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Choppy playbackspauses after rendering in AE

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Zvi_Twersky
Choppy playbackspauses after rendering in AE
on Mar 23, 2007 at 11:57:37 am

I started posting this in AE forum and was told that it is a question for here. Since there is no way for me to move my thread, I will post it here too, or else I would not double post.

Whenever I render anything, even if it's just an avi or mov file that I added a small effect to, the results are never smooth. It either has a little choppyness, or it has some pauses during playback.

I have tried all kinds of export and compression settings already. (Actually, I've tried them all!) I'm using the default NTSC settings.

I don't think it's a problem with the computer... I use Windows XP pro, P4, 2.56 CPU, 1GB RAM (%90 free) with plenty of free HD space.

What could be wrong??

**********************
I was answered:
**********************
It sounds as if you're rendering at too high a data rate. This is probably a Compression Techniques question, but I'll give it a shot.

Use "make movie" and pick a codec in the Output Module.
Did you try Quicktime Photo-JPEG at 89% quality?
Did you try Quicktime Sorenson?
What is the frame size of the movie?

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I replyed:
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Ok, I never tried to lower the quality... I'm rendering something now with %89 like you said, but if that DOES work better... Why should I have to live with %89 quality? What would I need to do to get best, full quality? Stronger computer?

Thank you.



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Zvi_Twersky
Re: Choppy playbackspauses after rendering in AE
on Mar 23, 2007 at 12:00:02 pm

Ok, I did Quicktime Photo-JPEG at 89% quality and it came out perfect. But my question still stands, why can't I benefit from %100 quality?



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Danny2007
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 8:44:30 am

As far as I know - under 90% is 4:2:2 and above 90% is 4:4:4.


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Zvi_Twersky
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 11:57:29 am

How can over %90 be 4:4:4? 4:4:4 means no compression at all, and I AM using a compreser.





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Danny2007
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 12:14:39 pm

Actually 4:4:4 means no colour sub-sampling - It's a chroma profile, not really a measurement of compression.


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Zvi_Twersky
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 12:23:22 pm

Isn't color sampling a kind of compression so that the file size will reduce? If we keep unique luminance and color for all 4 pixes in every image, hence 4:4:4, wouldn't this mean that the entire video is uncompressed?

Maybe I'm just not understanding but what else is there to compress in the video (not audio) besides the images?



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Danny2007
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 12:32:04 pm

Yes it is a kind of compression but it's not the whole story..

For example HDV uses 4:2:0 but is compressed with Long-GOP MPEG-2.

Additionally
There is uncompressed 4:4:4
There is H.264 at 4:4:4
and there is PhotoJPEG at 4:4:4
etc.

All the above will have different datarates and visual quality.


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Zvi_Twersky
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 12:36:25 pm

Thanks!

Well, so you know is it's correct that PhotoJPEG at under %90 is 4:2:2 and over %90 is 4:4:4? Because I render in PhotoJPEG - %89 and a 20 second clip is 61MB.



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Danny2007
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 1:09:01 pm

So about 9.5Mb/s - At what frame size & what frame rate?


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Zvi_Twersky
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 1:20:35 pm

Standard PAL settings. 720X576, 25.



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Danny2007
Re: Choppy playbackspauses after rendering in AE
on Mar 26, 2007 at 1:51:59 pm

Obviously much depends on the frame differences, but the datarate seems about right.


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