What is the difference between 'blend' and 'linear blend' deinterlacer?

[orion44]

Are they the same deinterlacers?

[FranceBB]

Uhm... in which context? I mean, in which program?
I don't think there is a difference in Avisynth, but I would advise against blend-deinterlace something.
This is because if your source is, let's say 25i truly interlaced, it could either be bobbed to 50p or deinterlaced to 25p.
Using blend-deinterlace will make the filter first bob to 50p and then blend the frames together to get a 25p.
What this means is that it will take a frame and "overlay" it to the very next one, hence halving the framerate.
Blend-deinterlace can lead to some very ugly results, like:

https://i.imgbox.com/adpTX9q4.jpg


So either deinterlace or bob-deinterlace, but please try to avoid blend-deinterlace as it's just bad and it doesn't really make sense in 2021...
It's an horrible hardware-era thing and we should leave it there...

[orion44]

Uhm... in which context? I mean, in which program?
I noticed that VirtualDub and PotPlayer have 'blend' deinterlace, while FFmpeg (libav) has 'lb' or 'linear blend' filter.
So I was just wondering if they are the same.


So either deinterlace or bob-deinterlace, but please try to avoid blend-deinterlace as it's just bad and it doesn't really make sense in 2021...
It's an horrible hardware-era thing and we should leave it there...
I only need single rate deinterlacing.

I tried QTGMC and yadif and I don't like the look of the video after it has been deinterlaced. It doesn't look 'natural'.
Not sure what the correct technical term is. It's barely noticeable, but there's definitely something off in the deinterlaced video.

BWDIF looks much better to me than yadif or QTGMC. It doesn't have that artificial look.

I actually prefer FFmpeg's linear blend filter because it's simple, clean, and the video looks neat (except for a slight blurriness).

[ognirats]

video looks neat

How can you enjoy blend deinterlacing?!

[anna1235]

Spam post. Deleted and struck.

[videoh]

I noticed that VirtualDub and PotPlayer have 'blend' deinterlace, while FFmpeg (libav) has 'lb' or 'linear blend' filter.
So I was just wondering if they are the same. Likely the same. The linear part probably just implies a 50-50 mix.

I tried QTGMC and yadif and I don't like the look of the video after it has been deinterlaced. It doesn't look 'natural'.
Not sure what the correct technical term is. It's barely noticeable, but there's definitely something off in the deinterlaced video. If you did single-rate deinterlacing you may be noticing the reduction of temporal fluidity.

BWDIF looks much better to me than yadif or QTGMC. It doesn't have that artificial look. You're going to have to at least attempt to characterize artificial here, because we have no idea what you are talking about.

[orion44]

You're going to have to at least attempt to characterize artificial here, because we have no idea what you are talking about.

When I was testing various deinterlacers in single-rate mode I noticed that Yadif and QTGMC deinterlaced videos have a slightly 'plastic' look,
while BWDIF doesn't have that effect and looks more natural.

Surprisingly, out of all the deinterlacers that I tested, I found that my two favorite ones are also the oldest ones, from decades ago.

Namely, TomsMoComp and FieldDeinterlace from Decomb package.

These two, to me, produced great looking videos, and I have been using them ever since.

[videoh]

When I was testing various deinterlacers in single-rate mode I noticed that Yadif and QTGMC deinterlaced videos have a slightly 'plastic' look, while BWDIF doesn't have that effect and looks more natural. I never tried BWDIF. I'll have a look.

Surprisingly, out of all the deinterlacers that I tested, I found that my two favorite ones are also the oldest ones, from decades ago.

Namely, TomsMoComp and FieldDeinterlace from Decomb package.

These two, to me, produced great looking videos, and I have been using them ever since. Flattery will get you everywhere. :p

FieldDeinterlace tries to leave progressive areas untouched while yadif and QTGMC touch everything, IIRC. Perhaps that is relevant.

[FranceBB]

I never tried BWDIF. I'll have a look.



BWDIF is alright. I consider it as a middle ground, so better than yadif but worse than QTGMC.
For HD/FULL HD stuff it's my de facto deinterlacer of choice and as such it's the one that the filter_builder in FFAStrans uses. ;)

[hello_hello]

When you're into "hard to de-interlace" territory, I don't think anything beats QTGMC. Plus it has lossless and semi-lossless modes and can add back noise, if you think the default settings look too plastic.

There's QTGMC and Yadif examples in this zip file, along with the source file if you want to compare another de-interlacer to QTGMC for troublesome sources.

Deinterlacing Examples.zip (https://files.videohelp.com/u/210984/Deinterlacing%20Examples.zip) (44.1MB)

[richardpl]

QTGMC is old and unreliable and looks plastic.

[Boulder]

QTGMC looking plastic is most likely related to settings. Plastic looks usually implies excessive denoising, and QTGMC does denoise quite a bit by default. I always set tr2=0 to reduce the effect.