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MillimeterEditing the V1's 24p in Final Cut Pro: A Workaround
May 29, 2007 11:57 AM, By Steve Mullen
For those who cannot wait for Apple to deliver native HDV support for the Sony HVR-V1U's 1080i60/1080p24 format, this installment of HDV@Work details a workaround for Final Cut Pro users. I’ll also provide an alternate workaround for those of you editing with Avid Media Composer or Xpress Pro.
As you learned in my review (part one, part two, part three) of the Sony V1, the camera shoots 24p using either of two modes. Sony decided to call one V1U mode “24A,” a term that Panasonic has used for many years to indicate a 2:3:3:2 rather than a 2:3:2:3 cadence. This has caused untold confusion with listserv posters, who question why reviewers have claimed that the V1U uses only 2:3 pulldown. So what are the two 24p modes supported by the V1U and which should be used?
First, to distinguish the V1’s “24p” from 720p24, 1080p24, and CineAlta’s 1080/24PsF, it may be helpful to use this notation: 1080i60/24p. This notation tells you that the V1’s 24fps progressive video inherently will be treated as 1080i by other video equipment. Second, when 1080p24 is converted within a V1 to 1080i60/24p, 2:3 pulldown is added. Every four frames become five frames, as shown below.
If you step through a 1080i60/24p clip, you will see four distinct frames in every five frames. When there is motion, at some point in the sequence, two frames will be identical. You can see this pattern in the sixth row in the diagram above (the diamonds). The “magic” A-frame is one frame after these two frames.
The V1U records 24p using two modes: a general mode and a more specialized mode for shooters who want a 24fps look, but who either “edit in camera” or do not plan to edit using a 24p timeline.
Note: an algorithm that detects the “A-frame” during capture or playback—in order to remove or ignore the 2:3 pulldown—will work equally well with both modes.
24 Mode
The specialized mode (“24”) will play back without any freeze frames between clips. This is the mode to use to use when you plan to edit using a 1080i60 timeline.
Note that the first clip (solid black circles) ends on frame 3—cadence frame C. The V1U begins a new clip that starts with an I-frame, as it should. Also note that while the cadence is unbroken, the new clip begins on a D cadence frame rather than an A cadence frame.
Continue the discussion on “Crosstalk” the Millimeter Forum.
