So I'm trying to use the 'color corrector 3-way' filter to crush the blacks in a short film I'm finishing up, and I'm running into the same problem every time I do. I apply the filter to one clip, dropping the black levels and boosting the whites and mids a little bit. I then copy that clip, and 'past attributes' copying the filter to the rest of the clips at the same time. Then I render. What happens next is that the entire film becomes one-tenth the size it was before, and is filled with compression artifacts, both in the sequence *and* as a final, exported .mov file.

I really can't figure out why applying a filter would do that, so obviously I'm missing something. Any ideas?

What video codec are you using? And does this happen if you work in another sequence?

I'm using h.264, 1920X1080 24p imported straight in from 5d MkII files. I haven't tried another sequence because I'd like to know why just using a color-correction filter is causing such trouble. I must be doing something wrong, so hopefully I can fix it. thanks...

You need to transcode your video files into ProRes before editing.

Interesting, I didn't know ProRes was the only codec that you could use filters on in FCP. I'll transcode them and give it another shot. Thanks...

It's not the only codec you can use filters on.

H264 is a very efficient codec in terms of file size to picture quality but it's a terrible codec to edit with. It is very processor intensive and there are many variants of h264. Final Cut likes QuickTime codecs that have every frame sitting in it's own package not referring to a frame a few frames back. The reaction you saw is a direct result of using a codec that Final Cut doesn't interact well with. Transcoding to ProRes might seem to be a nuisance but the savings in rendering time and computer performance is well worth it.

That makes sense, thanks for the great info. I've transcoded the clips and everything is going great. I am using clips from someone else's camera, I've not used h.254 before since all my clips are Excam or Prores. Always an adventure. Thanks for the help.