“That opting out [of creativity] that happens in childhood … moves in and becomes more ingrained by the time you get to adult life.” (David Kelley)

http://www.colorgradingcentral.com/archives/davinci-resolve-contest-giveaway

With the new SANLink Thunderbolt to Fibre Channel adapter from Promise shipping recently. I wanted to add a couple Mac Mini machines to the XSAN for Tosh.0.

The problems?  The XSAN is running 2.2.2 on OS X 10.6.8.  That means the Mac Mini’s, which only ship with OS X 10.7, wouldn’t be a good choice to add as clients until I upgraded the Metadata Controllers, but we are in the middle of a production cycle, so that wasn’t a viable option.  So I had to try to install Snow Leopard on those machines first.  After several failed attempts to build and update the installation, I came across an Apple Discussion with some very helpful tips, including what turned out to be the key for me, to copy over the kernel extensions from a 10.7 Lion installation.

The following is an abbreviated recap posted by user David Amis, recalling solutions by newfoundglory, Kasper E and others.

Full instructions for installing Snow Leopard 10.6.8 on a 2011 Mac Mini, version 2.

This is an assembly of what has been discovered and posted by newfoundglory, Kasper E, and others, with much detail added. These instructions look long and complicated, but it’s just detail and options.

The problem: The 2011 Mac Mini ships with Lion (10.7), which is unusable for many users. Snow Leopard (10.6.8) can be installed, but without some alterations it will be slow and will have the Phantom Display* issue.

There are three possibilities for how the installation will be used: clean new install, migrate from an existing computer during the install, and create an installation that can be copied to many 2011 Minis. It’s helpful to determine which type of installation you intend in advance, but only in your choice of user name. If you want a clean new install, use the user name you want to be the final user name. If you migrate during the install, the user name from the old machine will be used. Otherwise, use a temporary name, such as ‘Admin’, which you will replace later (Migration Assistant requires this if not run during install). When you have completed the installation, you can duplicate it to other Minis using SuperDuper or Carbon Copy Cloner.

To do the installation, you’ll need the following:

1. A 10.6.x install DVD, and any machine that will run it (also, it should have 10.6 installed). For example, the 10.6.3 retail install DVD will work on any machine introduced before 10.6.3, but a 2011 MacBook Pro must use the 10.6.6 DVD it shipped with. I used a 2011 MacBook Pro, so in these instructions I’ll refer to the second machine as ‘MBP’.

2. A Firewire cable. The Mini has FW800, so you need either a FW800-FW800 or a FW800-FW400 cable, depending on the second machine.

3. 10.6.8 Combo update, downloaded to the MBP.

4. A few kernel extension (kext) files from 10.7 and 10.6.8 (specific versions). Available here in a folder called “MacMini2011 Snow Leopard kexts”:

MacMini2011 Snow Leopard kexts

Install Snow Leopard:

1. Start the Mini in Target Disk Mode (TDM) by holding the T key, connect to MBP with the Firewire cable. The Mini’s hard drive will show up on the MBP’s desktop.

2. Boot MBP from the Mac OS X 10.6.x install disc. The next several steps will be performed on the MBP.

3. If you didn’t preserve the 10.7 installation as described above: You can’t install 10.6 over 10.7, so you need to erase the single partition on the Mini’s HD. Open disk Utility and select the partition (i.e.’Macintosh HD’) on the left (not the ‘Media’), click the erase tab, and erase it. You may want to use a different name from the MBP’s HD, so you don’t get them confused. In any case, the Mini’s HD will have the Firewire icon.

4. Install 10.6.x on the Mini’s HD. Be sure customize the install to add Rosetta and QT7.

5. At the end of the install, restart, but hold down the option key and boot from the MBP’s HD.

6. Install 10.6.8 combo update v1.1, and click “Change Install Location” at the Destination step, and choose the Mini’s HD for the install. If it doesn’t work, try it again. If it still doesn’t work, you’ll have to boot the MBP from the Mini’s HD and finish the install, then install the update.

7. Shut down MBP and Mini, and remove the Firewire cable.

8. Now connect Mini to a monitor and boot from its own HD. It should work, but it may have Phantom Display issues.

9. The final steps of the install will be done on the Mini, either migrating from an old Mac, or creating a new user.

10. (optional, perhaps a bad idea?) For good measure, and to make sure no drivers were missed, Install 10.6.8 combo update v1.1 again, this time directly from the Mini.

Fix kernel extensions:

1. Copy the “MacMini2011 Snow Leopard kexts” folder to the Mini’s desktop and open the folder.

2. Also open this folder:

/System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/ACPI_SMC_PlatformPlugin.kext/Contents/Resources/ 

An easy way to do this is to open a new finder window, copy the path above (from first to last ‘/’), choose Go to Folder from the Go menu, and paste the path.

NOTE: in step 3 and a few other steps, you’ll be required to Authenticate.

3. Drag Macmini5_1.plist, Macmini5_2.plist and Macmini5_3.plist from “MacMini2011 Snow Leopard kexts” to the Resources folder.

4. Now open this folder:

/System/Library/Extensions/ 

NOTE: After you perform step 5 and also after 6, you may get the “System Extensions cannot be used” dialog several times. You can ignore the error.

5. Find AppleIntelHDGraphics.kext and AppleIntelSNBGraphicsFB.kext, and move them to the trash.

6. Drag AppleIntelHDGraphics.kext and AppleIntelSNBGraphicsFB.kext from the “MacMini2011 Snow Leopard kexts” folder to the previously opened Extensions folder.

7. Open the Terminal app in the utilities folder, and type the following:

sudo su - 

It will then ask for your password.

8. Paste the following into terminal:

cd /System/Library/Extensions/IOPlatformPluginFamily.kext/Contents/PlugIns/ACPI_SMC_PlatformPlugin.kext/Contents/Resources chown root:wheel Macmini5* chmod 644 Macmini5* cd /System/Library/Extensions chown -R root:wheel AppleIntelHDGraphics.kext chown -R root:wheel AppleIntelSNBGraphicsFB.kext chmod -R 755 AppleIntelHDGraphics.kext chmod -R 755 AppleIntelSNBGraphicsFB.kext kextcache -system-prelinked-kernel kextcache -system-caches exit echo 'Finished' 

 the commands will take some time (a minute or so), and you will get an error about InternalModemSupport.kext that you can ignore. It’s complete when you see ‘Finished’.

9. Now reboot your Mini, and you’re done!

That was all great.  I got the Mini’s running 10.6.8 headless and was very excited when I got my SANLinks.  I unboxed them, hooked them up and nothing.  Oddly, the Mini’s were reporting them in the Thunderbolt section of System Profiler, so what was going on?  They were blinking because they were receiving a signal from the Fibre Channel switch, but when I connected an optical cable, I noticed there was no transmission signal.  Hmmm?  Update Thunderbolt.  Using Pacifist, I installed the Thunderbolt 1.0 and 1.1 updates and restarted.  Voila.  The Mini’s saw all the LUN’s, even though it is not connected to “Qualified” storage or Fibre Channel Switch.

Regardless, thanks to the users above for a nice, simple solution for helping me get these Mini’s on.  I set them up as additional Qmaster Clusters so they could help with our transcoding.  Already, they have saved us a couple of times by being available to help get cuts to where they needed to go faster.  Can’t wait to do it all again when I upgrade to 10.7!

Make sure to register to view the event online or in person.  At least make sure to upload your thoughts and view the video.

But what if you have multiple machines with access to file-level shared storage, like XSAN.   All client computers can have access and write access to the SAN simultaneously, so how can we utilize this fact to process distributed encoding tasks across multiple computers?

The typical setup goes something like this; Setting up the local machine as a “QuickCluster with Services” and setting the cluster storage to something local or leaving the default.

When I was first setting up a system for distributed rendering via Qadministrator into a single client managed cluster, there was a lot of regular maintenance and command line resets for all the client machines.  Often, the cluster would choke or freeze or clients would drop off unexpectedly.  Sometimes I would have to stop what I was doing to rebuild the cluster from scratch altogether.  But why not utilize one of the features built into Qmaster and Compressor to create a more flexible cluster environment?

Instead of forcing all the computers to adhere to the rules of a single managed cluster set up each machine on the SAN as an independent unmanaged QuickCluster with the “Include unmanaged services from other computers” checkbox checked.  This allows for clients to manage their own contribution to the distributed encoding process.  You can still utilize command line to turn on client services at night for example with just:

qmasterprefs -cluster on

There are a couple of other setup things you should do, like setting your cluster storage to somewhere on the SAN.  Make sure this directory has full Read/Write permissions or better yet, ACL’s.  Also, you will have to make sure you also have Read/Write permissions to whatever folder your source is located if you decide your target destination is source.  Ideally your source material and destination should always be on the SAN in order to take full advantage of the cluster.  If you want your client machines to administer their own contribution, an easy way for them to monitor and quickly change their status is by checking “Show Apple Qmaster service status in menu bar”.  Finally, open Compressor > Preferences on each client and be sure to set to never copy files to/from cluster.  This is done over the network interface you have selected and can be slow if you are transferring a massive quicktime to everyone.  Besides, everyone already has access in a SAN environment, right?

Now when you submit a batch from Compressor, you will have to option of which cluster to send the batch to.  Select your own cluster so you can monitor if needed, and check the box next to the cluster selection pulldown to Include unmanaged services.  Submit your batch and you should be good to go.  Now say edit03 has to drop off the cluster services to do some multicam editing.  Simply stop services in the Qmaster System Preferences pane and in most cases, the segments assigned to edit03 will either be finished or reallocated to available services.  Worst case is that current target won’t correctly reallocate and therefor won’t finish compressing completely and you have to do that one again.  In a large environment, this probably isn’t an issue because there are so many computers involved that compressions are extremely fast and don’t overly strain a single machine anyway.  In smaller environments, you can simply communicate your need to do large compressions and give everyone the option to drop off or keep services active.

I hope this helps some people get the most out of their equipment.  I am a big fan of distributed processing.  It just takes a bit of forethought and a little setup, but then you should be pretty happy with the results.  If you want more command line resources for a distributed processing setup, refer to the Distributed Processing Setup Guide.

Final Cut Pro composite modes determine how the brightness and color of one clip visually interact with those of another clip layered beneath it in a sequence. When you edit a clip into your sequence, it defaults to the Normal composite mode, meaning that it is a completely opaque layer that does not blend with the layers beneath.

How Composite Modes Affect Images

Composite modes mix colors from overlapping images together based on the brightness values within each color channel in an image. Every image consists of red, green, blue, and alpha channels (or one luma and two chroma channels in the case of Y′CBCR component video). Each individual channel contains a range of brightness values that defines the intensity of each pixel in the image that uses some of that color.

The effect that each composite mode has on objects that overlap in the Canvas depends on the range of color values within each object. The red, green, and blue channels (or Y′CBCR channels) within each overlapping pixel are mathematically combined to yield the final image.

These value ranges can be described as blacks, midrange values, or whites. These regions are loosely illustrated by the chart below.

For example, the Multiply composite mode renders color values that fall into the white areas of an image transparent, while the black areas of the image are left alone. All midrange color values become translucent, with colors falling into the lighter end of the scale becoming more transparent than the colors that fall into the darker end of the scale.

 

Important: Final Cut Pro composite modes work in conjunction with a clip’s Opacity parameter. The composite mode you select determines how the color values of one clip interact with those in the clip beneath it. Additional changes made to a clip’s opacity can lighten or intensify this effect.

Composite Modes in Final Cut Pro

The following section describes how composite modes affect two layers in a sequence.

About the Examples in This Section

Most of the examples in this section combine the following two reference images to create a third composite image. The composite image illustrates how the color values from each image interact when using each composite mode. When examining the results, pay particular attention to the white and black areas of the colored squares, as well as the highlights and shadows in the monkey image. These show you how each composite mode treats the whites and blacks in an image.

The other brighter and darker colors serve to illustrate each composite mode’s handling of overlapping midrange color values. The yellow, gray, orange, and blue squares, in particular, all have very different color and luma values that contrast sharply from example to example.

Important: Depending on the composite mode, layer ordering may or may not be important. Certain composite modes behave differently depending on which image is on top.

Add

Add emphasizes the whites in each overlapping image, lightening all other overlapping colors. The color values in every overlapping pixel are added together. The result is that all overlapping midrange color values are lightened. Blacks from either image are transparent, while whites in either image are preserved.

The order of two clips affected by the Add composite mode does not matter.

Suggested uses: The Add composite mode is useful for using one image to selectively add texture to another, based on its lighter areas such as highlights. You can also use Lighten and Screen to create variations of this effect.

Subtract

Subtract darkens all overlapping colors. Whites in the foreground image go black, while whites in the background image invert overlapping color values in the foreground image, creating a negative effect.

Blacks in the foreground image become transparent, while blacks in the background image are preserved.

Overlapping midrange color values are darkened based on the color of the background image. In areas where the background is lighter than the foreground, the background image is darkened. In areas where the background is darker than the foreground, the colors are inverted.

The order of two clips affected by the Subtract composite mode is important.

Difference

The Difference composite mode is similar to the Subtract composite mode, except that areas of the image that would be severely darkened by the Subtract composite mode are colored differently.

The order of two clips affected by the Difference composite mode does not matter.

Multiply

Multiply emphasizes the darkest parts of each overlapping image, except that midrange color values from both images are mixed together more evenly. Progressively lighter regions of overlapping images become increasingly translucent, allowing whichever image is darker to show through. Whites in either image allow the overlapping image to show through completely. Blacks from both images are preserved in the resulting image.

The order of clips affected by the Multiply composite mode does not matter.

Suggested uses: The Multiply composite mode is particularly useful in situations where you want to knock out the white areas of a foreground image and blend the rest of the image with the colors in the background. For example, if you superimpose a scanned sheet of handwritten text over a background image using the Multiply composite mode, the resulting image becomes textured with the darker parts of the foreground.

Screen

Screen emphasizes the lightest parts of each overlapping image, except that the midrange color values of both images are mixed together more evenly.

Blacks in either image allow the overlapping image to show through completely. Darker midrange values below a certain threshold allow more of the overlapping image to show. Whites from both images show through in the resulting image.

The order of two clips affected by the Screen composite mode does not matter.

Suggested uses: The Screen composite mode is especially useful for knocking out the blacks behind a foreground subject and is an alternative to using a luma key. Screen is mainly useful when you want the rest of the foreground subject to be mixed with the background image as well, based on its brightness. It’s good for glow and lighting effects, and for simulating reflections. You can also use the Add and Lighten composite modes to create variations of this effect.

Overlay

Whites and blacks in the foreground image become translucent and interact with the color values of the background image, causing intensified contrast. Whites and blacks in the background image, on the other hand, replace overlapping areas in the foreground image.

Overlapping midrange values are mixed together differently depending on the brightness of the background color values. Lighter background midrange values are mixed by screening. Darker background midrange values, on the other hand, are mixed together by multiplying.

The visible result is that darker color values in the background image intensify overlapping areas in the foreground image, while lighter color values in the background image wash out overlapping areas in the foreground image.

The order of two clips affected by the Overlay composite mode is important.

Suggested uses: The Overlay composite mode is particularly useful for combining areas of vivid color in two images.

Hard Light

Whites and blacks in the foreground image block overlapping areas in the background image. Whites and blacks in the background image, on the other hand, interact with overlapping midrange color values in the foreground image.

Overlapping midrange color values are mixed together differently depending on the brightness of the background color values. Lighter background midrange values are mixed by screening. Darker background midrange values, on the other hand, are mixed together by multiplying.

The visible result is that darker color values in the background image intensify overlapping areas in the foreground image, while lighter color values in the background image wash out overlapping areas in the foreground image.

The order of two clips affected by the Hard Light composite mode is important.

Soft Light

The Soft Light composite mode is similar to the Overlay composite mode. Whites and blacks in the foreground image become translucent but interact with the color values of the background image. Whites and blacks in the background image, on the other hand, replace the overlapping areas in the foreground image. All overlapping midrange color values are mixed together, creating a more even tinting effect than that created by the Overlay composite mode.

The order of two clips affected by the Soft Light composite mode is important.

Suggested uses: The Soft Light composite mode is useful for softly tinting a background image by mixing it with the colors in a foreground image.

Darken

Darken emphasizes the darkest parts of each overlapping image. Whites in either image allow the overlapping image to show through completely. Lighter midrange color values become increasingly translucent in favor of the overlapping image, while darker midrange color values below a certain threshold remain solid, retaining more detail.

The order of two clips affected by the Darken composite mode does not matter.

Suggested uses: The Darken composite mode is useful for using one image to add texture to another selectively, based on its darker areas. You can also use Screen for variations on this effect.

Lighten

Lighten emphasizes the lightest parts of each overlapping image. Every pixel in each image is compared, and the lightest pixel from either image is preserved, so that the final image consists of a dithered combination of the lightest pixels from each image. Whites in both images show through in the resulting image.

The order of two clips affected by the Lighten composite mode does not matter.

This information was reproduced here from the Final Cut Pro Help website.

In the RGB color model, all three channels contribute to the perception of brightness. In the early 1950s, this was a problem when developing a three-channel color television system that would be compatible with existing black-and-white televisions. The solution was to encode a single channel that represented luminance—light intensity as perceived by humans—which existing black-and-white televisions could decode. Color televisions would receive the same luminance channel and two additional color channels that could be decoded back into RGB color for display.

The UV representation of chrominance was chosen over straight R and B signals because U and V are color difference signals. This meant that in a black and white scene the U and V signals would be zero and only the Y’ signal would need to be transmitted. If R and B were to have been used, these would have non-zero values even in a B&W scene, requiring all three data-carrying signals. This was important in the early days of color television, because holding the U and V signals to zero while connecting the black and white signal to Y’ allowed color TV sets to display B&W TV without the additional expense and complexity of special B&W circuitry. In addition, black and white receivers could take the Y’ signal and ignore the color signals, making Y’UV backward-compatible with all existing black-and-white equipment, input and output. It was necessary to assign a narrower bandwidth to the chrominance channel because there was no additional bandwidth available. If some of the luminance information arrived via the chrominance channel (as it would have if RB signals were used instead of differential UV signals), B&W resolution would have been compromised.

Luminance

Luminance is a measure of physical light intensity modified by the spectrum sensitivity measured in human vision. In other words, red, green, and blue contribute to the perception of brightness, but not equally. Since two of the cone cell types in the eye favor light in the green portion of the spectrum, the luminance channel is weighted to mostly represent the green color channel. This makes the luminance channel appear to have the equivalent brightness that we see in a color image.

The YʹCbCr color model derives luminance from the Commission Internationale de l’Eclairage (CIE) XYZ color system, in which the Y component represents luminance (X and Z represent color components).

In video systems, a gamma adjustment is applied to the RGB color channels to make efficient use of the bandwidth available for carrying and recording signals. The gamma-adjusted channels are called R′G′B′, and the derived black-and-white channel is called Yʹ, or luma.

Luma

Luma describes the brightness of video, from absolute black, through the distribution of gray tones, all the way up to the brightest white. Luma is completely separate from the color of your video. In fact, if you viewed the luma of a video clip by itself, you would see a grayscale image completely devoid of color.

Luma is measured by Final Cut Pro as a digital percentage from 0 to 100, where 0 represents absolute black and 100 represents absolute white. Final Cut Pro also allows you to see super-white levels (levels from 101 to 109 percent) if they exist in your clip. Although super-white video levels are not considered to be broadcast-safe, many consumer camcorders record video at these levels anyway.

Note: In analog video, luma is measured in IRE units. These IRE measurements are irrelevant in Final Cut Pro because it deals only with the digital signal that exists in your computer as a straight percentage from 0 to 100 for NTSC and PAL video.

About Gamma

Gamma is an implicit or explicit transfer function that maps input intensity to output intensity, usually in a nonlinear way. The most common example is a CRT monitor, where the brightness onscreen is less than expected based on the input voltage. If the input voltage ranges between 0 (black) and 1 (white), one would expect a voltage of 0.5 to generate a brightness value of about 50 percent gray on the screen, but in fact only 18 percent gray is generated. This is simply the nature of a CRT’s electron gun response to input voltage.

The CRT applies an implicit power function in which the input signal is raised to the power of 2.5 (V2.5). Gamma is usually defined by the value of the exponent in the power function—in this case, 2.5.

Keep in mind that in most computer systems, images are encoded with a gamma of about 0.45 and decoded with a gamma of 2.2; a notable exception, until the release of Mac OS X 10.6 (Snow Leopard) in September 2009, were Macintosh computers: they used 0.55 and 1.8 respectively. In any case, binary data in still image files (as JPEG) are explicitly encoded (that is, they carry gamma-encoded values, not linear intensities), as are motion picture files (such as MPEG). The system can optionally further manage both cases, through color management, if a better match to the output device gamma is required.  Monitor your images with an external Monitor please.

Color Difference Channels

The color channels, CB and CR, are derived by subtracting Y from the R and B signals and are sometimes referred to generally as B-Y and R-Y, or color difference channels. Analog video systems such as Betacam SP use PB and PR channels, and digital video systems use CB and CR. Each color channel format performs the same function, but the underlying specifications are slightly different.

In digital video, the color channels are typically sampled less often than the luma channel, reducing the video data without noticeable loss of image quality. The ratio of sampling between the YʹCBCR channels is often written as 4:2:2, 4:1:1, and so on, depending on the sample rates used.

Chroma

Chroma describes the color values in your clips, ranging from the absence of color to the maximum levels of color that can be represented. Chroma has two properties, hue and saturation.

Hue

Hue describes the actual color itself, whether it’s red or green or yellow. Hue is measured as an angle on a color wheel.

Saturation

Saturation describes the intensity of a color, whether it’s a bright red or a pale red. An image that is completely desaturated has no color at all and is a grayscale image. Saturation is also measured on a color wheel, but as the distance from the center of the wheel to the edge.

As you look at the color wheel, notice that it is a mix of the red, green, and blue primary colors that make up video. In between these are the yellow, cyan, and magenta secondary colors, which are equal mixes of the primary colors. These colors are most intense at the outer rim of the wheel and gradually desaturate to pure white at the center, indicating the absence of color.

This information was reproduced here from Wikipedia and Final Cut Pro Online Help Documentation.