tips for low bitrate encoding with megui x264

[forum king]

Hey ya folks :)
i have asked this question at a lot of forums but still things are not at all clear so i am starting from scratch and posting in this section .
i like to compress my stuff as much as i can : using megui and using x264 profiles, i have a few questions:

let us set aside the type of sources i mean dvds or Hd sources ..

1.. which filters will give good results ( i mean denoisers, and all ) when used with x264 in low bitrate encoding.
2.. which preset ( from the latest ones ) or x264 settings are suitable for low bitarte encoding
3.. which is the most stable and low bitarte suitable build we are having here for x264.

Please suggest guys and should there be any change in encoder settings at low bitrartes when encoding SD sources and HD sources.

Regards

Glenn

[mariush]

Skip MeGUI and just run:

x264 --preset placebo --tune film --pass 1 --bitrate ### -o output.mkv input.avi
x264 --preset placebo --tune film --pass 2 --bitrate ### -o output.mkv input.avi

[Blue_MiSfit]

Well, some people need a GUI, and --preset placebo is a terrible idea unless you're a masochist. MeGUI is fine, just make sure to use the latest patched build. Old release builds aren't compatible with x264's "new" presets / profiles / tuning system.

Use the slowest preset you can stand, but I wouldn't personally go lower than --preset slower for anything other than mastering purposes.

If you're targeting low bitrate, it's generally a good idea to reduce the resolution of the source. Also, denoising filters are usually a good idea, especially with grainy sources.

For fast results, I would suggest DeGrainMedian, with relatively high settings. It's very very fast, and will give a substantial compressibility boost. It does chew up the source somewhat, so I'd use fft3dfilter/fft3dgpu or MDegrain2 if you have the CPU time to spare.

There are no specific builds optimized for low bitrate. Just use the latest official build.

Remember "low bitrate" is a relative term. To some, 3mbps is a low bitrate for 720p, and for some this is a high bitrate. Also, 3mbps may be very low for a given source, and complete overkill for others.

If you have issues with a specific source, you can always post a sample.

~MiSfit

[forum king]

Thanks folks :) by low bitare i mean 500 to 900
what i am doing atm is :
using latest core from stable servers
latest stable update of x264
settings : 2 pass , high profile, threads=0 , preset slower, - things that i have twaeked = b frame 3 , ref frames 8 , adaptive bframes : 2 optimal, subme : 9 , ME : multihex ,
could u folks tell me if i am doing an over kill ?
and could u tell me how to use the filters , i mean first should i add thge plugin to avisynth ? also could u tell me how to give the values and all to the filters ?

[Guest]

and could u tell me how to use the filters Which filters? Have you read their help files and the Wiki information?

[osgZach]

I use preset Placebo and some other slow settings and its not really THAT big a deal.. To me anyway. I can do a 2-pass in less than 3 hours on a typical Anime episode.. works for me I guess :D

King,

You may want to consider just sticking with a good round number like 1000kbps. Unless you are planning to watch the output on a TV with a hardware player or via TV-out from your PC. Otherwise when you start dropping below 1,000 and try to watch something SD in full screen mode, you are really gonna be dissapointed with the quality. Although its NOT bad, its not the best either.

If you are watching on a TV you can get away with something around 600 - 800kbps for very decent quality. And the file sizes will be nice too. For HD content - I have no idea, however.

As for filter settings, that entirely depends on your source quality and what you want to do to it. You won't increase quality by filtering something, in the sense that you gain more detail. But you can clean up a video by removing grain, smoothing some things, and sharpening some things, depending on what's needed.. That will gain you compressibility. But we could spend all day talking about filters unless you can list a specific need.

If you just want to remove some grain or noise, you could use x264's internal filtering for that (I think you can only pick one though). Not much custom control there though, but it may do the job fine for you.

[Forteen88]

Thanks folks :) by low bitrate i mean 500 to 900Never do HD-encodes at this low bitrate, that only leads to macroblocking.