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H.264 web compression changes color & contrast....?


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#1 Matt Irwin

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Posted 10 February 2008 - 08:53 PM

I'm trying to export a clip to put up on my site as a showpiece and been having trouble with color and contrast mismatches.

The project was shot on film and TK'd to D5, and the quicktime file I was given for my reel was compressed in "XDCAM HD 1080p/24 (35Mb/s VBR)."

I am exporting in Final Cut Pro 5.1.2 using Quicktime Conversion:
Compression= H.264
Quality= High
Frame reordering= yes
Encoding Mode= multi-pass
Prepare for Internet Streaming= yes - Fast Start

Attached is a screen capture to give an idea of the before and after. Left-side image is the original XDCAM (looks correct), right-side image is after export to H.264 (looks like poop).

I wish I was a codec genius... any ideas on what the problem is?

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#2 Adrian Sierkowski

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Posted 11 February 2008 - 10:16 AM

I havn't seen anything like that when I am changing over to h.264, but I have noticed differences depending on computers(pc and macs with their different gammas!)/programs for playback.
Also, have you tried doing it through compressor, e.g. exporting it just straight from FCP and then bringing it into compressor and letting it handle the compression? I don't know if there is a substantial difference in terms of quality, but it's how I always handle it.
That is one hell of a substantial change though. . . the only time i've seen something like that is when i was dealing with some stuff coming out of apple's color on one machine, and "forgetting," the metadata for it on another machine.
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#3 Walter Graff

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Posted 11 February 2008 - 10:51 AM

Put your original up and then look at the FCP waveform and vectorscope and see if color is beyond legal limits. Also know that this has been an issue with H.264 for a few years that has to do with both Quicktime and different web browsers making different pictures. I know folks who have teh problem say they don't when they make the movie with compressor as opposed ot going through quicktime engine.There are workarounds. Search the web for color shift H.264 to see how folks deal with it.
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#4 Phil Rhodes

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Posted 11 February 2008 - 12:11 PM

I have seen this quite commonly. I think it's actually Quicktime Player that's causing the problem as if I play these pumped-up videos back in mplayer the tend to come out a bit saner.

The only thing I can speculate is that some sort of gamma conversion setting is being made in the file. God knows why this is so because it appears to be wrong for everyone - I mean, we're used to Macs doing odd things and expecting everyone to dance to their tune, but this is obviously wrong for you too.

So in conclusion god knows, but it happens a lot. The H.264 subsystem in Quicktime is pretty feeble at the best of times - here's hoping we get something better soonish.
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#5 Matt Irwin

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Posted 11 February 2008 - 02:43 PM

Thanks for the help guys.

This is asinine, but I may have found a solution...
In Quicktime Pro--
-Open clip
-Window menu > Show Movie Properties
-Select "Video Track", then click "Visual Settings"
-Change Transparency (drop-down menu) to "Composition."
-Save clip

Doing this made the same terrible looking clip look normal. [See attached screen capture showing original ( L ), export ( B ), and fixed export ( R ).]

I previewed in Safari and Firefox, and fixed clip looks normal in both. Good....

What pisses me off though- and you were right Phil- is that when I check the original XDCAM clip against both the inital bad-looking export and the QT Pro corrected export using FCP, the image AND the waveforms look normal and identical for all three! It seems to be QT Player and Safari that are at fault...WTF.

Now as long as the fixed clip looks normal on Windows + IE/Firefox, all is well.... right?

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#6 Phil Rhodes

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Posted 12 February 2008 - 03:27 AM

It's not Safari; Safari (and many other web browsers) are just using the Quicktime plugin, so it's the same code at the core of it. Your fixed version still looks a bit sat-up to me.

Phil
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#7 Walter Graff

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Posted 12 February 2008 - 07:39 AM

It's not Safari; Safari (and many other web browsers) are just using the Quicktime plugin, so it's the same code at the core of it. Your fixed version still looks a bit sat-up to me.

Phil



Actually I read up on this problem last night and it is affected by different web browsers such as Safari.
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#8 Matt Irwin

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Posted 12 February 2008 - 01:24 PM

That's what scares me.
Footage looking different between different web browsers is unacceptable for showreel/resume material. I don't want to lose out on a job because a producer looks at my site with IE or the wrong version of "X" plugin and sees pale, washed out footage.

In your opinions, would flash video be a better way to go for this situation (having universally identical color/gamma), or should I keep messing with QT for a better solution?
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#9 Adrian Sierkowski

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Posted 12 February 2008 - 01:31 PM

I always find that flash doesn't do too well because it is so compressed. It gets "boxy," with large pixels.
Also even flash will look different because PCs and Macs use 2 different gammas, and lets not forget that there is a world of difference between CRT/LCD/and Plasma monitors.
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