synchronisation ???

[starn]

Hi!!

I read 64 bytes from a file like this:

ifstream in ("music.wav", ios::in | ios::binary );
in.read (buffer,64);

What do I have to do to read these 64 bytes 192000 times a second? (192kHz)

It's to simulate an input that recieve sound samples at 192 kHz....

Thanks a lot for any help and sorry for my english

Starn

 

[Nosferatu]

??? Why read them 192000 times a second??? I'm pretty certain it is imposible to do that with the current hardware-well, almost, if you exclud the buffered io Anyway, that would mean... 12GB/s!!.

You have to read that file just once into memory and the use the Windows API's to play the sound. (for example the PlaySound function) [red]Nosferatu[/red]
We are what we eat...
There's no such thing as free meal...
once stated: methane@personal.ro

 

[starn]

Well, I meant 64 bits at 192 kHz...

Now, I m trying to take a sound file with samples of 24 bits for each channel and transform it in the AES/EBU format : 2 channels of 24 bits + 8 bits of control, that makes 64 bits.
AES/EBU is a transport protocol of uncompressed sound but I dont have any reciever for it. So, to test my software, I would like to simulate it : I send to a buffer 64 bits samples at 192 kHz...
That's the only idea I got to do that...

But maybe, for the first step, how do I synchronise the reading from a file?
I don't know, maybe 64 bits every second...

Again sorry for my english and thanks a lot for the help!!

Starn

 

[MKuiper]

As far as I know, it is not possible to sleep or wait for a time less than 1 millisecond in Win32. So I think your only chance is to make an idle loop and measure its time so you can adjust it depending on processor speed. It has to run on real-time priority in order to prevent other processes taking over the cpu, which means that your system is going to be inresponsive. Not a good solution I suppose ..
BTW, who is going to buy a 12 GB disk from someone who claims 192000 * 64 = 12 GB??

 

[starn]

Well,12MB is better... ;-)

Do you know any function that read "x" bytes every "y" microseconds?
There is no other way to play with time other than with CPU speed?
I know that I'm going to have trouble trying to make real-time with Windows... Windows is not a real-time OS like Unix... But there isn't any way to give priority to an application?
(I know, the last question is off-topic...)


Thanks!

Starn

 

[Nosferatu]

Gulp... Yep... Well... uuh... Luckly I'm not selling computers...
Actually I was doing 192K*64/1024... I should divide that again...

No, there is no such function, you have to write it yourself.
I guess that the solution proposed by MK should do it and it would be the best, even if it seems a bit awkward and does not represent necesarly a correct solution, just because the priorities.
On Windows you have a function for that, SetThreadPriority so I suppose there is one on UNIX also.

[red]Nosferatu[/red]
We are what we eat...
There's no such thing as free meal...
once stated: methane@personal.ro