Re: Open hardware AV to digital conversion

From: Marko Mäkelä <msmakela_at_gmail.com>
Date: Mon, 5 Jan 2015 22:47:18 +0200
Message-ID: <20150105204718.GA1445@x60s>
On Sat, Jan 03, 2015 at 11:33:52PM +0100, Ingo Korb wrote:
>Many early consoles don't do that either, even on the Playstation 2 and 
>Gamecube a few games still use non-interlaced 15kHz modes similar to 
>the C64.

OK, this is good to know, and could extend the demand for usable 
adapters. But, the clock of the SD transition is ticking, and I would 
not be surprised if such adapters disappeared from the market in the 
next 10 to 20 years.

>>A bonus would be to make it so low-power that it would work with the 
>>small power supply that is available on the HDMI jack.
>
>The 5V line in HDMI(/DVI/VGA) runs from source to sink which is the
>wrong direction for this use case. It is used to power the EDID EEPROM
>in the display and some devices also assume that there is no valid input
>signal if the source does not power that line.

Oh, I see. However, let me quote a comment on 
http://www.androidauthority.com/chromecast-dongle-official-specs-features-release-date-pricing-248120/
"A reviewer on Amazon who apparently already has the device (developer I 
think) says that the device can be powered directly off an HDMI v1.4 
connector without using the USB power brick. If your HDMI connector 
isn't v1.4 or doesn't provide enough power or whatever then you'll need 
to use the USB power brick. I can't confirm this myself yet but it would 
be consistent with active HDMI accessory behavior. The HDMI spec only 
requires that the source device provide "at least" 55mA (at 5V) but many 
devices provide much more and therefore could power the dongle, although 
I have no idea how much power the dongle requires but it can't be much 
given the form factor. See 
http://www.hdmi.org/learningcenter/kb.aspx?c=13 for more info about HDMI 
accessory power requirements."

The linked FAQ page says that HDMI-powered devices should offer a 
fallback of an alternative power supply.

	Marko

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Received on 2015-01-05 21:00:52

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