I am trying to design a Windows KMDF driver for an old USB Webcam.
I think I have enough informations on the driver development / USB protocol side, but I am wondering how I should expose the webcam functionalities from the driver so that Windows program can take advantage of it.
This webcam has 3 functionalities:
a video stream,
an audio stream,
a "take picture" hardware button.
For each of those, what is the more natural way to expose it to Windows, so that my webcam can be used in relevant programs (gTalk, Skype, etc.)? Or, to revert the question: what is expected by those programs, and how do they detect webcams?
When you write a 'WebCam' driver, you should use kernel streaming as your driver model. this provides you with the correct interfaces, so that other programs can communicate with your device through DirectShow/VfW/etc. .
Currently kernel streaming is implemented in the AVStream mini driver base. The WDK contains a AVStream mini driver sample to base your own driver on. The backend to the device can then be implemented using KMDF.
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I have an "off the shelf" commercial software using an ANT USB dongle to communicate with a cycling trainer.
My trainer is not compatible with the software because the protocol is slightly different (not a lot).
My goal is to write a protocol translator. The only thing I can think of is to write a UMDF virtual device driver (like Magic ISO Virtual DVD) looking like an ANT USB Device in the device manager (same PID\VID) while connecting itself to the physical ANT device. The virtual device driver will perform the protocol translation.
I looked at several examples from Microsoft here https://github.com/Microsoft/Windows-driver-samples but I was unable to find anything relevant. I thought this example would be a good start https://github.com/Microsoft/Windows-driver-samples-master/Sensors/CustomSensors but it is impossible to load the driver using the given procedure from the inf file.
BTW I am familiar with the content of INF files and the basics of KMDF & UMDF device drivers programming. My problem is to write something that will load in the device manager and present itself as a real USB device even if it is not enumerated by the USB bus subsystem.
Can anybody with driver development experience point me to some relevant code sample or documentation?
Best regards !
I am currently developing a UMDF CCID (smartcard reader) driver. This project helped me at the beginning because it compiles out of the box and creates virtual device nodes (smartcard readers) visible in the device manager.
I am trying to connect a Bluetooth Low Energy enabled MIDI hardware to wirelessly send data to a Windows PC and get it to detect as a MIDI device in Windows. Currently, the device is able to pair with my Windows 10 laptop and I am able to read the incoming data off of it.
The same hardware is configured and working fine as a wireless MIDI device on Mac and iOS devices(which natively supports MIDI over Bluetooth). I am trying to get this feature implemented on Windows(which doesn't support MIDI over Bluetooth, although it was promised in Windows 10).
The device, when is paired, is showing up in the 'Bluetooth devices' section in device manager, I am trying to make this device showing up as a MIDI device in 'Sound, video and game controllers' section.
Any help/resources somebody can provide to help me crack this problem is highly appreciated.
Following is my current thought process to implement this.
Pair the device and read the data off of it. (Already implemented)
Create a virtual MIDI port. (Don't know how to implement this, I am currently checking out rtpMIDI)
Send the MIDI data which was read from the BLE device to the virtual MIDI port. (Still don't know how to implement this)
Any suggestions/comments on the above thought process as I am absolutely new to Windows Driver Development.
Grabbing the system audio using 'Stereo Mix' is easy, but most modern drivers don't support that anymore. Steam local streaming somehow managed to do it without, i can clearly hear other apps audio output while streaming an arbitrary game.
How does steam do that? Did they silently install a driver? Is there any other way of grabbing system audio?
From Windows 7 and up that is.
From Vista and later you can use WASAPI. It allows to use loopback for any output device, just use an output as an input with the AUDCLNT_STREAMFLAGS_LOOPBACK flag for this function: http://msdn.microsoft.com/en-us/library/windows/desktop/dd370875(v=vs.85).aspx
I would like to experiment with real time audio and was wondering what options are there for accessing audio via a usb port?
I would like to get data from this hardware in an audio stream.
Is this sort of thing best handled by audio frameworks or should the data be fetched using IOKit and passed to e.g. an audio component using a framework?
Also, how is this access effected if e.g. A DAW is accessing the audio from the port? Is dual access handled by the OS?
The specs page for that hardware (Moog Minitaur) doesn't claim that it can transmit audio over USB, only that it has USB MIDI- essentially it has a built in MIDI interface.
If you wanted to get audio from it into your computer you would have to connect it to your computer's line or mic input, or an external soundcard - which may itself connect via USB. One way to handle audio in OSX would be Core Audio. You shouldn't need to write any drivers or anything to deal with the low-level I/O with the soundcard, as the soundcard should come with a driver if there isn't one already in the OS.
I am working on building a USB Video Class camera, which is supposed to work well with various flavours of Windows. The camera needs firmware upgrade support to upload new software images into it. There are two ways to do it, as far as I know.
Use DFU.
Use control endpoint of the UVC Class device to transfer bytes into the device.
To use the second option, it looks like, one needs to write a Filter Driver. Is this correct? Is there any other way to accomplish this task?
There are several ways to do what you want.
The standard UVC Class driver supports a user mode interface, from which you can send USB packets to the device. This interface is called: USB Video Class Extension Units.
Another way is to use WinUSB, where you install the WinUSB driver for your device. After that you can send USB packets through the WinUSB interface.
The most involved solution would be, to write a complete USB driver. Just see the samples in the WDK.