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joedandrea
09-01-2008, 11:09 PM
Greetings! I'm not sure if this is my TV, the TiVo or some combination of the two:

Running a Series 3 HD (SA CableCARDs), using component R/G/B to a Mitsubishi RPTV.

TV is _not_ set to zoom or otherwise alter the image. TiVo is set to 16x9, 1080i fixed.

Now let's say I'm watching a 4:3 broadcast (without side bars added in). I don't want to zoom in, but let's say I do want to stretch the image so it fills the 16x9 space. When I do that, it actually stretches a bit _too_ much, vs. just stretching enough to fill the screen and keep the entire image in view.

Wondering if this is this par for the course or if I may be doing something wrong?

Also ... I was watching a TiVo recording of an HD channel the other day - looked wonderful, crystal clear - and eventually I saw the closing credits at the bottom. Turns out they extended beyond the bottom of the display, or were otherwise cut off!

A quick check of the TV and TiVo showed there wasn't much I could do - it was a 16x9-ish broadcast and that was that. Is it common for some of these shows to get clipped like that? Again, the picture looked fantastic, so I'm not sure what was happening here. (The Olympics, by comparison, looked just fine.) I also saw CNN HD one day during the DNC and it too appeared clipped, but especially on the right with their rundown of upcoming events.

Clues/advisement appreciated. Thanks!

TolloNodre
09-01-2008, 11:17 PM
Yep, for that scenario, it does the same thing on my TV. (an old Toshiba CRT HD TV)

I first noticed it using 'Native' view. When viewing 480 in panel mode, it cuts off a bit of the right side of the image. Most noticeable on the sports networks where it cuts into the ticker a bit. Funny thing is if I select '1080i' FIXED output, the SD is framed perfectly and I get all the image (but obviously, not in full aspect). Oh well, it is what it is so I just leave it at 1080 fixed...

wmcbrine
09-02-2008, 01:59 AM
What you're seeing is called "overscan". It's normal. The degree varies, depending on your set. You may be able to adjust it, or even turn it off.

All TV sets have always done this, since the beginning. It's only becoming more obvious now, what with new formats, upconversions, etc. People haven't quite got it sorted out yet, as they had in the standard def world. Your TV is probably overscanning too much, but at the same time, CNN may be overzealous in using the edges, assuming that HD sets have little or no overscan (which is often true -- just not often enough that they ought to rely on it).

joedandrea
09-02-2008, 07:05 AM
I first noticed it using 'Native' view. When viewing 480 in panel mode, it cuts off a bit of the right side of the image.
Yipe! Now that problem I don't have in panel mode. Or, rather, I don't notice an obvious issue. Content appears to be "all there" (albeit with the black bars on the sides). It's only when I go to stretch the image that it overshoots left and right ... and we're not talking by a little bit. By a lottle bit! :)

See this shared DropBox (http://snurl.com/3m7i8) page for example images. The images are taken from TiVo Desktop playback. Also included are versions with crop marks denoting what I'm actually seeing on-screen. Note that the 480 image is not stretched as it is on the TV, but the outlined viewing area is consistent.
Funny thing is if I select '1080i' FIXED output, the SD is framed perfectly and I get all the image (but obviously, not in full aspect).
Bingo! That's exactly what I'm trying to do with my 480 images. Get them to fit in 1080i - stretched, without overstretching.
What you're seeing is called "overscan". It's normal. The degree varies, depending on your set. You may be able to adjust it, or even turn it off.
Ahh! I thought it was overscan at first, but here's where I got confused.

First, when comparing full/stretched to panel display (not zoom), it's really losing a decent chunk of the left/right sides, but not the top/bottom at all. Maybe a tiny amount of top/bottom is missing, but the key is the top/bottom remains consistent whether the image is in full or panel mode. Is there such a thing as left/right-only overscan? (Maybe there is?)

Also, does overscan apply to full/stretched images, or isn't that a function of the TiVo and/or TV? (To recap, the TV is not in any zoom/stretched mode, and the TiVo is set to 16:9, 1080i Fixed. Then I use the TiVo Aspect function to switch between Full and Panel modes for comparison.)

Also also ... is this overscan consistent in HD no matter what? On some HD channels I see it more consistently than others.

CNN HD is consistently chopped off at the sides, but only by a small amount. ESPN HD and ESPN2 HD are spot-on (or I think they are because the ESPN logos you sometimes see on the sides appear fully in-view, and any crawls on the bottom are also in full view).

At least one Science HD program I watched was chopped off at the top/bottom - but this time more than a small amount. I noticed it because there was at least one and a half full lines of program credit text missing from the bottom.

To be fair, I'm assuming it was truncated at the top. I don't really know. But I know what I saw along the bottom!

I still have it on the TiVo, in fact. I'm going to transfer it to my Mac and see if it has the same issue there. (I want to see if it's the content or the TiVo/TV. Assuming TV, but then compared to ESPN and CNN ... hmm ...)

UPDATE: See my shared DropBox (http://snurl.com/3m7i8) page for the results. It's actually cropped on all sides - even HD! It just looks like it's heavily cropped vs. lightly cropped to me. Perhaps this is real live overscanning (http://en.wikipedia.org/wiki/Overscan#Modern_sets) in action? What threw me off was the top/bottom - now known to appear cropped - is consistent whether the 480 video is in Full mode or Panel mode.

Your TV is probably overscanning too much, but at the same time, CNN may be overzealous in using the edges, assuming that HD sets have little or no overscan (which is often true -- just not often enough that they ought to rely on it).
Agreed! For me, it's mostly the 480 material that I try putting in Full/Stretched mode (not Zoom) that overshoots the left/right sides by a considerable amount, I thought I might be doing something wrong with the setup.

I wonder if I'd have the same issue with HDMI? I could try that via the HDfury and Box1020 connections I use for the PS3 Blu-ray.

http://photos-2.getdropbox.com/i/l/nsv8HOxFx1WSPxHf7CbIfXe-hQMphNO7pS8fL93Gr4A#2

http://photos-4.getdropbox.com/i/l/jp-uRxRjsTJhN_HteQqsSIwFuz4np-A3FgnMrctZsx4#4

TolloNodre
09-02-2008, 04:18 PM
What you're seeing is called "overscan". It's normal. The degree varies, depending on your set. You may be able to adjust it, or even turn it off.

All TV sets have always done this, since the beginning. It's only becoming more obvious now, what with new formats, upconversions, etc. People haven't quite got it sorted out yet, as they had in the standard def world. Your TV is probably overscanning too much, but at the same time, CNN may be overzealous in using the edges, assuming that HD sets have little or no overscan (which is often true -- just not often enough that they ought to rely on it).

True, I could go into the Service Menu for my TV and try to 'correct' it.

But I've had DirecTV, Dish Network, a Comcast DVR and a TiVo DVR hooked up to my CRT. Only with the TiVo does it show THAT much overscan, if indeed that's the issue. So I do think it's something in how they pump out the signal...

wmcbrine
09-02-2008, 05:03 PM
I had already posted a long reply to this, but it mysteriously disappeared. While I hope for its recovery, I'll redo just this one bit:

At least one Science HD program I watched was chopped off at the top/bottom - but this time more than a small amount.The Discovery channels upconvert their 4:3 programs by zooming and cropping, so that more of the screen is filled than with standard pillarboxing, but without the distortion of stretch-o-vision. It's a questionable compromise.

joedandrea
09-02-2008, 05:13 PM
True, I could go into the Service Menu for my TV and try to 'correct' it.
The thought has crossed my mind (and I do have the service manual for my Mitsubishi WS55411) but ... Iiiii think I'm going to wait for someone with a clue to calibrate it for me and clean all that up.

I should mention - it wasn't a big deal for me until after seeing that HD show, and then my wife comparing panel with full mode on The Daily Show. Then later on I noticed the cropping on CNN, and that's when I went on my li'l mission.

Before all this, we thoroughly enjoyed the video of the olympics on NBC HD. We still have some of it recorded - and it's still excellent! I suspect now I'm going to check it out on TiVo Desktop. Hehehe.

What I'm hoping to find is a consistency in the overscan. The HD crop in my previous example is fairly centered. In the SD crop, not so much. But I've now read that it's not uncommon for the SD crop to be a little off center. So I'm learning a lot here. Good!

Here's another thread that briefly touches upon overscan and RPTVs (http://www.avsforum.com/avs-vb/showthread.php?t=808673).

Only with the TiVo does it show THAT much overscan, if indeed that's the issue.
With that Daily Show (non-digital) channel, maybe I could also try a direct COAX connection to the TV and see what I get.
I had already posted a long reply to this, but it mysteriously disappeared.
<!> I didn't touch it, scout's honor!
The Discovery channels upconvert their 4:3 programs by zooming and cropping, so that more of the screen is filled than with standard pillarboxing, but without the distortion of stretch-o-vision. It's a questionable compromise.
Wow. Dodge, zoom, burn, crop, fold, spindle, mutilate. Fun! :)