video flicker (dvx100e / 25p)

[serra]

hi all

i get a lot of horizontal flicker when exporting
25p-originated clips from AE6. now maybe i'm missing
something, but as the source footage is progressive,
i turned "field separation" off for the clips. and as i'm
trying to create a clip for web-distribution (progressive displays), i've
turned "field rendering" off as well... but, no matter what quicktime
codec i use, i get the described artifacts... i even get the artifacts
when doing a ram-preview from within AE. interestingly, i do not get
the described problem when exporting to the "Microsoft DV" codec...


btw, the footage itself is pristine... single stepping through the frames,
there are no flaws to be discerned whatsoever.

what gives...? i'm really puzzled by what i'm seeing... can anybody
out there help?


thanks,

serra

[scharky]

It sounds like you are talking about a horizontal line that appears inbetween frames (one frame to the next) when playing back your footage? If you can step through your footage fine (frame by frame) then don't worry about it, your footage is good, it is your computer that is having trouble playing back your footage. I have seen this happen a lot with quicktime footage especially, basically, when you render to an uncompressed codec, your footage is much larger per frame than dv footage. Basically, it is your computer chugging along trying to display each frame. Since each frame is so large, it can actually take longer to display each frame, even though it is running at a set frame rate. This intern causes the "tearing" effect that you are talking about. I wouldn't worry too much about it in your NLE, if you do a rendered preview "DV" then your footage will look fine.

[serra]

yes... that's exactly what i'm talking about...!
i follow your line of reasoning... in fact, i had theorized much along the same line... the only thing that befuddles me about this bandwidth argument is that i wasn't rendering to an uncompressed codec, rather the tearing happens with rendered files that are substantially smaller (i.e. lower data rate) than what you'd get by rendering to a DV codec (Sorensen 3, for example)... nonetheless, i think you are right in suggesting that it's probably not worth losing sleep over, considering that the frames, when viewed one-by-one, are in good shape...
damn annoying though... !

cheers,

serra