. It's likely to be the solution with the broadest support at the moment.

I've been using jffmpeg in the same way you use FOBS, it works pretty well, although I haven't compared them.
I would also love to see an easy way to interface with native codecs the way that JavaFX does, but there doesn't seem to be real integration between JavaFX and Java.
There has also been some work trying to get the VLC library libvlc into java. I haven't tried it yet and would be interested to hear back from anyone who has.

haven't tried Xuggler (which i'm interested in) but I'm having a good time with VLCJ. The drawback I find in it is only that you have to have VLC installed prior to your application.

I'd recommend using MPV. You can use it in combination with JavaFX quite easily, see this example.
In short, you use a little JNA magic to use the MPV native libaries directly, and then let the video display on a JavaFX stage. If you use a child stage, you can even overlay JavaFX controls on top of the video (with full transparancy support).
VLC (with VLCJ) can be used in a similar fashion, but I find that the MPV solution performs better (faster seek and start times).

Frame/clip grabs using Java from a network video camera/adapter (no activex)

I'm interested in doing image processing in Java with frames collected from a network video adapter. The first challenge is finding network video adapters/cameras which don't require an ActiveX control for PTZ control and therefore require IE. Then the issue is how to do still image grabs from network video adapters which only make MP4 available.
Does anyone know of some Java friendly network video cameras and adapters?
Anyone know of some Java code to control PTZ on a network camera?

Two ways in Java that I know of. The first (and the one I current recommend) is the LTI-Civil project. The second is to use Xuggler which uses FFmpeg webcam code behind the scenes.