Scaling 720i to 1080p for theater projection

[molecool]

I know that's a major rescaling job. Let me explain - I've build a special lens setup, and without wasting anyone's time on the gory details - after my cropping I've got an approx. resolution 1080x720 in interlaced format. I've experimented with iip and limitedsharpen, but although the source material is pretty good I'm just not satisfied with the results so far. Admitably, I've only played with the respective settings for two weeks now, so I'm not a pro.

One thing I know is that iip or limitedsharpen should be used with progressive content, so my first question would be if there's a really good script or filter out there that would prepare my 720i clip to be scaled up. I also would like to get some input on what you guys think would be good base settings for iip (or limitedsharpen). Is it at all possible to scale a clip up by a factor of 2.6?

One more thing: this is going to be shown on a large projector (QuVis/Christie setup) in a theater setting :eek: , so artifacts that might not show on an HD monitor might easily be detectable.

Any pointers and suggestions would be welcome.

[Chainmax]

Well, IIP is touted as created for 720x480--->1280x720 (~2.67) upconversions, so it would fit the bill. As for good calls, you could try this one (http://forum.doom9.org/showpost.php?p=615990&postcount=182) which yielded very nice results in that case.

[molecool]

One more consideration I wanted to throw in is the format of the clip and the colorspace. What I have are clips off of an HDV tape - so, if I'm not mistaken the 'original' format is YUV 4:2:0 - however I'm using the Cineform Intermediate codec for editing and it scales it up to YUV 4:2:2 (without loss they say, but I doubt that - see other discussion in this forum on going from 4:2:0 to 4:2:2). So, let's say I've got YUV 4:2:2 - if I use iip or limitedsharpen they both require me to convert to YV12 - don't I introduce visible artifacts? So, in fact my add-on question is: does iip or limitedsharpen lend itself mostly to upscaling DVD content and not HDV or DV clips from a camera?

Finally, I also mentioned that I am doing some cropping and need to de-interlace before editing in Premiere. The cropped clips get stored in lossless MJPEG (from LEAD) and I don't know what colorspace this thing uses (YUV or RGB).

Some input would be helpful - I'm a bit lost in this department.

[Chainmax]

I know nothing about colorspaces, you'll have to ask Didée (IIP creator) about that.

[Mug Funky]

if these are being deinterlaced, then you can do that before running IIP/limitedsharpen.

as far as what deinterlacer to use, are you in favour of erring on the side of blur rather than artefacts? a "twittering" line (my own term) from a motion-adaptive deinterlacer could be quite noticable on a big screen, but perhaps a little blurring is more tolerable?

if you want detail with possible artefacts, use Tdeint. if you want less artefacts (but still the possibility of some), use Kerneldeint (or leakKernelDeint which is the same but speed optimised).

don't be too worried about detail though - the cinema experience is quite blurry for most people. so much so that i doubt there'd be much difference between film and scaled-up SDTV in a lot of cases. i'm too lazy to get new glasses, so darkened rooms and long distances mean lots of blur...

[molecool]

if these are being deinterlaced, then you can do that before running IIP/limitedsharpen.

That is being mentioned all over the place, but running IIP + limitedsharpen seems to produce a LOT of artifacts. I was able to download that alpha version of IIP that contains limitedsharpen, but for some reason at 1080p resolution I am unable to see much of an improvement. Must be my settings - if you have any suggestions I'm all ear. Also what's the best way to mix IIP with limitedsharpen?


as far as what deinterlacer to use, are you in favour of erring on the side of blur rather than artefacts? a "twittering" line (my own term) from a motion-adaptive deinterlacer could be quite noticable on a big screen, but perhaps a little blurring is more tolerable?

if you want detail with possible artefacts, use Tdeint. if you want less artefacts (but still the possibility of some), use Kerneldeint (or leakKernelDeint which is the same but speed optimised).

I've been experimenting with smartdeinterlacer for AviSynth and it looks pretty good - how do I get my hands on those other two?


Well, I have been playing around with IIP for most of the last weekend and had to make huge leaps of faith and some surprising settings to make things look good for 1080p content (source 720i). The results look actually pretty impressive, considering that the image is 4 times larger and was interlaced to begin with!!! Some settings were very different to what's recommended for 'regular' upscaling. Will post my script later...

Thanks for the input so far - any further comments would be appreciated.

[scharfis_brain]

where Did you got that 720i from?
There is no official Standard for interlacing with 720 scanlines.

possible standards are:
480i, 480p
576i, 576p
720p
1080i, 1080p

[Leak]

I've been experimenting with smartdeinterlacer for AviSynth and it looks pretty good - how do I get my hands on those other two?
Well, grab LeakKernelDeint here (http://140.78.145.103:8888/~kp/AviSynth/LeakKernelDeint/), and for (literally) everything else take a look here (http://www.avisynth.org/warpenterprises/).

HTH. :)

[Didée]

I was able to download that alpha version of IIP that contains limitedsharpen, but for some reason at 1080p resolution I am unable to see much of an improvement. Must be my settings - if you have any suggestions I'm all ear. No, not your settings - something is fishy in the alpha. I've forgotten what exactly it was, but iirc a certain setting is producing a mask that erroneously 'protects' almost everything from getting processed ... debug="showall" should reveal it.


running IIP + limitedsharpen seems to produce a LOT of artifacts.
[...]Also what's the best way to mix IIP with limitedsharpen?
I would *not* recommend to use iiP PLUS LimitedSharpen. With the settings adapted to the source, iiP's output should be "maxed out", so that applying LS afterwards will do more harm then good for sure. So: either-or, but not both.

In the alpha, it's another story: there, LS is implanted into iiP, and replaces the SSXSharpen routine.

Moreover, using iiP after deinterlacing is tricky. You might think the deinterlacing was good ... but iiP has the better eyesight ;) - If there are any small residual artefacts (and with thresholded smart deinterlacers, these are always there), then there is danger that iiP will enhance them.
Eventually it would be better to first make a "normal" interlaced upscale and then deinterlace this one, before doing any enhancement.

But I also wonder what this 720i should be at all ... never have seen such a thing.

[Backwoods]

I know that's a major rescaling job. Let me explain - I've build a special lens setup, and without wasting anyone's time on the gory details -

I wouldn't mind hearing them, maybe others wouldn't either.

Eventually it would be better to first make a "normal" interlaced upscale and then deinterlace this one, before doing any enhancement.

I'm sorry, but I do not follow that part. Can you please explain that part again?

[bill_baroud]

i second the two others ... where did you find 720i material ? if you shooted something with an HDV cam, the only ones i know output 720p or 1080i but not 720i.... there is something fishy there, unless you explain what did you use/do. And btw i wouldn't mind wasting time on you lens setup, it's always pretty interesting ;)

[Didée]

@ Backwoods

I meant, instead of

deinterlace().iiP(upscale)

do

separatefields().upscale().weave().iiP()


, at least basically. I've done that this way only once, for a pretty crappy music concert, but the result was definetly better. If doing so, I suggest trying ela- or ela2- interpolation by TDeint or TomsMoComp.

For the passionated, scharfis_brain once had made a dedicated upscaling routine for interlaced content (interlaced upscaling for combed parts / progressive upscaling for still parts). A search should dig it out.

There's one hurdle, however: the PixieDust denoiser used in iiP is only reliable for framesizes up to 1024*1024, beyond that it starts acting silly. So, either don't feed anything bigger than 1024^2 into iiP, or replace PixieDust with another denoiser ... fft3d should be a good alternative.

[molecool]

where Did you got that 720i from?
There is no official Standard for interlacing with 720 scanlines.

Okay, since you asked ;-) I'm actually working on a 3D (stereoscopic) short, and am using 1/2 of an 1080i frame for each eye. It's a special setup I built. Hope this makes [kind of] sense ;-)

[molecool]

I would *not* recommend to use iiP PLUS LimitedSharpen. With the settings adapted to the source, iiP's output should be "maxed out", so that applying LS afterwards will do more harm then good for sure. So: either-or, but not both.


Yeah, these are my findings as well....


But I also wonder what this 720i should be at all ... never have seen such a thing.

hehehe :-) see my previous reply...

[molecool]

@ Backwoods

I meant, instead of

deinterlace().iiP(upscale)

do

separatefields().upscale().weave().iiP()


So, I would basically use interlaced clips during my edits and the IIP process would entail deinterlacing as well. Thanks for clearing that up...

Molecool

[scharfis_brain]

What exactly does half of an 1080i frame mean?

and how did this went to 720i ?!?

[bill_baroud]

uhuh ok, understood .... infact it's not 720i (which would be 1280x720) but 720x1080 interlaced (most of HDV cam shoot in 1440x1080 anamorphic), right ?

[Didée]

So, I would basically use interlaced clips during my edits and the IIP process would entail deinterlacing as well. Thanks for clearing that up...
No. Sometimes my fingers are too slow to follow my thoughts, and here I typed botch ;) - That 2nd line of course shoud have read

separatefields().upscale().weave().deinterlace().iiP()

since iiP won't do any deinterlacing. The input for iiP must be free of any sort of combing, else the result will get ugly. This applies to LimitedSharpen as well.