I read this code to play video files using xuggler as a library.When i run this code , the video without sound plays.Why is that ?
If not what should i do to play audio with video.?
Quite simply, it's because that code doesn't play any audio. It was never written to do so!
If you want to play audio and video, check out the example here:
The question to me suggests that you've just grabbed the source without looking at the tutorials - I'd strongly suggest doing so so you can understand the code behind what's going on rather than just throwing it in there and expecting it to work - especially if you're planning on using Xuggler in any great depth!
As a further note, if all you want to do is play videos I probably wouldn't advise using Xuggler because it's just not really designed for that sort of thing. Sure it will play them, but you have to manage all the sync issues yourself (which the above example doesn't do a great job of), it will only use your CPU and therefore really eat into its consumption especially if you're doing things like HD video, and the sheer amount of background code is just overkill (getting the streams, finding the stream IDs, extracting each packet, determining the type of the packet, dealing with it appropriately, managing errors, etc. etc.) It's a great piece of software, but if you're only using it to play stuff then it'll probably give you far more trouble than its worth.
Instead I'd advocate having a play with VLCJ - it's a bit complicated to get set up to work reliably (out of process players are required for rock solid stability) but when you've got that far it plays near any file type under the sun and manages all the issues above for you much, much better than you'll ever cope with by hand!