A bit Offtopic but i have to post it.

I found a new button at Quicktime. So long i wonder why in quicktime movies...

white scenes looks grey, and black scenes looks also grey

Sample PIC from a video:

and i now found the answer. every rendered mov file has the graphic mode "dither copy"... that makes black and white looks grey... but you can change the "graphic mode" to "Premultiplied black" and the white will be white and black will be black.

1. Open the Quicktime File.
2. Press "STRG+J"
3. Select "Video layer"
4. "Optical Settings"
5. change "Dither Copy" to "Premultiplied black"

         

Thanks luk, that comes in handy! I have always used the same quicktime settings for web compression but never changed the optical settings. I'll let you know how it goes.

         

What is "STRG+J"?

         

strg=steurung=option=apple=⌘

         

i made some screenshots (sorry, german version):

         

erm... on my macbook that "dither copy" transparency option is labelled more explicitly: "none (allow dithering)". tried changing it to "premultiplied black alpha" - doesn't make the video look any different. however, on my screen that same video actually already has the proper black values to begin with, exactly like the right side of your screenshot.

so maybe it's a problem specific to your pc/video card/screen: that it dithers where it would be better not to...?

         

yeah, maybe. I found nothing on the internet about that.

The "funny" thing is... when i play a "dither copy" (which is on my pc grey) in fullscreen with the quicktime pro version... than the grey is black! (i make screenshots and checked the color in Photoshop... the 91% black in fullscreen mode is 100% black. It's not my videocard... i think its something from apple)

that makes not sense at all. I know so many people that tries to fix the white and blacks in their videos... and everbody just say: its because of converting files... or such things. But its not.

its just a stupid "option button" from Apple. And all the mov files in html on the internet looks grey on a PC. (maybe they look black on an Mac. i don't know.)

i could also switch to "none" but the black looks grey, too. Only when i switch to "premultiplied black / white" the black will be black.

         

i think a know where the problem is. The Backround of a mov will be grey (you cannot change it. Its quicktime) but in fullscreen you can change the color to black) Quicktime Pyler options...

So every mov on the internet got a grey backround... that makes the white and black looks grey... you can change to "premultiplied black alpha" and the video will looks good.

I will check that also on a mac in some days. That really sucks in my opinion.

         

i made some tests an konvertet a mov file that looks "grey" to mpeg4 (not h.264) and opened the file qith Quicktime Player. The black looks black. Not Grey!

h.264 = black looks grey mpeg4 = black looks black

but with mpeg4 is not as good as h.264 (which is also a mpeg4 codec, i know)...

so i use "pre. black" to get black videos.

         

A word of caution:

As you increase contrast (by using the dark/black areas as a multiply layer), you sacrifice subtle detail... it's an inverse relationship.

         

"increase contrast" has nothing to do with it. couse the video itself is 100% black. You can't increase the contrast to 110% :)

The Quicktime Player (also mov files in html) makes it looks grey. DVPal, Sorensen3, 3ivx, h.264.. all grey.

but there are some formats QT will display them BLACK. But there is no "small format" for internet files... h.264 for example.

So the only trick is. Use 264 and then save the video with ""premultiplied black"... (thats nonsens but it works)

In my opinion apple has to fix this.

         

Hmm. It's actually all about contrast. What you're seeing is output using a lower contrast ratio with the alpha channel being ignored or falsely set to white.

Not all compression algorithms support an alpha channel when rendering the output. In cases where they do, it might be set incorrectly to white.

So yes, in some cases you will want to force Quicktime to use the available (black) alpha channel.

This isn't Apple's problem, but rather an issue with the way the video is being compressed and saved.

When you force pre-multiply on a clip that doesn't actually have an alpha channel, you're essentially throwing a full black multiplier over the entire thing. This will make your blacks black, but it'll also kill subtle detail on each end of your visible pixel range. You can blame the person who created the file for that...

         

No. It has nothing to do with Contrast. When i play movs (H.264, Sorensen3) with the Quicktime Player Pro (V.7.0.4) than the black will be white.

It has nothing to to with the rendering / konverting...

When i import the video in After Effects or Adobe Premiere the black is black! When i play the movs with the VLC Player the black ist black! When i play the movs with Quicktime Player the black is grey!

In the Video its 100% black. It's a problem with the quicktime player!

look:

         

Ah... we're talking about two different things :) I thought your video was rendered incorrectly and you were forcing it to use an alpha channel that wasn't there.

But it's still not a problem with Quicktime. You're talking about properly rendered videos WITH an alpha channel. Your video layer is not 100% opaque. If you don't tell Quicktime there is an alpha channel, it won't sense it automatically. That's why that button is there.

         

Well. I don't know what to do. Couse i render all my files corectly. Not only my files. Also other files displayed with "dark grey" instead of black.

If someone look at my files on my website... i have no chance to view them correctly. The file is correct... but Quicktime displayes it wrong.

And i want to fix that. And so i try the "black alpha thing"... which sucks. i know... but i want my files displayed correctly. ANd other files, too.

         

Ah, yeah I see what you're saying. You can't specify pre-multiply from an embedded QT player.

         

Have you tried using compressor, cleaner or squeeze to encode your videos. In compressor you have a lot more options when you are making your quicktimes. I've noticed that for some content with a lot of black the web presets sometimes come out a little grey. This is probably just part of the algorithm of the compression being used that averages all the values. With some content I've made up for this by adjusting the gamma correction as well as there's an option for black/white restore.

As far as things looking different in Photoshop I wouldn't trust it because it applies its own Look-up Table (LUT) to the image. In photoshop this is in Edit/Color Settings/Working Spaces. I'm just guessing the different players probably have varying LUT for gamma and contrast. I've noticed this when we composite in Shake (which won't apply a LUT other than that of your system settings) and then look at the same files in Photoshop (which the LUT can vary from machine to machine depending on the setting being used) the images can vary greatly. This is mainly going to be noticeable in the gamma.

I wonder if the original files you compressed had an alpha channel? Does it make a difference how you output your pre-compressed media with or without an alpha. It would be interesting to test.

         

If i render DV Pal Files out of Adobe Premiere. Using the mov Container... the Video will displayed "grey" when i play the files with the Quicktime Player.

It has nothing to do with compressor or something. I tested a lot. The screenhot above shows exaktly the problem. The video itself is totaly correct!

It's not only a problem with the color black. White is also displayed grey. It's just a problem with the quicktime player. VLC Player playback the videos with the right colors. Also Adope Premiere and After Effects shows the correct collor.

And of course i got no alpha layer in my video files. Never. Why should i test it?

Since years i was beliving that the "grey" cames from compression, or konverting files.. but its not true. It's just a "display problem" from the Quicktime Player.

amnothe example from your website (hope its okay to take that file:)

         

That's wierd because it's definitely not grey on my system (OS X). Have you looked at this on a different PC other than your own?

         

Yes. i checked other PC's (at my Uni). It semes to be a problem with the QT Player at WinXP. On Win XP black and white will be grey.

On a Mac with OSX the black will be displayed black... but the white will be grey,too. Just like on a PC.

It's really wierd and anoying. It has nothing to do with Windows or konveting, or codec. It's just the "bad" display mode of the QT Player.

         

hey luk: just having encountered this issue with a client (we delivered QT's that were fine on Mac, they saw them grey on PC), here's the diagnosis&solution they found: "The problem lies in the default QT settings for PC/Windows. Settings can be changed under Preferences -> Quicktime and then select 'GDI Safemode' on the Advanced tab."