Artefacts at 1000kbps

[BioZ]

I'm having some problem encoding an anime episode off DVD.

I'm going for 1000kbps at 640x480 (1006 to be exact) with DivX 5.1, with n pass encoding with 2 passes.

Bidirecional Encoding on
GMC off
Quarter Pixel off

Read/Write log as appropiate
MV write on

Psychovisual Enchancemets light

Encoding speed standard.

The end result shows strong artefacts around lines, which I have not experienced before. What am I doing wrong?

Anyways, here's some frames:

Source (http://filespace.brentdax.com/BioZ/uncompressed.jpg) and Output (http://filespace.brentdax.com/BioZ/compressed.jpg)

Thanks in advance.

[manono]

Hi and welcome to the forum-

Sorry, but when I click the link, it says:

We're sorry, but this page is currently unavailable for viewing.

However, the usual reason for such artifacts is low bitrate or high resolution. Try encoding at 512x384 and see if the artifacts go away.

[BioZ]

Seems Geocities aren't playing ball...

Updated the links. Hope they work now.

Is 1000kbps too low? The anime release by fansub groups are generally at much lower bit-rates (less than 800), but look much better.

[jggimi]

Hmmm... I think you're struggling with a bitrate vs. resolution issue. 4:3 video is difficult enough compared with widescreen content, due to the number of pixels per frame.

The suggestion to lower your resolution or raise your bitrate is a good one. Here's why: 640x480 = 307,200 pixels per frame. 25 frames per second PAL video = 7,680,000 pixels per second. 23.976 frames per second NTSC/Film = 7,365,427.2 pixels per second.

At 1,000 kilobits per second of video bitrate, the bits/pixels*frames value for PAL is 0.133. For NTSC/FILM, it is 0.139. Even though b/p*f is used as a rough guide prior to performing a compressibility check, both of these are below Doom9's recommended minimums in his DivX 5 guide (http://www.doom9.org/gknot-main3.htm).

Forgive me if I make a couple of incorrect assumptions. It isn't completely clear, but it looks like you are not using Doom9's b/p*f guidelines, and it looks like you might not be using compressibility tests, either. I highly recommend using b/p*f for estimating your initial resolution and bitrate, then using compressibility tests for final settings.

[manono]

Hi-

Is 1000kbps too low?

For 640x480 it generally is. Read jggimi's reply carefully. Although someone's sure to pop up and say he encodes all his anime at 640x480 and 1000kbps and they look great.

...generally at much lower bit-rates (less than 800), but look much better.

And these are also 640x480? And the same anime series? Even if so, you don't know which resizer they're using, and what other filters they might be using to make them more compressible (Dup, C3D, MipSmooth, and/or other spatial/temporal smoothers).

The link works fine now. The second pic is a classic case of bitrate starvation, to coin a phrase. :) It doesn't look bad, though. I've seen much worse.

[matthewmalay]

FLCL is very difficult to encode without having any artifacts or macroblocking. It's very bright and has lots of high motion scenes and sharp lines.

I've seen DVDrips of FLCL released by RG in ogm format encoded with Xvid and each episode was 350mb.

[temporance]

I would definitely NOT use MV file. It can wreck your encode, especially anime.

[kl33per]

Originally posted by temporance
I would definitely NOT use MV file. It can wreck your encode, especially anime.

MV File reuse should have no effect on quality (unless you change the Performance slider).

[temporance]

> MV File reuse should have no effect on quality (unless you change the Performance slider).

Trust me, it does hit quality (at least according to my PSNR tests).

So you pay for a small speed increase with a small quality decrease.

The effects are worse with anime as precise motion vectors are very important when you have sharp edges.

I presume this is why xvid ditched MV hinting a while back.

[Acaila]

MV file reuse reduces quality because it copies the motion vectors from the file that were calculated during the previous pass. Since motion vectors are dependant on the quantizer that was used on the frame (and quantizers change between passes), the stored motion vectors will most likely be different than if they were calculated anew.

However in most cases the quality drop shouldn't be (and isn't) visible, and the speed increase can more than make up for it.

And just as temporance said, I also believe that is why the XviD guys dropped it. Because it couldn't be done without a PSNR decrease.

[BioZ]

Originally posted by manono
And these are also 640x480? And the same anime series? Even if so, you don't know which resizer they're using, and what other filters they might be using to make them more compressible (Dup, C3D, MipSmooth, and/or other spatial/temporal smoothers).

There are some really amazing encodes out there. Things like Scrapped Princess are sometimes encoded at less than 700kbps, at 640x480, with very reasonable artefact levels. There were also some 115Mb for 23min Wolf's Rain episodes (excuse me if I'm going on about meaningless names for some).

Anyway, thanks. I'm trying again for a 233Mb files without MV, and if that doesn't work out, I'll look into more AviSynth Plugins and maybe goto 350Mb files.

[hakko504]

Originally posted by BioZ
(excuse me if I'm going on about meaningless names for some). We will excuse you - if you stop hinting that you engage in piracy by downloading movies off the net. That is a violation of rule 6 and we don't want newbies to get in trouble early just because they failed to read the rules.

Welcome to the forum BTW.

[BioZ]

Thanks for the welcome.

I'd just like to point out that Fansubs of anime unlicensed in the North America are widely accepted as legal. The studios who makes the anime don't even seem to mind. The anime I downloaded are unlicensed or at least were unlicensed at the time.

I have read and respect all of the Doom9 forum rule.

[hakko504]

Originally posted by BioZ
I have read and respect all of the Doom9 forum rule. Read this announcement in the newbies forum also. (http://forum.doom9.org/announcement.php?s=&forumid=6)

[Sirber]

Originally posted by manono
Hi-

Is 1000kbps too low?

For 640x480 it generally is. Read jggimi's reply carefully. Although someone's sure to pop up and say he encodes all his anime at 640x480 and 1000kbps and they look great.I encode that rez at ~400kbps for that content and get better results than the picture I saw.

[Soulhunter]

@Siber
I encode that rez at ~400kbps for that content and get better results than the picture I saw.
Yeah, I bet you have ! ;)

And you used what codec... ???

I know, I know... !!! :D :D :D

Bye

[manono]

I encode that rez at ~400kbps for that content and get better results than the picture I saw.

And you can talk about it all you want in your own forum, and stop your trolling in this one. This one's devoted to the discussion of DivX5 encoding the last I looked.

[Sirber]

I know, but people with bad results are in that one :eek: