Significant Other wants "true" HDTV quality recording

[wtsitmn]

Originally Posted by Opus4

wtsitmn: I read your posts, but you aren't listenting to what is being said...

1) If you are recording via an OTA HD tuner card, it is simply storing the HD transmission. There is no re-encoding going on at all. The Default recording quality setting has no effect on a digital tuner; that is only for an analog SD encoder.

2) For analog SD tuners: I don't remember how the list of recording rates is sorted (if at all), but DVD Standard is not the highest; Max Quality at 5.9 GB/hr is the highest. But, this has no effect on your HD digital tuner.

The others are suggesting that you either need a different decoder that can handle HD video, or you need a connection to your TV that can actually provide the HD signal to the TV instead of something like svideo.

I may have missed this part, but I don't think you've mentioned how your SageTV PC is connected to your TV.

- Andy

Andy, thanks for being so patient with me. I really appreciate it. This whole experience has been rather stressful, so I apologize.

So you're saying I have no control over the size of HD recordings? Does that include all digital recordings, regardless of whether they were broadcast in HD or not? (FYI, I'm using only digital tuners.) If so, the folks at Sage might want to turn the recording quality feature off when using digital tuners. That was the source of much of my confusion. Not that I fault them, they've done a great job from what I've seen.

Okay, so far, so good. So it sounds like the probable culprit is the decoder. That makes sense. BTW, my PC is connected to the TV using DVI/HDMI, so I think the hardware is probably not to blame.

So, what next? I've tried the nVidia and Cyberlink decoders. They both produce the same result as far as I can tell. I suspect this may be about as good as it gets for the moment. Do you happen to know if there are any video cards with built-in decoders which do a better job? Bear in mind that I think we're talking about only a 5-10% improvement. I wonder if it's even realistic to expect to get an identical picture using a PVR compared to what I get using the TV's own built-in HD tuner? But since it's all digital, it should be possible, at least in theory.

Thanks again for all your help.

-John

[salsbst]

I know I'm probably on your s**t list, but I really think we could be more helpful if you told us which card you're using to record the TV signals and which input on the card you're using.

[wtsitmn]

Originally Posted by salsbst

I know I'm probably on your s**t list, but I really think we could be more helpful if you told us which card you're using to record the TV signals and which input on the card you're using.

Not at all. I now realize it was my mistake. All the folks here have been extremely helpful, especially when you consider I'm no expert.

I've spent days re-reading all sorts of technical specs and marketing claims. It's enough to give one a real headache. It seems the reason my tuner card manufacturer was bragging about DVD quality was because that's what most people identify with. At least I hope that's the reason!

I have FusionHDTV5 RT tuners which I'm using in digital mode only (as opposed to analog). The signal is from a new outdoor antenna (via coax) which is split between the HDTV and the HTPC. I have an ATI X1300 graphics card with a DVI output. That is connected directly to the HDTV's HDMI input. (All these acronyms are giving me another headache!)

Just to reiterate, the issue is image quality only. The motion is perfectly smooth. So I don't think there's a performance issue. After reading more about image quality of HTPC's, I think perhaps this is about the best there is at the moment. And again, we're talking about only a 5-10% difference in quality. Not a whole heck of a lot. HDTV recordings look great in my opinion, they're just not quite as clear as watching live using the TV's own built-in HD tuner.

[flashbacck]

what resolution are you outputting?

[wtsitmn]

Originally Posted by flashbacck

what resolution are you outputting?

Why, 1080i of course!

Because of the TV's 2-3% overscan, the image doesn't quite fit within the screen, but I figure in order to obtain maximum quality, I don't want the video card recalculating the image to get it to fit.

[bcjenkins]

Originally Posted by wtsitmn

Why, 1080i of course!

Because of the TV's 2-3% overscan, the image doesn't quite fit within the screen, but I figure in order to obtain maximum quality, I don't want the video card recalculating the image to get it to fit.

What TV is this going to? Someone please correct me if I am wrong. It is best to let the video card in the PC scale everything to the native resolution of the TV. Which I am going to guess is likely not 1080i. If you output to native, then the TV doesn't have to do any scaling to produce the image at native. Also, not all content being broadcast is 1080i. Essentialy, you would be upconverting everything to 1080i, which is being downconverted back down by the TV.

B

[Opus4]

Originally Posted by wtsitmn

So you're saying I have no control over the size of HD recordings? Does that include all digital recordings, regardless of whether they were broadcast in HD or not?

Right -- if it is recorded via an OTA digital broadcast, it is stored on disk as it is aired instead of encoded on the PC in some fashion.

If so, the folks at Sage might want to turn the recording quality feature off when using digital tuners. That was the source of much of my confusion.

That would have been done already, but there are behind the scenes reasons why it isn't done that way yet. Maybe in the future.

Originally Posted by wtsitmn

Just to reiterate, the issue is image quality only. ... And again, we're talking about only a 5-10% difference in quality. Not a whole heck of a lot. HDTV recordings look great in my opinion, they're just not quite as clear as watching live using the TV's own built-in HD tuner.

I don't do any digital recording at the moment, so there's something I'm curious about: for others who are recording & watching HD shows, is there much, if any, difference between watching the recording vs. watching the airing live via the TV's digital tuner?

- Andy

[wtsitmn]

Originally Posted by bcjenkins

What TV is this going to? Someone please correct me if I am wrong. It is best to let the video card in the PC scale everything to the native resolution of the TV. Which I am going to guess is likely not 1080i. If you output to native, then the TV doesn't have to do any scaling to produce the image at native. Also, not all content being broadcast is 1080i. Essentialy, you would be upconverting everything to 1080i, which is being downconverted back down by the TV.

B

This is a big screen HDTV with 1080i resolution. The issue is to get an HTPC to produce the same image as is produced by the TV using its own built-in HD tuner. Right now, the image from the HTPC is 5-10% poorer than what is produced with the TV's own tuner. From studying the image, my gut feeling is that it's an issue with the decoder. There are minor artifacts and a general slight graininess in the HTPC picture compared to the HDTV's internal tuner image.

[bcjenkins]

Originally Posted by wtsitmn

This is a big screen HDTV with 1080i resolution. The issue is to get an HTPC to produce the same image as is produced by the TV using its own built-in HD tuner. Right now, the image from the HTPC is 5-10% poorer than what is produced with the TV's own tuner. From studying the image, my gut feeling is that it's an issue with the decoder. There are minor artifacts and a general slight graininess in the HTPC picture compared to the HDTV's internal tuner image.

What model TV is it?

[wtsitmn]

Originally Posted by Opus4

I don't do any digital recording at the moment, so there's something I'm curious about: for others who are recording & watching HD shows, is there much, if any, difference between watching the recording vs. watching the airing live via the TV's digital tuner?
- Andy

That is the very issue I'm trying to resolve. The image off my HTPC is about 5-10% poorer than that seen using the HDTV's digital tuner. I don't mean to brag, but I just bought a 60" Sony SXRD, which has about the best picture I think I've ever seen. The downside is that even the slightest irregularity is easy to see. Hence the problem of getting an HTPC to produce an image to match the TV's own internal digital tuner.

[wtsitmn]

Originally Posted by bcjenkins

What model TV is it?

It's a Sony KDS-R60XBR1

[bcjenkins]

Sage has its own way of dealing with overscan if you want. Looking at the specs, the native display is 1080p, but none of the inputs will take a 1080p source. I wonder if your pic improves if you go to 720p? Is it easier to go from i to p or increase size for the TV. Also, is you X1300 Pro version?

Does anyone know how to tell if content is being broadcast 720p or 1080i? Has it been asked what decoder is being run?

B

[Lucas]

Originally Posted by wtsitmn

That is the very issue I'm trying to resolve. The image off my HTPC is about 5-10% poorer than that seen using the HDTV's digital tuner. I don't mean to brag, but I just bought a 60" Sony SXRD, which has about the best picture I think I've ever seen. The downside is that even the slightest irregularity is easy to see. Hence the problem of getting an HTPC to produce an image to match the TV's own internal digital tuner.

wtsitmn, the differences you see are most likely to do with the video decoder you are using.

Without knowing what you mean by the image being off 5-10% off, I suspect that it has to do with the deinterlacing done inside your HTPC and the reinterlacing since you are outputing 1080i. Subsequently, the deinterlacing performed inside you TV (for display on the 1920x1080 sxrd panels which are progressive) could be using altered frame information compared to the original 1080i signal fed to the TV's tuner.

[salsbst]

For any LCD, even big ones, you probably want to give it the highest resolution progressive signal it will take for starters. It sounds like you may be deinterlaticing, interlacing and then deinterlacing the signal again by feeding 1080i to this display.

I have a bone to pick with Sony, after hearing that this TV won't accept a 1080p input even though that is the display's resolution. That flaw afflicts my (miniature in comparison) 26" LCD.

But, just double check and make sure, because if the TV does accept a 1080p signal, that's surely the one you want to give it. Perhaps try out its VGA (aka PC) input if it has one. That is probably the most likely port to support 1080p.

EDIT: the more I think about it, I don't think I understand the part where I claim the decoder is deinterlacing a 1080i recording. Perhaps if the decoder knows it's hooked up to a 1080i interlaced image, it can skip that step? I know that if any scaling needs to take place, deinterlacing has to take place first, but if the stars are in alignment and no scaling needs to happen, then maybe a 1080i recording could pass to the TV without the round trip. I know that for a 720p recording, you would definitely suffer by interlacing it only to have the TV deinterlace it. I guess I'm less clear on what happens with a 1080i recording.

[Mahoney]

Just to clarify, for myself as much as anyone...

His desktop is presumably set to 1920x1080. Windows desktops always work with a progressive image, so the decoder will be taking his 1080i content and deinterlacing it by working out the alternate missing lines to provide a 1080p desktop.

The graphics card, however, is set to output a 1080i signal. So it is discardig alternate lines from each frame, and then passing the resulting interlaced signal to the TV.

The TV then has to deinterlace the signal again to turn it into 1080p, as all LCD panels are progressive, even if the whole TV cannot accept a 1080p signal.

In contrast the OTA tuner is passing the original 1080i signal to the TV, which is only deinterlaced the once.

Now, as I see it the PC situation is only a problem if the graphics card is discarding the "wrong" alternate lines - the ones that were actually int he original 1080i signal - and keeping the lines the PC's deinterlacer calculated. Otherwise the TV's deinterlacer would be receiving exactly the same input as the original 1080i source. No?

[mikejaner]

I don't do any digital recording at the moment, so there's something I'm curious about: for others who are recording & watching HD shows, is there much, if any, difference between watching the recording vs. watching the airing live via the TV's digital tuner?

Yes, there is a slight difference between an internal tuner on the TV displaying the HD signal, and a PC with Sage with the Nvidia Decoders. The internal tuner on my TV (Hitachi 51" Rear Pro) wins every time. The difference is only slightly obvious and accountable to the video card and it's capabilities. I output at 1080P over DVI and get a wonderful picture with the
PC, but the image is slightly crisper with the internal tuner on the TV. This is totally understandable as the TV is natively displaying the image on the fly, whereas the PC is decoding the video in software (which is good, but never as good as hardware) rendering it and then sending it to the TV.

[wtsitmn]

The current resolution is indeed 1080i 1920x1080. The TV does not support 1080p, only 720p.

So it sounds like regardless of whether the problem is simply the decoder, or the picture is losing quality via being redundantly interlaced, there isn't anything that can be done for now.

Since I'm no engineer, can someone tell me why I can't get the highest resolution (1080i 1920x1080) in 60Hz, only 30Hz? And would this have any effect on the image?

Besides not providing 1080p, I have my own bone to pick with Sony. How do I reduce the overscan so I can see the whole picture without my having to change the resolution? I've been in contact with Sony's "support" staff, who are outsourced to some third world country to save a few bucks. They don't know what I'm talking about. In my experience, companies would be better off discontinuing support than outsourcing it to people who can't understand English, let alone have no technical expertise. I want to go back to the good old days when all the geometry controls were on the back of the set, and you could totally screw things up without needing help from anyone. (Am I revealing my age?!!)

[stanger89]

Originally Posted by wtsitmn

So you're saying I have no control over the size of HD recordings?

Exactly.

Does that include all digital recordings, regardless of whether they were broadcast in HD or not? (FYI, I'm using only digital tuners.)

Yes

If so, the folks at Sage might want to turn the recording quality feature off when using digital tuners.

It is turned off. However they're not removed from the recording config screens since recording qualities are per recording not per tuner.

So, what next?

What resolution are you running and what's the native resolution of your display.

I've tried the nVidia and Cyberlink decoders.

Both are capable of HD decoding

They both produce the same result as far as I can tell. I suspect this may be about as good as it gets for the moment. Do you happen to know if there are any video cards with built-in decoders which do a better job?

Just about any video card from the past several years offers hardware accelleration. However the GeForce 7 series (specifically the 7600GT or better) are ther cream of the crop right now.

Bear in mind that I think we're talking about only a 5-10% improvement. I wonder if it's even realistic to expect to get an identical picture using a PVR compared to what I get using the TV's own built-in HD tuner?

Yes it is.

[salsbst]

Originally Posted by wtsitmn

The current resolution is indeed 1080i 1920x1080. The TV does not support 1080p, only 720p.

So it sounds like regardless of whether the problem is simply the decoder, or the picture is losing quality via being redundantly interlaced, there isn't anything that can be done for now.

Yes, there is something that you can do. Switch your video card to 720p if the TV supports that. That should improve things.

EDIT: apparently (see below), it may very well not improve things if the PC can be convinced that it doesn't need to do any scaling at all??

Since I'm no engineer, can someone tell me why I can't get the highest resolution (1080i 1920x1080) in 60Hz, only 30Hz? And would this have any effect on the image?

The interlaced signal is represented as 30Hz since it has half the number of pixels in the vertical dimension (there's a lot more to it than that, but that's a relatively simple way to sort of understand it). Since you say your TV doesn't do 1080p, then if you are determined to run at 1080-something, you're stuck w/1080i. 720p would be at 60Hz. By the way, 720p has almost the same number of pixels (per time period) as 1080i, since in 1080i you only get 540 lines per frame.

Besides not providing 1080p, I have my own bone to pick with Sony. How do I reduce the overscan so I can see the whole picture without my having to change the resolution?

You can use SageTVs overscan controls in the setup menu to reduce the size of its fullscreen output.

[stanger89]

Oh, try setting your aspect ratio settings to 100% horizontal and vertical zoom and 0 offset.

Originally Posted by salsbst

Yes, there is something that you can do. Switch your video card to 720p if the TV supports that. That should improve things.

Judging by the comments in the HD DVD threads, that's not likely. Granted the HD-A1 might have a crappy scaler, but most claim noticably poorer image by setting their HD-A1 to 720p vs 1080i output, even on 720p displays.

The interlaced signal is represented as 30Hz since it has half the number of pixels in the vertical dimension (there's a lot more to it than that, but that's a relatively simple way to sort of understand it). Since you say your TV doesn't do 1080p, then if you are determined to run at 1080-something, you're stuck w/1080i. 720p would be at 60Hz. By the way, 720p has almost the same number of pixels (per time period) as 1080i, since in 1080i you only get 540 lines per frame.

It's actually a lot more complicated than that, and that description really doesn't clarify the issue.

1080i does have more vertical resolution than 720p. Things get confused because that resolution is spread over two fields. Now most content on TV is actually film sourced, what that means is that properly deinterlaced (inverse telecined, which the high-end Geforce 7's can do) you've got a full 1080p picture out of the original 1080i source. Further, there should be no degridation going from 1080i30->1080p24->1080i30->1080p60 since telecine/inverse telecine is a lossless operation, if done correctly.

Further, well deinterlaced 1080i video should have more spacial resolution than 720p, though 720p would have more temporal resolution.

Originally Posted by wtsitmn

Since I'm no engineer, can someone tell me why I can't get the highest resolution (1080i 1920x1080) in 60Hz, only 30Hz? And would this have any effect on the image?

If you're asking why your TV won't accept 1080p60, only the engineers at Sony know that. However there are no 1080p60 sources, the two best sources available are 1080i30 (video) and 1080p24 (film), both of which can be sent to the TV losslessy at 1080i30, and converted (losslessly) to 1080p60 (what the TV actually displays).

You might want to see if you're TV supports 1080p24sF (not sure if that's the right terminology).

Originally Posted by salsbst

You can use SageTVs overscan controls in the setup menu to reduce the size of its fullscreen output.

You can, but you really want to keep HD at 100% H/V or the video card will have to start scaling the video which will degrade the picture, however slightly. This scaling may well be the source of the 5-10% difference.

Originally Posted by wtsitmn

Besides not providing 1080p, I have my own bone to pick with Sony. How do I reduce the overscan so I can see the whole picture without my having to change the resolution?

The simple answer: You can't. That's the way the TV was made, and there's no way to change it. TVs are built with overscan (usually 5-10%) to guarantee that there's no "wasted" space around the picture.

What are your decoder settings? DXVA/Hardware Accelleration? Deinterlace mode? What shows do you notice the difference on?