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| Re: Why does streaming use 1080p60/RGB? |
Sun, 15 April 2012 03:19   |
jim_peterson
Messages: 1072
Registered: November 2004
Location: Beaverton Oregon, USA |
Lumagen Expert
Lumagen Guru |
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For 1080 sources they are either 1080i or 1080p24. There are no consumer 1080p60 sources, so the box is upconverting to 1080p60. That's our job.
There is no good reason to output 1080p60 for either of these from your cable/settop/DVR box unless you think the TV/projector - or video processor - might mess them up. Or if the TV/Projector does not support 1080p24 for the film case. It is best to let the Radiance do all the heavy lifting.
For 1080i sources if you feed them to the Radiance at 1080i and they are true film source (pulled-down to interlace) then the Radiance has the opportunity to reconstruct the frames, and even output 24p for the best quality. Not so if the player outputs 1080p60.
For 1080p24 sources it is already in frame format, so why change it to 1080p60 which would then only display at 1080p60.
As you mention 1080p60 has a higher pixel rate (148.5 MHz) verses 1080i or 1080p24 which are at 74.25 MHz and much easier on cables.
Jim Peterson
Lumagen
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| Re: Why does streaming use 1080p60/RGB? |
Tue, 17 April 2012 19:20 |
jim_peterson
Messages: 1072
Registered: November 2004
Location: Beaverton Oregon, USA |
Lumagen Expert
Lumagen Guru |
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I can think of no good reason for the Roku to always output 1080p60. As you say it should output at the source rate.
If they have issues with HDMI resolution changes they may have opted to always output 1080p60 to hide these issues by never having to change their output resolution.
Or perhaps they opted to prevent the image from being lost on an input source change by always outputting the same resolution, for what they preceive is a better user experience. For people who don't have a Radiance, it is not necessarily a bad idea since who knows if the TV would do a better job than the Roku on deinterlace and/or scale. Of course as you point out, this is a bad idea when you have a Radiance.
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We have talked about reinterlacing 1080p60, but it takes more gates and memory than 480p/576p in our FPGA. I am not sure we have the gates/memory for this in the current units. We still have it on the list to consider though.
Jim Peterson
Lumagen
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