My equipment is as listed in the thread title (STB vs. Plasma). My question is, which one should I let do conversion from 1080i to 720p? The HD channels in my area broadcast in both, but my TV is a 720p. So 720p->720p is fine, but which unit has a better scaler for 1080i->720p? Should I tell my STB to put out 720p only (thus using its scaler) or let the box put out whatever signal is being broadcast (thus using the Plasma's scaler)?

Is there a general rule on this? Are either STBs or TVs known to have good/crappy scalers? Or do I need to figure out what scaler each component uses and then decide? If so, how to do so (Googling hasn't cut it so far). I wish I could compare them directly by eye, but it takes too long to switch scalers.

Thanks for any thoughts.

Its hard to know without knowing the exact scaling chips used in the display and the cable box/DVR which is a better scaler. Just try it both ways, once with the SA8300HD doing the scaling and check the results on 720p channels and again the other way with the SA8300HD outputting native 720p and using the Plasma TV to do the scaling. Either way the plasma has to do scaling for all inputs since it scales to the native 1024x768 resolution. So my guess it would be best to let it do only one scaling instead of both the DVR and the display scaling from 720p->1080i->1024x768
With the DVR outputting native formats you would get 720p->1024x768 or 1080i->1024x768, only one scaling pass. Set the DVR to output both 720p and 1080, and maybe 480p for the SD channels for native output formats.

Thanks for the reply! I hadn't realized that the TV has to do another scaling pass anyway. Also, having done some more searching, a few people seem to have the opinion that the scaler in the 8300's aren't as good as the ones in most TVs. So I think I'll take your advice and let the TV do all the work, and all in one pass.

Thanks for the reply! I hadn't realized that the TV has to do another scaling pass anyway. Also, having done some more searching, a few people seem to have the opinion that the scaler in the 8300's aren't as good as the ones in most TVs. So I think I'll take your advice and let the TV do all the work, and all in one pass.

So when you went to the setup menu on the 8300 box, could you tell me what items you did or did not select in order to allow the TV to do the scaling?

-G

The setup menu for the SA8300HD varies with the OS used, some cable systems use Passport and others use SARA. For Passport, you can enable individually any or all of the various output formats: 1080i, 720p, 480p, 480i. If one or more formats are not enabled, the unit will convert that format to the next higher one.
My TV doesn't support 720p input, so I don't enable that one and let the DVR convert 720p channels to 1080i which I have enabled. I also enable 480p since it appears to do better than 480i for the SD channels.

Note SARA has different options for the output formats, I don't think it allows individual format selection instead gives several set options.

So when you went to the setup menu on the 8300 box, could you tell me what items you did or did not select in order to allow the TV to do the scaling?

Basically what Joxer said, plus one more thing. With the box power on and TV running, I hit "settings" twice on my remote to get to the second settings menu. In there is a setting called "Set: Picture Format" and I set that to "pass through."

With cable STBs/DVRs, picture quality has a lot to do with the setting on the box. You need to make sure you are outputting SD as 480i.

For Scientific Atlanta STBs/DVRs like the SA8300HD, the instructions differ depending on whether your box uses SARA, Passport, or TWC Navigator software. With SARA, turn the unit off, then press and hold down the info and guide buttons until the setup screen appears; choose Advanced Setup and enable 4:3 480i, 720p, and 1080i; save that change, turn the box back on, and choose Passthrough/AutoDVI/AutoHDMI in Settings -> Settings -> Set: Picture Format. Pass through, AutoDVI, and AutoHDMI all refer to the same setting, they are just named differently depending on whether you are using component, HDMI, or DVI cables.

With Passport, enter the Settings -> Settings menu and find the output settings; enable native mode with 480i, 720p, and 1080i checked.

For Motorola STBs/DVRs like the DCT641x and DCT341x, turn the box off, press menu, and then enable 4:3 override set to 480i. The output setting should be 720p or 1080. The best setting is one that outputs 720p channels as 720p and 1080i channels as 1080i, but unfortunately, Motorola STBs/DVRs do not offer that option. You've got to convert 720p channels to 1080i or 1080i channels to 720p, neither of which the Motorola STB does well, although you may not see a difference at smaller sizes. The Motorola's 720p output setting is optimal for ABC, FOX, ESPN, ESPN2, A&E, and NGCHD. The 1080i setting is optimal for most other HD channels.
Yes, enable just 480i, 720p, and 1080i in Advanced Setup, then choose Passthrough in Settings -> Set: Picture Format. If your display doesn't support 480i input through HDMI, then choose 480p.

Basically what Joxer said, plus one more thing. With the box power on and TV running, I hit "settings" twice on my remote to get to the second settings menu. In there is a setting called "Set: Picture Format" and I set that to "pass through."

Thanks to you and Joxer for the responses. I generally have enough knowledge to set up a system and have it work properly but I am totally baffled by this ordeal, i.e. I cannot configure a Panny TH-42PX60U to display the HiDef stations (Discovery HD, HDNet, etc) without the gray bars across the top and bottom of the screen.

The Panasonic is not in my home (it's a relative's) but I have a Pio 5070HD that will display these programs over the entire screen (without distortion) using the identical equipment:

HDMI cables, SA8300-DVR, Comcast, etc.

Picture format on the cable box is set to: AUTO DVI/HDMI (think this equates to 'PASS THRU' and all resolutions (1080i,etc) are selected in the General Settings menu (accessed by simultaneous pressing of the Guide & Info buttons on the box).
Selecting/changing the various Aspect Ratios via the cable box and plasma will not resolve the issue.

Any thoughts?

-George

Picture format on the cable box is set to: AUTO DVI/HDMI (think this equates to 'PASS THRU' and all resolutions (1080i,etc) are selected in the General Settings menu (accessed by simultaneous pressing of the Guide & Info buttons on the box).
Selecting/changing the various Aspect Ratios via the cable box and plasma will not resolve the issue.Enable just 4:3 480i, 720p, and 1080i. Disable the other resolutions in Advanced Setup.

If I were to guess, I would say they have the box connected via s-video or composite, which cannot pass HD signals. Check that.

There is also a setting "Aspect Ratio" on the SA8300HD that should be set to normal also make sure it is setup for a 16:9 display. Some of the other settings and particularly if its set for a 4:3 display may add gray letterbox bars, which also happens on the 480i outputs (composite, s-video, or RF). Check how the box is connected, only component (red,green,blue) and DVI/HDMI will provide proper fullscreen HD output.

Thanks for your responses guys.

The connection from the cable box to the TV is definitely HDMI and I'm pretty sure all of the other settings mentioned except for one, are in-place. But I'll check 'em all again and modify the selected resolutions to display only 480i, 720p, and 1080i.
It'll probably be a week before I'm able to do this but hopefully, it will work!

Thanks again for the help.

-George