Deinterlacing apps

[miamicanes]

What open-source deinterlacing apps or libraries are currently floating around, and how do they compare to one another as far as platform, performance, quality, etc.? I'm toying with the idea of writing an app that needs to be able to deinterlace 59.94 field/second video into 59.94 FRAME/second progressive video as part of its featureset, but it would be nice if I could avoid having to reinvent the wheel if someone else already wrote a library that can be used instead (not to mention the fact that I haven't got the slightest idea in hell how to write a deinterlacing app)

OK, I guess I can admit it's not entirely an academic thing... I'm hoping to get a DLP projector for my living room in a few weeks (to be driven by a PC), and I'm thinking about writing an app to let me painlessly drop in a DVD and have the app rip it to HuffyUV AVI (one AVI per chapter), parse the disc's menu structure so it'll know how to navigate among the pile of AVI files, and ultimately show them at 800 x 600 fullscreen by deinterlacing them on the fly and resampling them horizontally to make the native 640 x 480 res fit vertically (480 lines of video + 120 lines of black letterbox to fill in the remainder of the 600 lines) and horizontally (resampling it to 853 pixels to make it 16:9, then whacking off 26 and 27 pixels from the left and right sides to make it fit 800 pixels).

In other words, do exactly what a good progressive-scan DVD player should do anyway (deinterlace and resample to 800x600 entirely in the digital domain), but isn't Allowed™ to do by the DVD Alliance...

[BJ_M]

you are talking of a scaler, of which there are many ..

or the ones built into even inexpensive dlp projectors like the InFocus X1 will far outperform anything you can build on a pc.

[miamicanes]

or the ones built into even inexpensive dlp projectors like the InFocus X1 will far outperform anything you can build on a pc.

Even taking into consideration that a scaler built into the X1 has to deinterlace analog, but doing it via the rip & decrypt method lets you work directly with clean digital source?

As far as I know, there aren't any progressive-scan DVD players capable of natively outputting 800 x 600 via analog, even if it's just letterboxed 16:9 640x480 inside a 4:3 800 x 600 screen. The DVD Consortium's licensing won't let manufacturers offer it. It's unfortunate, but thanks to the nice folks in Hollywood, if you want to watch a DVD on a display connected via HD15 VGA or YCrCb component and feed it anything higher than 640x480, you've gotta metaphorically give 'em the finger and relish the freedom having a real PC gives you to hack around their evil schemes. In their paranoid, computer-illiterate universe, output resolution matters more than the resolution of the actual detail letterboxed within it, so 16:9 640 x 480 letterboxed inside 4:3 800 x 600 is still taboo

In theory, I guess the player could output progressive 640x480 with pixels intended to be interpreted as wide rather than square and hope the X1 itself is smart enough to leave the 480 scanlines alone and stretch the 640 pixels out to fill the available width, but I'd be shocked if it actually worked with any affordable combination of proscan DVD player + X1 (or comparable projector) available today. And even then, it's still adding a needless layer of analog to screw things up along the way.

[BJ_M]

you input into it off DVI - but non the less , even taking a normal DVD player , i play them all the time on screens 24 - 28 feet wide (and HD for the same size screens and larger).. this is through the built in scalers found in such large format projectors from NEC and DPS mostly .. the picture is awesome .. even from a dvd source through component ..

problem with a PC source is that not being a dedicated machine w/ a real time operating system ,, the signal is not stable enough for the most part adding in the complexty you are advocating ..

we do use embeddded OS servers for serving HD content .. these are single use only type machines (they only have to do one thing) ..

The scalers you can purchase from $2000 - $40,000 are also of course dedicated .

im not sure what you mean by the output is now always letterboxed , because its not .. i use full frame 16:9 on dvd , it comes out as full frame 16:9 w/ no boarders or i do an anamorphic 4:3 picture instead (depending on throw and lens combo i have to use) and stretch it out with an anamorphic lens..

[hustbaer]

@miamicanes: hi!

"DScaler" is the best all-purpose de-interlacer i know.
the project is open-source ( http://deinterlace.sourceforge.net/ ) but not really a library...

however you should have one other thing in mind:

normal PC video playback is not synchronized to the refresh-rate.
if you playback a 30Hz movie with other than 60, 90, 120...Hz it simply is not possible.

if you match the output frequenzy of your super-vhs out on the vga card to the framerate of the source material it is possible, but you need special software to do so.
otherwise the refreshrates will not be synchronized 100% (because different clocks are used - playback is usually glued to the audio-clock) and the movie will "stutter" every few seconds.

you might want to have a look at the "reclock" filter ( http://ogo.nerim.net/reclockfilter/ - also in the "tools" section of dvdrhelp).

i think - no, i know software deinterlacing can be better than (or at least equal to) hardware solutions in concerns of quality.
the question is, is there any open-source stuff you can easily integrate into your planned program - AND - is it fast enough?

one other thing:
if you plan on playing telecined ntsc movie-dvds (and only if!), you will get better quality if you just use a "force-film" decoder that outputs 24 fps progressive, double the framerate, speed it up to 50 fps so the beamer can "eat" it (reclock can do this for you) and output to the player.
the results will be better than any hardware or software solution possible.

bye,
--hustbaer