Editing the V1's 24p in Final Cut Pro: A Workaround
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.
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.
The 24A mode forces every clip to begin with an A cadence frame. Due to the forced A frame, when playing 24A from a camcorder or VTR, brief pauses may occur between clips. This is the mode to use to use when you plan to edit using a 1080p24 timeline.
Again, the first clip (solid black circle) ends on frame 3—cadence frame C. The V1U repeats frame 3 until the end of the five-frame cadence—at cadence frame E. (These appear as a freeze frames to the viewer.) The new clip begins with cadence frame A. Therefore, while the cadence is unbroken; there are repeated (yellow) frames at the end of the outgoing clip. Note also that the new clip begins on an I-frame, as it should.
To use this workaround, you must shoot “24A” mode so that every clip begins with an A frame. You should capture in FCP using the Apple Intermediate Codec (AIC) 1080i60 preset. Auto Scene Detect will automatically leave a set of clips from a capture in a bin.
(When capturing to AIC, you have neither deck control—nor is timecode captured. If you require both, use FCP to capture native HDV into .MOV files. Then follow the instructions below on using DVFilm Maker to batch process these clips to 23.98fps native HDV .MOV files. In DVFilm Maker, be sure to turn off the YUV Process Option. Now import these 23.98fps files back into FCP for use in 23.98p Sequences.)
Now, open Cinema Tools and use File > Open Clip to select the first AIC clip you captured. (It will be within the FCP Capture Scratch folder.) Next, use Clip > Reverse Telecine to open the dialog box shown below.
If the clip had come from telecined film, timecode information would be “burned” into all frames of the video. See the “A” in the lower-right corner.
Instead, because we used 24A mode, we assume the first frame of each clip is an A frame. Cinema Tools will discard two fields, thereby dropping one frame in every six. Thus, every five frames will be converted to four frames.
Now, click the Rev Telecine button and the dialog box shown below will open.
Next, select F1–F2 because all clips have both fields 1 and 2 in an odd (1) and even (2) order. Click New (smaller), select 23.98, and check Standard upper/lower.
Select Style 2 and then select the C2D1 field pattern. Click OK. Delete the “.rev” extension in the Save As: to replace the original file. Click Save.
The clip will be converted from 29.97fps to 23.976fps and audio will be adjusted to fit over 24 frames rather than over 30 frames. The new file will be 20 percent smaller.
(Although Cinema Tools has a batch function, it seems not to use the correct C2D1 field pattern. Hopefully this will function will work correctly in Final Cut Studio 2.)
Close Cinema Tools and return to FCP.
In FCP, you will open new AIC 1080i60 Sequences. As you open each, you must set its frame rate to “23.98.” Confirm that Field Dominance is “None.” Also, set Process Maximum White to “Super White.”
Those of you editing with Media Composer or Xpress Pro can use DVFilm Maker to remove pulldown. Capture 1080i60/24p from the V1U via IEEE 1394 using DVHScap (PC) or HDVxDV (Mac).
In DVFilm Maker, use File > Open to select a file. (DVFilm Maker also supports batch processing.) Now, use Process > View Options to obtain the Options menu. Click the Advanced Options button.
Turn on the YUV Process Option.
Check User Selects Compression for an encode to DNxHD. (To output native HDV .MOV files, do not check.)
Click OK to return to the Options menu.
Click No Letterbox
Click the 24P Editing Options button.
Select Convert 60i to 24P.
Check Output 23.976 Exact
Click OK to return to the Options menu.
Click the Start button and select the DNxHD-TR 145 codec. The output file(s) will be QuickTime movie(s). After importing these 1080p24 QuickTime movies into Media Composer or Xpress Pro, you can edit them in a 1080p24 timeline.