Experimental Physics and
Industrial Control System

On 2018-08-30 14:00:01+02:00 Mark Rivers wrote:

?Hinko wrote:


I have some alpha code for taking mjepg from an IP webcam and producing jpegs inside the URLDriver, but I have not fully implement and test it yet due to the lack of time.


By strange coincidence I received the following query from Peter Heesterman yesterday:


Hi Mark,



Could we discuss this?



I now have a second (cheep'n'cheerful) security camera.

It's a Vstarcam C23S<http: www.vstarcam.com="" vstarcam-c23s-1080p-mini-ip-camera-194.html="">, alongside my earlier Panasonic BL-VP101<https: security.panasonic.com="" products="" bl-vp101=""></https:>.



These type of IP cameras usually work with video streaming data (i.e. motion jpeg).



I'm not able to get the newer camera to work with the ADURL module, as it has no 'snap shot' (i.e. single frame) mode.



The older camera works perfectly when using its 'snap shot' mode.

It also has 'streaming mode' (which, likewise, doesn't work with the ADURL module).



I could of course get a different camera, one that has 'snap shot' mode.



But it seems to me that streaming capability could be a valid usage for the module, and make it accessible for a wider range of cameras.



I don't think the existing code parses and paginates the data stream - which it would need to, for this to work.

I believe it just reads data, until the socket connection closes (which is never, in this case).



What do you think, is this a worthwhile objective to pursue?



Thanks,



Peter.




And my reply was:


Hi Peter,



That seems useful.  I don't know much about streaming, but my understanding is that there is both:

- mpeg which is compressed in space and time

- mjpeg which is compressed in space but not in time



Which type does the camera stream?



Mark


It seems like Peter should definitely start with whatever Hinko has already done, and that perhaps it could handle both the stream from an Ethernet Web camera and the stream from /dev/videoX as Bruno suggested.

Mark

________________________________
From: [email protected] <[email protected]> on behalf of Hinko Kocevar <[email protected]>
Sent: Thursday, August 30, 2018 3:15 AM
To: Bruno Martins
Cc: [email protected]; [email protected]; tech-talk
Subject: Re: areaDetector driver for webcams?

Hi Bruno,
You could maybe use ffmpeg, as ffmpegViewer does it, to convert video to series of jpegs.
It is can be found in the this QThread::run():

https://github.com/areaDetector/ffmpegViewer/blob/master/ffmpegWidget/ffmpegWidget.cpp#L110

I have some alpha code for taking mjepg from an IP webcam and producing jpegs inside the URLDriver, but I have not fully implement and test it yet due to the lack of time.

Hope this helps,
Hinko

On 29 Aug 2018, at 20:30, Bruno Martins <[email protected]<mailto:[email protected]>&gt; wrote:

I think Axis webcams export their images on a webpage. I am looking for something to read off of a USB Webcam (that ends up showing up as /dev/videoX on Linux).

Bruno

On Wed, Aug 29, 2018 at 2:27 PM Mark Engbretson <[email protected]<mailto:[email protected]>&gt; wrote:
ADURL reads from webcams such as those from Axis.


From: [email protected]<mailto:[email protected]> <[email protected]<mailto:[email protected]>&gt; On Behalf Of Bruno Martins
Sent: Wednesday, August 29, 2018 1:24 PM
To: tech-talk <[email protected]<mailto:[email protected]>&gt;
Cc: [email protected]<mailto:[email protected]>
Subject: areaDetector driver for webcams?

Hi everyone,
Has anyone developed an areaDetector driver that reads from /dev/videoX on Linux?
Thanks!

Bruno
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