Re: [Openexr-devel] OpenEXR image sequence files...

[Drew Hess]

There's been some interest in this, but nothing is being actively
developed, as far as I know.  At SIGGRAPH 2003 I had a few people
approach me after the OpenEXR sketch asking about using OpenEXR for
video, but nothing came of it.

We'd certainly be interested in hearing ideas.  The major issue for us
is that it takes about 400MB/s to stream uncompressed HD-res RGBA
16-bit OpenEXR images, and that's not very practical for an artist's
desktop machine.  Then again, it's not a Herculean effort, either,
just takes a stack of maybe 10-12 7200rpm IDE drives; so for other
markets, like digital cinema, maybe it's not such a big deal.

BTW, you probably want the alpha channel for padding reasons, even
though it costs you another 100MB/s; otherwise, either your app or the
OpenGL driver has to reformat the data as RGBA before sending it to a
16-bit FP pixel shader, since that's the only native 16-bit FP format
that current video cards support.  

I dunno, maybe if you have a 2nd processor you can be doing that one
frame ahead and save on some disk bandwidth while still maintaining
the frame rate to the video card, but it'd be challenging, esp. since
video cards aren't typically able to render while you're downloading
the next texture/frame.  With a fast Pentium 4 or Athlon 64 and an
NV40, I can get about 40fps on HD-res OpenEXR image sequences, but
downloading a texture to the card and rendering it is basically a
serial process -- you can't overlap it.

d



"David Kuo" <address@hidden> writes:

> New to the list. 
>
>  
>
> Don't think this has been discussed before, but is there any effort
> underway to extend OpenEXR to image sequences?
>
>  
>
> I am working on displaying real-time HDR video sequences, and would
> rather not invent yet another file format.
>
>  
>
> David 
>
> _______________________________________________
> Openexr-devel mailing list
> address@hidden
> http://lists.nongnu.org/mailman/listinfo/openexr-devel

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