[Elphel-support] change camera parameters through Telnet

Fri Dec 14 00:42:22 PST 2012

Oleg
the delay of Gstreamer is 40ms which is a frame at 25fps while this might
contribute It's not the bigger contributor

how do I see the speed of my WiFi in my laptop?
-----------------------------
if 3 frames are lost (in the worst case example) this means that at 25fps:
3frames * 40ms = 120ms this still is way under the delay times I'm
experiencing, the question still is that the downloading of a file in the
middle of the process stops the process until it's finished

if there are other php programs that "might be quicker" what are their
limitations? and how do I use them in order to change parameters in the
camera?

2012/12/14 support-list <support-list at support.elphel.com>

> **
> Biel,
>
> so it is not the Python script?
>
> parsedit.php is a development tool - for quite a while it did not have GET
> mode, and by default it schedules the parameter modification to 3 frames in
> the future (you may use EXPOS=1000*0 to overwrite that, but the frame +0
> will to be affected anyway - 2 frames will be lost in the sensor) - the
> longest delay it may take the sensor (different commands have different
> latency). Actually parsedit.php allows you to make multiple parameter
> changes at different frames and then open 9 last images with the parameter
> values below so you can troubleshoot latencies.
> 3 frames will take 12 ms, the rest may be the laptop opening and running
> wget.
>
> Andrey
>
>
> ---- On Thu, 13 Dec 2012 17:10:06 -0800 *Biel Bestué de Luna<
> 7318.tk at gmail.com>* wrote ----
>
> ok,
>
> about the wget:
>
> I'm currently using a WAN router attached to the camera, I connect the
> camera to it via ethrnet, and I connect my laptop to the router via WiFi
>
> then I setup the camera to triggered in order to have a fixed rate of 25
> fps with the API I talked before
>
> I open a real time stream with gstreamer at low latency in my laptop to
> see the real time reaction:
>
> "gst-launch-0.10 rtspsrc location=rtsp://elphel:554 protocols=0x00000001
> latency=40 ! rtpjpegdepay ! jpegdec ! queue ! xvimagesink"
>
> then I open the terminal and write this:
>
> "wget --delete-after 'http://elphel/parsedit.php?immediate&EXPOS=100&'"
>
> (EXPOS at some strange value so I see the change easily)
>
> I see the change 1 second after I touch intro
>
>
>
> 2012/12/14 support-list <support-list at support.elphel.com>
>
> **
> Biel,
>
> It will be quite a work to do a C program - as I said the easiest will be
> to adapt the php extension code (written in C). But agan - I do not think
> you'll get much of the performance gain (if any) compared to PHP - we use
> it ourselves and it is fast.
>
> Andrey
>
>
>
>
> ---- On Thu, 13 Dec 2012 15:51:45 -0800 *Biel Bestué de Luna<
> 7318.tk at gmail.com>* wrote ----
>
> Andrey
> you talked before about the possibility to create a C coded program, how
> would someone interact with that program would that be a daemon like the
> php application seems to be working? if so would it be any better than php
> resource-wise?
>
> if a C coded application could be added in order to cover this rapid
> control and data acces, could both applications (php application and C
> coded application) coexists using the same parameters? so if you change
> EXPOS via wget you see the change right away in the C coded program and
> vice versa...
> so both applications would cover diferent usages of the camera, one could
> cover the current usage, where you can do everythin in camera, and the
> other would cover a more service-like usage where the camera serves the
> purpose of recording/shooting device, and other functions remain in another
> computer not inside the camera. what do you think?
>
>
> 2012/12/14 support-list <support-list at support.elphel.com>
>
> **
>
> > the idea was to unload that work from the camera, and leave all the
> important processing to the external computer,
>  Yes, we do the same with Eyesis, there is a lot of processing, but PHP is
> still used in to control the camera
>
>
> > like Flavio Soares does, he deactivates the php functions of the camera
> so it can record at a higher quality jpeg compression.
> What does "deactivates the php functions of the camera" mean?
>
> He does not use the camera GUI? Yes, that GUI is rather slow, but not
> slower that it was before the PHP was implemented in the camera (camvc is
> rather old - at least 6-7 years).
>
> Using PHP in the camera is the fastest way to control it. Of course, if
> you will run Drupal there - it will be terribly slow, but just changing few
> parameters you really need - it will be faster than telnet.
>
>
> > what would be cool would be to have an abstraction layer that would
> cover that kind of usage of the camera, for rapid interaction with the
> camera.
>
> Camera control functionality is implemented in PHP extension -
> http://wiki.elphel.com/index.php?title=PHP_in_Elphel_cameras . Any simple
> "API" like in many cameras would definitely limit the functionality, so we
> decided that user can make her own API, coding it in PHP. It can be
> universal, but big and likely slow. Or it can be tailored to particular
> application - and be really fast.
>
> Andrey
>
>
> _______________________________________________
> Support-list mailing list
> Support-list at support.elphel.com
> http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
>
>
>
> _______________________________________________
> Support-list mailing list
> Support-list at support.elphel.com
> http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
>
>
>
> _______________________________________________
> Support-list mailing list
> Support-list at support.elphel.com
> http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://support.elphel.com/pipermail/support-list_support.elphel.com/attachments/20121214/5efce0c6/attachment-0002.html>