[gentoo-user] Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[gentoo-user] Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[meino.cramer]

Hi,

the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps
(H.264).

Now I am trying to display (watch) and record the video stream.
Currently I am using guvcview.

Most of the time watching is not an problem: no video delays, no
frame drops, no ultra low fps...wonderful!

But beware of pressing the "record" botton...

KABOOM! guvcview ends with an error message, which does not say
anythong to me...:

(guvcview:19104): Gtk-CRITICAL **: gtk_widget_set_sensitive: assertion 'GTK_IS_WIDGET (widget)' failed
initiating video file context
STREAM: add stream 0 to stream list

I tried "cheese" which interestingly dies similiarily...

Since there a zillions of things to tweak with the video and audio
setting I still hope that someone got this nice camera running and
recording with full hd and audio ....

?

Any ide to fix that?

Best regards,
mcc

[gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[James]

 <meino.cramer <at> gmx.de> writes:


> the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps
> (H.264).
> 
> Now I am trying to display (watch) and record the video stream.
> Currently I am using guvcview.

This 'gstreamer tidbit' might be useful to you:

http://www.oz9aec.net/index.php/gstreamer/473-using-the-logitech-c920-webcam-with-gstreamer



hth,
James

Re: [gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[meino.cramer]

James <wireless@tampabay.rr.com> [14-06-07 17:40]:
>  <meino.cramer <at> gmx.de> writes:
> 
> 
> > the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps
> > (H.264).
> > 
> > Now I am trying to display (watch) and record the video stream.
> > Currently I am using guvcview.
> 
> This 'gstreamer tidbit' might be useful to you:
> 
> http://www.oz9aec.net/index.php/gstreamer/473-using-the-logitech-c920-webcam-with-gstreamer
> 
> 
> 
> hth,
> James
> 
> 
> 
> 
> 
> 

hie James,

Thanks! :)

I found it before...this is the updated, more recent version:
http://www.oz9aec.net/index.php/gstreamer/487-using-the-logitech-c920-webcam-with-gstreamer-12

It works so far as I can view the stream...but cannot trigger a
record.

(Background: I am watching crows with this cam, and if anything
interesting happens I want to press REC to capture everything to
disk)


Bets regards,
mcc

[gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[James]

 <meino.cramer <at> gmx.de> writes:

> I found it before...this is the updated, more recent version:
>
http://www.oz9aec.net/index.php/gstreamer/487-using-the-logitech-c920-webcam-with-gstreamer-12


Thanks, I do not keep current with video anymore....

> It works so far as I can view the stream...but cannot trigger a
> record.

You cannot record with any of several application or just one in
particular?

It seems like I vaguely remember somewhere a howto, to setup
a generic small ram drive to 'enhance' the performance of 
recording on a linux system, but I cannot find the link right now.

I use to have problems with resources where if much of anything else
was using the HD, even though (record) bandwidth of the mobo sata
chip and the drive were no where near the limit, I'd have problems with
sustained video recording. Buffer overload? Registers can't keep up?
Commerical system all have CAM (Content Addressible Memory) to
put the memory on steroids for all sorts of low latency performance
capabilities and gains.... I never tracked down that problem nor found a fix
that was not too expensive. My guess is it would be a customized,
minimized, highly tweaked kernel that would work best for video recording
and latency-bandwidth issues, etc..... I was working on multiple
medium resolution streams. A singular, hi-res video stream might
be even more problematic. It would be an interesting test
to put your recording efforts onto a multi disk (raid) array
specifically tuned for write speed and see if that fixes your issues?
Drop the quality way down and see if you can record then. It that works,
then what I just wrote about is your demon. If not, then it's a bug,
syntax,decoding or other algorithmic issue.....

Dunno.

> (Background: I am watching crows with this cam, and if anything
> interesting happens I want to press REC to capture everything to
> disk)

If you are drawing a paycheck, for watching crows, or just maximizing
crop yeilds, you are my new, favorite hero.......

Black Crows are one of my favs......
Red-headed woodpeckers are a close second....... (we have lots in Florida)

hth,
James

[gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[James]

 <meino.cramer <at> gmx.de> writes:


> the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps
> (H.264).

Some interesting notes and comments at the bottom of this page:

http://www.ideasonboard.org/uvc/


Also, in the past, I have found the best comments on various camera
hardware in the relevant kernel driver. Sometimes that is a unique
driver, other times it is a unified kernel driver for a similar group
of video cameras. Sometimes you can go way back to where the kernel
driver for a given video camera first appeared (got supported) in the linux
kernel for detailed information on the limitations of a given piece
of hardware. Often, the poorer performance on Linux, was intentionally
due to the actions of the manufacturer, particular on max frame rate,
bit minipulations and other key parameter settings of the cameras. Once 
folks learned the protocols (decoded them) on windows, they would make
those adjustments with windows software and reverse engineer the 
driver software so as to be able to support various linux drivers.

Logitech is very reasonable (at least compared to other vendors) but even
there newer hardware rarely works with the best of a given feature set,
until the product has been out for a while. If not, Logitech should
have a published interface specification so and to make reverse engineering
not necessary?

Dunno know the specifics on the model your listing, as I've been out
of that 'game' for a while now, but all those tigers still have the same
stripes....

Good hunting!
hth,
James

Re: [gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[meino.cramer]

James <wireless@tampabay.rr.com> [14-06-07 17:52]:
>  <meino.cramer <at> gmx.de> writes:
> 
> 
> > the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps
> > (H.264).
> 
> Some interesting notes and comments at the bottom of this page:
> 
> http://www.ideasonboard.org/uvc/
> 
> 
> Also, in the past, I have found the best comments on various camera
> hardware in the relevant kernel driver. Sometimes that is a unique
> driver, other times it is a unified kernel driver for a similar group
> of video cameras. Sometimes you can go way back to where the kernel
> driver for a given video camera first appeared (got supported) in the linux
> kernel for detailed information on the limitations of a given piece
> of hardware. Often, the poorer performance on Linux, was intentionally
> due to the actions of the manufacturer, particular on max frame rate,
> bit minipulations and other key parameter settings of the cameras. Once 
> folks learned the protocols (decoded them) on windows, they would make
> those adjustments with windows software and reverse engineer the 
> driver software so as to be able to support various linux drivers.
> 
> Logitech is very reasonable (at least compared to other vendors) but even
> there newer hardware rarely works with the best of a given feature set,
> until the product has been out for a while. If not, Logitech should
> have a published interface specification so and to make reverse engineering
> not necessary?
> 
> Dunno know the specifics on the model your listing, as I've been out
> of that 'game' for a while now, but all those tigers still have the same
> stripes....
> 
> Good hunting!
> hth,
> James
> 
> 
> 
> 

Hi,

I've git "somethiong" working for me:
With vlc "Capture device" and a lot of setting I am able
to wath and record if wanted the stream of the c920.
BUT
There is big delay between audio and video (audio delayed)
and a smaller delay between reality and strem (which doesn't
matter in my case).

How can I fix the delay between video and audio?

Best regards,
mcc

[gentoo-user] Re: Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[James]

 <meino.cramer <at> gmx.de> writes:

> I've git "somethiong" working for me:
> With vlc "Capture device" and a lot of setting I am able
> to wath and record if wanted the stream of the c920.
> BUT
> There is big delay between audio and video (audio delayed)
> and a smaller delay between reality and strem (which doesn't
> matter in my case).

> How can I fix the delay between video and audio?


http://www.videolan.org/developers/x264.html


Is my recommendation to ask the folks for some syntax snippets.
I use to have a link to all sorts of command line examples to
manually filter, convert and perform all sorts of video magic.
I cannot find the link now. These x.264 devs a VLC/videolan are the
best open source h.264 coders around....

good hunting!

James

Re: [gentoo-user] Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[thegeezer]

On 06/07/2014 04:18 PM, meino.cramer@gmx.de wrote:
> Hi,
>
> the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps
> (H.264).
>
> Now I am trying to display (watch) and record the video stream.
> Currently I am using guvcview.
>
> Most of the time watching is not an problem: no video delays, no
> frame drops, no ultra low fps...wonderful!
>
> But beware of pressing the "record" botton...
>
> KABOOM! guvcview ends with an error message, which does not say
> anythong to me...:
>
> (guvcview:19104): Gtk-CRITICAL **: gtk_widget_set_sensitive: assertion 'GTK_IS_WIDGET (widget)' failed
> initiating video file context
> STREAM: add stream 0 to stream list
>
> I tried "cheese" which interestingly dies similiarily...
>
> Since there a zillions of things to tweak with the video and audio
> setting I still hope that someone got this nice camera running and
> recording with full hd and audio ....
>
> ?
>
> Any ide to fix that?
>
> Best regards,
> mcc
>
>
>
>
>
have you tried something like media-video/motion  which would do much of
this for you (although it would qualify "any motion" as "interesting")
i just thought that if it is a daemon in the background always with the
record set this might work ...

Re: [gentoo-user] Logitech C920 HD Pro Webcamera ... view: YES record: NO ?

[meino.cramer]

thegeezer <thegeezer@thegeezer.net> [14-06-10 17:08]:
> On 06/07/2014 04:18 PM, meino.cramer@gmx.de wrote:
> > Hi,
> >
> > the Logitech c920 HD Pro webcam is able to deliver 1920xq080x30fps
> > (H.264).
> >
> > Now I am trying to display (watch) and record the video stream.
> > Currently I am using guvcview.
> >
> > Most of the time watching is not an problem: no video delays, no
> > frame drops, no ultra low fps...wonderful!
> >
> > But beware of pressing the "record" botton...
> >
> > KABOOM! guvcview ends with an error message, which does not say
> > anythong to me...:
> >
> > (guvcview:19104): Gtk-CRITICAL **: gtk_widget_set_sensitive: assertion 'GTK_IS_WIDGET (widget)' failed
> > initiating video file context
> > STREAM: add stream 0 to stream list
> >
> > I tried "cheese" which interestingly dies similiarily...
> >
> > Since there a zillions of things to tweak with the video and audio
> > setting I still hope that someone got this nice camera running and
> > recording with full hd and audio ....
> >
> > ?
> >
> > Any ide to fix that?
> >
> > Best regards,
> > mcc
> >
> >
> >
> >
> >
> have you tried something like media-video/motion  which would do much of
> this for you (although it would qualify "any motion" as "interesting")
> i just thought that if it is a daemon in the background always with the
> record set this might work ...
> 

Thank you for your help !:))

yes, I tried that software with my previous webcam, which does not
offer HD or Full HD as the current one. With my setup (means: may be I
did something wrong...;) it eats too much resources...there is only
one Linux box for me work and for detecting motions and for recording 
video.

The Logitech offers 1920x1080 Full HD HD264, which needs to be decoded
frame by frame, analyzed and when found "interesting" to be recorded
to disc while further analyzing steps are running.

If motion failed (with my setup) to work with """"low res"""" video
streams I dont think that it will successfully run under the load of 
Full HD.

Furthermore there is a delay of ~1 second between "reality" and video
possbly due to not that fast compression hardware in the camera...