Software DVD player deinterlacing w/ TV-out

[nikthebak]

The issue in the subject has bothered me for quite a while now and eventually I was stuck into a point where my knowledge about this issue was just inadequate.

Let me start by elaborating the issue a bit. Software DVD players are meant for computers where a monitor is the primary display device. Interlaced content looks terrible with progressive scan device, such as a computer monitor, so the DVD player usually implements some sort of deinterlacing.

The problem is what to do when one wants to use the TV-out and watch the DVD's through a television set. My TV set is unfortunately old-fashioned interlaced PAL so I can't feed it with progressive signal (or I could with 60 Hz sources but I live in PAL country where DVD's are without exception PAL) no matter how much I wanted to. What happens when software DVD player deinterlaces the content and TV-out reinterlaces it for the TV?

From what I've gathered the process goes something like this;

Standalone DVD players:
[interlaced source] -> [TV set]

PC with SW DVD player and TV-out:
[interlaced source] -> [deinterlacing] -> [reinterlacing] -> [TV-set]

The reason I'm babbling about this issue is that I've run into serious problems recently with interlaced DVD's. The content is Xena R2 DVD's, which are originally shot at 30fps interlaced NTSC and (poorly) converted to 25fps interlaced PAL. The DVD's are totally unplayable with SW DVD player and TV-out. The reason is that the deinterlacing algorithms provided by SW DVD players fail miserably.

Both PowerDVD's and WinDVD's "force bob" deinterlacing causes the picture (on the television) to bob up and down rapidly, which hurts my eyes. "Force weave" generates so much ghosting that high-motion scenes are completely blurred and thus unwatchable. "Auto-detect" defaults to bob which is much worse than weave. On the monitor bob looks ok, but on television it's for some reason totally unwatchable. I reckon it's because of the reinterlacing done by the TV out.

My friend watched these DVD's through a standalone device and said that the picture quality is superb, no bobbing or ghosting whatsoever.

So I'm kindly asking for your advice on the situation because frankly, I don't know what to do. Is there a SW DVD player in existence which allows the option not to deinterlace the content at all or something like that? A tuning software maybe? I own a Radeon 8500 so TVTool is right out.

And on a theoretical level, would sending the interlaced signal to the TV work at all? I mean would the already interlaced signal get "interlaced again" by the TV-out, making the picture a total mess? I can think of incorrect field order, incorrect timings and such.

I'm probably going to get a standalone DVD player next month because I'm so sick of PC DVD playback, but it would still be nice to know how to fix this situation nonetheless :D Thanks for your time.

[avih]

the best shot would be to:
1. use weave (= don't deinterlace), and:
2. make sure your display resolution when using tv-out is <something>x576 for pal tv (or <something>x480 for ntsc) (if you're using nvidia drivers, you might have to download tweaked drivers that support such resolution), and:
3. use tools such as 're-clock' to synchronize the playback framerate to the refresh rate of the display (tv-out included), and:
4. hope that it'll work for you.

theoretically, you should be able to produce the 'original' interlaced content through tv-out (as mentioned in this 'mini-guide'). but in practice, it can be hard to setup.

good luck.

[nikthebak]

Thanks avih!

I have done all 3 parts, just part 4. is giving me trouble :)

It turned out that it was in fact tab "Use Hardware Decoding" which caused ghosting image when using "force weave". Dechecking hardware decoding made force weave look correct, i.e. very, very interlaced.

I already had set my TV-resolution to 720x576 with R3Tweak and have used ReClock for few months now, no problem with that.

Unfortunately when using these settings (force weave, 720x576, ReClock) there are plenty of interlacing artifacts on the picture on TV. The interlacing artifacts look quite different on TV than on monitor.

On the TV it seems like a bunch of sequantal lines are displaced horizontally, i.e. different fields are not clearly visible (like on the monitor) but only parts of the fields. Things just don't seem to "sync up".

Force bob clears these interlacing artifacts but smoothens the image considerably.

I tried zooming the picture in and out with Zoom Player, but it made no difference. I also tried resolutions 640x480, 720x576 and 800x600 without success. After that I ran out of ideas :)

[avih]

zoom is NOT the solution. on the contrary, the picture must be full screen @ <something>x576 such that it matches the scanlines on the actual tv. one more thing you should set (forgot to mention it) is to setup the tv-out (using tv-tool?) for overscan mode, since the underscan mode zooms out a bit, which breaks the scan-line compatibility.

and as i said, playing interlaced content trough tv-out it's not the easiest thing to do, and your milage may vary depending upon too many system variables and your determination ;)

good luck again

[nikthebak]

@avih

I've used overscan mode for ages now :) Unfortunately I own a ATI Radeon 8500 so I can't use any of the "good" tweaking software. R3D Tweak is so damn limited.

Just had some weird experiences regarding the topic of this thread.

For some reason, I managed to display interlaced content properly using Catalyst 3.2 drivers. The problem is that with Catalyst 3.2, the driver switches immediately to underscan mode upon activating DVD playback. Catalyst 3.1 retains the overscan mode properly in all situations.

So, for some mysterious reason the interlaced contet looked ok in underscan mode with Catalyst 3.2. Unfortunately since I lose about 3-4 centimeters of image area when in underscan mode, I reverted back to Catalyst 3.1, which overscans properly. Back to square one.

It seems to be impossible to display interlaced content properly with ATI Radeon cards and Catalyst drivers. I've read somewhere on the net that some folks with Matrox G400 and G550 cards have managed to display interlaced content properly. Possibly nVidia owners can do that too, because of TVTool software. And we Radeon owners just have to buy a standalone DVD player.

[dZeus]

as for a videocard which can output interlaced material PROPERLY, try a Matrox G400, with 'field based scaling' enabled in the DVD-MAX properties tab. One side effect is that progressive material like most AVIs looks like crap with field based scaling enabled.. you'll have to change the setting every time you change from progressive to interlaced material and back.

[nikthebak]

Originally posted by dZeus
as for a videocard which can output interlaced material PROPERLY, try a Matrox G400, with 'field based scaling' enabled in the DVD-MAX properties tab.

I'm already aware that proper TV-out display of interlaced content is possible with Matrox G400 and G550 cards, but even though the old Matrox cards are extremely affordable now, I can't take that route because;

1) I can't use two AGP cards simultaneously.
2) I don't want to change my Radeon 8500 to a performance-wise inferior card.

But I'll take that route into consideration. If I could get a G400 really dirt-cheap (0-50 €), I'll definetely buy one. Although gaming performance is important to me, proper TV-out is even more so.

[avih]

iirc, there's an avisynth-equivalent for dvd (possibly a wip). if such tool does exist and functional, you could use it with the method i described several times here before http://forum.doom9.org/showthread.php?s=&threadid=51105 (deinterlace to 50fps in real time, playback through tv-out) which should solve it with any card capable of tv-out, even nvidia ;), but you'll need a fairly fast pc. prob 1.5G+

[nikthebak]

Thanks avih, you just gave me another lead on something :)

I use Zoom Player 3.00 Pro to watch DVD's and coincidentally ZP allows to use ffdshow with DVD's.

That was the good part. The bad part is that none of the ffdshow deinterlacing routines (which include bob and framerate doubler) seem to quite work. Framerate doubler did give the best-looking effect, but unfortunately I don't seem to have enough CPU power (I own a 1.8B P4). The audio and picture started stuttering occasionally after activating "framerate doubler" in ffdshow, and naturally CPU usage hitted 100% quite often. Regular hardware-accelerated DVD playback takes hardly any CPU cycles on my machine.

It seems that using ffdshow through ZP yields a significant processing overhead, especially since hardware MPEG-2 decoding cannot be used.

Furthermore, it seems that the content (Xena DVD's) is completely screwed. In some fast-motion scenes framerate doubler gives perfectly sharp and artifact-free image, but instantly when the camera changes, the screen is completely messed up. Probably the field order changes for certain cameras or something.

This thing is completely new to me. Until now every single PAL DVD I've watched has contained progressive video. Interlacing should be banned by law. All governments should make progressive HDTV signal mandatory for all TV-related usage :)

[avih]

Originally posted by nikthebak
...
It seems that using ffdshow through ZP yields a significant processing overhead, especially since hardware MPEG-2 decoding cannot be used.
...
This thing is completely new to me. Until now every single PAL DVD I've watched has contained progressive video. Interlacing should be banned by law. All governments should make progressive HDTV signal mandatory for all TV-related usage :)

yes, i couldn't use ffdshow deinterlacer perfectly too. you should also remember that some of the features of the deinterlacer require you to exit the player and re-launch it, since it changes the framerate.

but interlaced content is VERY important, especially for fast action. i.e. in sports or races, where you can't see the small details anyway (hence, the reduced resolution doesn't really matter), BUT the 50fps instead of 25fps makes a HUGE difference.