Deinterlace Flag

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gregz8jklj
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Deinterlace Flag

Post by gregz8jklj » Tue Feb 13, 2007 12:11 am

Is there a downside or any negative impact if you check Delinterlace (either as a default in Preferences or in a specific movie rip screen) and the movie not interlaced?

I'd like to leave it on all the time, but don't want to negatively affect progressive anamorphic movies that don't need to be deinterlaced.

Thanks for any suggestions.

Greg

baggss
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Post by baggss » Tue Feb 13, 2007 12:36 am

I personally have not had any issues with Movies when it is on or off, but I have seen a difference with TV shows between on and off. My general rule of thumb is to check it for TV shows but uncheck it for movies.

jbrjake
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Re: Deinterlace Flag

Post by jbrjake » Tue Feb 13, 2007 1:32 am

gregz8jklj wrote:Is there a downside or any negative impact if you check Delinterlace
YES there is a HUGE downside. You lose half your vertical resolution. MediaFork deinterlaces with ffmpeg's method (lavcdeint). That means dropping one field from every frame and doubling the other to make up for it. Avoid this whenEVER possible.

Here's an example of what I mean. This is from the opening credits of a progressive DVD:

Image

See how smooth the edges of the curves are?

Compare that to this, what it looks like when you check deinterlacing:
Image

baggss
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Post by baggss » Tue Feb 13, 2007 1:46 am

So should I not check it for TV shows? I have noticed they look better with it checked....

jbrjake
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Post by jbrjake » Tue Feb 13, 2007 2:11 am

baggss wrote:So should I not check it for TV shows? I have noticed they look better with it checked....
If the TV show is interlaced, you have no real choice, so deinterlace. You're still losing half the lines, though.

I would like, some day, to fold in the post-processing library from Mplayer (libmpcodec) so we can get a better deinterlacer. But that is not on the horizon.

If your content is interlaced, yes, use the deinterlacer. But NEVER use it on progressive content--which does include most modern TV shows.

golias
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Post by golias » Fri Feb 16, 2007 3:43 am

jbrjake wrote:
baggss wrote:So should I not check it for TV shows? I have noticed they look better with it checked....
If the TV show is interlaced, you have no real choice, so deinterlace. You're still losing half the lines, though.

I would like, some day, to fold in the post-processing library from Mplayer (libmpcodec) so we can get a better deinterlacer. But that is not on the horizon.

If your content is interlaced, yes, use the deinterlacer. But NEVER use it on progressive content--which does include most modern TV shows.
I used to de-interlace TV rips, but no longer. Why?

Because VLC has built-in de-interlace options which are vastly superior to the simple frame-doubling method that MediaFork (and many other apps) rely on.

I set the preferences in VLC to use the "blur" type interlacing by default. Now I use VLC to watch TV shows, and QuickTime for everything else.

VLC's blur de-interlace looks beautiful compared to pretty much any other method I have tried. When you are done ripping an interlaced show, just go into the Info panel and set it to open with VLC by default instead of Quicktime.

So now, I *never* use the de-interlace button on my rips, and I couldn't be happier. I'm almost tempted to go back and re-rip some of the stuff I had previously done.

Nonsanity
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Post by Nonsanity » Sun Feb 18, 2007 9:10 pm

I would think that even if HB or MF deinterlaced a TV show, it would look the same after VLC's blend deinterlacing. VLC would just ignore the lines that HB/MF created and make its own.

If you want to really understand interlacing, check out at least the pictures in th wikipedia entry: http://en.wikipedia.org/wiki/Interlace

latchkey
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discard deinterlace

Post by latchkey » Mon Feb 19, 2007 9:44 pm

Nonsanity wrote:I would think that even if HB or MF deinterlaced a TV show, it would look the same after VLC's blend deinterlacing. VLC would just ignore the lines that HB/MF created and make its own.
Except that post when you set MediaFork to deinterlace while encoding it will discard half of the lines from the picture so later deinterlacing methods will only have half the information they need. I am actually in the same boat as golias and just recently stopped deinterlacing my TV show backups.

When I did a test encode and saw this http://i153.photobucket.com/albums/s239 ... erlace.png
(a file deinterlaced at encode time)

compated to this
http://i153.photobucket.com/albums/s239 ... erlace.png
(an interlaced encode playing in VLC with the "Mean" deinterlacing method)

I realized how much I had been throwing away in previous TV backups. Of course, the animated material suffered much more noticeably than live action because of the increased importance of clear lines.

thanar
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Post by thanar » Tue Feb 20, 2007 8:32 pm

Seems a bit strange that non-deinterlaced material plays better than deinterlaced under VLC using VLC's build-in deinterlacer. UNLESS the original shows you are talking about do not need to be deinterlaced, because they aren't.

Here is how it sums up: Interlaced video is far more difficult to be compressed than progressive (especially on motion shots), since the 8x8 or 16x16 blocks often loose their solidity. Therefore, compressing an INTERLACED movie twice, first with deinterlace off and thyen with deinterlace on, would make it so that the deinterlaced video will have better overall quality, although the other one could have a bit more detail than the deinterlaced one, thanx to the extra lines.

cbud
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re-encode?

Post by cbud » Thu Feb 22, 2007 2:30 am

I am encoding a TV show that is 29 fps. I rarely (1 in 20) see a frame (in MediaFork) that looks like it needs to be deinterlaced, but I checked deinterlace anyway. Are some shows deinterlaced more? Why can I see it more on other shows?

I plan on watching these with an Apple TV. Should I re-encode without deinterlacing? Will Apple TV deinterlace for me?

golias
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Post by golias » Fri Feb 23, 2007 12:24 am

thanar wrote:Seems a bit strange that non-deinterlaced material plays better than deinterlaced under VLC using VLC's build-in deinterlacer. UNLESS the original shows you are talking about do not need to be deinterlaced, because they aren't.

Here is how it sums up: Interlaced video is far more difficult to be compressed than progressive (especially on motion shots), since the 8x8 or 16x16 blocks often loose their solidity. Therefore, compressing an INTERLACED movie twice, first with deinterlace off and thyen with deinterlace on, would make it so that the deinterlaced video will have better overall quality, although the other one could have a bit more detail than the deinterlaced one, thanx to the extra lines.
The problem is that the De-interlace method used by HandBrake and MediaFork (which comes from open source tools which nobody currently has the ambition to upgrade) are rather destructive to the end product. It is especially easy to see the problem with animated features.

VLC has TERRIFIC de-interlacing playback software, so if you leave the source material interlaced and watch it through VLC, you get the best possible result (in fact, the picture is frequently superior to watching the original DVD via the Apple DVD Player!)

Once the material is de-interlaced during the encode, you are stuck with the jagged lines and jagged motion caused by the simplistic de-interlace method of the encoding, and it will look like the "Family Guy" example posted earlier in this thread no matter what you do.

Bottom line: Unless you are ripping for an iPod or some other means which prevents the use of VLC, you are better off leaving the interlacing unmolested.

icaruscollapse
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Post by icaruscollapse » Fri Mar 30, 2007 3:44 am

Does the Apple TV have any sort of deinterlace function to it?

rhester
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Post by rhester » Fri Mar 30, 2007 1:30 pm

No. The Apple TV does not support interlaced material.

Rodney

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Post by Fastfwd » Fri Mar 30, 2007 3:33 pm

Very few DVD videos need to be deinterlaced. The only one I found up to now have been the "baby einstein" DVD series and the "Asterix et cleopatre" movie.

I usually do everything with deinterlacing and just check it when there is visible problems on the resulting file.

rhester
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Post by rhester » Fri Mar 30, 2007 6:45 pm

Virtually all US television shows up until the mid-to-late 1990s are interlaced NTSC on DVD.

Rodney

jbrjake
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Post by jbrjake » Fri Mar 30, 2007 6:50 pm

rhester wrote:Virtually all US television shows up until the mid-to-late 1990s are interlaced NTSC on DVD.
Though it's worth noting that mid-to-late 1990s shows that are just coming to DVD now, often have the deinterlacing done (badly) by the studio, so the DVDs are progressive. For example, I have the early 90s Fox series The Adventures of Brisco County Jr. on DVD. It just came out late last year, and it's progressive. But you can tell that it used to be interlaced, because you'll see combing at some scene cuts, when the cadence got screwed up during editing or whatever.

cbud
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Post by cbud » Fri Mar 30, 2007 11:06 pm

jbrjake wrote:
rhester wrote:Virtually all US television shows up until the mid-to-late 1990s are interlaced NTSC on DVD.
Though it's worth noting that mid-to-late 1990s shows that are just coming to DVD now, often have the deinterlacing done (badly) by the studio, so the DVDs are progressive. For example, I have the early 90s Fox series The Adventures of Brisco County Jr. on DVD. It just came out late last year, and it's progressive. But you can tell that it used to be interlaced, because you'll see combing at some scene cuts, when the cadence got screwed up during editing or whatever.
You think that is bad? Voyager will have an entire scene interlaced and then suddenly (not even at a chapter break) go back to progressive. It is rare, so I don't deinterlace and just live with it.

icaruscollapse
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Post by icaruscollapse » Sat Mar 31, 2007 1:24 pm

rhester wrote:No. The Apple TV does not support interlaced material.

Rodney
Wait, what? Does that mean if I -don't- deinterlace the material, it just won't even work at all?

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