(2019-03-07, 11:13 AM)Stamper Wrote: How do NTSC footage end up in Pal at the same lenght in the first place?
There is probably some interlacing at work.

I think a very common method is to take the 30fps NTSC version and drop every 6th frame. Sometimes they even do frame blending.

(2019-03-07, 11:13 AM)Stamper Wrote: How do NTSC footage end up in Pal at the same lenght in the first place?
There is probably some interlacing at work.

On a note, this happens with the cut scenes, and all the extras of the first Terminator.

Also all the Abyss second disc video in Pal are playing the same, 25fps/50hz but exact same lenght as the NTSC version.

It's cool because you take the subtitles of the european disc, and mux them with the NTSC disc without hassle.

NTSC isn't 23.976 fps, it's 30/29.997 fps. Film > NTSC requires a simple 2:3 pulldown. PAL > NTSC would usually be done using what's called a motion-adaptive standards conversion as described by this patent. Basically every 5th frame is either interpolated or repeated and to smooth the motion all surrounding frames will have intra-field blending applied. It can be reversed in avisynth pretty well since it has the ability to subtract one frame from another (unblended frames can be recovered from blended ones by subtracting the frame leaving the "ghosting").

Another possibility is that the material was filmed in NTSC and then converted to PAL which means dropping every 6th frame, and usually applying field belnding to the others as well. The easy way to tell which is the original if you have both PAL and NTSC is to check frame-by-frame which one has ghosting and whether there's a repeated frame every 5 frames in the NTSC or not.

I've seen instances of sped up 25fps material having -4% pitch correction to match the 24fps pitch, but that's not what this source sounds like unfortunately.

If the PAL encoded content in question runs the same length as the version on a NTSC source (which can usually be ether 23.976 telecined to 29.97, or 60i/30fps if it were shot or animated that way), it's almost always interpolated with nasty ghosting to boot (known as "blending") and is extremely difficult to "completely" remove with good results from what I've seen.

If there's no ghosting, but notice a sudden "freeze" every couple frames or a "skip" about every second during playback, then the source has "dupe" frames. This happens when the source was a 24 or 30fps progressive master directly converted to 25fps progressive (not interlaced) without the 4% speed up. On rare occasions, i've seen the reverse on some US or BD titles that had 25fps content converted to NTSC progressive or 24fps without slowdown (or sometimes was a NTSC-PAL master that was transcoded to NTSC/24fps again without proper adjustment).

Unfortunately, there's no way to fix sources like that. I would strongly suggest tracking down another element in the original frame rate (if it exists elsewhere in the same form) and trying to properly convert from that if needed.

(2019-03-09, 01:35 AM)SpaceBlackKnight Wrote: Unfortunately, there's no way to fix sources like that. I would strongly suggest tracking down another element in the original frame rate (if it exists elsewhere in the same form) and trying to properly convert from that if needed.

It is repairable, it's not perfect. Here's a few consecutive frames from Highlander HDTV:









And here is the "middle frame" above recovered in Avisynth:



In the code below that frame corresponds to the averaged frame where you can see the two centre frames are combined and surrounding frames are subtracted from it:

Mind you though that's film material, you need to handle interlaced video differently.

Thanks. I finally fixed what I wanted to do (I was trying to blend both NTSC and PAL versions of the deleted scenes of The Terminator), by getting the same footage from the Blu-ray.

It's encoded H264, but not from the NTSC disc as I expected, they went back to the source and did the rencode from it. Magnified at 400% you can clearly see it as twice the detail of the other sources. Still interlaced, but I reencoded it progressive.