shaking image using re-encoded 720 footage?

[Kevin Camp]

i might try taking the original 1080i footage into ae. make sure the footage is interpreted to correctly separate fields, and i would probably check the ‘preserve edges’ option.

i’ll assume that the footage is 29.97 interlaced. create a comp that is 720×1280, square pixel and 59.94 fps. drag the 1080i footage in and choose layer>transform>fit to comp. now use that comp like it is footage… i.e. drag it into your main comp for effecting. this should do a pretty good job of converting the 1080i footage to 720p60. sometimes enabling frame blending (frame mix) for the footage can help further smooth some of the details.

as long as you don’t need to check the ‘continuously rasterize’ option for that nested comp the footage should not take much longer to effect.

as far as the a time effect creating a vertical shift in the image, i can only think that is due to interlacing and ae or the effect trying to use pixel motion to interpolate new frames and fields are messing with it’s calculations. try them on the nested comp that i described above. if you still see the shift, then pre-render the nested comp so you will have actual 720p60 footage, then see how the time effect reacts to progressive footage.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Steven Dileo]

Thanks for the reply, I am a little confused when you mentioned that I don’t need to have checked continuously rasterize isn’t rasterizing for vector pictures? also my other problem is prerendering. What I used to render before was the cineform codec that came licensed only for vegas, and haven’t found any other decent codecs out there. I hear everyone talking about using the animation or photo jpeg codec with quicktime but from what I remember the file sizes were pretty big and was slow when editing, might as well stick with uncompressed avi.

[Kevin Camp]

the continuously rasterize/collapse transformations check box will change how ae sees that comp. when enabled ae will see the footage within that comp as the full resolution 1080 footage, if unchecked ae should treat it as the comp frame size (720×1280), thus effecting fewer pixels and operating more quickly.

as far as the prerender, you may not need to, but if you did, uncompressed or lossless would be good options. neither will edit or play back in realtime unless you have a very fast disk array, although ae will work much better with those than any codec that uses temporal or interframe compression. however, this is just an intermediate step. you will want the final render to go the codec you are editing in, or convert a uncompressed/lossless file when importing into vegas (or any nle) to edit.

the method i was suggesting of going back to the original 1080 footage was to bypass the transcoding you did to get it to 720, which may be leading to the shifting of the image. from what you described it seemed like it may be due to interlacing, so i figured you could let ae do the de-interlacing and conversion to 720p60 and hopefully eliminate the problem.

it is possible that the codec that you exported to from vegas may be causing some issue. if the cineform codec uses temporal compression this may cause problems for temporal effects. if you think that it may be causing problems, try uncompressed, lossless or photojpeg to save some drive space, none of them will use temporal compression (well lossless can, but not by default and rarely on shot footage).

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW

[Steven Dileo]

I tried using the precomp without the rasterize being used I couldnt tell a difference in speed but there was no shaking with any effects. I notced the draft switch and turned it to draft mode and there was a big difference in speed, but then the shaking came back. Also I tested this using the original raw material with a 1280×720 comp.

[Kevin Camp]

now that i’ve though about it a little more…. converting 1080×1920 at 29.97 fps to 720×1440 at 59.94 fps is actually the same number of pixels per second…. 720 is half the number of pixels per frame as 1080, but double the frame rate.

so the render times would actually be the same, sorry for the confusion.

if you converted the 1080i to 720p30 it should render faster, but i would want to keep the higher frame rate for 720p.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW