Interlaced 2600 Display revisited, for HDTV flicker-free flickering

[RevEng]

SeaGtGruff has made some comments in the past that his HDTV displays flickered content without flickering. I suspected that other HDTVs might do this too if interlaced 2600 frames were used instead of the usual progressive.

 

I put together a quick test, and indeed that is the case with my HDTV. In fact, the flickering players look sharper and less fuzzy in this mode than non-flickering players! (though they are striped) Moving the non-flickering player didn't result in combing as I would have expected.

 

On my CRT, flickered players with interlaced display look pretty much the same as under progressive display, with just a gentle bit of softening of non-flickered sprites due to them moving up and down a half line on alternating frames.

 

Can anyone else confirm this is the case with their HDTVs? If it's fairly universal, I would see this as a great option to include in games that use a lot of flicker, like DK VCS.

 

The following quick and dirty demo defaults to interlaced display mode, and switches to the usual progressive display mode if the fire button is held down. Player0 is static and movable, Player1 is flickered for 2 independent objects.

 

interlace.bas.bin

 

Also, it's worth mentioning that Stella doesn't yet support interlaced display, so testing it there won't yield anything interesting.

[iesposta]

I was going to write your binary doesn't do anything different until I tried it on a real television and that shows the difference between progressive and interlace.

My HDTV, in all "tv modes," and with or without the button shows a barely seen flicker of the blue & green.

All modes report 480i with or without button.

No "striping."

The DLP projector shows the blue guy with stripes. No change with button.

[iesposta]

Also DLP projector tested with s-video and composite, not RF.

LCD TV tested with s-video.

CRT TV tested with RF.

[RevEng]

It sounds like one or both of your TVs might be assuming the material is interlaced instead of progressive, like SeaGtGruff's.

 

Hopefully we'll get some more data points!

[RevEng]

Anybody else get a chance to test?

[SeaGtGruff]

I'll try to test it later tonight.

 

On my TV a 2600 display will be interleaved even without trying to draw an interlaced display. I really like it, because it's flicker-free-- like when you alternate between two sets of background/playfield colors from one scan line to the next on a non-interlaced display, except the alternating lines of color are half as thick and there are twice as many of them, so the colors blend together better.

[RevEng]

Thanks!