[aravis] Re: Debugging latency & long pause issues with Blackfly camera...
- From: Patrick Doyle <wpdster@xxxxxxxxx>
- To: aravis@xxxxxxxxxxxxx
- Date: Thu, 17 Apr 2014 09:51:35 -0400
After all of that, it turns out that there was a bug in the firmware
in my camera (which has firmware that is newer than that available on
the Point Grey website). Point Grey sent me a new firmware image
(1.31.3.0) and the timestamps now make sense.
Now, on to debugging the lost packets problem… I anticipate that Tom's
suggestion that I increase the network buffer sizes will go a long way
towards making that problem go away.
Emmanuel,
Would you object to a (yet to be written, let alone tested and/or
debugged) patch to add a packet-resend flag to the gst plugin? Now
that I have timestamps working, I am less concerned about dropped
frames, as I will be able to detect those events from the camera
timestamps.
--wpd
On Wed, Apr 16, 2014 at 9:39 AM, Patrick Doyle <wpdster@xxxxxxxxx> wrote:
> Actually, after writing my long email, my long email, I (finally)
> decided to look at the PointGrey documentation. Scanning through
> their Technical Reference manual, I see that they offer the ability to
> encode the timestamp, gain, exposure, brightness, etc… in the first N
> bytes of each image transmitted. They then go on to document the
> timestamp format that gets encoded in the image as being a 32 bit
> integer, where the top 7 bits represent seconds, and wrap around every
> 128 seconds (presumably incrementing the high order 32 bit register
> when they do so, as I observed). The next 13 bits contain a 13-bit
> "Cycle Count" in units of 125 uS that increments from 0 to 7999. And
> the lower order 12 bits contain a "Cycle Offset", which I don't
> understand yet. It seems reasonable that the out-of-band timestamp
> would follow the same format as the in-band data.
>
> Scanning briefly the 3 data logs I collected, I see that the 13 bit
> Cycle Count value increments by 100 for each frame received when I
> (think I) configured the camera at 60 fps, and by 200 for my 30fps
> log.
>
> Hmmm…
>
> --wpd
>
>
> On Wed, Apr 16, 2014 at 9:22 AM, Emmanuel Pacaud <emmanuel@xxxxxxxxx> wrote:
>> Hi,
>>
>> Le mercredi 16 avril 2014 à 09:02 -0400, Patrick Doyle a écrit :
>>> I can think of 3 possibilities:
>>> 1) Handle timestamps from BlackFly cameras as a special case within
>>> the Aravis framework.
>>> 2) Extend the Aravis framework to allow it to report raw timestamps
>>> received from a camera and write my own gstreamer plugin to convert
>>> Blackfin timestamps to ns.
>>> 3) Do something smarter suggested by one of you.
>>
>> A last possibility is to contact PointGrey support and submit what you
>> have observed. It can be a bug in Aravis, but also in the camera
>> firmware. If it is the latest, a fix in the firmware would be the best
>> solution.
>>
>> Cheers,
>>
>> Emmanuel.
>>
>>
Other related posts:
