DivX V5.0...is it better or not?

[Rodger]

I know there have been loads of threads named like this or asking for it.
But...some time has gone now after the release of DivX5 and some other codecs.

So now...after our heads of the encoding scene had time to test DivX5 for it´s full features what is result, the final conclusion?

There were so many telling about filesize and the results on the displays (TV and Monitor).

This thread is meant for the best encoders out there to answer, not people like Me using it only to backup DVD-Movies.

It would be helpful for the main-stream if there was a helpful guide how to BACKUP DVD-QUALITY.
I had to find out that still 1200Mbit/sec doesn`t bring the full DVD quality.
What features should be enabled for the best quality for Output on TV, which for monitor output and which is the best for both and stuff like this.
Those questiones should be answered.

This thread is not only for me but also many many people not asking for it.

greetings
Rodger

[Neo Neko]

In my 3 or 4 years of using MPEG4 codecs of one kind or another I would definatly say it is better. You still do not have the file size predictability of Xvid or Nandub, but it is very possible to have better quality files in a smaller size than that of even a well done Divx3 encode. The Qpel feature at the moment is the one most responsible for this. B frames can help even more, but there are a few problems sometimes with it ATM. Global Motion Compensation with a clean video source like a DVD will bring even further gains. But if you have a dirty source you will probably want to avoid GMC for now. It will make parts of the image seem to "swim". The "psycho-visual moddeling" feature is very buggy ATM. And I have yet to get any good results with the image pre-processing slider.

I can not reccomend the "best" settings as there are no general "best" settings. As with any codec and video they each have their sweet spot at wich you will have optimal results. The one thing I will say is to use 2-pass for the best results possible. But outside of that you will have to decide what bitrate to use or if you need to alter the quantizers. Anyone who does sugest that such and such are the best settings to use can not do so in good concience.

The best thing to do is look for yourself. Never let someone elses oppinion decide for you, no matter who they are. If simply went by everyone elses opinions I would likely be using Divx3. But I am glad I am not using Divx3 because for myself it is just to flawed and has to many drawbacks. You can let others oppinions guide you, but the final choice should be yours.

[Acaila]

@Neo Neko:

I think you're mixing a few things up here. Qpel hardly increases quality or decreases filesize, that's B-frames instead. And B-frames is the feature (I believe) the most users are reporting that it's working without bugs so far.


@Rodger:

Basically every pro feature still has issues so be very careful when you use them. Always check the output thoughroughly because it's not to be trusted at this point.
Also, be sure to stick with a resolution that is divisible by 16 or 32 because that will save you a lot of grief in the end.

[Neo Neko]

@Acaila
You are right Qpel does not decrease file size, but I have had significant improvement in quality using it. I did not specify in the original post whether it increased quality or dropped file size, But increased quality is what I was meaning to imply. For me B frames work just fine, but I have seen some posts here and elsewhere by some claiming problems. Who's to say, I just thought I would put it up there.

[theReal]

It would be helpful for the main-stream if there was a helpful guide how to BACKUP DVD-QUALITY.To reach DVD-Quality with no drawbacks, there's one single solution: Do NOT encode to mpeg4 at all, but backup the .vob files. ;)

[Doom9]

hmm.. in my experience qpel is a big nono.. it made large areas "swim", not gmc. gmc had very little effects for me but I thought I noticed a few problems around the edges of the screen (using a regular 32x x 16x image so the size cannot be a problem).

and the size gain comes mostly from the b-frames. I even posted some numbers on that in the news a while ago

[Rodger]

Even the everyday-users are not sure about the new codec it seems ;)

Well I´m definetly not one of those everyday users (I´m more in the things of IfoEdit *smile*) but as I´ve read several postings now.
I´d say to conclude several postings I´ll set "rules" and you guys discuss it.
_________________________________________
Do not use Quarter Pixel if the output is for playback on monitor (PC)!

Do not use Bidirectional Encoding if you want to reduce filesize!

You can use GMX to get more accurate filesizes out of bitrate calculators!

"Psychovisual Enhancements" and "Pre Processing Source" are to use with care!

2pass encoding ALWAYS is better than 1pass encoding!
_________________________________________

I´ve done my own test and can say that I really dislike this QPel feature! To Me this feature just doesn`t do the trick.
Bad image quality on monitor and it slows the encoding speed so damn down!
I definetly recommend to turn off this feature of DivX5. On the other hand I´m pretty lucky with GMC. This feature works and I`ll always leave it turned on.
The Bidirectional Encoding brought image quality (recognizeable!!!) but I´ve not checked for filesizes because I´m a quality-freak ;) But it´s good to know for sending clips via internet. The psycho-shit feature can be left always OFF!!! ;)
Pre processing the source takes too much CPU-Power for it´s results. That´s my opinion even that I´m a quality freak.
But I´m not sure about that scene change treshold feature. Anybody out there who has experience with this? Coming to the keyframes I always use 5sec(interval-125)

greetings
Rodger

[theReal]

Do not use Bidirectional Encoding if you want to reduce filesize!That should be:
ONLY use Bidirectional Encoding if you want to reduce filesize!

b-frames do result in smaller files, always. I think these smaller files are virtually the same quality as without b-frames, but of course for PERFECT quality, you shouldn't use b-frames. However, if you want to make a 1 CD rip, I recommend using b-frames because at a given (relatively small) size, using b-frames will result in higher quality!

[Beave]

Would you say that 2-pass is always better? Why?

I thought it is just better for getting the filesize right. If I'm encoding a short clip for Downloading or putting some Specials from the Dvd onto the CD, where Size won't matter that much, do you still think 2-pass gives better Quality?

So for the Specials I usually use 384x288 or lower and do some CompCheck in GKnot. Then I use the appropriate bitrate.

If I don't have the time for intensive testing, would You say it is better to stick to DivX4?

[Rodger]

Well...in my complete experience 2pass encoding has ever been better than single pass. While encoding in 2pass each frame gets compared which one first pass ot second path is looking better. The better is chosen to be in the final output.
So...if you want to workabround a 2pass you will have to turn up the bitrate to gain comparable results.

Rodger

[Awake]

2-Pass is NOT always better. Use min/max quantizers of 2 and it is pointless.

As far as the codec deciding which frame to use during a 2-pass encoding, it has far more to do with how it compresses than how it LOOKS. And the more compression, obviously the more likely it will look worse.

[theReal]

The only downside about fixed quantizers of 2 is: you will get a file of unpredictable size.
When you want to achieve a certain size, you need to encode with a bitrate setting rather than a quality setting - and in this case, 2-pass is always better than 1-pass.

[Beave]

But what if you simply want a certain quality, where size won't matter? Say you are satisfied with a quality of 500kb/s and a resulting size of 450mb with single pass. You guys think it will look the same, but less mb with 2-pass? Or look better with the same size? Hmm, maybe! Or not?

[theReal]

You guys think it will look the same, but less mb with 2-pass? No, definitely not - that is what the bitrate is for.


Or look better with the same size?
Yes, it will.

[dragoman]

Hi,

There is one sure way to encode a video to the limit of a codec's ability.

Encode in 1-pass quality based encoding set at 100%....the best results for every frame you will get....

But unpredictable filesize. Still, this is a good way to discover a good bitrate to set for a two-pass mode...if you have that kind of time, that is.

dragoman

[jonny]

I always use a compressibility test (for DivX 5, as described in another thread...), i've discovered that going over 80%-85% will result in an undersized file... it seems that DivX 5 don't use quant 2 (in some frames) because think it is not necessary..., if comp. test is something near 95% i think it's better to go with 1-pass 100% quality or you'll get an undersized file...