WDM and broadcast

[Jean-Francois]

Hello,

Does somebody have some experience with the QHY broadcast WDM driver ?

What I want to do ? ... I do observations with a spectrometer. The guiding is done on the slit itself with PHD2.
But, it is not possible to zoom on the image in PHD2. The small region around the target is too much processed and so the slit in no more visible.
My idea is to use SharpCap for centring the star in the slit and then to do the guiding with PHD2.
For that it is necessary to disconnect the camera in SharpCap before connecting it in PHD2.

So I tested the WDM Broadcast driver from my QHY camera. It works (not 100%).

The main problem is ... only VGA resolution and only if selected in SharpCap ... so 640x480 is not so much from our several mega-pixels camera.
Is that a "problem" on the PHD2 software side or the WDM driver ?

Is it a way somehow to use the full resolution of the camera with the broadcast driver (and PHD2) ?

Regards,
Jean-Francois

[admin]

Hi Jean-Francois,

try accessing the WDM feed in a second copy of SharpCap to see if that gives you any options to change resolution. Even if different options do not show up in the capture area dropdown, there might be adjustments you can make in the 'Pin Options' window which comes from the QHY WDM driver.

cheers,

Robin

[Jean-Francois]

Hello Robin,

OK, I will try it with a second SharpCap instance.

Jean-Francois

[Jean-Francois]

Hello Robin,

I tired yesterday evening. It works with 2 SharpCap instances.
But, I have the same resolution "selection" ... mean: 640x480, 640x360 or something smaller.
I have the QHY-200 camera with 1920x1080 pixels. It is not so nice to limit.

I can have the full resolution on the camera, but the "transfer" with the WDM driver is downscaled to 640x480.

So I used a ROI with 640x480 on the SharpCap with the camera and so the same image without downscaling on the second SharpCap.
The limitation comes from the WDM driver of the camera ... so not from PHD2 software.

Other not so nice thing ... it works only in 8 bit !

Regards,
Jean-Francois

[admin]

Hi Jean-Francois,

it sounds like those limitations are built into the QHY WDM passthrough code then unfortunately (well, DirectShow is limited to 8 bit, but there's no theoretical reason why the code that makes the virtual WDM camera couldn't take higher bit depth data from the camera and drop it to 8 bit for DirectShow).

I think the WDM driver was written by QHY for live streaming the camera signal while the camera was being controlled by other software. Of course now people just stream the entire desktop, so its probably a feature that doesn't get much attention any more.

I can't think of much else to suggest, unless there happens to be software out there somewhere that makes a fake webcam by grabbing part of the screen?

cheers,

Robin

[Jean-Francois]

Hello Robin,

May be a different manufacturer has a WDM driver with higher resolution.
The point is I will need a new guiding camera ... so I could use a different brand for this new guiding camera. But which one ?

Can somebody try and say me if a different camera with WDM (DirectShow) driver uses the full resolution of the camera ? and in 16 bit ?

As alternative to solve my problem ... I was thinking to use the "Folder Monitor Camera".
But for that the other software (in my case PHD2) shall use this folder as input of the images (or it is the opposite).

Regards,
Jean-Francois

[admin]

Hi,

as far as I know, QHY is the only camera brand that has the 'WDM' passthrough feature, so it's difficult to see what the right solution would be here

cheers,

Robin

[Jean-Francois]

Hello Robin,

OK.
WDM is a "good" thing, but only if it usable with all the camera features. The time of 640x480 resolution is gone !

Concerning the "Folder Monitor Camera" ... it can only works if PHD2 has a "Folder Camera" too.

But I found the "Camera V2 Simulator" ... it takes an image and use it for the guiding.
The problem is ... I can not actualise the image with a new one, while the image stays "open" in PHD2 and Windows does not allow to delete or rename it.

I think it is something possible, like the "Sky-Simulator". I need to contact the PHD2 development team

Regards,
Jean-Francois

[admin]

Hi,

actually, you may be on the right track - SkySimulator ASCOM driver just loads 'image.png' from the sky simulator folder every frame. Normally the separate SkySimulator app re-writes that file as the co-ordinates change, but if you don't use the SkySimulator app and just the ASCOM driver, something else can re-write the image.png file (I think).

cheers,

Robin