Getting XviD quality.

[x2x3x2]

Does anyone know what XviD encoder(s) are used for those scene released tv show downloads?

I tried with Xvid4PSP using one of the many XviD profiles, specifying bitrates matching those of the scene releases, but I can never get as good quality as theirs. I would only get comparable XviD video quality if I specify a much higher bitrate.

How are the scene releases doing it?

[thezanny]

Well, encoding is a Big Process.
Simply, Resolution/Bitrates and the codec matters ...

A Small resolution of about 640 x XXX is good for TV series.
And audio of about 128Kbps and 2 channel audio is great.

A Video codec like XviD is superb in 2 pass. But 1 pass only gives crap sometimes.[2 pass is @ top]
Or use H264 kinda loose-less thing..

And if you want to make more quality, increase bitrate which propotionally increases file size though.

[guns1inger]

You don't say what your source is.

[jagabo]

Scene releases use reduced frame size to lower the bitrate requirement. They trade off resolution to get fewer compression artifacts at low bitrates. This made sense when it was important to fit a 90 minute movie on a 700 MB CD. But it's completely arbitrary now.

Does it matter if your file is 700 MB or 800 MB? Why should a 90 minute movie be the same size as a 100 minute movie? Given that different movies compress differently, even if they have the same running time, why should they be compressed to the same size? Use Target Quantizer encoding to encode with constant quality. You pick the quality you want and the encoder uses whatever bitrate is necessary to deliver that quality.

When a Target Quantizer and 2-pass VBR encoding end up with the same bitrate the quality is similar. The difference is this: With 2-pass VBR you know what the file size will be but you don't know what the quality will be. With Targe Quantizer encoding you know what the quality will be but you don't know what the file size will be. They are flip sides of the same coin.

Try a quantizer between 2 and 4, the lower the quantizer the higher the quality and the larger the file. At 2 the video will look almost exactly like the source but it may be larger than you want. At 3 the video will have a little more macroblocking than the source but it won't really be noticeable at normal playback speeds. That is a good compromise of quality vs. size. At 4 the macroblocking is more obvious and the file sizes are even smaller.

And, as noted, some movies simply require more bitrate than others. Many things require more bitrate -- high action, film grain, VHS noise and jitter, frame bounce from poor film transfers, smoke, fog, flickering lights, explosions, a sunset reflecting off ocean waves, bright high contrast shots... basically anything that causes pixels to be different from the pixels around them both spacially and temporally.

Don't expect your own handheld camcorder video to compress as well as professionally shot movies. The shaky camera work and noise from cheap CMOS sensors are killers of compression.

[x2x3x2]

Sorry for not being more specific, I meant assuming all source video and output parameters are the same. Nope it doesn't matter what size a movie should be. I understand that different video, as those with more action will require higher bitrates due to more pixels shuffling ard. But my question pertains more to a comparison of similar/comparable material.

For example with a 16:9 DVD video source, converted to the common 624x352px size used by the scene releases.
The scene releases usually encode with Advanced Simple@L5 profile with video at 1 015 Kbps (or thereabouts) with MP3 audio at 128kbps joint stereo.

When I try to encode with similar bitrate settings (with 2-pass of course) using any of the Xvid encoders, I just can't seem to match their quality. I just happen mentioned Xvid4PSP cos it has consisntently managed to output relatively good video at lower bitrates for x264/mp4 files. The quality difference if really quite noticeable with blocking to a certain extent even.

[gonwk]

Hi folks,

x2x3x2, I have converted couple H.264 files into AVI ... not using any logical reasoning ... from couple of clips that I played around with ... try using "XMedia Recode" with your bitrate set at least 1.5 times of that of your H264 video file ... and see how you like that ... if not happy then up it to 2 times the bitarte.

BTW, my experience is that XMedia gives a "Crisper" picture and better "Color" compare to Xvid4PSP ... but then again it might be just my imagination!

G!

[jagabo]

I see nothing special about scene releases. Aside from their obsession with 716 MB files. Try using VirtualDub and the Xvid codec. That will give you complete control over resizing and encoding. Better yet, use AviSynth for resizing and VirtualDub simply as a UI (Video -> Fast Recompress).

[El Heggunte]

The VfW interface of Xvid allows you to use "encoding ZONES" and "custom quantization matrices". In theory at least, these features may help you to achieve higher visual quality at lower average bitrates (N.B. , I am not talking about "1-pass with average bitrate"). However these techniques really are not "newbie-friendly", and require not only a lot of Googling, but also many hours of trials-and-errors.

[Caveman456]

I think you'll find the reason for the higher quality scene releases is because the the original source is HD not DVD.

[Cauptain]

I think you'll find the reason for the higher quality scene releases is because the the original source is HD not DVD.

Correct. Its the point.

[manono]

I think you'll find the reason for the higher quality scene releases is because the the original source is HD not DVD.

For TV show releases, maybe, not for DVD movies to XviD AVI, which is what he's talking about. Neither do I think there's anything special about the scene releases. Anyone with a working knowledge of AviSynth and a fair amount of experience can do the same. I don't think x2x3x2 has either. As for El Heggunte's comment about using custom quantization matrice, it's a good idea but custom matrices aren't allowed under the scene rules. You're limited to the two standard ones. And most of the encoders, the decent ones anyway, don't use the all-in-one encoding programs but do it all manually.

[jagabo]

Some other things you can do to reduce the bitrate requirement in Xvid: use two B frames, enable adaptive quantization, use the h.263 matrix, don't use GMC, don't use QPel. Before feeding Xvid use a (precise) bilinear resize filter rather than a sharper filter like bicubic or lanczos3.

[x2x3x2]

Thanks for the replies guys.

Yup, I'm usually able to get comparable x264 quality if I use a higher bitrate for the XviD encodes. Though it still remains that I'm unable to match the scene released XviD's at similar bitrates.

So from the responses saying that there's nothing special about the scene releases, well I didn't imply they were. I'm just saying it seems odd that the common encoders/transcoders aren't outputting, at the very least, similar quality at the given bitrate of the scene releases.

I may be wrong here, but I don't suppose the scene releases actually custom configure each encoding job for each file. Especially for those frequently TV shows, just doesn't seem it would be practical I think. So I just assumed that they have a specific set of encoder/parameters which they use whenever they encode their releases. Do you think this is the case? And if so, any idea what software they use?

manono, you're right. I indeed do not have intricate knowledge of video encoding as I suppose most of you do over here. Hence, that is why I've started this thread to ask such questions. Perhaps you or any of the more knowledgeable ones can help me answer them or point me in a specific direction?

[poisondeathray]

what are you using for the source? is it the same source they used ?

current TV shows are usually HDTV caps, not DVD or blu-ray sourced releases

if you're using HDTV cap as source, then how are you recording it and processing it ? what bitrate for recording?

[x2x3x2]

I referred to the scene releases as an example. As I realize that the TV shows are more varied with some converted from HD sources while others are not, etc. That's why I mentioned a sample scenario of a DVD source (not HD or Blu-Ray).

My test was with the Aliens vs Predator DVD, comparing it to the scene release. I can't seem to get the same quality at similar bitrates.

[davexnet]

Take a look at this encoding guide, tells you how to setup the encoder:
http://www.mediafire.com/download.php?fm49m077w10i97m

[manono]

Yes, you have to make apples-to-apples comparisons, your encode as compared to a scene encode that used the same source. The A .v P encode would be a good example. jagabo gave some good tips. But you don't know how to properly filter the source to make it more compressible, and some of the AviSynth filters might improve your encodes quite a bit. Perhaps you don't know how to give the long end credits lower quality so the bits that are freed up can be put towards improving the movie itself. There are lots of little tricks you can use, if it were important that the encode be able to fit on a CD or two. Since it's not, what do you care if yours is 100 MB larger in size?

I'm just saying it seems odd that the common encoders/transcoders aren't outputting, at the very least, similar quality at the given bitrate of the scene releases.

It has nothing at all to do with the encoder being used except in the sense that some of the programs you use might not let you tweak the settings in the encoders.

[x2x3x2]

Thanks for the link and info. While it doesn't bother me if a file is larger by a 100mb or thereabouts, I kinda feel that the HDD space on my DivX/XviD compatible box is being wasted when I'm having to use up 1.5-2x more space to get comparable quality. Would just be nice if I could make efficient use of my storage space when archiving my DVD's.

Would AviSynth be the tool of choice which allows the tweaking you mentioned? If so, I wouldn't mind starting to read its documentation and get accustomed to using it.

One a side note, how important is adaptive quantization with regards to XviD video encoding? I notice it really does help with x264 encodes for retaining detail.

Thanks again.

[jagabo]

how important is adaptive quantization with regards to XviD video encoding?

It depends on the video. I've seen it make as much as a 20 percent difference. And as little as a few percent. 4 or 5 percent typically.

The easiest way to see what effects different settings have is to use constant quality (Target Quantizer) encoding. When you do that the differences show up as file size -- which is much easier to quantify than visual quality. Ie, better compression settings give a smaller file.