deinterlaced output is not deinterlaced

The one thing I haven't seen anyone else mention is that the same thing is happening in QT, and I don't mean im09 QT conversions, I mean just in QT itself, however I am getting no combing when doing FC QT conversions with the same source.

Another oddity that I've noticed is that if (for example):

I use QT to export a source to lets say 720p using a certain set of settings and label the export as V1, then go into im and fiddle about with some QT conversions and make some exports using various settings, then go back to QT, use the same source as before and ensure the same settings are used as before, then export and label the export as V2, then compare V1 and V2 they may be different, not always, but sometimes.

For me this problem is beyond im09 and has more to do with QT, however I don't recall having this problem with QT before installing im09 and I don't have issues with FC QT conversions.

Whether the problem lies with QT, im09, core video, quartz or even some GPU update I really have no idea.

Whilst I don't really accept this is  trying to promote a certain set of video resolutions, it does seem that im09 is currently only useful for working with these resolutions. The real big issue for me is that I now seem restricted to these resolutions when working with QT too.

"Export using QuickTime as follows:

• Video: compression type Apple Intermediate Codec, frame rate Current, compressor preset "Other", Interlaced and "top field first" ticked

• Size: "1920 x 1080 HD" and not "HD 1920 x 1080 16:9" is vital for iMovie '08 since it holds video at true 1080i."

I agree -- with 08 this produces a nice looking 1920x1080i60 or 1440x1080i60 movie for BD. In fact, it is the ONLY way to get a true 1080i movie out of 08.

HOWEVER:

1) This leaves the question -- why in 08 does "1920 x 1080 HD" work, but not "HD 1920 x 1080 16:9. I have always assumed that Apple made "1920 x 1080 HD work with how iM08 handles 1080i video. BUT, there is another possibility. The "non-combing combing" is a scaling artifact. (You mention it.)

2) If "HD 1920 x 1080 16:9" scales the video down slightly before it crops it -- then the reason it looks bad could be because of the down-scale while the reason "1920 x 1080 HD" looks fine is because no scaling is used. In other words, Apple didn't do anything to make "1920 x 1080 HD" in 08 work better. What we got was simply the result of how QT worked.

3) There is evidence to support this. In the sample of 1080i exported as 720p -- the pattern is not normal interlacing combing. It is exactly what one would expect if 1080 were converted to 720 by dropping every third line! Exactly.

4) Which means it may be possible for an application to tell QT what QUALITY scale to use. If Apple tells QT to scale as fast as possible -- then it would indeed drop every third line going to 720p from 1080i. The output will be odd, even, even, odd, even, even, etc.

And, as you point out -- for 540p output this works by accident to drop every other line. One gets only odd, odd, odd.

5) So what's happen in 09 with export using "1920 x 1080 HD" thats different than with 08. Why is any scaling going on?

Why did you say " ... but since reports indicate that iMovie '09 scales this a bit, ..."

This is the only way that worked in 08:

"Export using QuickTime as follows:

• Video: compression type Apple Intermediate Codec, frame rate Current, compressor preset "Other", Interlaced and "top field first" ticked

• Size: "1920 x 1080 HD" and not "HD 1920 x 1080 16:9" is vital for iMovie '08 since it holds video at true 1080i."

See comments by Pond.

Steve Mullen wrote:
This is the only way that worked in 08:

"Export using QuickTime as follows:

• Video: compression type Apple Intermediate Codec, frame rate Current, compressor preset "Other", Interlaced and "top field first" ticked

• Size: "1920 x 1080 HD" and not "HD 1920 x 1080 16:9" is vital for iMovie '08 since it holds video at true 1080i."

I understand this.

4) Which means it may be possible for an application to tell QT what QUALITY scale to use. If Apple tells QT to scale as fast as possible -- then it would indeed drop every third line going to 720p from 1080i. The output will be odd, even, even, odd, even, even, etc.

This makes sense

BUT:

When I'm using QT instead of imovie, there should be no application telling QT how to work.

I was trying DVCPROHD with iM08 and found that sometimes I got nice clean output and sometimes I did not.

This was with 10.4.11 and 7.3.1.

I too think this may not be iM09, but something deeper.

Nevertheless, I'm sure the Apple ilife team didn't miss this.

Here are some examples:

iMovie 08:
http://sanjeevandlisa.smugmug.com/photos/465409379_eQs7v-X2.png

iMovie 09:
http://sanjeevandlisa.smugmug.com/photos/465409433_C5Zna-X2.png

Both were exported using QT @720p

Great example. This shows what everyone is experiencing. How can we make Apple aware of this problem?

Thinking that poor quality could be a scaling issue caused by the use of Clean Aperture during export, tonight I've done two things:

1) I went back to my attempts to use 720p DVCPRO HD in iM08 because it plays back VERY smoothly. I converted h264/AVC to DVCPRO HD. (Result claimed to be 1280x720, but I know it was 960x720 because that's the definition of DVCPRO HD.) When imported and exported from 08, the DVCPRO HD movie looked horrible and was reported to be using Clean Aperture: 1248x702. This despite choosing the UPPER 1280x720.

In QT Player there is, under PRESENTATION, a way to switch off Clean Aperture and switch to Classic. Now the movie became 1280x720, but still looked horrible.

On a hunch I put an HDV 1280x720 as the first clip. The exported DVCPRO HD movie now looked wonderful, yet it still was reported as Clean Aperture. So Clean Aperture did not seem to affect quality, but scaling did. Therefore, I was motivated to keep looking at scaling.

--------------

I found, from Apple, this:

The Conform aperture setting allows you to specify how the outside edges of the video are processed during playback. Depending on how the movie was created, and its aspect ratio and resolution, the portion of the image area that has the best quality and is intended for display will vary. During playback, QuickTime adjusts the image using the selected aperture setting to obtain the best visual clarity.

Classic aperture uses the dimensions as specified by the track.

Clean aperture crops to the clean aperture area and SCALES the image according to the pixel aspect ratio of the track. The clean aperture area excludes the edges of the video where digital artifacts might occur.

Then, I found this:

Blackmagic Design has implemented a feature request from Apple that Final Cut Pro movies captured with our video capture hardware, be tagged with their nominal clean aperture attributes. Accordingly a 1920 x 1080 QuickTime movie will appear as 1888 x 1062 when opened with QuickTime Player. There is nothing wrong with the movie as the aperture setting is simply a metadata tag which instructs QuickTime how to display the outside edges of the movie and the pixel aspect ratio of the video track.

How does this affect my movies?

You will not see changes to your movies in Final Cut Pro as it does NOT invoke the clean aperture settings. However, other QuickTime-based video applications may use this setting which may affect how the files are presented or PROCESSED.

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In iM08, the UPPER 1080i setting works as it does in FCP. Clean Aperture is not applied. It takes 1080i video and, without scaling, passes it into a file. Looks good.

In iM08, UPPER 720p: Clean Aperture is generally not applied. DEINTERLACE is applied to 1080i and THEN scaled to 720p. Looks good.

In iM08, LOWER 1080i: Uses Clean Aperture that crops the interlace video and then UP-SCALES -- which screws it up.

Why?

Because, for speed, iM scales interlaced lines instead of de-interlacing and then scaling.

For 720p video and 540p video and one-field-only SD video -- this crude scaling works OK because each frame is progressive.

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With iM09, Apple may have decided that for uniformity, QT-based applications must apply Clean Aperture to all outputs. Thus, the UPPER 1080i and UPPER 720p settings now always use Clean Aperture. If I'm correct, this isn't a bug that Apple will fix.

But, why is the DEINTERLACE function disabled when you request the export of 720p? This seems like it is an issue that could be fixed. However, since the only use for 1080i to 720p is to support internet streaming AND since Apple has already got it's marketing buzz from supporting Utube -- they may have decided to prevent you from HD streaming. Apple may choose to later offer SHARE TO Utube HD or to SHARE TO MobileMe HD. (Perhaps when it finally kills iDVD?)

Of course, Apple could re-open the door to 1080i output. But, the only use for that is for those that want to burn BD using Toast (not from Apple) and a BD burner (not from Apple). I would not count on Apple opening this path since they make no $$$ by doing so.

Bottom-line: I think Apple knows full well that the use of Clean Aperture WITH fast-scaling has negative side-effects just as it knows full well the Share to IDVD doesn't improve quality of our DVDs. So, if you want to keep using iM you'll simply give-up on optical discs and HD streaming.

PS: Curious if 540p QT export is also now using Clean Aperture size video.

Steve, that all makes sense and seems to fit.

It seems strange that they would opt to use clean aperture by default in a process that inherently involves less and less analogue video as time goes by.

However, I'm now able to export to 1080i (1440) again without such issues. Not as though I use 720p, I can now deinterlace my export externally and then export to 720p without an issue in QT.

To be fair the problems with my 1080i exports were not so noticeable, I wonder if when the deinterlacing is fixed in QT whether any issues with 720p exports will be all that noticeable either.

My head hurts... 🙂

Will FCE make all this go away? I would gladly spend $150 if this issue becomes a non-issue and I can read all of these fascinating posts "just for the heckuvit." Don't get me wrong, I'm enjoying this and looking forward to some kind of response from Apple, even if not here. I just do want to get on with compiling and editing all those birthday videos...

--D

FCE holds no such problems for me, so yes it would make it all go away for you.

FCE has quite a learning curve associated with it, although it can do much much more than imovie.

If you are looking for a quick resolve for what I hope is a temporary problem, export to AIC using the same resolution as your source video, use JES deinterlacer to deinterlace and resize your video.

Steve Mullen wrote:
Thinking that poor quality could be a scaling issue caused by the use of Clean Aperture during export [...]

Your comments match my observations. I didn't know the correct term for the overscan/safe area stuff that was being applied with the 'lower' set of HD sizes or omitted for the 'upper' set. Someone else mentioned that an HD camcorder movie ingested by iMovie '09 showed a nominal size of 1888 x 1062 in QuickTime Player, so Conform/Clean Aperture seems to have been enforced for the stored video. This is a potential disaster for any downstream processing, since unwanted cropping and scaling may be performed. Doh.

I just can't understand the application of this data for ingested footage in the first place though. Why should iMovie insist that I didn't actually want to see all of the picture my camcorder recorded?

(Perhaps when it finally kills iDVD?)

This would be an iLife deal-breaker for me, although there are presently only rumours about iDVD disappearing and rumours are often wrong.

There's no better way to reliably and portably share decent quality video which can easily be displayed on a TV with pause/frame stepping/slow etc. controls. Flash video interfaces suck! Playback is often stuttering, seeking is inaccurate, pause/resume usually lags a few frames and there's no playback rate control. For the sort of video I share (rowing footage, often leading to slowmo and frame-by-frame technical analysis by the crews involved) DVD is usually the only way forward. Just about everyone has a DVD player, including the rowing club; far fewer people have a computer attached to a big TV; the rowing club has no Internet access anyway.

People keep predicting the death of physical media and yet, it just doesn't seem to happen. That's perhaps because physical media has compelling advantages over online media for certain tasks. Both have their function and those functions are often complimentary, despite inevitable overlap. It's not necessary for one to disappear just because the other exists.

Steve,
most of this went over my head 🙂

My workflow is very simple. I have a canon HD camcorder (HF100) that is supposedly 1080p (although I have read reports that it really records at 1080i). I want to import footage in iMovie 09 and then export it to a mov file @720p so that I can share the video with others. If this is not a bug, is this simple use case no longer supported? How are we supposed to create movies? Is there a different workflow we should adopt?

So, it looks like my camcorder was set to record at 60i. Changing to 30p makes everything good again. No more jaggies 🙂

For the 60i recorded stuff, it looks like the best option is to import 1080i footage as 960x540. Then I can export at 720p with no jaggies. Importing the same footage as 1920x1080 results in jaggies, but the resulting video at 720p seems a tad sharper to me than the one imported at 960x540 and exported @720p.

So, it seems like I am set for my future captures with the camcorder set to record at 30p. My older captures at 60i can no longer be exported at 720p using iMovie 09. Exporting the older 60i captures at 960x540 results in clean videos.