Re: [libusb] Integrating libusb library with a QT application

[Tim R. <ti...@pr...>]

On 7/29/24 3:39 PM, Fares MAHJOUB wrote:

> First of all thank you Tim for responding.
> Ok let me make my situation clear . I have an audio digital signal 
> coming from a microphone on the device. I'm streaming an FFT(Fast 
> Fourrier Transform) of this signal digital throught a Usb interface. 
> The interface uses 5 endpoints (4 input and one output) the 
> input/output is as you know from the host perspective. The usb device 
> driver uses a bulk transfer to stream the FFT data. From the device 
> side i'm ok but from the host side i want to receive the FFT data and 
> plot it (amplitude on the y axe and frequency on the x axe) using a QT 
> graphical user interface application. I just want at least to stream a 
> constant string "hello world" and then plot it on a graphical 
> interface. How can the libusb library
> be helpful in receiving the data stream using bulk transfer and how 
> can it work along with the QT framework ?

Don't worry too much about integrating.  You really have two separate 
problems: getting a continuous data stream from the device, and 
displaying FFT data.  I'd advise you to think about them separately.  
There are a LOT of sample Qt apps on the internet, including many that 
do different kind of graphing.  So, make an application that can plot a 
data buffer in a way that shows you what you want to learn.  Then, make 
a class that uses libusb to do a "continuous reader" to fetch the data.  
Again, there are examples of such apps on the internet.  Once you have 
the two, it should be easy to hook them together.

-- 
Tim Roberts,ti...@pr...
Providenza & Boekelheide, Inc.