Handbrake Creating Wavy Areas on MP4

[pone44]

I have a DVD that is 480 pixel and shows very high video quality throughout. After conversion by handbrake to MP4, the video has some of the sections becoming "wavy" or blinking almost like a small distant mirage. For example, the type on the side of books, when brought into a closeup, appear to be blinking. None of that irregularity is in the original DVD images.

My Handbrake settings are:
Anamorphic: strict
Filters: Deinterlace Bob
Denoise: NLMeans Medium Film
Video: Quality 20
X.264 Tune: Film
H.264 Level: 4.1

I guess the effect I am describing is not a noise problem as that is not seen in the original video. But what might cause a distortion as part of the MP4 creation process?

[jagabo]

Probably deinterlacing artifacts. Maybe resizing artifacts. You'd hove to show an example.

[pone44]

Probably deinterlacing artifacts. Maybe resizing artifacts. You'd hove to show an example.

You were right. I switched to Decomb Bob instead of Interlace Bob and this fixed it.

[LigH.de]

Yadif may also be suitable.

The currently best available deinterlacers (QTGMC and TDeint) are probably not available in Handbrake (which I never used...), they are mainly for AviSynth or VapourSynth. They try to repair the missing field in each new frame with a rather elaborate reconstruction based on motion estimation. A simple Bob only interpolates with a spatial average calculation, not taking the temporal development into account.

[pone44]

Yadif may also be suitable.

The currently best available deinterlacers (QTGMC and TDeint) are probably not available in Handbrake (which I never used...), they are mainly for AviSynth or VapourSynth. They try to repair the missing field in each new frame with a rather elaborate reconstruction based on motion estimation. A simple Bob only interpolates with a spatial average calculation, not taking the temporal development into account.

Those both sound amazing, and maybe we will get that in Handbrake some day.

The Decomb option will analyze each frame and see if it even has visible deinterlacing. So if you have a high quality source, that is at least a "do no harm" approach that improves your outcome. It also made the final MP4 smaller, so higher quality with smaller file size was a winning combo.

In theory, would the deinterlacers you reference work together with a decomb option, so that you could apply those deinterlacers only on frames that show interlacing effects?

[jagabo]

The Decomb option will analyze each frame and see if it even has visible deinterlacing. So if you have a high quality source, that is at least a "do no harm" approach that improves your outcome.

Decomb is for telecined film sources. It looks to see if the adjacent fields have the complementary field to complete the original film frame.

It also made the final MP4 smaller, so higher quality with smaller file size was a winning combo.

With NTSC film sources you also want to change the frame rate to 23.976. Otherwise you'll get several little jerks every second (as there is a duplicate frame every 5th frame). Decomb also works for film sources in PAL video where the two fields that comprise the original film frame appear in two successive video frames rather than in on video frame. With those you don't need to change the frame rate, leave it at 25 fps.

[manono]

Decomb is for telecined film sources.

You realize that Handbrake has redefined that word, don't you, and it's not an IVTC filter? For them it just means to deinterlace using Yadif when a frame is seen as being interlaced.

The decomb filter looks at each pixel of each frame of a video. It then only deinterlaces frames that show visible amounts of combing.

This means you never have to check if a video you're encoding is interlaced -- just run the decomb filter all the time and it'll take care of everything.

https://trac.handbrake.fr/wiki/Decomb

Their IVTC filter is named 'Detelecine':

https://trac.handbrake.fr/wiki/Telecine

And to be sure what pone44 has, I think he should make an untouched sample available.

So if you have a high quality source, that is at least a "do no harm" approach that improves your outcome.

Don't let them kid you. You can do a helluva lot of damage to a telecined source by using that filter improperly.

[jagabo]

Decomb is for telecined film sources.

You realize that Handbrake has redefined that word, don't you, and it's not an IVTC filter? For them it just means to deinterlace using Yadif when a frame is seen as being interlaced.

Sorry. I don't really use Handbrake and thought the function did the usual field matching. Shoulda checked.