deinterlace field order option

[balazer]

When viewing interlaced MPEG-2 programs (or perhaps any interlaced programs), the deinterlacer gets the field order wrong for half of the streams. This results in very jerky video playback for those deinterlace modes that produce double frame rate output (bob and linear). Instead of seeing a sequence of fields 1 2 3 4 5 5 6, you see 2 1 4 3 6 5: one step backwards, three steps forwards, repeating.

If VLC isn't going to figure out the field order by looking at the MPEG-2 stream, then at the very least the deinterlacer should have an option to set the field order.

Thanks

[balazer]

I meant 1 2 3 4 5 6

[someoneelse]

Hi everyone, I'm sorry to bump a 6 YEAR OLD thread, but this problem still exists in VLC. Every other media player I try can correctly deinterlace videos, or at least gives you an option to manually switch fields. I love VLC, but I hate that I have to switch to another player whenever I have a video that is interlaced. Plus, VLC is the only player I've tried that lets me view live, deinterlaced (although incorrectly) video from an old capture device I have (the plextor av100u)

Now you may say that VLC simply gets the field order from the video/capture device. While I don't know about this (other players like WMP can play back my interlaced mpegs just fine), I just simply request that a single check box be added to the program, "swap field order" in the deinterlacing options.

I really appreciate all the hard work that has gone into adding TONS of new features to VLC, including the new Yadif, but even Yadif 2x produces the same jumpy, wrong-field-order effect that VLC has had since I began using it years ago.

Thank you

[metaleonid]

The problem still exists for videos with top field first when using double deinterlacers like Yadif 2x or Phosphor. Videos with bottom field first play fine. When I have time, I will post bug report with 2 sample files.

[Jean-Baptiste Kempf]

You should report the bug with samples.

[wevowva]

The "jerky" (one step back) artifact you're seeing relates to incorrect field interpretation at some point, question is where. If the file has been previously transcoded or encoded on a capture card, it's very possible the metadata describing field order within the file is now incorrect. This misinforms VLC and results in the artifact. Typical example is misinterpretation of DV source footage, which by default is LFF, but is easily misinterpreted by an untalented transcoder, card or technician as TFF which is the more common.

Be aware the artifact does not occur just in the doubled modes (Bob and Linear). If you look closely, you will see the "one step back" fields faintly in all modes that show both fields. It's just that these other modes blend the two fields in some manner, but Bob and Linear display all fields independently for 1/60th of a second, making it quite jarring. For true field-discrete 60i video the defect occurs once every frame, for 3:2 pull downs you only see it twice every 10 frames.

In fact, VLC can step to show ALL FIELDS one by one by hitting the "E" key, but only in the Bob and Linear modes. All other modes step frames. This is because other modes are a blending of 2 fields to make-up each frame or they discard non-dominant fields altogether.

For me, VLC has corresponded with all other decoders I can put my hands on. I've created test files with the field metadata defect and verified this. My guess here is that VLC doesn't have a bug at all, and that the place to examine is how each file your looking at is created.

[Jean-Baptiste Kempf]

For me, VLC has corresponded with all other decoders I can put my hands on. I've created test files with the field metadata defect and verified this. My guess here is that VLC doesn't have a bug at all, and that the place to examine is how each file your looking at is created.

This is my observation as well. But we could invert the fields, if someone understands the subject enough and provide good and VISIBLE samples.

[The O.G. Tony G.]

Not to keep bumping the world's oldest thread here, but is this something we can expect to see?

There is a bug/feature listed in the tracker (https://trac.videolan.org/vlc/ticket/10191) that is well over 18 months old and nominally to create or enable the option to reverse field order on deinterlaced playback, but it hasn't been updated in 5 months. Will this feature ever show up in a vlc release?

[JonathanBeresford]

I can confirm that this problem still exists in 2018, 14 years after the creation of this thread. This problem arises when I download certain videos that have the same combing effect that normal interlaced video has, but the video itself is rendered as a progressive video.

[Jean-Baptiste Kempf]

I can confirm that this problem still exists in 2018, 14 years after the creation of this thread. This problem arises when I download certain videos that have the same combing effect that normal interlaced video has, but the video itself is rendered as a progressive video.

And probably your issue is different from the ones on this thread...

As for video who are not automatically deinterlaced, you can force them in the right-click menu.

[lcdvasrm]

I confirm the problem in 2020.
And even worse, I have (at least) one .avi that was de-interlaced properly by VLC some years ago and is not anymore.
That means that the way the default field order is selected (i bet it is fixed or based on some bad assumptions) makes that for some videos it is now reversed (and wrong)...
Or maybe, it is reading some meta data that are of course not guarantied to be accurate.

So, yes, we still need to be able to select which field is to be displayed first.
This is very simple to implement, I don't understand why this feature has not been added in the menus.