Interlaced video must be correctly deinterlaced for web video delivery - AVS Forum
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post #1 of 11 Old 03-01-2012, 04:17 PM - Thread Starter
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I decided to move this argument into a separate thread, because it may be more interesting to owners of the Canon G10 and other interlaced-only camcorders than to owners of native progressive camcorders like the Panasonics and later Sonys.

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Originally Posted by Philip_L View Post

Given the extreme compression of most on line video services it probably doesn't matter if you started out with progressive or interlace footage.

Absolutely not true (the image is clickable).



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Originally Posted by Philip_L View Post

It depends on the service if it de-interlaces or not, if the service is feeding back interlaced footage your media player/embedded flash player should be de-interlacing it so you don't see the combing.

Something is wrong with your playback software if you are seeing interlacing combing like that or the stream has been encoded incorrectly before upload and doesn't contain the correct flags, as it should be de-interlaced for you.

Any decent de-interlacing will give you an image that doesn't look much different to true progressive when they are both going through some strong compression seen with on-line services.

Edit: I've checked the video, basically it is interlaced footage that has been flagged as progressive, looks like a problem in the creation of the final output before upload to YouTube. When forced to treat it as interlaced, all that combing is gone and it looks pretty good.

Regards

Phil

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Originally Posted by Philip_L View Post

I've checked the video, basically it is interlaced footage that has been flagged as progressive, looks like a problem in the creation of the final output before upload to YouTube.

Maybe. Maybe it is YouTube's deinterlacer. You never know. Bottom line: you get predictable and consistent results with progressive source, you get unpredictable and inconsistent results with interlaced source. If you do deinterlace interlaced video so that it does not have neither combing nor ghosting you lose half of vertical resolution compared to native progressive video. And yes, this is noticeable even on YouTube.

As for TV viewing, all TVs have deinenterlacers, some are better other are worse, but even when deinterlaced "field-to-frame" (a.k.a. "bob") the image usually is still watchable. Which is why I would prefer consumer cams having 720p60 instead of 1080p60, but Panasonic does not want to hurt its professional lineup by offering what they think is a professional format (720p60), so they offer a format that is not used by pros (1080p60).

1080p60 is not BD legal, it can be watched only on AVCHD 2.0 - compliant players, it is not used in broadcast. This way Panasonic (and Sony) made it look like they offered a super-duper format to consumers while fully protecting their professional lineups. Bravo.

I convert all my interlaced videos into 720p60, I also render from 1080p60 into 720p60, and it looks good enough for me (I render 1080p60 too, but I don't give it away). Presently, I consider 720p60 the best middle ground, it is fully supported in BD players and in broadcast and I can render great interlaced DVD-Video from it if I needed. And it looks great on a computer without the need to tweak deinterlacing settings.

Compare frame size in pixels: 1280x720 = 921600, 1920x1080 = 2073600. Now compare bitrates: 24 Mbit/s for 720p60 and 28 Mbit/s for 1080p60 and you will see that 1080p60 has to work harder. Hence occasional macroblocking that I see from the SD600.

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Originally Posted by Philip_L View Post

Calm down I quite agree progressive footage is better, it's a no brainer when all we have now is progressive displays. I was just acknowledging the fact that many people are quite happy with interlaced footage especially when you are using online services.

A tip I've found, turn down the sharpness on the SD600 to -5 (if you have that option on the SD600, needs manual mode), which is actually no sharpness applied (as it should be for acquistion), that makes the footage much easier to compress at 28Mbit/sec @ 1080/60p and the footage looks so much better with no tell tale sharpnening artefacts. You can always add a touch of sharpening in post edit if you wish later.

I always re-encode back out to 1080/60p at Blu-ray bit-rates, average 35Mbits/sec which avoids as much as possible any more degradation in the picture quality and playback via the network on a Panasonic Blu-ray player that supports 1080/60p. Like you when I want to give the footage away I convert to 720p for Blu-ray using a spline resizing in AVISynth and encode with X264, this link here might be of interest. http://www.dvinfo.net/forum/what-hap...4-encoder.html

Regards

Phil

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post #2 of 11 Old 03-01-2012, 04:17 PM - Thread Starter
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Quote:
Originally Posted by Philip_L View Post

I was just acknowledging the fact that many people are quite happy with interlaced footage especially when you are using online services.

I don't know how you can acknowledge something which is not true. Interlaced video is ok for watching on a TV set from a BD or DVD player, but it blows for online services. Here is a fresh example of interlaced video deinterlaced with "weave" method: http://www.youtube.com/watch?v=ZTaVGjqrnVQ
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post #3 of 11 Old 03-01-2012, 04:18 PM - Thread Starter
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Here is an example of "blend" deinterlacing: http://www.youtube.com/watch?v=VVuGl3wMPxQ
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post #4 of 11 Old 03-11-2012, 10:35 PM - Thread Starter
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Look ma, 10 fingers (on one hand): http://www.youtube.com/watch?v=XF8_r61CXeY
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post #5 of 11 Old 04-01-2012, 07:16 PM
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So I like what your saying, but is there a guide or suggestion on just how to do this with 1080 60i video? That is, take 60i and convert/render it to 720 60p with deinterlacing?
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post #6 of 11 Old 04-01-2012, 08:21 PM
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What you should do is deinterlace the original 1080/60i video into an equivalent of 1080/30p with one of the deinterlacing methods, the crudest taking the shortest time but yielding the lowest quality up to the highly sophisticated, often taking incredibly long time on the average computer but giving the quality closest to the genuine 1080/30p video.

Don't do 720/60p as this involves frame scaling (down) as well as interpolating the 60i into 60p. Too much processing with inferior result to 1080/30p if viewed at 1920x1080.
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post #7 of 11 Old 04-02-2012, 01:02 AM
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Quote:
Originally Posted by P&Struefan View Post

What you should do is deinterlace the original 1080/60i video into an equivalent of 1080/30p with one of the deinterlacing methods, the crudest taking the shortest time but yielding the lowest quality up to the highly sophisticated, often taking incredibly long time on the average computer but giving the quality closest to the genuine 1080/30p video.

Don't do 720/60p as this involves frame scaling (down) as well as interpolating the 60i into 60p. Too much processing with inferior result to 1080/30p if viewed at 1920x1080.

Ok, just not sure how to do the deinterlace and what tools are best for best quality deinterlace. I found this post, but not sure the tool offers deinterlace but it seems to make it all easier by automating many tasks. I would certainly like to edit in Vegas, then render using x264 for best quality.

Seems that the consensus for best quality deinterlacer is QTGMC but I am not yet well versed on how it would integrate into the whole process.
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post #8 of 11 Old 04-02-2012, 07:20 AM
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I haven't tried QTGMC but I'm pretty sure you can deinterlace within Vegas or at the very least the deinterlacing should be incorporated into any export presets for targets that either require or prefer progressive frames to play back the video properly e.g. YouTube, Vimeo etc. If you just want to deinterlace your footage without being specific about how your exported video is going to be used, and can't find any function that explicitly says "deinterlace" within Vegas, try dropping your footage in another project/sequence that's set at 1080/30p. The footage should be re-rendered as 1080/30p but I have no idea how acceptable it will be to you.

Sorry that I can't offer more help as I'm on a Mac platform and the deinterlacing algorithm built into the export presets in both Final Cut Pro X and iMovie works like a charm. I used to try doing it the hard way by putting self-contained videos through Apple's Compressor and Sorenson Media's Squeeze, fiddling with several parameters in the higher quality options. The difference in the quality was hardly noticeable most of the time at the cost of hopelessly long render time and higher electricity bills.

If you really have a choice, my advice is shoot progressive and forget about all the above. The days of CRTs are long gone.
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post #9 of 11 Old 04-04-2012, 10:03 PM
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Found this guide, its very detailed and looks like a best of solution
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post #10 of 11 Old 04-05-2012, 11:31 AM
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Quote:
Originally Posted by jfcarbel View Post

Found this guide, its very detailed and looks like a best of solution

I have not dinked with frameserving to AVISynth for many years. Looking down that list of do's-and-don'ts I now remember why I stopped bothering with it.

I would be very interested to see samples, made of traditional 1080 60i video taken with one of today's average 1080i AVCHD cameras, that is run through that script as well as through the basic Vegas Pro deinterlacing rendering.

My guess is that for most things, it isn't worth the hassle.

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post #11 of 11 Old 01-18-2013, 02:48 PM - Thread Starter
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Quote:
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My guess is that for most things, it isn't worth the hassle.
I agree. Just deinterlace with "interpolate" and call it done.
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