Scientific America STB and native resolution question

[sbaker]

The native resolution on my Toshiba widescreen 46HM84 is 720P. According to the manual, the t.v. displays 480i, 480P, 720P and 1080i.

Now, when using the setup wizard on my Scientific Atlanta 4250HDC STB, I've got the option of choosing the following formats: 480i standard, 480P standard, 480i widescreen, 480P widescreen, 720P and 1080i.

Here's my question:

To ensure all pictures display correctly (when using the setup wizard), should I be selecting all of those options, or should I drop the 480i and 480P standard settings, seeing as my t.v. is a widescreen? (i.e. Is it pointless to choose 480i standard and 480P standard?)

Also, since the native resolution is 720P, does it make sense to use the Fixed, Pass through or the Upconvert 2 setting to ensure the best picture?

I've noticed that most HD channels fill the screen just fine, but some appear stretched and others have a slight overscan issue.

Any suggestions? If so, please post.

Thanks!

[Ratman]

This FAQ may be helpful:
http://www.hdtvoice.com/voice/showthread.php?t=8721

[57U]

Previously answered in the following thread:

http://www.hdtvoice.com/voice/showthread.php?p=193134#post193134

If channels appear stretched, it's probably because your TV is stretching those signals. For example, it'll remember the stretch mode for SD and HD channels separately, so it may be stretching the SD channels, while leaving the HD ones alone. Since your TV is not susceptible to burn in, you can watch 4:3 as 4:3 and 16:9 as 16:9.

Most TVs will show the best image if the original format passes directly to the TV, since the TV is usually better at upconversion than the STB. See:

http://www.hdtvoice.com/voice/showthread.php?t=38343


Perhaps the following additional FAQs will help:

http://www.hdtvoice.com/voice/showthread.php?t=1052 Black Bars

http://www.hdtvoice.com/voice/showthread.php?t=1044 Stretch Modes.

[sbaker]

I know my tv has an "auto aspect" feature. Would it make sense to turn that off? Also, since the native resolution is 720P, is my t.v. simply converting any incoming signal (such as 480i, 1080i) to 720P on screen? That's part of the reason why I wondered about the selecting the "Upconvert" feature on the STB.

Both upconvert selections convert 480i and 480P to 480P, but Upconvert 1 converts to 720P and 1080i to 1080i, whereas Upconvert 2 converts 720P and 1080i to 720P. Just trying to wrap my head around the logic there.

It sounds like if I choose fixed, the picture is displayed at just one rate (i.e. 480i, 480P, 720P, 1080i)

Pass-through made the most sense, but as I said, some HD stations had overscan problems, so I didn't know if was a matter of tweaking the overscan settings on the t.v. Any ideas?

[57U]

The answer to your upconversion questions and STB settings are found in the first link of post 3 and the following FAQ:

http://www.hdtvoice.com/voice/showthread.php?t=33975

It's best (for picture quality) to let the TV do the conversion, as I mentioned in post 3 and as indicated in the links.

It is true that there may be a little less overscan if you use a fixed format - say 1080i, so if overscan is more important to you than picture quality (or if PQ is not affected much), set the STB to 1080i only. That choice is yours.

And yes, turn your auto aspect off if you don't want the 480i signals from the STB stretched. (This may impact what the TV does to DVD player signals, depending on the player and the format - covered in the black bar FAQ) You may need to manually override, but it depends on the player/signals/TV settings.

[sbaker]

I know my Toshiba 46HM84 tv has an "auto aspect" feature. Would it make sense to turn that off? Also, since the native resolution is 720P, is my t.v. simply converting any incoming signal (such as 480i, 1080i) to 720P on screen? That's part of the reason why I wondered about the selecting the "Upconvert" feature on the SA STB.

The Upconvert 1 selection on the setup wizard displays 480i and 480P at 480P, and 720P and 1080i at 1080i, whereas Upconvert 2 converts 720P and 1080i to 720P. Just trying to wrap my head around the logic there.

It sounds like if I choose "fixed", the picture is displayed at just one rate (i.e. 480i, 480P, 720P, 1080i)

Pass-through made the most sense, but as I said, it's just one HD stations that has an overscan problems, so I didn't know if was a matter of tweaking the overscan settings on the t.v. instead. Any ideas?

[57U]

Why are you starting a new thread on this topic when I've already answered your questions in the posts above?

Auto-Aspect has nothing to do with the formats (480i, 720P, etc - it was difficult from your first paragraph to tell if you knew they were separate issues.) Auto-Aspect has to do with stretching the image. I've already provided links to the relevant FAQs to answer your questions. Please Read Them!

Are you reading the FAQs that I've linked to? Are you reading the posts above?

Just to clarify:

I know my Toshiba 46HM84 tv has an "auto aspect" feature. Would it make sense to turn that off? Yes. See the end of post 5 - information already provided.

...is my t.v. simply converting any incoming signal Yes, read the link in post 5.

Just trying to wrap my head around the logic there. The logic is to try to provide you with all available options. You don't need to avail yourself of them if you don't wish.

....it sounds like if I choose "fixed", the picture is displayed at just one rate It's not displayed in that format, it's sent from the STB in that format - exactly as stated in the link in post 2, as well as the link I supplied you in your previous thread, as discussed in post 3. Your TV will then convert and display incoming signals as 720P.

Pass-through made the most sense, but as I said, it's just one HD stations that has an overscan problems, so I didn't know if was a matter of tweaking the overscan settings on the t.v. instead. Any ideas?
If there is only one HD station that has an overscan issue, then it's likely an issue with the station and not an issue with the STB or the TV. You can measure the overscan on your TV using a setup DVD which we discussed in another thread.

I summarized some of the FAQ information in the posts above with specific answers to your previous questions.