David Esp Video Technical Blog

What are they exactly?

Some tips gained from forums:

• If the CFHD AVI is brighter gamma-wise and less saturated than expected, then try un-checking the Use Video Systems RGB (Default On) checkboxes for Encode and Decode.
• Conversely, if the image shadows are darker than expected, check the Use Video Systems RGB checkboxes for both Encode and Decode.
• Use 709 for everything bigger than SD.

• Example Google Search: [cineform codec settings decode “Use Video Systems RGB”]

Example DvInfo Search: [“Video, Systems, RGB”] in Forum: [CineForm Software Showcase ]

• http://www.dvinfo.net/forum/search.php?searchid=4926860
  • http://www.dvinfo.net/forum/cineform-software-showcase/476130-using-deshaker-plugin-virtualdub-cfhd.html
    • Q:
      • I’m noticing some major picture/colour quality loss, especially a LOT of loss in dark areas, where there used to be enough information to pull out some detail
    • A:
      • My guess, it is deshaker / virtualdub is losing the shadow detail, but through no fault of their own. These tools are likely using computer graphics RGB 0-255. Yet your source and the CineForm conversions are YUV 16-235 (mostly) but some details will end up in the 0-15 and 236-255 ranges — and FirsLight can no problem using this data unless you chop it off. When YUV is converted to RGB only the middle 16-235 is used (the rest are clipped.)
      • The easiest (solution). Set the decode to default to (Use) Video System RGB. Import any CineForm clip into VirtualDub. Go straight to setting you video compression, and select CineForm, and click on “Configure”. Set (Use) Video Systems (RGB) for encode and decode.
  • http://www.dvinfo.net/forum/cineform-software-showcase/133853-importing-cineform-into-virtualdub-601-709-rgb-issues.html
    • Q:
      • When I load a cineform avi into Virtualdub and go to set the compression settings, I select Cineform and then I can select the configure window which launches the Cineform Video fo Windows control panel. Do I check the two “709” boxes, the Use Video systems RGB boxes, all of them, none of them or what to ensure the best quality results for later avi file use back in Vegas?
    • A:
      • If you are doing 4:2:2 YUV encode from an RGB source (VirtualDub), the 709 switch sets the encoding method. Use 709 for everything bigger than SD.
  • http://www.dvinfo.net/forum/cineform-software-showcase/96996-color-gamma-shift-exported-video.html
    • Q:
      • The uncompressed AVI looks identical to the TIFF sequence. The CFHD AVI is brighter gamma-wise and less saturated.
    • A (inapplicable to their issue but generally informaative):
      • The issue is you have setup your Video for Window decoding to default to “Video Systems RGB” (black 16, white at 235), rather than computer graphic RGB (the default for AE, black at 0.) You need to open the VFW CineForm control panel, via the “Configure” button shown in the attachment, restore the top two checkboxes {Decode, Encode – Use Video Systems RGB (Default On)} to off. You can do this in the Render Output module controls (yes it impacts decoding as well.)

This entry was posted on Wednesday, June 20th, 2012 at 20:10 and is filed under Cineform. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.