x264 too slow on dual Opteron

[Daodan]

So, my problem is that I tried a movie encode (130 minute movie, Rez 800x384) using MeGui and a script made in Gordianknot (for some reason vdubmod behaved incredibly slow so I tried MeGui instead). I used 8x8 intrasearch, max ref frames 8, no B frames, RDO, exhaustive search, ME 16. My computer has two opteron processors (1800 mhz each) and 2 gb ram. I enabled 2 threads in x264. OS winxp 64 bit edition. The encode was 2000 kbps (I wanted the nearest DVD quality possible). The first pass was made with an average of 3 fps and the second 4.7. I find this to be reaaaly slow compring to nero recode 2.2 AVC, where with the same settings for resolution and bitrate and everything else set to the max I got 25 fps for the first pass and 6 for the second which was almost 3 times faster overall then x264. Is it normal? Were my settings incorrect? I forgot to mention that Nero only used about 55% of my processing power so I could do other useful things in the meantime without interfereng with the encode. Also, is x264 worth it at this speed comparing with Nero, or should I stick with the latter (because I don's think I see any differnece in quality)?

[Doom9]

Hmm.. your settings are borderline insane. More than 5 ref frames really don't make any difference except in the speed area, same goes for the ME algo (even multi hex doesn't make much sense). Using more sensible settings should help speed up things considerably. I'm quite sure your Nero settings are more reasonable than your x264 which should explain the speed difference. But even my X2 4600+ stays below 20 fps using very CPU intensive settings (RDO and 8x8imv).

[Daodan]

So, should I try multihex, or is hex good enough? Also, should I keep B frames off at this bitrate?

[akupenguin]

Hex is usually good enough. But B-frames always help, at all bitrates.

[Daodan]

:thanks:
I tried right now with 5 references, hex search, 2 B-frames, Me of 10 and the first pass goes at about 7 fps which is a big improvement.

[Doom9]

also, there's always the turbo option ;) It does speed up things a lot without visually noticeable degradation.

[nm]

I'm using similar settings on 64-bit Linux (and 64-bit x264) with a 1800MHz A64, and I get 6-8 fps on 704x576 sources for the second pass. Did you really have two threads running?

About the settings: you could use "turbo mode" to speed up the first pass. I don't know how it's done in MeGui, but it shouldn't harm the quality noticeably. You can also set the B-frames maximum to 3 or 4 when using adaptive B-frame decision (which is the default anyway). Pyramid B-frames and weighted prediction increase quality too.

If by "Me of 10" you mean motion search radius, AFAIK it only applies to UMH and exhaustive search and even then the default of 16 is best to be left as it is.

[Daodan]

Thanks for the tips. Indeed I didn't know it's wiser to let ME value to the default 16. I was using version 0.2.2.5 and I see there are some knew features in 0.2.28 like mixed references and RDO lvl2. Is it recomended to turn them on? And another thing, what command in megui stands for 'use b frames as references' in x264 VFW?

[Daodan]

And, yes, I did use two threads.

[Doom9]

what command in megui stands for 'use b frames as references' in x264 VFW?pyramid
I see there are some knew features in 0.2.28 like mixed references and RDO lvl2. Is it recomended to turn them on? there's a thread about each of those features so I suggest you read up on them, then make up your own mind ;)

[Daodan]

[QUOTE=Doom9
there's a thread about each of those features so I suggest you read up on them, then make up your own mind ;)[/QUOTE]
Good idea. i seem to be quite outdated anyway. :scared: