Few mencoder questions

[N715DP]

I have some questions as to what the best options are and what the following things do and when they should/should not be used:

Denoise
Dering
Deblock
Use B frames
4 motion vectors
Trellis qantization
Quarter pixel ME

If someone can lay out what the above stuff does, I would greatly appreciate it.

[tbluewater]

I have some questions as to what the best options are and what the following things do and when they should/should not be used:

Denoise
Dering
Deblock
Use B frames
4 motion vectors
Trellis qantization
Quarter pixel ME

If someone can lay out what the above stuff does, I would greatly appreciate it.

Look them up for yourself.

[N715DP]

I did, thank you. I was hoping that someone would be able to provide some real-world insight rather than the minimal technogarble I was able to cull from man pages and various google searches.

Why did you waste the time to post if you didn't want to help? If you don't have something to contribute other than attitude, why contribute (if you can call it that) at all?

[tbluewater]

I did, thank you. I was hoping that someone would be able to provide some real-world insight rather than the minimal technogarble I was able to cull from man pages and various google searches.

Why did you waste the time to post if you didn't want to help? If you don't have something to contribute other than attitude, why contribute (if you can call it that) at all?

Open your eyes, silly. I post more comments to help people than anybody here except Major the Admin and Case. I also offer two dozen free VTCs for ffmpegx and other applications to assist mostly Mac users. So what are your contributions?

[etruscan]

VTC lookup ... Virtual Teaching Center, Virtual Training Co., Vermont Technical College, Vehicular Technology Conference, Visual Thought Communication.... Nope, it must be "video." Let's see: Video Tutorial Center, Video Training Ca-something.... I give up.

Truth is, I've looked up the terms too and derived a basic understanding of what they mean. And I end up experimenting and applying them haphazardly sometimes.

Quarter pixel (Qpel?) is poison for some standalone DivX players. I don't see much noise or rings, but deblock is sometimes useful when you have scenes full of motion that are "blocky." How to avoid blockiness when encoding is a mystery - unless it's a question of a higher bit rate. How minimum and maximum quantization affects this (if at all) is also a mystery to me.

As for B Frames and 4-Motion Vectors and Trellis quantizations, my guess is as good as N715DP's. They are all mentioned briefly in the manual (which I've read four or five times at least). But barring some "real world insight," I don't use them.

[tbluewater]

As for B Frames and 4-Motion Vectors and Trellis quantizations, my guess is as good as N715DP's. They are all mentioned briefly in the manual (which I've read four or five times at least). But barring some "real world insight," I don't use them.

ggggg... You should apply B-frames if you want quality.

[N715DP]

Thank you (both) for the information so far.

I assume applying these options (all or some) would slow down the encoding proccess, is that correct? I am currently using (in options), high quality and 2-pass. I would like to squeak out as high a quality as possible at the bitrate I have set up. Encoding time is not all that important to me as my iMac runs over night to do it and it's one of the new Intel's that can move pretty quick (what a jump from the iBook G4 I had).

If turning on some of these options will bump the quality without changing the filesize, that would be great.

[N715DP]

I'm sorry, one other one I was looking at...

The scaling method, it defaults to fast bilinear... are the options below it (bicubic, lanczos) also quality enhancers (at the cost of encoding speed)?


Thanks again.

[Case]

The scaling method

I've tested those 5 months ago, and wrote a piece about it. The (externally hosted) pictures and links don't work anymore, but it should still provide some fairly good comparison.

[N715DP]

The scaling method

I've tested those 5 months ago, and wrote a piece about it. The (externally hosted) pictures and links don't work anymore, but it should still provide some fairly good comparison.

This was a great read, even without the images, thanks! It appears that overall, there is no need to juice this particular setting all the way up. Good stuff. Thanks!

[etruscan]

Wow! That really needs to go on a website! Oh, it is ;-) Pity we've lost the images.

>ggggg... You should apply B-frames if you want quality.

Guess I'll have to test this one m'self. My particular bugbear is burning subtitles. I need the highest quality because after burning them in I still have to reencode yet again for standalone player compatibility:

2) Mpeg4 avi (mencoder) at excess video bitrate because I don't want
compression when I'm burning the subs in - with 3-pass encoding (have
to wait for the manual selection of bitrate).

3) ffmppegX xvid 2-pass encoding to get the desired compatible file at specified size.

Maybe one day there'll be a lossless video preset except where the subs get "pasted" on.

(Apologies for my VTC rant. Verbosity helps more users)

[t42]

Could someone please explain the job of comparison functions? What are they "comparing"? What is their mathematical sense?