[aravis] Re: Debugging latency & long pause issues with Blackfly camera...
- From: Emmanuel Pacaud <emmanuel@xxxxxxxxx>
- To: aravis@xxxxxxxxxxxxx
- Date: Tue, 15 Apr 2014 15:52:46 +0200
Hi,
Le mardi 15 avril 2014 à 08:39 -0400, Patrick Doyle a écrit :
> 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.
For debugging, I'd suggest you to use ./test/arv-camera-test. It will
let you disable packet resend, using -r option. You can also enable the
debug output using option -d. "-d all" is a good start.
> 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?
The problem with the blackfly camera I own (a BFLY-PGE-14S2C-CS) is the
camera timestamp is wrong. The camera send in the image packet a
timestamp expressed as timing ticks. Aravis then use the content of the
register TimingTickFrequency in order to compute the timestamp in
nanosecond. Unfortunately, TimingTickFrequency register returns a wrong
value, and then the timestamp in nanosecond is also wrong.
The symptom on my setup is, before my fix, the viewer only chown the
first image.
Cheers,
Emmanuel.
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