[mdlug] Raspberry Pinewood Derby

Dan Pritts danno at dogcheese.net
Thu Mar 13 16:21:14 EDT 2014


On Mar 11, 2014, at 8:37 AM, Ingles, Raymond <Raymond.Ingles at compuware.com> wrote:
> What I'd like is to be able to record more frames per second. 

Make sure that whatever storage you are using isn’t getting pegged.  It’s quite possible you haven’t overwhelmed the USB but rather the storage bandwidth.  

I found something online that said YUV2 video is effectively 16 bits/pixel.  at 75fps that works out to 11.5Mbytes/sec (= 92Mbit/s).  

USB is notorious for not providding the rated 480Mbit/sec, I don’t know how much you can really expect to get - maybe you are really maxing out the USB.    But, 11.5MB/sec also sounds suspiciously like a slow thumb drive or SD card.

a usb disk drive (honest to goodness spinning disk) would be a simple way to test.   Any disk drive made in the last 5 years can handle more than that.   Most drives for the 5 years before that can too.  

danno


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