1080p 25 F55 into a 1080i 50 workflow

[Trevor Asquerthian]

25P is 25 images a second. Like film
50i is 50. Like TV

Thus movement *is* more steppy at 25P

They could shoot 50I if you wanted a TV look, either way your method is fine.

You might want to flag the imported/transcoded footage as ‘interlaced’ in field motion bin column if you work in a 50i project to avoid redundant 25P->50i motion adapters being applied.

[Shane Ross]

25p runs at 25fps. 50i also runs at 25fps…just needed to have that out there. But yes, 50i has two different fields per second, so has 50 images per second, so appears smoother

Shane
Little Frog Post
Read my blog, Little Frog in High Def

[Bouke Vahl]

[Shane Ross] “50i also runs at 25fps”
No, the framerate is the framerate. 50 runs at 50.
There is no 50i as standard, only 25i. (Perhaps it does exists if you overcrank a camera)

I don’t know who came up with the term 50i, but he should be shot.

And, 25i is only smoother on fast motion, at the cost of playing half the resolution. (And that is a good thing.)

Just had to get that out.

Bouke
http://www.videotoolshed.com

[Shane Ross]

[Bouke Vahl] “No, the framerate is the framerate. 50 runs at 50. “

Bouke…I thought you of all people would know this.

1080i50 doesn’t run at 50fps…it runs at 25fps. 1080p50 runs at 50ps

The letter preceeding the number does indeed mean IMAGES PER SECOND…but “i” means interlaced…so yes, 50 images per second, but there are two FIELDS in a FRAME…so 50 images, two per frame…25fps. The “p” means PROGRESSIVE, so 50 images per second PROGRESSIVE means 50 FPS. The “i” and “p” are important here.

[Bouke Vahl] “There is no 50i as standard, only 25i. (Perhaps it does exists if you overcrank a camera)”

https://en.wikipedia.org/wiki/1080i

“The European Broadcasting Union (EBU) prefers to use the resolution and frame rate (not field rate) separated by a slash, as in 1080i/30 and 1080i/25, likewise 480i/30 and 576i/25.[2] Resolutions of 1080i60 or 1080i50 often refers to 1080i/30 or 1080i/25 in EBU notation.”

I guess we need to ask the Original Poster…are we talking 50 full frames per second, or interlaced and 25fps. Look at the timecode to figure that out….if it goes to 24 and then to 00…it’s 25fps.

Shane
Little Frog Post
Read my blog, Little Frog in High Def

[Bouke Vahl]

My point is the bullshit in notation nowadays.
50p means 50 PROGRESSIVE frames per second.
So
50i means 50 INTERLACED frames per second, thus 100 FIELDS per second.

From your wikipedia link:
> Resolutions of 1080i60 or 1080i50 often refers to 1080i/30 or 1080i/25 in EBU notation.
Sad, but true, and a cosy rocking chair close to the furnace in hell.

And yes, I do know this stuff, and perhaps a tiny bit more.

Bouke
http://www.videotoolshed.com

[Shane Ross]

[Bouke Vahl] “50i means 50 INTERLACED frames per second, thus 100 FIELDS per second.”

Sorry, no. You are wrong. There is no such thing as 100 fields per second. No such thing as 50frames per second, interlaced. The only interlace frame rates are 25fps…and 30fps. 50i (25fps) and 60i (29.97fps). 60i is not 60 frames per second, interlaced. There is no such thing.

The video consortium of know it alls decided to go with 1080i60 instead of the better terminology 1080i30 (or 1080i29.97) because…well, because. I know in Europe, most people don’t go with that and use 1080i25 to indicate 25fps interlaced (50 fields per second)…and I agree that’s a better thing. FCP 7 would only show 1080i 29.97, even with an AJA card…because that makes sense. But no, the correct terminology (that I don’t like) is 1080i50 is 25fps interlaced…50 images per second…two image per frame.

Sorry, you are just wrong here. I’d love ANYONE ELSE to step in and back either one of us up.

Shane
Little Frog Post
Read my blog, Little Frog in High Def

[Shane Ross]

[Bouke Vahl] “And yes, I do know this stuff, and perhaps a tiny bit more.”

I know you know more about this stuff that I do…I’ll admit. But in this one case, I believe you are wrong. Thus my shock in your answer…you know loads more than I do about this stuff. It’s just this terminology that causes confusion.

Shane
Little Frog Post
Read my blog, Little Frog in High Def

[Bouke Vahl]

You really do not read, do you?
I am saying that the number reflects a frame rate, not a fieldrate. But it is used wrong, like in a typa. Everyone knows that I ment typO, but that does not mean that I wrote that, not that it means that.

So one more time, the number reflects the frame rate, not the field rate.
The I or P means that the frames are Interlaced (i) or Progressive (P).

I don’t give care that 90% of the world makes the same mistake. Something that is wrong does NOT become right if everyone starts believing in it.

Bouke
http://www.videotoolshed.com

[Bouke Vahl]

Oh, my reply is going to take some time and will not be mine as it will be moderated, as I used the ‘f’ word.
(very bad, may cause confusion.)

Bouke
http://www.videotoolshed.com

[Shane Ross]

Bob-Zelin like in snark? RIFE with F-bombs? Hopefully aimed at those in charge of the naming convention, and not at me. I really hate going head to head with you on this…because I know you know this stuff VERY well. I just know I’m right here…

*RUN*

🙂

Shane
Little Frog Post
Read my blog, Little Frog in High Def