Disable deinterlacing?

[mlbdude]

Is there a codec to use with SageTV or a way to tell SageTV directly to not deinterlace the video during playback? I have my HTPC connected directly to the TV so wouldn't video playback look better if I let the TV do the deinterlacing for me? Maybe this is not possible with the SVIDEO ouput...

[mlbdude]

I notice that one of SageTV's competitors can do this but I think it is because they are using their own decoder. Maybe something I can do with DScaler?

[dkardatzke]

What happens when you use different video decoders? What are you currently trying to use?

[Narflex]

Even if you disable it, it doesn't matter (I'm pretty sure, I've tried this and researched it failry heavily). You won't be able to get the scan lines to match up because of how the conversion to TV output works on your video card (using DXVA will match them up because the hardware knows its supposed to in that case).

There is a way to disable deinterlacing in SageTV. Just use the Elecard filter and don't select DScaler. Then set
HKLM\Software\Elecard\MPEG2 Video Decoder\SoftwareBob to 0
in your registry.

Then you'll have a completely interlaced output for the video.

[mlbdude]

Thank you sir! I was not sure if it would help or not, but I have a couple of divx's that are interlaced and they always looked good on the TV (none of the motion blur etc.).

[Amontillado]

Originally posted by Narflex
Even if you disable it, it doesn't matter (I'm pretty sure, I've tried this and researched it failry heavily). You won't be able to get the scan lines to match up because of how the conversion to TV output works on your video card

This isn't eniterly true, although for most cards you're right.
The matrox 550 can do this (and I guess the newer models as well, but haven't been able to test it). With the matrox DVDmax option enabled the lines match up perfectly. I use it all the time, and the result is a perfect picture with no artifacts what so ever.

[Narflex]

Amontillado,

Sweet! I was wondering when they'd get around to doing that stuff right in the hardware.

[mlbdude]

I am going to resurrect this old thread and would like to hear from anyone that believes they have this working with an ATI or nVidia card and how they did it. I get too many conflicting answers on this.

[gplasky]

Amontillado actually has a web site with some very useful Hauppague tweaks and tips. I'm at work so I don't have the web address and it is also available from SHSPVR's site. (Currently can't get to it.) I instituted one of his tweaks and will try to remember exactly how it goes. What's nice it is also on his website as a reg file. This would be if you are using the Hauppague decoder. In the registry where all the Hauppague settings are for video you would add BOBWEAVE as the dword with the setting of 00000002. (Not sure of the number of 0's and I'm just half-remembering because I used the .reg file. Anyways, after I did this on my Front room server connected via RGB to my HDTV set which is at 1280 x 720 (16:9) it did an incredible job of smoothing at the picture. Looks much nicer-and I hace Sage set at the Great rate of 2gb. I was impressed-but your mileage may vary. This is on a GeForce FX5200 VGA/RGB out to the HDTV. Now this probably works alot better for me because it is not an s-video or component out. I believe this resolution is native 720p on my TV. Hope this helps.

Gerry

[mlbdude]

I am surprised that works well for you in that setup. Setting BOBWEAVE to 2 actually disables deinterlacing for that decoder. A HDTV actually wants a progressive signal and not an interlaced one - especially through component, or vga. Can an HDTV deinterlace video via those connections? I though it only would via svideo or composite.

Also, how can you be outputting 720p when you are sending out interlaced video? Now I am real confused .

[mlbdude]

I started a thread in the AVS forums (the real experts ). If anyone can contribute please help us find the solution to this! Thanks!

http://www.avsforum.com/avs-vb/showt...68#post3198568

[gplasky]

OK
Here is where I got the tweak and his explanation for what it does. Maybe I have the wrong concept of what you're trying to do but I can attest to the fact that the picture just looks better. As as far as 720p is concerned I thought that the resolution being done at the TV determines this. 1280 x 720 equates to the same resolution as 720p. Maybe I'm misunderstanding the concept. All I know is my HDTV reports back that it is at 720p.

Here is the link on the tweak:

Amontillado's DVCR, PVR, HTPC info

Hope this helps. Let me know if I am missing the concept.


Gerry

[mlbdude]

Yeah I know of that site. I think what is happening is that your video card is outputting the desktop at 720p and the video is being sent out interlaced to the TV. Unless you are seeing interlaced images on the TV I would suspect that your HDTV is deinterlacing it itself. It must be doing a better job than the software deinterlace you were using before.

Maybe this is something that varies greatly with the TV you are using?

Also I found this in that website...

"Videocard : Matrox Millenium 550
I've tested an ATI radeon 7000, 9500Pro, a Geforce 2 MX400 with a chronotel and with a connexant chipset and the matrox, the Matrox is by far supperior to the other cards. It gives a prefect stable and colourful image, no borders (wich seems to be a big problem with PAL cards, even with the great TVtool program for the Nvidia cards). Matrox seems to be the only one that can make a tv-out that properly displays an interlaced image. It seems that aligning the scanlines is pretty difficult for the others. So with all the other manufacures you need to deinterlace wich means you lose quality (this is off course only an issue for interlaced recordings, like you get from tv recordings, movies (Divx play good enough on the other cards as well). It is extremely easy to set the Matrox resolution to 768*576 and the DVDmax feature gives you great control on settings like interlaced/progressive output and much more."

[gplasky]

Well here's the TV I am using:

Panasonic PT-40LC12

I don't see where it's going to do anything special for deinterlacing. Unless it's the Digital comb filter or the Progressive scan doubler. But then, wouldn't this have helped my image before I changed this setting?


I thought this kinda of explained why this setting would make the picture better on any TV:

Hauppauge by default de-interlaces the mpeg stream, which is fine if you plan on viewing it on a non-interlaced display like your pc monitor. If you only plan on viewing it on a tv set you might want to consider using the weave setting. This will allow you to get a proper interlaced picture which gives a higher quality picture on your tv set. You will probably also need to set the overscan settings to 0.

So to me this setting disables deinterlacing which causes the mpeg stream to be interlaced to the TV which the TV likes better than a deinterlaced image. All I know it works great on mine. I just recently made this change the other day. And I only have Sage at the Great setting. I'm getting ready to bump it up to 3.25 and see if the good image holds out-or gets better.

Quote on resolution:

1280 x 720 Pixel Resolution-The high pixel count of our multimedia displays allows them to accept and display native 720p HDTV program material, providing incredibly detailed, high-resolution images

Quote on filter:

Motion-Adaptive 3D-Y/C Digital Comb Filter-Displays bright colors and fast-moving scenes with incredible clarity by minimizing the "color rainbow effect" in closely spaced patterns, compensating for the motion that occurs between fields.

Keep in mind the Sage recordings I'm getting are off of standard cable. None of the recordings are HDTV so my TV is going to treat it just like a broadcast from a standard station. So in this instance I would think it would want to see the signals interlaced-just like any other TV set. Only when I'm receiving a HDTV broadcast would it deal with a progressive picture, ie 480p, 720p or an interlaced picture at 1080i.

Just my thoughts. If I'm way off here help me out. I'm always willing to learn.

Gerry

[mlbdude]

You are pretty much right . The HDTV in the mix is giving me new ideas. Ignoring the HDTV part though you are right that interlaced video is normally sent to the TV. This is where all the confusion is coming into play. It sounds like neither the ATI nor nVidia can do this exactly right. I know with my ATI I can see occasional scan lines in and around red objects and motion is not as smooth as deinterlaced or by watching the cable signal straight to the TV.

I think this is coming down to how picky people are on what they are watching. Just cause the ATI and nVidia don't do it perfectly maybe they do it enough for some people.

For my own proof and quality goals I am looking for a combination of something (new video card whatever) that I can throw in and loose those last interlacing problems.

[gplasky]

Well just to let you know. I am using an nVidia (PNY) GeForce FX 5200. Here are the reasons I picked this card:

1)Integrated TV Encoder
Provides best-of-class TV-out functionality for resolutions up to 1024x768.

2)Integrated Full Hardware MPEG-2 Decoder
Delivers full-frame, full-screen MPEG-2 video on your desktop.

3)64-phase Video Scaler
Highest quality for scaling DVD and other video to full-screen HDTV resolutions.

And because I connect to my HDTV via the VGA connection this helps contribute to an excellent picture. Most TV encoders only support 720 x 520 (?) in hardware yet this does 1024 x 768. Keep in mind your mileage may vary but it is one sweet setup for me.

Gerry

PS-Mine has 2-VGA outs. There another variation that has VGA and DVI out too.

[stanger89]

Originally posted by gplasky
OK
Here is where I got the tweak and his explanation for what it does. Maybe I have the wrong concept of what you're trying to do but I can attest to the fact that the picture just looks better. As as far as 720p is concerned I thought that the resolution being done at the TV determines this. 1280 x 720 equates to the same resolution as 720p. Maybe I'm misunderstanding the concept. All I know is my HDTV reports back that it is at 720p.

Here is the link on the tweak:

Amontillado's DVCR, PVR, HTPC info

Hope this helps. Let me know if I am missing the concept.


Gerry

Perhaps I can shed some light on this.

1280x720 is 720p

What the tweak does is force the Intervideo decoder to weave the two fields together, it is still a progressive picture. This is how film (24p) content is deinterlaced by DVD players.

I suspect that the Intervideo decoders default to bob, which blends fields together effectively halving the vertical resolution, making the picture softer. By forcing weave, the picture will be sharper, but you could run into problems with iterlaceing artifacts.

Great read about interlacing/deinterlacing:
http://www.hometheaterhifi.com/volum...e-10-2000.html

[gplasky]

Now I understand why the picture looks so good on my TV. The Motion Adaptive Digital Comb filter is deinterlacing.

Quote from article:

Motion Adaptive Deinterlacing-This is a whole class of algorithms that attempt to switch between different ways of deinterlacing depending on whether an area of the screen appears to be still or moving. If an area is still, the algorithm uses the image data from two fields and weaves them together, but for moving areas, the algorithm just interpolates (bobs) the current field. This preserves resolution on the still sections of the screen, where the viewer is most likely to notice it, and reduces combing on the moving sections of the screen, at the expense of resolution. Done well, this looks very good. Most good deinterlacers use some form of motion-adaptive algorithm.

Excellent article-thanks for the read.

Gerry

[Cayars]

Originally posted by stanger89
Perhaps I can shed some light on this.

<snip>

Great read about interlacing/deinterlacing:
http://www.hometheaterhifi.com/volum...e-10-2000.html

Great article. This debunks a lot of the information I've read lately and greatly clears a lot of things up for me!

Carlo

[stanger89]

From the feature list of your TV:

Digital Comb Filter Motion-Adaptive 3D-Y/C

This doesn't actually do any deinterlacing, it separates the brightness (Y) from the color (C) information in composite signals.

From the Mitsubishi Page
Motion-Adaptive 3D Y/C Comb Filter - Comb filters separate the luminance (black and white picture information) from the chroma (color picture information), a necessary stage in the video signal processing of any color TV. In order to provide more precise separations, 3D-Y/C comb filters store both fields of a complete video frame before they begin their processing. Until now, even the best comb filters did not provide full 3D-Y/C performance when the TV picture had fast motion because of the 1/60 of a second time difference between the two picture fields. The result was 2D-Y/C-grade performance whenever there was significant motion. Mitsubishi's new Motion-Adaptive 3D-Y/C comb filter actually compensates for any motion that occurs between fields. Even programming with bright colors and fast action is displayed with a new level of clarity

S-Video (YC), and component (YPbPr/YCbCr) already have the the Y/C info separated so the Comb Filter has no effect. And VGA/DVI are completely different, sending each color (RGB) individually. My TV has a "3-Line Digital Comb Filter" but does absolutely no deinterlacing on it's own, it shows 480i as 480i, scanlines an all.

The intervideo filters are still deinterlacing, they are just using a weave method instead of the bob they were probably using before, this will make the picture obvously sharper. This usually works fine with film (24fps) sourced content, but can be problematic with video (30fps) content. One thing I noticed when I used Dscaler before was that most shows are 24fps. I'm not trying to say what you did was wrong by any means, just trying to make sure everybody knows what is actually happening.

I've been following this stuff for a few years and it can definitely be confusing, especially when you throw a computer in the mix.