[mythtv-users] 5200 or 6200

Craig Courtney craig at dawnsedge.com
Thu Jan 25 05:35:20 UTC 2007

On Jan 25, 2007, at 12:11 AM, Jarod Wilson wrote:

>>> fields vs frames my friend. two fields = 1 frame.
>>> (1080 / 2) * 2 = 1080.
>> I'm not sure what the fields vs frames 'proof' adds to the argument
>> without taking into account the relative refresh rates of fields vs
>> frames also. Fields are irrelevant with progressive video as whole
>> frames are displayed.
>> 1080p60 has twice as many pixels/s as 1080i60, as Jarod stated
>> earlier:
>> 1080i60 = (1920x540 pixels per field) x (60 interlaced fields per
>> second) = 62,208,000 pixels/second.
>> 1080p60 = (1920x1080 pixels per frame) x (60 progressive frames per
>> second) = 124,416,000 pixels/second.
> Yep, that's more or less the same math I came up with... Also, note
> the mention on the page I linked to stating how 1080p60 raises
> bandwidth requirements versus 1080i60 "from 1.493 Gb/s to nominally 3
> Gb/s."

This really sounds like apples to oranges.  1080i60, 1080p60, 1080xx   
all display the exact same *resolution* on the display device which  
is 1920 x 1080 (2,073,600 pixels).  Folks are absolutely right that  
the data transmission speed and bandwidth (pixels per second)  
required is radically different and under 1080i each pixels has  
approximately twice as much latency between updates, but don't  
confuse people by saying the resolution is double.

Put in terms of relative refresh rates on computer monitors... no one  
ever claims that running 1024x768 at 75hz gives you 25% more  
resolution or pixels than running 1024x768 at 50hz.  It's the exact  
same scenario here, the resolution and amount of pixels are exactly  
the same the only thing that changes is how fast we update each pixel.


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