Re: YUV format

On Thu, 26 Dec 2002, Holger Waechtler wrote:

> Ed Okerson wrote:
> >
> > I thought 3D wavelets included the temporal domain as the 3rd dimension.
>
> You can enable this by defining N_FRAMES in tarkin.c to anything > 1.
> IIRC it was hardcoded to 1 because the time domain transform did not
> gained much - we saw that a 'real' motion compensation would be needed.

Any value here above 4 causes the encoder to seg fault.  And any value
above 1 causes the sdl player to crash before displaying anything.

> > I switch to a different source file, and it is more obvious what is
> > happening.  It appears first as some random noise on the picture and then
> > the noise level goes up exponentially until it is nothing but random noise
> > over the entire image.
>
> Hmm, I just was running a few frames from the venuscubes test sequence
> again, I had about the same results as I remembered:

I am using actual video clips that we use to test other codecs with.
Video shorts, movie trailers and movie scenes, etc.

> First: you want to modify the CFLAGS in the Makefile to enable
> optimisations (-O3 instead of -O0) and disable debug checks and
> assertions. Then I was running something like this:
>
> $  ./tarkin_enc <path>/AnimSpace0000%01d.ppm 3000 4 4
>
> which means that we encode the first 10 frames from venuscube sequence
> at about 3kBytes per encoded frame using (4,4)-wavelets. When I piped
> the status messages to /dev/null it needed about 2 seconds on my old
> vaio at ~500MHz.

Hmm, this may be a clue.  The video degradation only becomes obvious
around frame 12, but by frame 30 the original image is indistiguishable.
If you are only running 10 frame, you would probably never see it.  Also,
image quality is very poor at anything less than about 80000.

Ed Okerson

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