[opendtv] Re: 1080p/60 for the people !
- From: Tom Barry <trbarry@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Tue, 31 Mar 2009 05:09:24 -0400
I have no way to verify it but I have wondered if, on faster frame
rates, it would be best to use a full open shutter. This would be 1/60
here. The idea is how well it could aid in simple frame rate
conversions simply by averaging adjacent frames with no motion comp
involved.
For instance, something shot at 240 fps with a 1/240 shutter should be
able to be converted perfectly to an effective 60 fps with a 1/60
shutter just by averaging every 4 frames. The effect should seem like
motion blur, not a double image.
Or you could average 5 out of every 10 frames to get the effect of 24
fps with a 1/48 shutter, again with blur but no multiple images.
Generally if the frame rate is too slow I think I'd prefer the blur. But
I'm not a camera man so I may be overlooking important things here. Any
body that knows, please jump in.
Either way, nice to see more faster rate material appearing.
- Tom
Olivier Houot wrote:
> You may have noticed that some 1080p/60 video samples, shot with a
> consumer camera, have started to appear on the web. See for example :
>
> http://c-kom.homeip.net/review/blog/archives/2009/02/xacti_hd2000_fullhr_mp4play.html
>
>
> To be fair, i can't play them at full speed on my PC, but my two-year
> old cheap graphic card gives me slightly more than 47 fps, at almost no
> processor load (7% or less) in DXVA mode. So just changing it for a more
> recent model in the same price range would certainly allow for full 60p.
> A 25% increase in performance is all that's needed, and for 50P, a
> modest 6 % would do.
>
> My consumer projector handles 1080p/60 through HDMI, and possibly even
> 1080p/75.
>
> So it seems the 1080i/720p compromise is no longer unavoidable, even for
> mass market. The bitrate is 24 Mbps and some, so it could theoretically
> be put in an 8Mhz DVB-T channel, especially considering we would tend to
> use 50P instead (have to check if it is CBR, though). DVB-T2 or
> satellite broadcasts would make it even easier.
>
> Now, as for the quality of the sample, i am under the impression there
> is still a fair amount of motion blur. The shutter speed is probably
> close to 1/60th. I am wondering if 60 fps is high enough to remove any
> limitation on shutter. Could we do 1/125 or 1/1000 without lowering the
> perceived quality of motion ? Provided there is enough light available
> of course.
>
>
>
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