[Mike Jackson]

Thanks guys, I’ll give all those a try.

Blackmagic’s Disk Speed Test gave me numbers that were all over the map – My first test gave me a read speed of 240mb/s and a write of 40 (!), but subsequent tests quickly levelled out to the more usual 185 / 185. Very strange. The RAID *is* pretty full (I’m desperately trying to finish a feature), but the performance change was pretty sudden…

[Mike Jackson]

Well dang and tarnation. So much for socking away any spare cash from my current doc gig…

Anyway, thanks guys! Very much appreciated, as always.

[Mike Jackson]

Thanks guys. Bypassing FCP entirely seems to have done the trick, though it didn’t the first time I tried… mind you, that was at 2:30AM, so I probably just made a bleary-eyed mistake on that attempt.

What I’d love to know is what’s really going on. Is this a recent bug? Or is it something I’ve never encountered before because most HD shows I cut are 24P? I just about had conniptions though, adding and removing the shift-fields filter in the timeline, and watching harsh aliasing appear any time it became lower first.

[Mike Jackson]

I’ve been having these same rendering issues for the last month, on two vastly different edit systems… Crossfades mis-rendering, going black, having shots freeze, text overlays mis-rendering or vanishing entireley… even banding in dips to black!

It’s been happening on both my home system (dual 2.7 G5 with 3 Gigs RAM) and the office system for my current project (8 core MacPro, super new but don’t know the stats off-hand). The one commonality with both has been ProRes 422(HQ) and Uncompressed 10-bit sequences, with both color and motion rendering set to best. Dropping color rendering back to 8-bit solves the problem… except of course for the fact that color rendering quality is poorer.

I’m actually happy to know it may be a QT problem… I’ve been tearing my hair out…

[Mike Jackson]

I’m using that plug-in set, and so far no problems… but I haven’t tried every single filter (I do most of my work with 3 or 4 of them, and can go months without touching the rest).

My render times are longer than I remember, but I’m doing HD work right now with ‘force 16-bit processing’ toggled on everything, so I can’t really compare.

I’m on an old dual 2.7 though… Are you on an Intel Mac? Could that be part of the problem…?

[Mike Jackson]

I just finished up a show with a bunch of greenscreen footage from the HVX. Some of it keyed wonderfully, but one shot was an unbelievable pain in the ass.

Like DV, DVCProHD has a lower color space… so watch for bleed and buzzing on your brighter edges. We had a gold rim-light on our actors and the center of our screen was too bright, so the chroma got way too close. That caused no end of trouble for the key… Could’ve gotten away with it in HDCam, but in DVCProHD, not so much.

The HVX does an upres from a slightly smaller sensor, too, so you’ll get some softening in the image. I shot at 1080 which compounded my problems…

[Mike Jackson]

I’ve posted some frames here:

https://www.steampoweredfilms.ca/Temp/BadRenders.htm

Ironically, Color seems to be able to handle my graphics card just fine.

Using graphics cards for acceleration seems like a great idea in theory, but it adds so much more of a crap-shoot to every task, depending on your hardware. I’d kill for a button to force a render to work through the CPU, regardless of how long it takes, if it meant consistent, reliable results.

[Mike Jackson]

I’ll third Synthetic Aperature’s Color Finesse. Curves and secondary color-correction, plus 32-bit floating-point calculations, so no banding or artifacts. Be prepared for longer render times though… Definitely not an RT kinda deal.

I’ve also used the DFT 55mm filter package, and it sort of splits the difference – No curves or secondary, but more control and better results than the 3-Way corrector, and you can render in 16-bit.

Mike Jackson
Steam Powered Films

[Mike Jackson]

I get this problem too, and it drives me nuts. Not just because I can’t figure out what causes the error, but also because there’s no time saver in compressor like ‘use most recent settings’, so I have to re-do the entire export process, over and over, changing settings one by one until it works. I still can’t establish the pattern either – Though it seems to happen most frequently if I’m exporting through FCP and have a lot of filters on the footage, or if I dare to touch any of the re-sizing quality controls. I’ve never had so little success trouble-shooting an error, and all I really know for sure is that I *don’t* have a problem if I just use a preset and spit out MPEGs for DVD.

So I would LOVE to know what sets off this error, and how to at least avoid it. Until then, I’ve gone back to After Effects (of all things!) for any complex work.

-Mike Jackson
Steam Powered Films

[Mike Jackson]

Hahaha – Very interesting! I’ve just been looking at it unrendered (Unlimited RT). But here’s how it breaks down with further analysis –

Original footage flickers in RT, but plays fine if rendered (hooray!)

Nested footage plays *perfectly* in RT, and looks identical when rendered.

So why would nesting allow smooth RT slow-mo *without* rendering, if it doesn’t work with the original footage? Crazy.

And yes, full-quality, viewed on an external NTSC monitor. And in answer to Michael Alberts, yes, field dominance is exactly as it should be…

-Mike Jackson
Steam Powered Films