[aravis] Re: Debugging latency & long pause issues with Blackfly camera...
- From: <tom.cobb@xxxxxxxxxxxxx>
- To: <aravis@xxxxxxxxxxxxx>
- Date: Wed, 16 Apr 2014 08:01:11 +0000
I found that on some systems I had to increase net.core.rmem_default and max
using the instructions in this technical note:
http://www.ptgrey.com/support/kb/index.asp?a=4&q=354
Thanks,
Tom Cobb
> -----Original Message-----
> From: Patrick Doyle [mailto:wpdster@xxxxxxxxx]
> Sent: 15 April 2014 13:39
> To: aravis@xxxxxxxxxxxxx
> Subject: [aravis] Re: Debugging latency & long pause issues with
> Blackfly camera...
>
> Hmmm… I don't think that will address my particular issue. It appears
> that I am not receiving some packets from the camera and that is
> leading to problems. I need to insert a gigabit ethernet sniffer in
> the loop to determine if the camera is not sending the packets (I
> doubt this is the problem), the switch is dropping the packets (I don'
> think this is the problem either), or my embedded board is dropping
> the packets on receipt (I'm guessing this is the problem).
> Unfortunately, my hardware doesn't support jumbo packets, so there is
> ample opportunity to drop packets.
>
> I remain confused by the "do-timestamp" notion. I naively assumed
> that "do-timestamp=true" meant that the gstreamer pipeline would use
> camera timestamps. Now I see that it means the opposite.
>
> For my application (robot navigation), I need the camera timestamp,
> which I hope correlates very strongly with the time at which the image
> frame was captured.
>
> What is it about "do-timestamp=true" that makes things work with your
> blackfly camera?
>
> --wpd
>
>
> On Tue, Apr 15, 2014 at 4:32 AM, Emmanuel Pacaud <emmanuel@xxxxxxxxx>
> wrote:
> > Hi,
> >
> > Le lundi 14 avril 2014 à 21:53 +0200, Emmanuel Pacaud a écrit :
> >> > I'm not asking that anybody solve this (although, if you've seen
> this
> >> > sort of thing with the Blackfly, or other cameras and can tell me
> what
> >> > to fix, you would have my eternal gratitude), but if anybody has
> some
> >> > suggestions as to what I might look at, or what tools I might use,
> to
> >> > diagnose these pauses, I would be grateful.
> >>
> >> I have a blackfly camera with which I face some troubles similar to
> >> yours. I think it's due to the fact the register giving the Time
> Tick
> >> Frequency returns a wrong value. And this value is used to compute
> the
> >> image buffer timestamps.
> >
> > I've changed the viewer in git master to always use host time for
> buffer
> > timestamp. It fixes issues I was seeing using my blackfly camera.
> >
> > Using the gstreamer plugins, do-timestamp=true also allows to work
> with
> > a blackfly camera. It looks like there is around 100ms of latency in
> the
> > following pipeline, but I think it comes from the pipeline itself,
> not
> > aravissrc element:
> >
> > gstreamer 0.10 version:
> >
> > ./gst-aravis-launch aravissrc do-timestamp=true ! video/x-raw-
> gray,bpp=8,depth=8 ! ffmpegcolorspace ! autovideosink
> >
> > gstreamer 1.0 version:
> >
> > ./gst-aravis-launch aravissrc do-timestamp=true ! video/x-
> raw,format=GRAY8 ! videoconvert ! autovideosink
> >
> > Cheers,
> >
> > Emmanuel.
> >
> >
Other related posts:
