[FFmpeg-devel] [PATCH] make tiny_psnr work with 32-bit audio

Justin Ruggles justin.ruggles
Sun Nov 8 21:29:47 CET 2009

Justin Ruggles wrote:

> Hi,
> I was trying to do some comparisons with 32-bit audio, but tiny_psnr
> kept crashing with a float exception.  Then I noticed it does not really
> support 32-bit integer comparisons.  The attached patch seems to work.
> -Justin

Hmmm...  Most of the regression tests fail with this patch because of:

-        psnr= ((2*log16(max<<16) + log16(i) - log16(sse))*284619LL*F +
(1<<31)) / (1LL<<32);
+        psnr= ((2*log16(max<<16) + log16(i) - log16(sse))*284619LL*F +
(1LL<<31)) / (1LL<<32);

Looking at an objdump of tiny_psnr.o, it appears that the compiler is
treating (1 << 31) as a 32-bit integer (with a negative value), then
sign extending it to 64-bit.  Is that what is meant to happen?


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