[FFmpeg-devel] [PATCH] make tiny_psnr work with 32-bit audio
Sun Nov 8 21:29:47 CET 2009
Justin Ruggles wrote:
> 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.
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?
More information about the ffmpeg-devel