Better quality at low-ish bitrate...

[Raydancer]

First off, I'd like to say that Crunchie is a very fine app. I've downloaded at least a dozen xvid related tools in the past week or two and Crunchie does exactly what I'd been looking for...and with such little effort on my part.

My only problem is that the avi's Crunchie has produced for me are not quite on par with other xvid compressed videos I've seen. Are there any tweaks I could add to Crunchie's ini file to achieve better quality (i.e. less artifacting) without raising the bitrate or lowering the resolution?

Anything would be helpful...I'm new at this encoding stuff and it's quite a bit to soak in.

For information purposes, I'm capturing to 640x480 at 1000kb/s...

Thanks,
Don

[Z0r0b]

I don't use crunchie, but i do a lot of encoding using gordian knot. A bitrate of 1000 for 640x480 sounds a little on the low side to me. There's no point having a high resolution if your bitrate is too low. Have you tried lowering the resolution?

[arkay]

I'd agree. If you want standard 350meg/episode type results you'll need a bitrate of at least 1300.

The only other thing that really affects crunchie is mencoders deinterlace routines. They aren't the best. If you want perfect motion then use the double rate deinterlace mode. This is a full 25fps to 50fps progressive conversion and gives the best results.

Cheers,

Arkay.

[Raydancer]

Arkay, when you say 350Mb per episode, are you talking about hour length shows? (well...once commercials are removed they're more like 40 minutes, but you know what I mean)

I'm using GSpot Codec Information Appliance to get a few examples of xvids I've aquired:

example 1: 640x480, 952kb/s, 23.976fps, 0.129bits/pixel, runtime=22:33, 174Mb

example 2: 512x384, 877kb/s, 29.971fps, 0.149bits/pixel, runtime=11:13, 81.1Mb

example 3: 608x336, 977kb/s, 23.976fps, 0.199bits/pixel, runtime=41:48, 338Mb

These specs were taken from videos which, to me, look pretty good. What I'm having difficulty understanding is that I can set my resolution and bitrate the same as these videos, but they still don't end up looking as clean.

I've tried several different combinations with Crunchie...single pass, two pass, with and without the double interlacing...but I can't seem to get results that match the ones I've listed above...especially the bits/pixel spec...mine all tend to be under .1bits/pixel.

I've looked through some of mencoders commands, but, being the newbie that I am, it's taking a while to make some sense to me. Is there a such thing as variable bitrate for xvids?

It could be simply that my source is flawed. I'm getting ripping mine from analog and the vids I'm comparing them to are more than likely digital.

[Z0r0b]

The compressibility of video sources will vary from video to video - if you use the same settings as you see in another vid, it doesn't mean that you'll get the same visual quality for your encodes. The quality of the source will indeed have a big impact on the quality of the compressed vid. If we're talking TV shows, an HD capped source is going to look a lot better than an SD one. It also will depend (to a certain degree) on the mpeg bitrate used in the cap.

Note: you should always use 2-pass when encoding.

[arkay]

That's definately your problem. Video encoding is an art.

To really gain the best from any encode you need to filter the source, deinterlace it properly, smooth it, sharpen it etc etc, it all varies depending on the source. Once that is done (particularly the smoothing and undot type operations), the video is much cleaner and consequently compresses better. i.e. Lower bitrate maintaining quality.

Unfortunately you can't expect a tool (any tool), that automates conversion to ever do as well as what you see in the files you've got there (that are most likely processed manually) Analog sources are "dirty" by nature, lots of noise etc and don't compress as well.

My aim with Crunchie was to provide a tool that allows substancial disk space savings for people recording TV with the easiest use possible. Even at a bitrate of 2500 you save a pile of space. Crunchie isn't really intended to be a 350MB/episode type tool. You should try auto gordian knot for that type of functionality though learning avisynth and the filtering you can do on a source and when/how to apply them will give you far better results than either tool.

Cheers,

Arkay.

[Z0r0b]

Originally Posted by arkay

Video encoding is an art.

Can't agree with you more on that!

Raydancer you might want to give Gordian Knot a try. This guide will get you started. After encoding this way a few times you will begin to appreciate arkay's words of wisdom.

[Raydancer]

Thanks for all of the advice guys. You've got a really nice community going here.

I've actually tried Auto Gordion's Knot...I wasn't terribly happy with the results, but, again, my standards are most likely set too high. Of course, the manual version probably offers a lot more options. Thanks for that guide Z0r0B...there's nothing better than an illustrated guide to help you along...know of any for Virtual Dub (the "illustrated" part is very important for me...visual learner)? It seems that most of the vids I have were encoded with VDub. I've used it and got pretty decent results, but I think Crunchie (well...maybe mencoder) handled the deinterlacing better.

When you look at these other encoding softwares, it's very easy to see why you put so few options into Crunchie Arkay...it's all so overwhelming. I consider myself to be a moderately advanced computer user and it's a lot to learn even for me...I could never see my parents trying to figure it out. I do, however, have a suggestion. I've looked through a lot of the forum and it seems that a lot of more advanced users like Crunchie as much as I do. Is there any chance of putting together an advanced users guide? Something that might explain a few of the things you could do with the ini file? I don't think that would affect the mom & pop users, as they would simply use the program as it was meant to be used. Anyways...just a suggestion...not trying to make more work for you

[arkay]

I could but I don't know where I'd start or where I'd finish. Mencoder has more options than you can poke a stick at. Crunchie is hardcoded to some extent as to which you can use which would narrow it a litte. I always made the assumption though that if you're advanced enough to want to make changes to the ini, and are aware enough that you want something more from your encoding, you're probably pretty much at the point where you could manually do a better job anyway (or use automated tools to do it).

Gordian Knot (not the auto version), is a fantastic piece of work and allows you to edit the avs scripts prior to encoding. I'd really suggest you get over to www.doom9.org if you want to learn more on how to use vdub and avisynth for encoding. The guides you are looking for are already there. Check it out. That's where I learnt everything I know... (Took the best part of 8 months though).

Cheers,

Arkay.