There are a large number of variables that will affect the size of your files 
when doing capture. Resolution, framerate, and encoder settings are the 
biggest. As an example a recording I did with the "fast" preset of x264 of a 
powerpoint presentation with a video segment at the end was 10MB per minute 
roughly. This was captured at 30 FPS and 1024x768, so a bit smaller than 720p.

The tests that I conducted were anywhere from 0.1 to 0.03 bits per pixel per 
frame depending on settings, content and frame rate. This works out to ~33 MB 
per minute for 1080p content, to ~10MB per minute on the low end for a 
powerpoint slideshow.

For most codecs this fluctuation is very dependent on content, when dealing 
with x264. The large size samples I mentioned above were taken from a high 
motion movie trailer, with lots of action, fast cuts, and very differential 
content frame by frame. Where the powerpoint mention was probably 90 percent 
static content and could very well be less than 10 MB per minute.

I guess in summary I would like to reiterate that there are a lot of factors to 
consider, and that they can have a large impact on your file sizes. I feel that 
under most circumstances the larger the size video you can get away with, the 
better. You should target your expected file size toward your expected storage 
capacity and recording volume.

Micah

On Sep 23, 2011, at 9:40 AM, Steven M Lichti wrote:

> Hi all,
> 
> I know some of you are doing HD capture this semester. Can you provide me 
> with the approximate file sizes (or mpeg 2 or x264 file sizes) of your video 
> recordings, and whether they are 720p or 1080p?
> 
> We're planning to begin our testing soon, and would like to know what to 
> expect…
> 
> Thank you!
> 
> --Steven.
> 
> -- 
> Steven Lichti
> Academic Technologies
> Northwestern University
> [email protected]
> (847) 467-7805
> 
> _______________________________________________
> Matterhorn-users mailing list
> [email protected]
> http://lists.opencastproject.org/mailman/listinfo/matterhorn-users

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