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Old December 30th, 2009, 06:37 PM   #1
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Compressor increases contrast?

Hello all. Dumb question I know.. maybe I should actually read the manual that came with Final Cut....

But.... I swear Compressor by the act of shrinking HD to SD and the color conversion of HD to NTSC as well as dropping the bandwidth, that a lot of middle tones are thorwn away by compressor, leaving a more contrasty image. What really bugs me the most is on contrasty subjects... (girl in white shirt on a green field for instance) the black Mackie Lines that outline the constrasty white shirts. I'm going experiment when the Sun comes back out in (with my JVC HD110 with CineGama also experiment with CineColor matrix.. possibly EVEN dropping my color Gain) to make a more subdued image that I think would make a better DVD at the end.


I'm shooting a JVC HD110 with CineGama on, Color Matrix Normal (need to change to CineColor Matrix I think) Gain normal.. Detail -5, editing with Final Cut Studio HD (1st one) and shooting 720p 24fps edit native, convert to DVD via Compressor with most settings at Best and 6.2 to 8. bits a second.
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Old December 30th, 2009, 07:09 PM   #2
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I'm laid back about the changes Compressor introduces so I'm not the best to comment on this. I find that the DVD files are fine and that the changes introduced in web files are not enough to cause me headaches however if a client complains here is my method to find a solution. Video a color chart with a gray scale or better yet create or find a gray ramp video file (that is a gradient that goes from zero to 100 video). You can also find a stair step frame (zero percent, 10 percent, 20 percent and so on). FCP comes with a set of test signals that you can use also. Make a short video with the test signal of your choice and run that through Compressor and compare it with the signal as FCP plays it straight.

This way you can adjust the gamma in Compressor until you find the ideal setting for your needs. If that doesn't work, you can discover a global change that you can apply at the end of an edit in FCP (perhaps with the Color Corrector filter).
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Old January 4th, 2010, 10:35 AM   #3
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I have noticed that if I use the export option of exporting a full rez 422 HQ QT file, the exported .mov files are always brighter and maybe a little washed out.

Go into the settings and turn off "automatic gamma correction" and you'll get an output much closer to what you were seeing in FCP.

Make sense? The auto QT setting corrects gamma (as if I had it wrong!), so turn this option off.

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Old January 4th, 2010, 10:30 PM   #4
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This is a long-standing bug in FCP where the canvas and viewer are showing a color/gamma space that is closer to NTSC 601/HDTV 701 color standards but upon export QT is unable to display the same color space.

In QT 7 there was (and still is for Leopard users who opted for reinstalling that as an option) to have compatibility with FCS (see screen-grab).

If your output is primarily for DVD or broadcast (SD or HD) then having this checked will show you a very close approximation of what the end-users will see. However if your output is primarily web or mobile content then you need to un-check this option as web players even on the windows-side will have a brighter gamma response.

Quicktime "X" which is the default player for Snow Leopard does not have *any* controllable options for color-matching, in fact it has NO user-selectable options at all. Quicktime 7 should continue to be the de-facto standard player for any professional video playback.

Also, only FCP/FCS suffers from this gamma mismatch between canvas/viewer and external players. Premiere Pro, Avid and Media 100 all have this properly figured out; why Apple's own software hasn't had this bug addressed (going on more than 3 years now) is yet another head-scratcher from the wonderful world of "iPhone-land".
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Old January 8th, 2010, 11:10 AM   #5
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I wonder if editing in native hdv would be my biggest issue? I keep hearing thhat editing prorez hq and outputting from there holds up better with color etc than native hdv 720p 24fps does..... Sounds logical anyway. Something to try out and compare this weekend.
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Old January 8th, 2010, 11:31 AM   #6
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No, this has nothing to do with the gamma mis-match between the FCP canvas and how QT displays content.
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Old January 8th, 2010, 07:17 PM   #7
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Robert, hey thanks. but that really isn't what I think I'm referring to in my complaint about my DVD's. I think I have proved to myself that what i'm complaining about is NOT sourced in the encoder, but is in my camera. Meaning the black lines between bright white and medium dark colors... see the picture of the socks and green grass. There is black line between the two colors. The DVD encoder software does it's job to shrink the image and compress the image more, but retains this artifact. So I think the encoder is totally blameless.

My guesswork for what is the culprit is as follows. Anyone weigh in. I'll try to figure it out this weekend if it stops raining.

1. Edge enhancement. I think this one of the biggest factors. I'll dial the sharpness down from Normal to -5 and min (-10). In the past I got good results from -5.

2. Color Matrix (normal) need to switch to a more conservative color-gama like Cine-gama. I think this will also help the image. Dropping the overall contrast to a more film emulsion gama. Probably more the edge enhancement above.. but I think it will help.

3. CA from the stock 16x Fujinon lens in contrasty situations. This doesn't look like most CA to me. It's not Red/Green.. So I don't think this is the biggest cause... but I wouldn't mind a better sharper lens (Fujinon 17x or 13x or similar Canon) so edge enhancement will not be needed to snap up an image from a less than desirable lens (16x stock Fujinon). Meaning I could go to edge enhancement to Min or -7 and have the same sharpness because of the better lens.

4. HDV codec. Can't do much to fix except get a DVCPROHD or XDCAM-EX camera or a external portable capture device with componenet inuts that bypass the encoder and capture live in a less compressed format. In the image there is plenty of signs of HDV compression. Note the white shirts with the limited color change between shadow and bright with pixelation. I wonder how much of these black lines are exaggerated and increased by the HDV codec...

so the answer to this thread I think is camera related and not post production related.
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Old January 8th, 2010, 07:27 PM   #8
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Oh the above image is the 720p image frame grab with the Post DVD encoded footage frame grabbed, enlarged to match the 720p footage to compare the black "Mackie" lines on both images
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Old January 8th, 2010, 09:01 PM   #9
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Actually that's an issue common to many video cameras; there is an actual technical term for it (my friend in Burbank who's been doing broadcast work since before color TV could answer this) but what you're seeing is the "too hot edge shadow" which is common in many vid-cam imagers.

It's literally what the imager does to an image that has a lot of ultra-bright edges - it's *sorta* like CA, but not exactly. (damn, wish I could reference the technical term!)

It's not an HDV thing, and it's not an issue specific to your lens but it is specific to smaller-chipped cams. 2/3" inch cameras show this characteristic to a much lesser degree but trust me it's a "Video thing" altogether. Even RED and the SI camera suffer from this if contrast/pedestal/iris combos aren't kept in check.

There is however a fool-proof way to eliminate the phenomenon altogether: Shoot film. (^_*)
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