How to lower avg keyframe distance ?

[avdw]

Hi, I'm only starting in encoding, have read a lot about it but still a newbie.

As shown on the pic below, the Max keyframe distance is 250, so it good for a PAL movie.

I actually would like to lower the Average keyframe interval. Right now all my coded Xvid's are around 115, I would like to lower this value to around 90.

What settings in the Xvid encoder allow me to do exactly that ?
:thanks:

[foxyshadis]

No way to tune it like x264. You'd have to edit the stats file after a first pass.

[Zach]

As shown on the pic below, the Max keyframe distance is 250, so it good for a PAL movie.
First, I'm not seeing any picture. (Maybe I'm adblocking it? <shrug> :cool:)

Second, if that were true, why, then, do both Xvid and DivX default to 300 frames? (I know because I explicitly change it to 30 which, yes, produces bigger files, but the advantage is that it lets me finally properly forward and reverse seek the video on my DivX player.)

[avdw]

Sorry, I accidently forgot to upload the screen.
Here's it. Mines "Region-0011"

I'll probably get kicked and slammed and spitted and throwing axes at me from all angels here, but I'm refering to a well known guy who encodes his movie to Xvid too, he ain't using any special matrixes or stuff like that, he just knows how to get it fantastic yet keeping the size of a 1:45:00 movie well at 700MB.

I grabbed an encoding for seeing what's so different about his and encoding from 'the others' ....
(YES, I know I'll burn in hell now, I only did this once, you know forbidden fruits look so juicy éh ;))

Gspot shows the encoding as seen in "Region-0012" ....
Average keyframe-distance is only around every 90 frames.
At first look, all, even talented Xvid gurus will immediatelly shout "Horrible !! CRAP !! This is really badly encoded" .... Yet his encoding are the masterpieces of the Xvid gallore.



The only clearly difference is that all frontends, even default Xvid settings all use a maximum keyframe distance of about 10 x the FPS, and an average of around 150(!!).

So the reall question is : How come that an encoding with much more frequent keyframes do still stay small yet look so much better than the other ?

According to the thousands of manuals, FAQ's, walkthroughs, etc.... They all sound like they are the heaven of encoding knowledge, yet they all tell us completely contradictive info, lies, and more links to some other "Ultimate guides"......

So, I can actually conclude that, the few who know the in's and out's of MPEG4 encoding keep very well hidden and keep the real knowledge to themselves.

[Dark Shikari]

Sorry, I accidently forgot to upload the screen.
Here's it. Mines "Region-0011"

I'll probably get kicked and slammed and spitted and throwing axes at me from all angels here, but I'm refering to a well known guy who encodes his movie to Xvid too, he ain't using any special matrixes or stuff like that, he just knows how to get it fantastic yet keeping the size of a 1:45:00 movie well at 700MB.

I grabbed an encoding for seeing what's so different about his and encoding from 'the others' ....
(YES, I know I'll burn in hell now, I only did this once, you know forbidden fruits look so juicy éh ;))

Gspot shows the encoding as seen in "Region-0012" ....
Average keyframe-distance is only around every 90 frames.
At first look, all, even talented Xvid gurus will immediatelly shout "Horrible !! CRAP !! This is really badly encoded" .... Yet his encoding are the masterpieces of the Xvid gallore.



The only clearly difference is that all frontends, even default Xvid settings all use a maximum keyframe distance of about 10 x the FPS, and an average of around 150(!!).

So the reall question is : How come that an encoding with much more frequent keyframes do still stay small yet look so much better than the other ?

According to the thousands of manuals, FAQ's, walkthroughs, etc.... They all sound like they are the heaven of encoding knowledge, yet they all tell us completely contradictive info, lies, and more links to some other "Ultimate guides"......

So, I can actually conclude that, the few who know the in's and out's of MPEG4 encoding keep very well hidden and keep the real knowledge to themselves.Ever thought that his different keyframe distance has nothing to do with the higher quality?

Perhaps he is better at denoising than you are?

[Soulhunter]

Except for seeking n' error resilience it makes no sense to lower the max I-frame interval imo... I mean, its just the MAX span between I-frames... If there's a scenechange every 100 frames, XviD will put a I-frame every 100 frames, even if you set the max interval to 500 or whatever, no? Setting a high interval gives you the advantage that XviD will only use small P/B frames for long static scenes which saves some bitrate... For the settings of 250/300 in the guides: I guess they are probably chosen because this way you have max 10 sec. [10x 25/30 fps] jumps when seeking!


Bye

[foxyshadis]

The original question is about how to lower the I-frame threshold, though, so you can increase them without setting the max lower. I don't think it'll work for quality, because adding more I-frames will lower quality instead; each of them take much, much more space than a P frame.