No camera connected – but why?

[happysmash27]

I recently bought an ELP camera for use on a science fair project (one of the cheapest I could find, since I plan to modify it), and am trying to use it with Entangle. It is on /dev/video0, and although it has worked with every single other camera application I have tried, Entangle says that there is no camera connected, and reloading does not help anything.

Does Entangle support the normal UVC interface, or is it for some other type of camera andl/or interface? If it does support it, then what could be stopping it from detecting it on my system?

I am using Gentoo Linux with a freshly compiled kernel to enable UVC support, and used an ebuild to install Entangle, so if there are any compilation options that may have been set wrong, that could be a cause for this too.

Thank you very much!

– happysmash27

[Daniel P. Berrange]

On Tue, Apr 07, 2020 at 07:21:00AM +0000, 'happysmash27' via Entangle Development wrote:
> I recently bought an ELP camera for use on a science fair project (one of
> the cheapest I could find, since I plan to modify it), and am trying to use
> it with Entangle. It is on /dev/video0, and although it has worked with
> every single other camera application I have tried, Entangle says that
> there is no camera connected, and reloading does not help anything.

There are two main standards (and many vendor specific) for camera
control protocols - UVC and PTP2. UVC is commonly used for webcams
or similar video based cameras, while PTP2 is commonly used for still
image cameras, aka DSLRs.

Entangle right now is targetting still image cameras, and so uses the
PTP2 protocol, supported by the libgphoto2 library API.

Since your camera appears on /dev/video0, is is *not* a PTP2 based
camera, but is instead a webcam or similar.

> Does Entangle support the normal UVC interface, or is it for some other
> type of camera andl/or interface? If it does support it, then what could
> be stopping it from detecting it on my system?

At this time, we only support libgphoto2 and PTP. I have long wanted
to add support for UVC to entangle, but there is no ETA for this
feature. So for your camera you'll need to pick a webcam program,
such as Cheese from the GNOME project.

Regards,
Daniel
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