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View Full Version : ASK DBSTALK: no 480i on DVI output?


pculley
01-08-04, 08:58 AM
The DVI output does not appear to be putting out a (good?) signal in 480i mode (screen goes blank, and no mode indicator on the TV). The output works correctly in all other modes, and 480i comes out the s-video jacks ok. Still have to try the component output in 480i, need to tear into the cabinet to install this and disconnect the DVI for the test.

TV is a Hitachi 57s500, which according to the manual should support 480i on the DVI port.

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Pculley

Mark Lamutt
01-08-04, 09:14 AM
That is by design - 480i is only output via svideo and composite video. 480p, 720p, 1080i are only output via component video and DVI. The hardware doesn't support outputting 480i via component or DVI.

Slordak
01-08-04, 12:26 PM
Question on this... If one is receiving a standard definition satellite signal (e.g. Food Network), is the signal already interlaced video when the receiver decodes it, or is the receiver interlacing it for output to the TV?

I ask because if its already interlaced when coming down from the satellite, then the receiver is doing the de-interlacing (to convert from 480i to 480p). Since most people with $3000 HDTVs have substantially better de-interlacers in their TV sets (e.g. Faroudja DCDi) than whatever is available in the receiver, it's a waste to try and have the receiver do the conversion.

This is a hardware limitation? Doesn't it seem odd to not be able to output the source at its native resolution and let the display device worry about conversions?

Mark Lamutt
01-08-04, 12:35 PM
SD satellite channels are interlaced natively (480i), and when outputting at 480p or 720p, the 921 deinterlaces them.

I've posted the results of my testing on my Sony KP51HW40 television - letting the 921 deinterlace a 480i native signal and outputting 480p to my Sony looks better to me than letting my Sony deinterlace the 480i signal. That's my case - yours may be different.

pculley
01-08-04, 03:22 PM
It would be nice if --something-- was output on the DVI when operating in 480i mode; that would avoid an extra input (and setting change) on the main TV when I wanted 480i for the other TVs in the house (connected via RF modulator). I understand that support for 480i and Hidef scaling at the same time might be hard, but putting the same thing on both outputs at the same time does not seem difficult.

I just noticed the comments elsewhere that the 921 DOES support outputs on both the DVI/Component and SD outputs at the same time, but it seems to be called a "safe mode", (push/hold front panel "output" button for three seconds) and is not generally available. Be nice if this was supported as an output option...

PCulley

Mark Lamutt
01-08-04, 03:36 PM
It would be nice if --something-- was output on the DVI when operating in 480i mode; that would avoid an extra input (and setting change) on the main TV when I wanted 480i for the other TVs in the house (connected via RF modulator). I understand that support for 480i and Hidef scaling at the same time might be hard, but putting the same thing on both outputs at the same time does not seem difficult.

I just noticed the comments elsewhere that the 921 DOES support outputs on both the DVI/Component and SD outputs at the same time, but it seems to be called a "safe mode", (push/hold front panel "output" button for three seconds) and is not generally available. Be nice if this was supported as an output option...

PCulley

I agree it would be nice, but it's not possible with the hardware. There's no way to do it. In safe mode, you will get 480p and 480i output together, but the 921 is NOT designed to run in that mode for an extended period of time, and if you try to, you WILL run into problems.