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Color management for HDTV and Final Cut Pro (Ray Maxwell)
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Color management for HDTV and Final Cut Pro (Ray Maxwell)



Hi to all,

The issue of color management for HDTV is an interesting topic. I'd like to take a few moments to give you some background that relates to why you don't find "color management" and particularly why you don't find ICC color management in general practice in this industry.

Point 1. Signals that have been encoded to HDTV standards are what is termed "output referred" . In the case cited by Ray Maxwell, his Canon HV20 has performed all the color management for the signal prior to the HTDV encoding. The signal is generally encoded, compressed and delivered in a YCC-4:2:2 format. There's not much room for massive transformations because the encoding has been performed rather agressively. The HDTV standards basically set all the colorimetric and photometric standards that are necessary for this encoding practice. ICC technology has been generalized to provide a robust mechanism for taking data from various source technologies, rendering those images into a common Profile Connection Space, and then outputting that data into an arbitrary output space dictated by an output device. If you are capturing a scene from video for reproduction in another medium, I would recommend using the new ICC sRGB perceptual rendering profile. Go to www.color.org and post a question to Phil (see ask Phil) and ask about the status of this work.

Point 2: Now we ask a simple question, "Why can't we calibrate a display and use an ICC profile to display to the screen?". If you are going video to video, the trip through the PCS is quite unnecessary. If you are working in a known color space, such as the one described by HDTV standards, the ICC technology is not really useful UNLESS you want to take a video image to paper or potentially record the video frames on to film. Here, the technology based offered by ICC technology is quite useful. If you are simply moving an HDTV image from file, or stream to display, then the display should be calibrated to match the HDTV standards. I believe that these are defined as REC 709 primaries, D65, gamma 2.4 (this possibly wrong, as I don't have the standard in front of me), and a defined encoding dynamic range (Once again I apologize, I am at home and don't have access to the standard). Essentially, this is the sRGB specification with a slightly different gamma. There is a lot of change going on in this area, and things may change shortly. The big problem on a computer system is that video path through the display card is not necessarily the same path used for images written into the normal display buffer. If you calibrate your display using standard products which use the LUTs, you may be disappointed to note that they are not used in the video path. This is very hardware dependent. Therein lies the biggest issue: We can sell hardware and software solutions, but there is no guarantee that any of it will be useful on a particular computer

Point 3. To circumvent these pit falls, specific displays have been designed to be calibrated outside of the OS to display the HTDV image correctly. See: http://www.cine-tal.com
This is a display that contains the calibration routines and interfaces to an i1Display directly. There are other offerings as well. Displays such as the high end Eizo displays and offerings from HP and NEC can be set up to a specific color standard based upon internal luts and the graphic scalar used in the display. These displays can be used, but the end-user has to be guided through the setup.


We do have a team within X-rite taking a careful look at this industry and we continuously meet with the manufacturers of hardware and software to get a better sense of the products that are required to fulfill the needs of this industry. The complication comes from the wide range of hardware, software, and non-standard workflows employed currently in the industry. From my own personal perspective, I believe that offerings which allow the color management of video images to be performed in the display rather than the video card, should be the direction the industry takes. The VESA DDC specs take us to this point. Now if we only could reliably talk to a display from any operating system.....

Regards

Tom Lianza
Video and Motion Picture Technology
X-rite






Message: 2 Date: Sat, 02 Jun 2007 23:21:20 -0700 From: Ray Maxwell <email@hidden> Subject: Color management for HDTV and Final Cut Pro Cc: email@hidden Message-ID: <email@hidden> Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi Group,

Most of us in this group come from a printing and photography background. However, I have recently made the move to HDTV and have purchased a Canon HV20 HDV camera. I also have Final Cut Studio 2. This new software comes with a "Color" application.

With that background...Let me tell you my experience.

There is no mention of computer monitor calibration or ICC color management to make your computer monitor match your video monitor. There is no mention of using any of the tools like EyeOne monitor calibration for the HDTV montior. It seems to be an whole new world that has never heard of color management.

They talk about placing the standard "PLUNGE" color bar pattern and than adjusting the monitor by eye. This sounds very primitive to me.

Final Cut Pro makes no mention of color management or ICC profiles. What is going on?

Has anyone else in this group made this transition and could you point me to a book or tutorial somewhere?

Thanks,

Ray Maxwell



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