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questions from newbie to the DVX


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#1 Ruby Gold

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Posted 04 May 2006 - 12:52 PM

I've been shooting stuff for productions with a GL-2 and am about to make the big leap up to a DVX100-B. Do people have opinions about the relative merits of the DVX vs. Canon XL-2?

Two other questions:

1. People talk about the "flicker" inherent in shooting 24p vs. interlaced video. "Flicker" doesn't sound like a good thing--can someone explain what this looks like and/or point me in the direction of a sample, so I can see what they're talking about?

2. I capture my tape from a Sony clamshell into my computer and don't plan on transferring to film for any projects in the near future. Can someone explain to me (in basic terms) what the purposes are for the 24p Advanced vs. 24p Normal setting. I don't really understand what the various pulldown ratios associated with them mean--can someone explain to me what you'd use the different ones for?

3. I edit with PPro 1.5, use AE 6.5, and author in U-Lead's DVD Workshop 2--any conflicts or special settings to use in any of these apps for stuff shot with the DVX?

Thanks so much-
Ruby
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#2 Daniel Sheehy

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Posted 05 May 2006 - 03:37 AM

2. I capture my tape from a Sony clamshell into my computer and don't plan on transferring to film for any projects in the near future. Can someone explain to me (in basic terms) what the purposes are for the 24p Advanced vs. 24p Normal setting. I don't really understand what the various pulldown ratios associated with them mean--can someone explain to me what you'd use the different ones for?


You can get a fairly good explanation here: http://www.adamwilt....p/#24pRecording

Hope it helps
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#3 Will Novy

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Posted 07 May 2006 - 09:38 PM

I've been shooting stuff for productions with a GL-2 and am about to make the big leap up to a DVX100-B. Do people have opinions about the relative merits of the DVX vs. Canon XL-2?

Two other questions:

1. People talk about the "flicker" inherent in shooting 24p vs. interlaced video. "Flicker" doesn't sound like a good thing--can someone explain what this looks like and/or point me in the direction of a sample, so I can see what they're talking about?

2. I capture my tape from a Sony clamshell into my computer and don't plan on transferring to film for any projects in the near future. Can someone explain to me (in basic terms) what the purposes are for the 24p Advanced vs. 24p Normal setting. I don't really understand what the various pulldown ratios associated with them mean--can someone explain to me what you'd use the different ones for?

3. I edit with PPro 1.5, use AE 6.5, and author in U-Lead's DVD Workshop 2--any conflicts or special settings to use in any of these apps for stuff shot with the DVX?

Thanks so much-
Ruby

Usually for the DVX vs. XL2 it is just personal preference. As for the flicker, it usually happens when 24p footage is blown up to big screen. Since you said you arent going to do that, 24p is fine. And as for the difference in 24p vs 24pa, that link should be helpful.
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#4 Hans Kellner

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Posted 08 May 2006 - 12:12 AM

1. People talk about the "flicker" inherent in shooting 24p vs. interlaced video. "Flicker" doesn't sound like a good thing--can someone explain what this looks like and/or point me in the direction of a sample, so I can see what they're talking about?

The "flicker", that I believe you are talking about, is sometimes called "judder" or described as "jerky motion". It is the result of capturing only 24fps as apposed to 60 interlaced. To shoot 24fps with the DVX or any other camera that shoots at a slower frame rate, you must understand how that effects capture. Any motion, panning for example, can begin to show signs of judder when the image travels too far between frame captures. When shooting 60i you are able to pan around twice as fast before the judder begins. This issue is well documented and the American Cinematographer's Handbook even includes a section on how to deal with it.

So, the "flicker" you describe is not a problem of the DVX. It is simply an issue you must deal with when filming with any camera that captures at a slower frame rate.
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#5 Ruby Gold

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Posted 08 May 2006 - 01:28 PM

Thanks all for your responses. One other (potentially stupid) question:

Are DVD productions made with footage shot in 24p or 30p only playable on DVD players and tvs with progressive scan capability? Most of the DVD productions I make need to be playable on a fairly wide variety of set-top DVD players and tv's, as well as on computers with DVD players. Many of the set-tops and tv's they'd be played on are older models that don't have progressive scan capability. Can anyone tell me if this means they won't play well?
thanks so much-
Ruby
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#6 Michael Nash

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Posted 09 May 2006 - 04:18 AM

As I undersdtand it, most DVD players will add the 3:2 pulldown to 24P material when the player is set up for an NTSC monitor. The best course is to burn some test DVD's and play them on a variety of players.
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#7 Ruby Gold

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Posted 09 May 2006 - 11:54 AM

As I undersdtand it, most DVD players will add the 3:2 pulldown to 24P material when the player is set up for an NTSC monitor. The best course is to burn some test DVD's and play them on a variety of players.


Thanks for the response Michael--and testing is always the best way, to be sure--but I haven't bought the camera yet, so I don't have that ability. Please forgive my ignorance, but I'm not entirely clear what the various "pulldowns" mean when it comes to progressive modes. If you could explain in simple terms or point me in the direction of a good source, that'd be terrific.
thanks again-
Ruby
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#8 David Mullen ASC

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Posted 09 May 2006 - 12:24 PM

An NTSC CRT monitor runs at 60 fields per second interlaced-scan (actually 59.94). Anything played from a tape deck to an NTSC monitor has to be in that format, 480/60i.

But since a DVD player can add its own 3:2 pulldown (a sequence of extra fields to convert 24 frames into 60 fields, understanding that in video there are two fields to build each frame of video) you can record 480/24P to a DVD and let the player convert it to 60i. This allows the DVD to also play 24P on a progressive-scan monitor, which does not need the conversion to 60i.

So on the DVX100, you would shoot, most likely, 24P Advanced, remove the Advanced pulldown (which is just easier to remove than standard 3:2 pulldown of regular 24P) when importing the footage into your editing system like FCP, edit in 24P, and burn 480/24P to a DVD and also make a separate tape master (maybe to DVCAM) with a master that was converted by your editing system to 480/60i by adding standard pulldown. You may want a separate 480/60i master in case you also need to make NTSC tape dubs. But you would use your 480/24P master for everything else.

Remember that whether you shoot 24P or 24P Advanced, the camera always records 60i (which is why you can play back the footage on any NTSC monitor) so you are just choosing between two different types of pulldown to convert 24 into 60. Unless you shoot 30P or 60i mode on the camera.

24P Advanced is actually a simpler pulldown scheme -- I think every fifth frame is just repeated -- designed to make it easier to remove. So if you watch the footage with the Advanced pulldown, it will look worse (clunkier) actually than standard pulldown -- because it's only purpose is to be removed easily by the editing system, allowing you to work in true 24-frames. Standard pulldown looks smoother because the extra fields are more imbedded in the sequence. So you shoot with Advanced pulldown, remove it in editing, cut in 24-frames, and add standard pulldown back in to the edited piece for any 60i master you need.
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#9 Hans Kellner

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Posted 05 June 2006 - 12:13 AM

24P Advanced is actually a simpler pulldown scheme -- I think every fifth frame is just repeated -- designed to make it easier to remove. So if you watch the footage with the Advanced pulldown, it will look worse (clunkier) actually than standard pulldown -- because it's only purpose is to be removed easily by the editing system, allowing you to work in true 24-frames. Standard pulldown looks smoother because the extra fields are more imbedded in the sequence.

The difference of encoding for normal vs advanced is that the cadence for normal is 2:3 vs. 2:3:3:2. That means that in 24p normal four frames (A,B,C,D) would be encoded as:

AA BB BC CD DD

Where the pairs above represent the upper/lower fields of a 60i frame.

In 24p advanced four frames (A,B,C,D) would be encoded as:

AA BB BC CC DD

The benefit of 24p advanced is that the full frames may be extracted without loss of data. Looking at the encoding for 24pa above, note that the 3rd 60i frame can be tossed and the remaining frames contain all the information needed for the original 24p frames. In the 24p normal encoded footage the C frame is encoded between two 60i frames (3 and 4). Extracting the C frame would require a decompression and a generation loss in quality.

Therefore, if you would like to edit 24p footage for later final output to 24p then shooting 24p advanced is the better route to go.
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