Proper playback of interlaced video

[jkprague]

Hi,

I was wondered the VLC doesn't play back interlaced video properly. I would expect both fields of 50i will be displayed independently with interpolation at 50fps rate. But they are not. Well I guess only MPEG2 50i is played back properly (at least in Mac OS X).

It there any plan to improve it? Thanks

jk

[Jean-Baptiste Kempf]

What?

[jkprague]

What "what"?

How VLC does playback of 50i video? It blends both fields together and makes 25p, right? So? It's wrong! 50i is of course 25 frames per seconds but 50 fields per seconds. Making 25p from 50i creates jerky video. I mean "home" video where most people don't care about camera movements. Professionals do special technique how to shot films not being jerky at 24fps.

[Jean-Baptiste Kempf]

What "what"?

How VLC does playback of 50i video? It blends both fields together and makes 25p, right? So? It's wrong!

It doesn't.
Where did you find this assumption ?

50i is of course 25 frames per seconds but 50 fields per seconds. Making 25p from 50i creates jerky video. I mean "home" video where most people don't care about camera movements. Professionals do special technique how to shot films not being jerky at 24fps.

Some deinterlacers are doubling frames, some are not.
Use yadif(x2) that is the best deinterlacer and that is doubling frames.

[jkprague]

What "what"?

How VLC does playback of 50i video? It blends both fields together and makes 25p, right? So? It's wrong!

It doesn't.
Where did you find this assumption ?

It generates visually the same result (if it looks like a duck and it sounds like a duck ... ). Sure I didn't check it in source code.
I simplified it by "blending". There are 2 or 3 exceptions. See below...

50i is of course 25 frames per seconds but 50 fields per seconds. Making 25p from 50i creates jerky video. I mean "home" video where most people don't care about camera movements. Professionals do special technique how to shot films not being jerky at 24fps.

Some deinterlacers are doubling frames, some are not.
Use yadif(x2) that is the best deinterlacer and that is doubling frames.

[/quote]

yadif(x2) is absolutely unusable for on the fly deinterlacing of HD on most of today's machines. Try the following clip: http://bit.ly/aWIxNC. The best result you can get with linear or bob. But whenever you reencode it to h.264 the playback is horrible even with linear and bob deinterlacer.

Or do you know how to reencode the given HD MPEG-2 file to h.264 and keep interlacing and playback with on the fly deinterlacing that double frames? Thanks a lot.

[Jean-Baptiste Kempf]

bob, linear and yadifx2 are frame doublers.

yadif(x2) with HD decoding works fine here with GPU decoding.

[Lotesdelere]

yadif(x2) is absolutely unusable for on the fly deinterlacing of HD on most of today's machines. Try the following clip: http://bit.ly/aWIxNC. The best result you can get with linear or bob.

I have no problems at all using Yadif 2x with your sample and in software mode but I agree that Yadif 2x is not working fine with some interlaced videos (for instance the Beyonce sample but there are other ones) while BOB is doing the job properly.

[jkprague]

bob, linear and yadifx2 are frame doublers.

yadif(x2) with HD decoding works fine here with GPU decoding.

But bob and linear didn't work for me if h.264 was used.

I haven't found any combination of codec and player(with frame doubler deinterlacer) to play 1080i coded in h.264 on machine with N9400.

Do you know any workflow for this? Right now I have to generate 50p that doubles filesize.

[jkprague]

It looks like there is really no way how to properly play 1080i h.264 with linear or bob deinterlacer, isn't there? I haven't seen any 1080i h.264 sample working with VLC. Is it linear/bob bug or h.264 decoder?