[FFmpeg-devel] [PATCH] correct make test failure from 15261 release until now (15899)

Michael Niedermayer michaelni
Fri Nov 21 21:46:08 CET 2008

On Fri, Nov 21, 2008 at 09:15:30PM +0100, Vitor Sessak wrote:
> David Geldreich wrote:
> > Hello Guillaume,
> > 
> > Le 21 nov. 08 ? 17:25, Guillaume POIRIER a ?crit :
> > 
> >> This is not the way to go. Reg tests pass on AMD64/Linux, so the code
> >> must be fixed to work the same on any plateform. The md5sum should not
> >> match X plateform results, but all plateforms result.
> > 
> > That's why I made another post to tell to ignore my proposed patch.
> > 
> > I found no way of making sin/sinf works the same way on all the  
> > platform. In my case, OSX ppc and intel gives different results.
> > 
> > So changes r15261 and r14982 are incomplete ... they correct the  
> > problem for AMD64 but breaks in on Intel32.
> > 
> > We must iterate to find a "stable" sine window generating function.
> Even if we find a way to generate a sine window in an arch-independent 
> way, the codec still uses floating points in other places, so if it ever 
> is bit-identical across PPC and I32, I don't see any reason not to see a 
> different output when testing on ARM or SH or GCC 6.4 or whatever we'll 
> encounter in future. Unless someone tells me why it is supposed to work 
> as is, I think that this test should be removed...

ratecontrol in video uses floats, and other parts do too, we arent seeing
problems with these and arent disabling them

If you argue that the wma test should be disabled because it is not
matching between some important systems, thats something i can understand

but, arguing that itz should be disabled because it might theoretically not
work on some architecture or not yet existing compiler is well ...

And last, id say disable the float code for the regression tests,
replacing the whole fft by a memcpy() if it doesnt match beteen archs
is alot better than removing a regression test.
These tests are important to catch bugs early ...

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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