[opendtv] Re: Samsung Rep admits HDMI won't support 1080p until v.1.3
- From: Ron Economos <k6mpg@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Wed, 09 Nov 2005 03:04:42 -0800
The pixel rate for 1080p@60 for dual-cable HD-SDI
(SMPTE 292M and SMPTE 274M) and also DTV
over HDMI (EIA_CEA-861-B) is 148.5 MHz.
Unfortunately, the pixel rate for 1080p@60 from
computers is something over 165 MHz (as determined
by the VESA GTF). The exact pixel rate can be calculated
with this spreadsheet:
http://www.vesa.org/Public/GTF/GTF_V1R1.xls
So the problem with 1080p@60 displays and the current
crop of 165 MHz HDMI chips (or 150 MHz speed
binned parts from Silicon Image) is that you can do DTV
1080p@60, but not computer 1080p@60.
In a related area, the BBC has proposed a novel
compression scheme for 1080p@50 and 1080p@60
over single cable HD-SDI.
http://www.bbc.co.uk/rd/pubs/whp/whp-pdf-files/WHP119.pdf
Ron
Jeroen Stessen wrote:
>Hello,
>
>Richard Hollandsworth:
>
>
>>FYI: I posted a copy of Samsung Rep's slide re 1080P and HDMI v.1.3 at
>>
>>
>end
>
>
>>of this thread:
>>
>>
>http://hdtv.forsandiego.com/messages/460/3459.html?1131406822
>
>I don't see a problem per se with 1080p@60 over HDMI. 2 megapixels times
>60 Hertz = 120 MHz pixel rate, plus some margin for blanking. For a CRT
>display that margin would be excessive, and you would need 165 MHz pixel
>rate. That still falls within the limits of DVI 1.0, and since HDMI uses
>the same hardware as DVI, it should still work. For matrix displays that
>don't require as much blanking time, it should be even easier.
>
>The difference might be in the cable, though. HDMI typically uses thinner
>cables than DVI, and there might be a bandwidth limitation with that.
>Also, the receiving end might just not be ready for 1080p, the chips that
>process the signal might not have enough bandwidth at their inputs.
>
>The 10-bits and 12-bits story is a different issue. HDMI was designed for
>YCbCr 4:2:2 signals, to replace the analog YPbPr links (common in Japan).
>2 pixels of 12-bits YCbCr 4:2:2 take as much room as 2 pixels of 8-bits
>RGB 4:4:4. You don't need any extra bandwidth for that.
>
>So what's Samsung's problem ? I don't know.
>
>Best,
>-- Jeroen
>
>
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