Heavy pixelation at shot changes - QTime

K

kellyboy

Well-known member
Am I doing something wrong? Sorry if this is the wrong forum, but I tried the other "output and compression" and I can't get anyone to respond.

This is a link to my demo reel that I've posted on line. It's not DVX footage, but I'm an actor/ filmaker and use my DVX ll the time. This is my acting demo.
On my demo here, using Quicktime for exporting, I get bad pixelation every time the shot changes for about a second or so. On other movie trailers and stuff, I don't see that. AAHHH!! Driving me crazy. How can I fix it?
I use Sorenson 3, not the new H.264.

Joseph Kell

http://www.kellfilmandvideo.com/500.html

Thanks for any advice!
 
the pixelation is cause becuase of the sudden change in scenery.. the codec uses other frames to re-create parts of other frames.. so when frames are very dissimilar then things fall apart, especially at low bit rates.

Up the bitrate and this shouldn't be too much of an issue.
 
First off, congratulations on a number of good guest start roles. The reel is really a little too long in my opinion. Instead of showing every scene that you are in its entirety, you should edit them down, give a prospective CD (or agent) something to wonder about, not your entire performance. Most CDs won't go more than 3 - 5 minutes into a reel, at the very most. During that time, you should have shown them a bit of all the projects.

As for your fundamental question, I think that a shorter reel would allow you to use a little less of a heavy hand in compression; this could easily help (if not resolve) the problem. The reason for the "pixelation" is that you are using a compressor that is based upon an entropy approach and the data rate for a complete scene change isn't really high enough to support a smooth transition. You could improve this by adding some black frames (about 1/2 second worth) between each scene and then a short fade up to the new scene. This will give the decompresser an untaxing bit of video to work with before a complete new and unrelated frame appears.
 
Hey man!

Thanks for the kind words! Nice to hear that stuff.
And thanks for the help and advice. I will try those things to see if it helps.

Joe
 
No problem, happy to help. Let us know how it works out and if you edit your reel down post another link so that we can see how it turned out.
 
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