What a bad quality!

[safigo]

Hi everyone!

I searched in the forum looking for how to set new keyframes and I took your tips. HOWEVER, I put keyframe interval in 1 frame - because I wanted - at GordianKnot, in both steps, and the resulting avi had several pixels.

How do I do to have keyframe interval frame-a-frame and the same quality in the default value (300 frames)?

I would appreciate the help.
Thanks.

[manono]

Hi-

How do I do to have keyframe interval frame-a-frame and the same quality in the default value (300 frames)?

It's different for each codec. Which are you using? But I don't think it's such a good idea to make each frame a keyframe, as keyframes are, in general, much larger than the other frames. That means that for a given filesize, the overall quality will be much worse than if you had kept the defaults.

But I may have misunderstood you. If so, please set me straight. :)

[safigo]

Thanks for the reply.

I'm using DivX 5.0.2.
I want each frame a keyframe because I don't want complications in splitting the avi in two cds. Sometimes, at the point I want to cut, there is no keyframe. That's the reason I want each frame a keyframe.

So, there is really no chance of better quality on having each frame a keyframe? And can I put keyframe interval at 25 so that the quality is the original?

The point is that I want the same quality as in the original avi and I want a chance to split the avi at the exact frame I want.

Thanks.

[sekxx]

Short explanation:
Every not(KeyFrame) are interpolate from KeyFrame, meanning that KeyFrame are fully describe by the codec (So are huge(in octect) frame) and not(KeyFrame) are not (light in octect).
So, when you set the codec to put a keyframe every frame, for 1 or 2 CD, the codec can't produce all frame with a descent quality because every frame has to be fully describe.

The current usage is to set a keyframe every 10secondes.

If you want to cut your movie at a particular point, there are somme solutions, search the forum, I remember one thread explaining how to modify Pass 1 (of 2 pass) txt file to force a keyframe at a particular point (for DIVX), and there is a tool for XVID that automaticaly modify the Pass 1 file to force a keyframe.

Hope you'll find it.
SeKxX
(Forget my english)

[maf]

Hmm, I have never messed with the keyframes option in GK. I'm not sure what the default is (1 every 10sec, sekxx?), but I've not changed it in over 20 movie encodes (DivX 5.01 and 5.05).

I usually split my movies over two 700MB discs, and because I want to be able to find a good editing spot to end the first part and begin the second part, I try and set the file size to roughly 50-60MB under the 1400MB available - making movies approx. 1338MB in size.

This way, I get some room to navigate through the keyframes and find a satisfactory "break" in the flow of the film. That's my method, anyway (I recently read I could smoothly move through keyframes in VDubMod by holding the Shift key).

[manono]

Hi-

So,if I understand you correctly, the reason you want keyframes at every frame is because you can't split where you want. So, perhaps you have a scene change where you want to split sometimes, but there's no keyframe there? I have that problem also. One way around it is to change the scene change detection to make it more sensitive and set more keyframes. I have DivX 5.05, but I think it's the same for 5.02. In the General Parameters Tab, in the bottom left is the "Scene change threshold". The default is 50%, but if you change it to 45% or even 40%, it becomes more sensitive, and sets more keyframes. Just above it is the "Max keyframe interval". You can lower it from the default to set more keyframes also.

[safigo]

Well, if I do it, will the quality be the same or it will worse?

Thanks again.

[manono]

Hi-

I'll assume you're going to reencode from the source DVD, and not just reencode the .avi (which will, of course, make it worse). I've found that when there are a series of dark scenes, or scenes where the luma is about the same (is that the correct term?) that the default Scene Change Threshold isn't good enough, and a keyframe may not be set where I want. But if I change it to 45% (and leave the Max Keyframe Interval alone), then the keyframes are set where they should be. And the quality will be about the same. You certainly won't be able to tell any differences with your eyes.

[colordog]

@max

A less elegent solution to getting your movie split exactly where you want for a multi-CD encode is simply to just create two separate .dv files in DVD2AVI. Just set the end to where you want to cut, save the project, and then set that point to the beginning and save the second project.

[sekxx]

colordog>
it's really not a good Idea, let's imagine a movie of 2hours.
During the first hour a bad guy hijack some car, kill people, ... car race ... ( So first hour is Fast Motion )
During the second hour, the bad guy is in jail ( Slow motion ).
(I know it's a little bit exagerate ;))

Most people would like to make two *.d2v (or *.avs) file of 1 hours,
but the bit distribution, will be very bad, because the first hour of the movie need's (a lot) more bit than the second hour, so first CD will be blocky, and second undersized.

The most elegant solution if you want to cut at a particular point is to edit the X-pass log file before the last pass (with n-path in DivX, you should disable log file update if you edit the log file)...

[safigo]

sekxx,
can you explain me step by step how to edit that file? Or, at least, can you show me where is the explanation on doing that?

Thanks.

[TheWEF]

all you have to do is to reencode the few seconds of the keyframe interval where you want to split.

wef.

[sekxx]

safigo>

At the end of this thread, somebody tell how to edit log file for DivX.
This thread also contain information on a software that should be able to force keyframe after encoding.
http://forum.doom9.org/showthread.php?s=&threadid=33910

You should also see this page from a member, with a tool he make to force keyframe at a specific point (before second pass):
http://zuludev.de.vu/