Decoder iDCT for Athlon64 X2 3800+

[^JazzMan^]

What setting should I use for my CPU? Would 64bit IEERE-1180 Reference be most suitable? And how other values affect on the final result?

cheers

[Fishman0919]

iDCT has alittle to do with your type of CPU, it's an algorithm of how accurate the DGDECODE.DLL is to decode.

From the DGDecode User Manual....

Which iDCT you should use depends primarily on what CPU you have and to a lesser degree, on how accurate an iDCT you desire. Most people will not be able to tell the difference in quality between these algorithms but they can be easily observed by combining the AviSynth filters Subtract() and Levels(). All of the available options are IEEE-1180 compliant, except for SSE/MMX (Skal).

Qualitywise: IEEE-1180 Reference > 64-bit Floating Point > Simple MMX (XviD) > Remaining iDCTs.

Speedwise: SSE2/MMX and SSE/MMX (Skal) are usually the fastest. The IEEE-1180 Reference is easily the slowest




so really it's a question of how long do you want to wait for your movie -vs- do you think you can see a difference between the diff idct settings...

I did this test awhile back LINK (http://forum.doom9.org/showthread.php?p=682312#post682312)

Can anyone really see a difference between 99.63% and 99.93% over 7000 frames of video

[feedback]

I was, at one time, using IEEE-1180 Reference but now use SSE/MMX (Skal). I couldn't see any difference in quality except maybe by going frame by frame (But that's just me).

After using the SSE/MMX (Skal) iDCT with NaN's DGDecode 1.1.1, I happily sped up my backup's with RB with no obvious loss in quality... at least not to my 4 eyed self.:)

[rahzel]

i use simple mmx (xvid). seems like a good mix of quality and speed.

[NaN]

In Don's DGDecode I would recommend the MMX/xvid idct, become it's awesome fast at great quality.

If you're using NaNDecode, I recommend idct=6, which is a further developed version of Skal's original idct that is extremely fast AND IEEE1180/Walken compliant - means great quality (even a tad better than xvid/mmx). No more wishes left unfulfilled :-))

Cheers, NaN

PS: if you don't care too much about compliancy, you can use of course also Dmitry's idct (idct=3 in DGDecode 1.4.5).

[Guest]

If you're using NaNDecode, I recommend idct=6, which is a further developed version of Skal's original idct that is extremely fast AND IEEE1180/Walken compliant I wasn't aware of this development. Can you supply the source code for incorporation into DGMPGDec? Thanks.

[rahzel]

which decoder is recommended?

i just use DGDecode 1.4.5 that comes with DVD-RB 1.09.3.

[jdobbs]

That's the recommended one for DVD-RB.

[Jeffster]

That's the recommended one for DVD-RB.
If I'm not mistaken, it isn't supported by the freeware version though, only Pro?

[rahzel]

If I'm not mistaken, it isn't supported by the freeware version though, only Pro?
im pretty sure. this is why the freeware version comes with 1.1.0 i believe.

[jdobbs]

That's correct. The freeware version was designed for v1.10 (or the NaN versions).

[NaN]

Code is already available in the 1.1.1-srcs!

BTW sorry for the late reply!

Cheers, NaN

I wasn't aware of this development. Can you supply the source code for incorporation into DGMPGDec? Thanks.