How to Play "interlaced videos" on TV via TV-out of PC graphic card ?

[aleste81]

Can a PC with TV-out emulate a DVD player ?

I have a 720x576 interlaced video, and a interlaced TV.

If I play the interlaced video on the interlaced TV via a DVD player, obviously the 576 interlaced lines will be displayed correctly on their 576 interlaced phosphored places on my interlaced TV.

BUT if I play the interlaced video on the interlaced TV via the TV-out RCA plug of the PC, I feel there is very few chances that the 576 interlaced lines of the original interlaced video will be displayed correctly on their 576 interlaced phosphored places on my interlaced TV (since the video is stretched by the PC).
And I get "ghosting" effect.

Is there a trick to emulate a DVD player from a PC ?

[2Bdecided]

There is a world of pain involved in trying to get this to work. The main problem you have is that TVs run at 50Hz, and PC displays and graphics cards normally don't. The other major problem is that standard TV-out functions don't attempt to perform a pixel perfect output of the display, so you can't get those 576 lines out properly.

I've read threads discussing this before (not on this forum) - a google for powerstrip 50Hz RGB etc might help. Also try searching uk.tech.broadcast, uk.tech.digital-tv and similar groups. People also battle this with Windows Media Centre, so browsing UK MCE forums might help.

I don't think I've heard of people making this work properly via a standard TV out. The closest they get is bobbing the content, forcing the PC to 50Hz, and hoping there's not too much scaling.

You can do it properly without scaling via the VGA output of some graphics cards with a VGA>RGB adapter into a SCART plug. Read about Powerstrip for more info.

Hope this helps.

Cheers,
David.

[reepa]

You don't need Powerstrip if you have an NVidia video card. NVidia's drivers allow you to adjust timing parameters (Advanced timing under Screen resolutions & refresh rates). You can generate all kinds of wacky video modes such as 2048x1152 @ 100Hz interlaced. There is a predefined 625-line mode, 720x576 @ 50Hz interlaced, which you could feed directly to a TV with an RGB scart socket (you need a simple HD-15 -> SCART adapter).

I'd love to hear how to get what you want working using the tv-out of a video card. Standard definition tv-out seems to be very neglected.

edit: Seems like NVidia cards/drivers don't support composite sync so you need some electronics instead of just a simple adapter.

[Didée]

That's why I still love my DH Matrox for feeding a SD television. No tricking-around with 3rd-party tools, no need to build electronic circuits.
Just connect to the TV. Everything perfect.

[SeeMoreDigital]

That's why I still love my DH Matrox for feeding a SD television. No tricking-around with 3rd-party tools, no need to build electronic circuits.
Just connect to the TV. Everything perfect.This is why I was so fond of my Sigma Xcard too!

You'd think the graphics card manufacturers would have recognised the need to provide good quality interlaced support for TV connected users many years ago :(

[ivanjr]

Can a PC with TV-out emulate a DVD player ?

I have a 720x576 interlaced video, and a interlaced TV.

If I play the interlaced video on the interlaced TV via a DVD player, obviously the 576 interlaced lines will be displayed correctly on their 576 interlaced phosphored places on my interlaced TV.

BUT if I play the interlaced video on the interlaced TV via the TV-out RCA plug of the PC, I feel there is very few chances that the 576 interlaced lines of the original interlaced video will be displayed correctly on their 576 interlaced phosphored places on my interlaced TV (since the video is stretched by the PC).
And I get "ghosting" effect.

Is there a trick to emulate a DVD player from a PC ?


Yes, there is a way. I bought this little box, just for test:

http://articulo.mercadolibre.com.mx/MLM-553078512-mini-adaptador-convertidor-hdmi-a-rca-av-audio-video-_JM

My surprise, when I connected it, my PC (under Debian 8.6) recognize the NTSC-DVD native resolution of 720x480 (It supports PAL too).

I played a NTSC interlaced video with VLC and voilà, the picture was perfect at my analog TV (like a native DVD).

Just two cons:

1.- This is a home solution, not recommended for pro or broadcasting. This box haves cheap Chinese components so audio decoding must be poor; just suitable for TV speakers.

2.- For any resolution or aspect ratio different to 720x480 (or 720x576 for PAL) and 4:3 you must to activate deinterlace (if necessary) and apply a command in order to scale the non-square pixels. For Debian (and NTSC), I use:

xrandr --output HDMI1 --mode 720x480 --scale 1x1.125

For PAL must be:

xrandr --output HDMI1 --mode 720x576 --scale 1.0666667x1

Please let me know your results!

[ChiDragon]

How is field order maintained?

[StainlessS]

Please let me know your results!

aleste81 has not been on-line since 2008.

[ivanjr]

How is field order maintained?

This HDMI2AV converter is a kind of "dummy" demodulator, the frame is just forwarded to TV; so I think the fields order is depended of codec/video player, or the source itself.

I used VLC playing an ISO DVD with video 720x480 (4:3) interlaced. Obviously full screen and VLC option "always fit window" must be disabled. I tested a lot of video concerts with success. Maybe the queen test is to play an old video filmed on Hi8 or miniDV.

[ivanjr]

aleste81 has not been on-line since 2008.

Yeah, unfortunately my answer was a little delayed :(

[aleste81]

aleste81 is here, folks !
I still have those interlaced videos, and spend some time trying to find some software filters that would transform them into ideal progressive videos for progressive displays, but found the result was sub-par.

My eye just got used to the ghosting effect of the offbeat slim parallel lines.

So basically I asked my brain to do the conversion in real time. I do this for most problems lately, since most solutions seems out of reach for the rational man.