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Old 27th August 2009, 17:49   #1  |  Link
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Megui Experience - All modes with all presets

Firstly, please excuse me for my bad English.
Secondly, I'm not sure if anyone who actually reads in this forum will find any this stuff useful.
Thirdly, I don't know much about x264 and some terms I use may sound strange/plane wrong to you. Not professional.. Please have patience with me.
Fourthly, If you want correct me or post suggestions for better ways to compare speed, please do!

I was wondering what all the differences of all the different presets realy do regarding speed and different modes.
How much faster is faster compared to fast etc.? Basicaly, all the stuff you can choose without going too much into advanced options and those where only used if I realy "needed it" for any reason.

Stats are fun!
Long post but this might be interesting for some. Specially for those who have read "Use the preset system" in X264 Encoding Suggestions:
(I won't do these with Turbo for 2&3pass, see below why)
#Without convertoYV12:

#The Megui log log for all 72 jobs - if anyone wants to do the math better and whosoever can use it (the stuff that I see people post in this forum as code and what makes posts scrollable): Log.txt (rapidshare)
#With converttoYV12: Graph.png (messy, explained below)

Only a snapshot of the current state of the latest versions of x264 and megui I was able to grab then. Since Revision 1232 sse 'n stuff things may be faster already.

My test-setup:
AMD Phenom(tm) 9950 Quad-Core Processor 2,60GHz
Windows Vista(tm) Ultimate 64bit Service Pack 2, using x264 *32bit x264 Revision 1232 from x264.nl
Megui core latest what I got from Kurtnoise's update url via Megui Update. (Would be awesome to use Megui with x264 *64bit by default.). At the time I started testing, the megui.exe from x264.nl had no preset slider and I realy wanted to use it.
10104 frames, 25fps, 1280x720

# It was realy fun to slide threw the presets, naming and saving them, queue the output file, started the job and 5 seconds later, another preset was selected and queued. This stuff is addicting and it urged me to do tests.

# I'm kinda missing "almost fast", "almost medium", "little slower", "almost slower". "slooower", "sloooooower", maybe "very slow ultra" & placebo≤, placebo≥. 15 presets from the people who know what they are doing, just 6 more like those sane already implemented ones..
that would be wonderful! There is so much potential provided by x264 together with Megui's preset slider and it can't be bad for CLI users, if they use presets at all.

# When I notices almost no difference between faster, very fast & ultra fast I learned that converttoYV12 alone took alot of CPU-Power. It seemed I was limited to 40fps max. Without converting its like a 70FPS limit. With converting my system slowed down (browser and windows opening took up to 40 sec slowly) accept with placebo and ABR selected.
Filesizes uncompressed: with YV12 = 13GB, YCbCr = 26GB. This may explain everything, maybe.

# I might be wrong, but Megui set no --mbtree and thereby overrides the default preset setting of --mbtree from fast to Placebo. I've left it like that. Being aware of not using a "stable" Megui version. CLI user would never experience this.

Some more information about the test-setup:

Source: 1280x720, 25fps 10104 frames, uncompressed. (formerly compressed xvid.avi 10000kbits made uncompressed and denoised via VirtualDub).
To have a quick look: Youtube HD (Fanvideo about a HL2 Mod)

1) Source in YV12 no-mbtree?:

About differences in some modes regarding output-file-size:
Const. Quality: x264 revision 1232
1 = Ultra Fast; 2 = Very Fast; 3 = Faster; 4 = Fast; 5 = Medium; 6 = Slow; 7 = Slower; 8 = Very Slow; 9 = Placebo
preset / size:
1 -357MB, 2 - 263MB, 262 - 174MB, 4 - 180MB, 5 - 181MB, 6 - 174MB, 7 - 170MB, 8 - 162MB, 9 - 9905 - 164MB

Const. Quantizer: revision 1232
preset / size:
1 - 410MB, 2 - 282MB, 3 - 253MB, 4 - 259MB, 5 - 261MB, 6 - 254MB, 7 - 249MB, 8 - 248MB, 9 - 250MB

ABR VBV Buffer Size 1204, VBV Maximum Bitrate 2151, x264 Revision 1232
only very little change in output-file-size. (from 58,1MB to 53,4MB)

2) With converttoYV12, no-mbtree?:
This just revealed my former and current ignorance regarding uncompressed Sources, Avisynth and what that does to encoding speed on my system setup.
In Automated 3pass the first pass was fast with preset Placebo for any reason.
Placebo mostly produced an error with 16 B-Frames and I've had to lower them to 15 or 14. Therefore, the speed doesn't represent the default preset. Once only 10 sec from the beginning were encoded correctly and the rest of the video was a pretty good compressed series of black frames. Realy anoying, kinda funny, but frustrating for sure.
I think it was a videobuffer problem or so and it blocked processes. Sorry, I didn't realy care at that moment.

I will never ever again convert uncompressed YCbCr to YV12 with the same avisynth script used for encoding with x264.
I doubt you want to do the tests with my source, but you can download it from Megaupload or splitted into 10x50mb or from my MSN Skydrive

*No tune settings used
*'Cause I'm a looser when it comes to scripting, it may take a while until any image comparisons are done (If I ever do that.. there is so much already about quality on this forum)
Just a small note:
Seriously. Good job on the no-mbtree and the lookahead and whatever improved quality that much in this month. I can imagine what it will be like when B-Pyramid and weightedp or whatever may be implemented or made to work again.. NOT.

That would be it. I had much fun and I haven't touched tune settings yet. I missed turbo fast-pass too but any other testings may occur on a stable Megui and a newer x264 Build/Revision/Version..
I don't think that anybody reads all this, but now I want to say thanks to the people who were and are involved in creating and developing x264 as well as Megui again. You guys do mind blowing stuff. Thanks so much and please keep up the good work! =)

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Old 27th August 2009, 17:58   #2  |  Link
Dark Shikari
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The minimal difference among the fastest settings suggests that you are bottlenecked in reading the file from disk. My tests show ultrafast as up to twice as fast as veryfast.
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Old 28th August 2009, 16:52   #3  |  Link
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Originally Posted by Dark Shikari View Post
The minimal difference among the fastest settings suggests that you are bottlenecked in reading the file from disk. My tests show ultrafast as up to twice as fast as veryfast.
Yes, I think so.
I've tested the xvid-source.avi without converting it into any lossless format and Ultra Fast was 21% faster than very fast. But very fast took longer to finish and faster took even longer than from uncompressed YV12. Maybe it's a good idea to learn a little about decoding, source-files and much more about converting for future tests. ^^
As I've said, nothing professional.

And wow! I've found out that loading the source from my velociraptor is way slower than loading it from the 7200ups HDD.. bummer.. but that's another topic..

Last edited by Teddl; 28th August 2009 at 17:19.
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comparison, megui, mode, presets, speed

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