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What is Progressive Mode?


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#1 Marcus Phipps

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Posted 16 October 2009 - 10:08 PM

This is my fifth newbie post.

1)
What is Progressive Mode?
2) How does progressive mode affect a shoot?
3) Does this have anything to do with frame per seconds?
4)What is the standard frames per second for film?
5) What is the standard frames per second for DVD?
6) What is the standard frames per second for local news?


Anything you with to elaborate on regarding this is very much appreciated!



Most Respectfully,
Acastle
:rolleyes:
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#2 Chris Bowman

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Posted 17 October 2009 - 12:18 AM

This is my fifth newbie post.

1)
What is Progressive Mode?
2) How does progressive mode affect a shoot?
3) Does this have anything to do with frame per seconds?
4)What is the standard frames per second for film?
5) What is the standard frames per second for DVD?
6) What is the standard frames per second for local news?


Anything you with to elaborate on regarding this is very much appreciated!



Most Respectfully,
Acastle
:rolleyes:


4) Film was the original standard. The vast majority of film has been shot at 24 frames per second (24fps) over the last century or so.

1) When video came into existence, the engineers who designed broadcast television and video systems decided, for a variety of technical reasons, to work at a different rate than film. Here in the US, the standard was to refresh (scan a new picture) at a rate of 60Hz. However, the equipment of the day could not produce an entire frame 60 times a second, so broadcast equipment was made to interlace the picture. Interlacing means that rather than scanning the entire picture every refresh, only half of the lines are scanned. The other half of the lines are scanned on the next refresh. These separate sets of lines are called fields, and when one field is being scanned the other is sitting idle. This means that if your camera or TV is in 480i @ 60Hz what you are really getting is fields of 240 lines of resolution alternating, with each field scanned 30 times per second.

Progressive Scan is an attempt to make video higher quality and more film-like. Instead of having 2 fields, Progressive scan will scan the entire image in one pass, so that if your camera or TV is in 480P @ 60 Hz mode, it is scanning 480 lines of resolution 60 times per second.

2&3) Progressive mode will affect a shot in several ways. Most cameras cannot shoot as high of frame rates in progressive mode as in interlaced mode because progressive literally doubles the amount of data being processed. This means that you may be limited to shooting at only 30 frames per second in progressive mode, when interlaced would let you shoot 60 fields per second. Although the progressive frames are higher resolution than the interlace fields, the interlace fields will likely make fast motion look smoother because of the grater number of image samples.

Progressive is the ONLY way to go if you are going to be rotoscoping or doing a final output to film. Otherwise you are just shooting yourself in the foot.

Progressive is also much better for computer applications and web video. This is because computers natively work in progressive mode, and because interlacing makes the compression that most computer formats (and especially web formats) use less efficient.

4 (again)) Film is almost always shot at 24fps, and is always shown in theaters at this speed.

5) DVDs are able to be recorded in either 480i@60Hz, 480P@30Hz or 480P@24Hz. When a DVD is made from a film source, it must use a method called pull-down to make the framerate work on a TV that can only display 60i. Basically each frame is split into fields, and in order to fill all 60 fields from only 24 frames, some fields must be displayed twice in a manner something like this. AB*BC*CD*EF. A DVD may be recorded with this pull-down already added, or may be recorded as 480P@24Hz, causing the DVD Player to add the pull-down on the fly.

6) The local news is almost always shot at 60Hz. In these days of HDTV it is often shot in progressive scan now, but for many decades the standard was 480i@60Hz.

Hope this clarifies things.
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#3 Marcus Phipps

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Posted 17 October 2009 - 01:22 AM

Thank you, Chris. It was a bit technical for me to comprehend all of it. But I certainly learned and that's what it's all about!!

Thanks sooooo much, sir.



Most Respectfully,
Acastle
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NIBL

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Visual Products

Lemo Connectors

Glidecam

Robert Starling

Cinelicious

Aerial Filmworks

Ritter Battery