60i or 24P?

[Matt Buys]

I'm just about to go to Africa to shoot a documentary on a chemist that's spearheading a manufacturing facility to make generic drugs that would help fight AIDS. Most of my shots will be stationary interviews but I'm sure there'll be plenty of shots with the merlin steadicam too. I will be bringing 3 HV20's and using my SD722 for sound.

I've used both formats. I like cineform's 24P look (especially with the Letus I plan on bringing) but I like the 60i form factor more. 24p does better in low light yet not so good with movement. At least in my hands.

My audience is a bit of a three ring circus. I'm hoping to submit the film to some festivals, show it on the local public access channel (yeah, I know) and also provide the kilimanjaro school of pharmacy some footage for their website. I know it's a matter of personal preferance and there's no right or wrong per se but I was curious what others would do in my situation. All thoughts, suggestions, questions, appreciated.

[Shaun Roemich]

My position is: if you're going to do TV, do interlaced, at least over 24P. I shoot 60P at 1280 x 720 but that's a bit different.

Also, 24P is still an effect when talking about TV. Audience is the web or festivals? Have at 'er!

[Johan Staeck]

[QUOTE=Shaun Roemich;964265]My position is: if you're going to do TV, do interlaced, at least over 24P. I shoot 60P at 1280 x 720 but that's a bit different.

I would rephrase it like this:
If the intended end-user equipment can benefit from interlaced material, shoot interlaced.
Otherwise, shoot progressive.

And, in Europe it seems that > 95% of all new household TV sets (CRT:s are a quickly dying breed here) are "flatscreens" (LCD/Plasma).
And these flatscreens have to do de-interlace on all incoming material before displaying it.
Agreed, they de-interlace quite well, but nothing is gained quality-wise compared to true progressive...

/Johan S

[Ron Evans]

Shooting progressive at 60P would be great but shooting at 24p or 30P means that fast motion is forever lost. At least a lot of modern flat panel displays do a good job of deinterlacing and retain most of that motion especially the higher refresh rates like 120HZ here in North America. For a documentary I would shoot interlace that way you would cover most of the possible viewing options and occasional fast camera movements won't make your audience sick from judder!!!

Ron Evans

[Les Wilson]

I have a similar gig but a different country. I seem to recall that 24p locks you into needing a Canon HDV playback capability and is not as future proof as 60i. Not sure about 60p.

[Ron Evans]

I think the other thing that people seem to be getting confused about is thinking that 60i is 30fps . I have recently read several article where the writer states that NTSC is 30fps with each frame split into an odd and an even field. Implying that the camera shoots at 30fps and each frame is split for recording or transmission. The real fact is that the cameras shoot at 60fps and the recording/transmission only records/sends half the vertical information in each of the 60 fields. So the motion recorded is at 60 fps giving the smooth motion the 60i on a CRT gives. Our eyes/brain and the CRT phosphors fill in the missing lines from the fields. For lots of flat panel displays this fluid motion is destroyed by the deinterlacer simplistically changing this interlace frame rate to 30fps progressive displayed twice to get the necessary 60hz refresh rate leading to backround judder etc. I would still shoot interlace and then manipulate in post for the intended audience. Shoot 16x9 HDV 1080i can always be cropped to 4x3 if you are aware of that when you shoot.

Ron Evans

[Bob Willis]

60i is 30 Frames per second.

The difference is in the difference between interlace and progressive footage. With Interlace footage, say 1080i, 30fps refers to 30 Frames per second or 60 Fields per second. You can not have 1080i 60 FRAMES per second. It is 60 fields per second

With progressive footage the number 30fps represents only frames, because their are no fields in progressive scanning. So with 720p60 refers to 60 frames per second. The same with 1080p60.

Except, when you have Progressive Segmented Frames (PsF). In this mode you don't have 60 frames per second.

The frame rate you can have in PsF is :
23.98
24
25
29.97
30 frames per second

[Shaun Roemich]

Originally Posted by Bob Willis

60i is 30 Frames per second.

The difference is in the difference between interlace and progressive footage. With Interlace footage, say 1080i, 30fps refers to 30 Frames per second or 60 Fields per second. You can not have 1080i 60 FRAMES per second. It is 60 fields per second

With progressive footage the number 30fps represents only frames, because their are no fields in progressive scanning. So with 720p60 refers to 60 frames per second. The same with 1080p60.

60i is 60 fields per second. Calling it 30 frames per second is incorrect.

30 frames per second = 30 PROGRESSIVE frames per second.

1080P60? If I could shoot that, I would. Right now we're "stuck" with 1080P30.

[Chris Medico]

I think what Ron was describing is even though you are shooting 60i the two fields are placed into one frame BUT each of those fields are 1/60th a second apart in time. This renders motion very well and even on flat panel displays the electronics do a great job of deinterlacing the video.

With my V1U it can capture 30p but it still encodes it into a 60i stream. In this case both fields are from the same timeslice and not 1/60th a second apart as they would be in a true 60i capture. Judder isn't bad but it is there. You have to watch your panning speed with 30p. Either do a slow to moderate pan or a very fast one. You'll have to do some experiments and judge for yourself. Also if you are shooting with a long lens with some camera shake 30p can start to look awful. Especially if you have to crank up the shutter speed some.

60i will render motion more pleasingly than 30p. I only shoot 30p when its going to be a web distribution or if that extra stop of sensitivity I gain makes a difference.

I would recommend 60i for the documentary and avoid 24p if at all possible. You can try 30p and see if you like the look.

[Ron Evans]

Thank you Chris that is exactly what I wanted to say. The cameras are taking pictures at a rate of 60 a second but only recording half the information!!! So has twice the motion information of 30fps.
I too have an old retired VX3, a retired TRV740, retired TRV50 retired PC10 and now use FX1( now getting old too as I got it when they first came out), SR11 and occasionally my HC96.

Ron Evans

[Andrew Kimery]

Originally Posted by Shaun Roemich

60i is 60 fields per second. Calling it 30 frames per second is incorrect.

30 frames per second = 30 PROGRESSIVE frames per second.

1080P60? If I could shoot that, I would. Right now we're "stuck" with 1080P30.

It's no more incorrect than calling NTSC video 30 frames per second. 59.94 fields per second is the same thing as 29.97 frames per second interlaced.


-A

[Ron Evans]

Originally Posted by Andrew Kimery

It's no more incorrect than calling NTSC video 30 frames per second. 59.94 fields per second is the same thing as 29.97 frames per second interlaced.


-A

This is exactly the confusion I was addressing in my post. I understand that 29.97 interlace is just a name convention. It does not imply that the camera is shooting at 29.97 frames a second( 30fps drop frame) and interlaced into a 60i transport stream. The camera in fact is shooting at 60 frames a second but only recording fields each time( half the vertical information). You cannot just add these fields together to make a frame and get 29.97 fps progressive. I understand the confusion. Two fields make a frame, so 60i divided by two and using drop frame timecode would be 29.97. The only problem is the odd and even fields are not from the same frame!!!! The fields are displaced by 1/60 of a second each time. They are fields extracted from a 60P image capture in camera processing, especially from some of the newer cameras ( like the Panasonic HMc150) that have the option of multiple output formats. I just feel that 29.97i is an unfortunate convention.

Ron Evans

[Shaun Roemich]

Originally Posted by Chris Medico

even on flat panel displays the electronics do a great job of deinterlacing the video.

I'll happily disagree with that with the notable exception of newer consumer displays. Point of sale displays, LCD projectors, computer LCD screens and other such displays do a TERRIBLE job of displaying interlaced footage.

[Bob Willis]

Originally Posted by Shaun Roemich

60i is 60 fields per second. Calling it 30 frames per second is incorrect.

30 frames per second = 30 PROGRESSIVE frames per second.

1080P60? If I could shoot that, I would. Right now we're "stuck" with 1080P30.

I don't believe so Shaun.

"The field rate of 1080i is typically 60Hz for NTSC countries (such as United States, Canada and Japan) or 50Hz for PAL/SECAM countries (such as in Europe, Australia, much of Asia, Africa). Because of this the two most common frame rates are 30 frames per second or 25 frames per second. Both variants can be transmitted by both major digital television formats, ATSC and DVB. The frame rate can be either implied by the context or specified after the letter i, such as "1080i30". The European Broadcasting Union (EBU), prefers to use the resolution and frame rate separated by a slash, as in 1080i/30 and 1080i/25, likewise 480i/30 and 576i/25."

[Chris Medico]

Originally Posted by Shaun Roemich

I'll happily disagree with that with the notable exception of newer consumer displays. Point of sale displays, LCD projectors, computer LCD screens and other such displays do a TERRIBLE job of displaying interlaced footage.

Computer screens and computer projectors were never designed for video. They don't even work in the same colorspace as video.

I was actually referring to flat panel television sets. They do a great job displaying either interlaced or progressive sources.

Sorry for the confusion.