1080i/25p with MC ???

[Terence Curren]

There is NO such thing as an “i” and “p” format.

“i” = Interlaced capture: https://en.wikipedia.org/wiki/Interlace

“p” means progressive capture: https://en.wikipedia.org/wiki/Progressive_video

No edit system in the world is going to have a setting for something that cannot exist. This is like asking why you can’t buy a “hot/cold” button at the hardware store.

Terence Curren
http://www.alphadogs.tv
http://www.digitalservicestation.com
Burbank,Ca

[Michael Phillips]

I believe that is Panasonic’s way of indicating 25p capture but storing the files in a 1080i video stream – like a film transfer to 1080i/50.

Michael

Michael Phillips

[Terence Curren]

[Michael Phillips] “I believe that is Panasonic’s way of indicating 25p capture but storing the files in a 1080i video stream – like a film transfer to 1080i/50. “

See, you didn’t say 1080i/50P.

Obsfucation by the manufacturers is not an answer. Or, in other words, “standards, we got a million of ’em.” :-/

Terence Curren
http://www.alphadogs.tv
http://www.digitalservicestation.com
Burbank,Ca

[Job Ter burg]

Michael is right. Panasonic has a format labeled 1080i/25p which means that the camera chip captures 25p which is stored in 1080/50i DVCPRO-HD on disk.

Just like transferring 25p film to 50i video.

I recently did a P2 project that was shot in this Panasonic mode, and I transcoded it into DNxHD120 non-TR in a 1080/50i project and finished that way.

I haven’t tried this myself, but I think that if you need to deliver a 1080/25p master tape from that, you could transcode the DVCPRO-HD video into DNxHD in a 1080/25p project. Or you might be able to simply switch the Project Format into 1080/25p after editing and playout at 25p.

However, if you need to deliver a 1080/50i master tape, I’d say there’d be hardly any reason to transcode to 1080/25p.

[Terence Curren]

Okay, I don’t get it.

I understand why you want to store 24P as 30i with added fields to make up the frame rate. But why would you want to call something shot progressively as “i”.

And what difference would that make? You are recording one frame of video that was either captured at the same time “progressive” or half the picture at one time and the other half a little later “interlace”.

Either way you end up with ONE frame. At this point there is no difference on tape or in a file other than metadata saying how it was captured. It is still a 1920 by 1080 frame of video. Just calling it “1” after you captured it “p” doesn’t make any difference.

What am I missing here other than Panasonic being weird?

Terence Curren
http://www.alphadogs.tv
http://www.digitalservicestation.com
Burbank,Ca

[Job Ter burg]

It’s not as weird as it may appear, it is actually being very clear.

If you were to call it 1080/25p, well, it simply isn’t. The signal itself is 1080/50i. Just like any old PAL tape will be 625/50i. When I take 35mm film and put it on a telecine and transfer to PAL, the signal on tape will be 625/50i, even though the picture itself is 25p. There’s progressive content stored in an interlaced format.

The Panasonic camcorder allows the chip to capture 25p, but DVCPRO-HD does not come in a 1080/25p flavor, so it stores this 25p within a 1080/50i stream.

It’s not much weirder than XDCAM or DigiBeta, both of which – in their PAL variants – have a 25p progressive mode, both of which store this progressively captured footage in a PAL 625/50i stream.

[Terence Curren]

Okay, now you’re talking about a confusion with nomenclature. The reason Sony refused to call the HDCAM recording format “fields” instead they came up with “segmented frame” to avoid just this situation.

Splitting a frame into pieces to record on tape doesn’t make it interlaced. Capturing those pieces of the frame at different points in time does.

If the chip is a progressive one in the camera, then it doesn’t matter how many pieces I break the file into for ease of recording, it will still be progressive.

So it sounds like Panasonic has decided to confuse the issue once again.

Terence Curren
http://www.alphadogs.tv
http://www.digitalservicestation.com
Burbank,Ca

[Job Ter burg]

Terry, I respectfully disagree. The Panasonic camcorder will record into the DVCPRO-HD codec, which is 1080/50i. To accomodate for a “film look”, very popular among European filmmakers, they allow the chip to capture either 50i or 25p. However, the codec itself does not have a p-variant.

As said, not just Panasonic use this method, so do Sony on XDCAM and DigiBeta. So does Avid, by the way. one can shoot 35mm, transfer to DigiBeta at 625/50i (but actually having 25p in there), then capture into Avid in either an interlaced (25i) or progressive (25p) resolution. There are no fields in 3:1p, but there are always fields in 3:1(i).

Actually, in Avid, if you shot 50i and you capture in 25p, you still get a usable end result (unless you use motion effects), simply because the two fields of the source footage will be combined into a signle frame and stored as such, then upon playback in PAL, that frame will be divided into fields again, in the exact reverse way that they were combined before. So the the codec itself can be interlaced or progressive, no matter the actual content.

I think Panasonic has the right logic. Both capture and codec can be interlaced or progressive, independently. They name it for what it actually is.

[Terence Curren]

Following your logic, there is NO tape format that records progressive.Can you name one?

If we are going to call it interlaced whenever the entire frame isn’t recorded as one piece, we are in for some serious name changing in the industry.

One can even argue that the RED camera isn’t progressive as the CMOS chip actually scans as opposed top capturing all at once..

This is a BIG can of worms, but I think Sony had the right idea. Keep Progressive and Interlaced as definitions of how the image is captured, not how you put it on tape.

Terence Curren
http://www.alphadogs.tv
http://www.digitalservicestation.com
Burbank,Ca

[Job Ter burg]

It’s not about tape formats, it’s about codec variants.

There is actually no such thing as DVCPRO-HD 1080p. There is 23.98p-within-60i and there is 25p-within-50i. Rather than claiming a truely progressive format, they are honest about how they capture and store.
DVCPRO-HD 1080 is an i-codec. Like PAL is an i-codec, as well as NTSC.

The difference with the Sony formats is that their hardware (VTRs) actually can play out a 23/24/25PsF signal from P-tapes. But I don’t think that Sony HDCAM 50i is the same signal as HDCAM 25PsF. You cannot set one deck to playback 50i and record that signal onto another deck at 25PsF, can you?

Do I feel that Sony does a better job at creating P-formats, rather than pulling P down to I? Yes, I do.

So in a way, we agree somewhere, I guess.

However, if you look at BBC delivery specs for HD, they require 1080/50i masters. Even if your content is captured in 25p, they require rolls and crawls to be 50i, and 50i is what they broadcast. So it does make sense to have a camcorder that scans progressively but stores in an interlaced codec from there.