View Full Version : Compressor introducing artifacts


Dana Salsbury
May 21st, 2009, 03:01 PM
Far too common problem:

FCP exports perfect non-self contained QT file. Compressor (w/ up to 90min/highest quality setting) leaves behind pixelated 'stamps' toward the end. It's a nine minute video! I'm wasting many DVDs trying to baby this thing. Am I doing this wrong?

I'm on an 8-core Mac Pro, 8gb memory.

Robert Lane
May 21st, 2009, 03:38 PM
The export from FCP is "perfect" because it hasn't been compressed yet; you're looking at the original timeline codec/format prior to any conversions. And you'll never get optimal results from the built-in Compressor settings, you need to tweak them.

What formats are you converting from and to?

Dana Salsbury
May 21st, 2009, 10:35 PM
I'm compressing Pro-Res 422 1920x1080 60i 48kHz w/ capture preset HDV Apple ProRes 422.

In Compressor I'm using an MPEG2, m2v, progressive sd dvd w/ a 6.2 averae bit rate (Max 7.7) 15 IBB closed GOP.

Robert Lane
May 21st, 2009, 11:33 PM
You've got your terminology mixed up a bit; either you're capturing HDV into a ProRes timeline or you're editing in HDV. There isn't an HDV/ProRes setting, it's one or the other.

Either way your capture preset should match your timeline settings, if they don't that might be part of the problem. Or if you've got mixed formats - as you mentioned in a previous thread - you'd still need to convert one of them into the other format.

If you're down-converting HD to SD-DVD don't mess with the GOP structure, there's no reason to do that.

Here's ideal settings to use in Compressor; read the book I recommend: Compressor 3 Quick Reference Guide, Brian Gary... and understand why these work. It will take much longer to do an encode than the built-in preset you're using but the results will be far superior. Use a Frame Rate that best fits your final output intent. If you're converting interlaced into progressive during the encode you may need to tweak the deinterlace settings a bit and see what looks best on your footage. Remember to test small sections at a time, only 5-10 seconds is all that's required to know what you're getting.

I'll send you a bill for doing your home work for you. (laughs)

Brian David Melnyk
May 22nd, 2009, 12:18 AM
not sure about the compressor settings (though Mr. Lane has posted some great ones that work really well for me- maybe a sticky thread of them would be in order?), but you can stop wasting DVDs and instead build and format a disc image in DVDSP. you can then mount and test it, and burn copies with disc utility.

Dana Salsbury
May 22nd, 2009, 09:01 AM
Tha capture preset is HDV Apple ProRes 422, but I'm not capturing anything -- it's Panny AVCHD SD cards. If I needed to capture a minidv I'd have to use it. The Sequence Preset is Apple ProRes 422 1920x1080 60i 48kHz.

I made some changed per your screenshots, though I kept the Frame Rate at 29.97 since I didn't shoot in 24p.

As per quality, it looks fine until it starts flashing artifacts, and some of my DL DVDs are skipping though I burn at 2x.

Robert Lane
May 22nd, 2009, 10:20 AM
Dana,

You're still getting your terminology mixed up. There is no capture preset for "HDV ProRes". Maybe you're confusing the "HQ" setting in ProRes?

One thing you need to make sure is that since you're transcoding AVCHD into ProRes that you're using the proper sequence settings during edit *before* you send out for encoding to MPEG2. (see screenshots) Make sure you have "Motion Filtering Quality" at "Best".

As I've suggested before, you should get some formal training on how to accomplish the tasks that are giving you headaches; you're missing some basic information that is required to pull off good-looking edits and encodes.

If that's not financially feasible the on-line documentation in FCP and ProRes white-papers on the Apple website clearly outline the proper methods for transcoding, editing and final output. Here's the pages you need to find in your FCP Users Manual; all you need is right there:

Dana Salsbury
May 22nd, 2009, 01:43 PM
Thank you Robert,

When I Export to Quicktime Movie I have no options for deinterlacing like I have when I export to QT Conversion -- but that's just for web, so I'm not sue where to tweak deinterlacing.

The only ProRes options I have in the A/V Settings/Seqence/Summary/Capture Preset are:
HDV-Apple ProRes 422
HDV-Apple ProRes 422 (HQ)

What Capture Preset should I use when working with Pro-Res 422 1920x1080 60i 48kHz?
I changed it to Generic Capture Template since nothing else looks right.

I just don't see wha the capture preset has to do with it since the sequence setting is right.

The bigger problem now, since I changed my Compressor settings, is that a 20 second clip takes seven hours to compress, and my other clips are saying 47 hours.

Robert Lane
May 26th, 2009, 08:22 PM
The answers to all your questions are easily found within the references I've already given you. Set aside some time to sit down and read the materials; you're never going to learn this stuff if you're always asking someone else to do your homework.