[libdv-dev] Re: libdv changes

[Erik W. <om...@cs...>]

On Thu, 27 Apr 2000, Scott F. Johnston wrote:

> I've played around some more with my changes.
> I was puzzled to see that the ycrcb to rgb conversion
> is taking up 25% of the run-time. This seems long.
> I was able to eek out a few percent, but nothing major.
Yeah, it's slow by definition, and C doesn't help.  I hope to get a 4:1:1
version of my MMX routine ready at some point, which should reduce it from
~30 cycles/pixel to about 7.5.

> The "unshuffle" routine isn't taking up much CPU,
> so there's no need to convert it into a table yet.
> We've got bigger fish to fry.
Sounds good.

> If you want to keep track of the dif sequence number and
> dif blocks by counting rather than pulling from the headers,
> that's fine, but I'd rather keep them "difseq" and "difblock"
> identifiers rather than (i,j,k) indices.
I do want to use the ID fields, but have the option of keeping track
somehow.  This morning I was suggesting an API that allows mutliple calls
to the decode routine per frame, which would be good for streaming, and
which requires the ID fields be used.

> I'm sure we'll use bitstream when decoding the other blocks,
> I'm just doing the initial fread to pull it into a buffer,
> as is done for the video blocks.
OK, that'll change once we have a more stable API for the library...

> Nice ducks.
Yeah, tell that to the property managers.  They tried to get rid of them
(there are a *lot*).  They failed.

> P.S. Do you like the Elura? I was thinking of getting a Sony PC-100,
> but I don't like where they put the zoom.
I think it's a nice camera.  The zoom on the Elura is in a reasonably sane
position, not sure if the PC-100 is the same.  In general most of the
controls are properly placed, given the hand position.  The two major
problems with the Elura are the upwards-pointing microphone (yeah, I
really want to hear the ballast of our flourescents over the *actual*
*scene*...), and the lack of certain connectors without attaching a
(presumably) bulbous 'dock' onto the bottom.

         Erik Walthinsen <om...@cs...> - Staff Programmer @ OGI
        Quasar project - http://www.cse.ogi.edu/DISC/projects/quasar/
   Video4Linux Two drivers and stuff - http://www.cse.ogi.edu/~omega/v4l2/
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