PE4 HDV PROBLEM

[dalelpaq]

Maybe someone can help - I import a large uncompressed avi file - say 10G - dreived from HDV footage (specifically, I import 1440 X 1080 p30 into After Effects into a 1920 X 1080 p30 comp and render out as an uncompressed avi.) Anyway, PE4 loads it fine but is temperamental about playing it - it goes in fits and starts and the sound cuts in an out. Whenever it stops I can either wait 10 seconds until it recovers by itself or hit pause and then play again. I'm thinking my PC is just too slow! But maybe there's something in the program I'm missing. Thoughts? Also, I don't suppose there is any way to take advantage of OpenGL when using/playing PE4? Does PE7 have advanced capabilities in handling HD and huge files? Thanks, Dale

[Paul LS]

The problem with the uncompressed high definition avi file is that it is huge... for high definition it can be 2 to 3GB per minute. The biggest issue is probably with PE4 accessing it from your hard drive.

[Steve Grisetti]

There's also no value using uncompressed video in a Premiere Elements project. The program will convert it to a DV-AVI anyway in order to edit it.

So port it out of AE as a DV-AVI (or an MPEG2 if you're working on an HDV project). The quality will be excellent, and it will flow through PRemiere Elements effortlessly.

[Paul LS]

Yes, it will try to play the AVI file unless you render the timeline, then it will be converted to HDV MPEG2 as it is a HDV project.

[dalelpaq]

Alas, it's as I figured. I am confused by Steve's statement that the vid is converted to DV-AVI for editing - isn't this the SD codec? Anyway, what I do id output two modules from AE - one uncompressed which I use later to add visual effects and one compressed for ease of viewing. Thanks. BTW, the uncompressed version does indeed eventually get compressed for viewing.

[Paul LS]

If you use your clip in a standard definition project it will be rendered to DV-AVI and this will be placed on the timeline when you render the clip for smooth playback... if you use it in a HDV project it will be rendered to HDV MPEG2 when rendered.

[dalelpaq]

Thanks, got it. What's really going on is I capture my footage (HDV) and import it to after effects for CC, effects, etc. and then render it as uncompressed for use in PE4. If I render it compressed from AE (I could go right back to mpeg-2, for example), then PE4 - I think - has to uncompress it, do it's thing, then recompress it. In theory, every recompression results in degradation of the already degraded (sorry HDV) footage. Then again, degradation is in the eye of the beholder and perhaps I might never see the difference. Though I suspect segmenting a long movie into separate compressed files for later compilation into a long movie for viewing might begin to show the effects of multiple compressions.

[Paul LS]

Yes, that is the problem with the compressed format... multiple renders will kill the quality. That is why, like you, I use uncompressed AVI with AE. I should really look into a slightly compressed but "lossless" video codec. However, generally I tend to only edit short clips in AE.

[dalelpaq]

Part of my effort now is to correlate the writings of Stu Maschwitz (DV Rebel's Guide) with what I think I know about PE4 and AE. Stu's goal is to eventually get to film and thus some of his ideas may be overkill for pure video. That said, he's big on avoiding recompression so as to maintain quality until the final output (For me, that's Bluray mpeg2). I'm afraid I'm a little squishy on the following questions for lack of knowledge.

As I said, I'm starting with HDV footage (mpeg2, 1440 X 1080, PAR 1.33, 4:2:0) which I capture with HDVSplit. I really don't know what this utility does wrt compression? But, by the same token, I also have no idea what PE4 would do with the footage either if I used it for capture. In either case, is it being converted to RGB? Or, does PE4 work natively in the Y'CbCr space? Stu says that in this space, many NLEs can work with IREs up to 110% (he mentions Premiere Pro and by extension, I kind of assume PE4?). But when the Y'CbCr material is converted to RGB, the top 10% gets clipped. He proposes a means to avoid this so as to maintain highlight detail that involves using levels which PE4 doesn't have. PE4 offers a file>export option with an uncompressed Microsoft avi option that can be set for either 8-bit or 10-bit (10 means it includes an alpha channel I think) Y'CbCr compressor. I'm not sure what this means. Does the (lossless?) compression occur in Y'CbCr space? If this is used, does PE4 maintain the full luminance range so that the clipping problem can be corrected for in AE?

I know I'm getting kind of technical here and the answers may be of little practical value in the final analysis. Guess I prefer to know and understand the rules before I go ahead and break them.