Using QSound::play("...") not working

[Charvi]

Hi all,

I have developed a small program which will play a tone on any Key press. Now when I runt he application on desktop it works fine. But when I cross compile it for my device and run the application there no sound output is achieved. I have used QSound:lay("..."); for playing the sound. The file is a .wav file. It gives the following error:

get volume of audio device failed
Floating point exception

Any idea what the problem might be anybody??? I have read that QSound directly accesses the /dev/dsp on an embedded device. When I use aplay on my device the tone is played fine.

Edit: Do I need to put any specific library on the device. Right now I have put three as per my requirement which are QtCore QtGui and QtNetwork.

Help soon.

Charvi Mehta.

[wysota]

What platform are you targetting? On Unix QSound requires NAS. Better use Phonon instead.

[Charvi]

Can't try with phonon right now. But what I assume is I will need to put the QtMultimedia library on my embedded device before I run the program. Is that it? Do I need anything else to run a program that uses the phonon?


Yes my embedded device uses the Unix platform.

[wysota]

QtMultimedia nad Phonon are two separate things. Both will require you to have a proper version of GStreamer though.

[Charvi]

okay. But why isn't there anything which can directly access the /dev/dsp and work?

[wysota]

You can open /dev/dsp with QFile and stream data to it if you want.

[Charvi]

okay I used a workaround due to lack of time to experiment. I used the system command from within Qt and used aplay utility.

Now I get a key press sound on every keypress which I have handled in the event filter; because there I use the system command. But what should I do for the keys which are not handled by the event filter and which are internally handled by Qt. Like I have used a QScrollArea. The scroll bar navigation takes place with the up and down arrow keys. This is internally handled by Qt and hence no sound is played here. Is there anyway I can play sound here also? Ofcourse there is a way. Can anybody point out please.

Please reply.

[Charvi]

Please reply.

[wysota]

Install an event filter on the application object and intercept key events there.

[Charvi]

No but then I will have to write the code for all the basic key press events also. That will be tedious and not desirable. Like then I will have to write event for scrolling; that's not going to be as smooth as the internal handling. It will also increase the lines of code.

Reply soon.

[wysota]

No but then I will have to write the code for all the basic key press events also.

No, you won't.

[Charvi]

Could you please give me an example or explain in more detail.

"Install an event filter on the application object and intercept key events there. "

How exactly?