• Blackmagic Design

  Red-Blue Reversal with DVI Extender and Polycom HDX 7000

  Posted by Boyce Johnson on May 20, 2014 at 11:04 pm

  I’m trying to convert the DVI output of a Polycom HDX 7000 videoconferencing box to HD-SDI using a Blackmagic DVI Extender, and blue and red are reversed in the resulting image. Prior to the arrival of the Polycom unit, I tested the DVI Extender using the DVI output of a Dell laptop. That worked fine, and it still works. According to the HDX 7000 data sheet, the outputs are DVI-I, but I would assume the DVI Extender just uses the digital portion. I’ve tried single-link and dual-link DVI-D cables. I don’t have any dual-link DVI-I cables, but I don’t see how adding the analog pins would help.

  Boyce Johnson replied 11 years, 12 months ago 2 Members · 2 Replies
• 2 Replies

• 

  Chad Pearson

  May 21, 2014 at 3:55 am

  I have my polycom hooked up using the regular Blackmagic HDMI -> SDI converters and a $2 DVI to HDMI adapter, works great. What you are probably seeing is a colorspace issue (RGB vs YUV). Have you tried changing the Display settings on the polycom to various resolutions? I had to switch them to something else and then back again to get it to work right. Also make sure the DVI Extender is in “Video” mode and not “Extender” mode.
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  Boyce Johnson

  May 21, 2014 at 1:10 pm

  The extender is in video mode. I’ve tried changing the Video Format and Resolution settings on the Polycom box, as well. I figured it was a YUV/RGB colorspace issue.

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