[mdlug] Raspberry Pinewood Derby

[David Wood]

Just an idea but what if you made a ramdisk to save the video first and
then transferred it after the video is finished.  Also you could have the
video transcoded when it is moved off of ramdisk.  Not sure how much
performance gain that would get you if any but would be worth testing.

I know the pi only has 512mb if you have the b model but for only a few
seconds of video, you wont need alot of space.


On Mon, Mar 10, 2014 at 12:44 PM, Ingles, Raymond <
Raymond.Ingles at compuware.com> wrote:

> Just for completeness, here's the command line I was using to record the
> video:
>
>      ffmpeg -f video4linux2 -input_format yuyv422 -i /dev/video0 -vcodec
> copy output.mkv
>
> The camera's native format, so far as I can tell, is "YUV2" or "YUYV
> 4:2:2" - hence the input format param.
>
> Before that, I'd set up the camera for the correct format:
>
>     #    Set resolution
>     v4l2-ctl --set-fmt-video=width=320,height=240
>     #    Set frames per second
>     v4l2-ctl --set-parm 75
>
> And, to play it, a little shell script:
>
>
>     #!/bin/sh
>
>     FPS=${1:-15}
>
>     mplayer -vc rawyuy2 -fps $FPS output.mkv
>
> Note, that if it got an arg, it would use that as the desired fps value.
> If no arg, it would default to 15 fps.
>
> If anyone has any tips or suggestions for how to improve this, in
> particular how to get more FPS out of it, I'd be interested.
> ________________________________________
> From: mdlug-bounces at mdlug.org <mdlug-bounces at mdlug.org> on behalf of
> Ingles, Raymond <Raymond.Ingles at compuware.com>
> Sent: Tuesday, March 04, 2014 1:42 PM
> To: MDLUG's Main discussion list
> Subject: Re: [mdlug] Raspberry Pinewood Derby
>
> > From: Mat Enders
> > you could hook the pi up to a holding physical switches on a teeter
> along with something on the start line and capture all of the times
>
> That's my basic plan. Probably some kind of electric eye. The Pi takes a
> little under two seconds to wind up and actually start recording, but the
> runs take about three seconds so that should be enough time.
>
> I didn't get a chance to pull the scripts last night but I'm actually
> curious to see what improvements people might recommend. Really, it's just
> the command line to ffmpeg that's the key. The rest is just setting a few
> video4linux2 parameters and playing the resulting file.
>
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