iDCT, what's the best towards quality

[apfraats]

I know there are quite some options for iDct.

I just wanted the DECODER to produce the most accurate results.

I use setting 64 bit fp, now IEEE setting.

a) What's the best concerning exact picture reproduction for AVISYNTH ?
b) Are all options equal in reproducing exact results ?
c) Is it only a speed iossue, if so what's the fatest ?

Why is this a user setiing after all ???

What can be done with it, pragmatically seen ?

Thanx a lot

[Fishman0919]

Again... something I did sometime back

IDCT SSIM Time
--------------------------------------------
1 32-bit MMX 99.63% 2:15
2 32-bit SSEMMX 99.63% 2:14
3 32-bit SSE2MMX 99.63% 2:14
4 64-bit Floating Point 99.88% 2:41
5 64-bit IEEE-1180 Reference 99.93% 2:52
6 32-bit SSEMMX (Skal) 99.67% 2:11
7 32-bit Simple MMX (XviD) 99.74% 2:12


All idct were compared with a simple script and DGIndex 1.40 rc5 from the movie "The Pacifier"
(I did 4 diff movies but all gave the same results)
and was the first 7000 frames... time is how fast each idct was
encoded with CCE Basic with an AMD 64 3700+ OC (about 4000+)....

LoadPlugin("C:\Test\DGDecode\DGDecode.dll")
mpeg2source("C:\Test\test.D2V",idct=?)
ConvertToYUY2()

and compared dirtectly to the Original D2V file

[dragongodz]

Please read and follow rule 12: do not ask what's best. Thank you.

WOOT! beat neuron2 to another one of these. :D

[apfraats]

Don't forget rule 99, DON'T ASK ANYTHING :)

I did DEFINE what I uderstood regarding to the 'best'.

So rule 12 doesn't apply here.....

My question was defined in detail , so no need for rule 12.

[apfraats]

@fishman0919

Thanks a lot, it answered my question.

IEEE should be the best and also the slowest, that's the way opf live.

Although all results are look-a-like, the IEEE setti g is now prefered by me.

Thanks again !

[neuron2]

iDCT, what's the best towards quality

a) What's the best concerning exact picture reproduction for AVISYNTH ? Two rule 12 violations. Please read and follow forum rules. Thank you.

[dragongodz]

ok was just going to reply that it wasnt up to me but a mod to decide that validity of apfraats arguement but neuron2 has made the judgement already.

so i will say no more.

[Sulik]

Actually, the question of the 'best' idct for a decoder does have a valid answer.
The answer is that the best iDCT in a decoder is to use the exact same idct that was used in the encoder (no mismatches between encoder and decoder).
Unfortunately, if you don't know what encoder the source is using, then the next best option would theoretically be the standard double-precision iDCT as specified in the standard (Different in practice, since most encoders do not use the double-precision iDCT).

[dragongodz]

simply asking what the differences were with the IDCT's and any difference from using them etc would have been fine. however the question "whats best" was asked. i even advised of that before a mod got involved so apfraats could have changed it. apfraats chose to ignore it and neuron2 made the judgement that it was inappropriate. end of story.