Any benefit?

[Noel Evans]

Quick question - maybe someone can provide the quick answer.

Is there any benefit to rendering out of motion as uncompressed 8 bit then importing into a FCP SD timeline?

 

[epicedium]

Quick answer is Yes!

Longer answer is: "it depends". What material is it, animated graphics? If you're not rendering uncompressed then you're obviously rendering using a codec- which one? DV is dreadful for graphics, motion jpg is better ...

Personally I always go with uncompressed for graphics, to avoid the re-compression step and the associated artifacts.

ie., Motion [8bit uncompressed) => AVI/MOV File (8bit uncompressed) => NLE/FCP timeline [8bit uncompressed] => RENDER OUT

rather than
Motion [8bit uncompressed) => AVI/MOV File (compressed by codec) => NLE/FCP timeline [uncompressed by codec] => RENDER OUT [to different codec]


Of course, it's far better to use a "lossless" compression codec rather than pure uncompressed ... Same uncompressed result, less hard disk space (think lossless PNG vs. TGA). I use huffyuv or similar for PC, I'm not sure what options exist for lossless codecs on the Mac.

 

[Noel Evans]

Thanks for the reply. Just wasnt sure if I was going to achieve anything plus take a hit in render time.

 

[epicedium]

If you're using a decent loss-less codec (my apologies that I can't recommend one for the mac.. anyone?) then the only hit should be hard disk space. Render times shouldn't suffer at all- infact, some lossless codecs are probably faster than mjpeg. If anything, you'll be bound by your disc speed ... ie., your render speed might be constrained slightly due to your hard drive not being able to write as quickly as the cpu is processing.

If your project has complex grading/filters/etc then it will be purely cpu-bound, and the disc writing slowdown won't come into play. If your project is extremely simple and renders blazingly fast, then the hard disk issue will come into play.

Regarding the quality difference, how significant it is depends greatly on a) the type of material, b) the forgiveness of your output medium (and how pedantic you are), and c) whether you'll be further processing the material in the NLE.

Lossy codecs are shown in their worst light when you do this:-

[creation] => [render to m/jpeg] => uncompress to compositor/nle => compositing and grading pass => [re-render to m/jpeg]

These lossy codecs make "assumptions" about what the human eye can and can't see. It tries hard to drop the information that you can't see, while keeping enough targeted information that you hopefully can't see the difference. As soon as you composite or grade, then the messy bits get pushed into places that you can see... artefacts become more and more visible. And, of course, re-compression amplifies them further.

Hope that helps. Ultimately, if it looks good it is good There are projects where this is worth the hassle, and projects where the difference doesn't justify the hard disk space... but it is good to know exactly whats going on, as sometimes making the right decisions actually doesn't involve any more time/effort at all.

Kris