Movies may have a universal appeal, but video standards do not. To send movies from North America to Europe (and some other places), you must first convert the video from the NTSC standard to the PAL standard. Until recently, that meant paying for a standards conversion—a process that can cost anywhere from $100 to $1,000. But if you have Apple’s Final Cut Studio, you can get the same results from your Mac.
For reasons buried in antiquity, European and North American television signals evolved along very different paths. The North American NTSC standard runs at 29.97 frames per second and has a visible resolution of 720 by 480 pixels for DV (720 by 486 pixels for uncompressed signals, such as Digital Betacam). The European PAL system runs at 25 fps and has a resolution of 720 by 576 pixels—giving it 96 more lines and 5 fewer frames per second.
Third-party Final Cut plug-ins, such as Nattress’s Standards Conversion 2 ($100), can convert from one standard to the other for you. But a robust standard converter ships with every version of Final Cut Studio—it’s called Compressor 2. (Compressor also ships with the stand-alone versions of Final Cut Pro 5 and DVD Studio Pro 4.)
One of the major improvements in Compressor 2 is the addition of Optical Flow technology. Optical Flow tracks the movement of images at a pixel level. So if Compressor 2 needs to create 5 more frames per second, it can predict where those pixels would naturally go. However, to get the best quality from your conversions, you’ll need to play with some of the settings within Compressor.
For simplicity’s sake, these instructions cover only DV conversions. However, once you understand the workflow, you can easily adapt it to other formats, including uncompressed video and DV50.
One downside to using Compressor for this process is that it’s rather slow—my dual-2.5GHz G5 needed 30 minutes to convert a minute of NTSC footage. Compressor 2 does allow you to combine the processing power of several networked computers to cut down significantly on conversion time ( click here for instructions on setting this up).
Converting from NTSC to PAL
To convert NTSC video, launch Compressor 2 and drag the NTSC movie to the Batch window. The movie’s name will appear in the Source Media column. Click on the Settings pull-down menu and choose Advanced Format Conversions: DV PAL.
Although you could press the Submit button now, the results would likely disappoint you. The default settings leave much to be desired. To get the best results, you’ll want to modify some of the settings and create a custom preset.
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High Standards Using Compressor’s DV PAL preset as a starting point, open the Inspector window’s Frame Controls panel (A) and adjust the settings as seen here to fine-tune the NTSC-to-PAL conversion process. |
To adjust the conversion settings, open the Inspector window (Window: Show Inspector). Click on the Frame Controls button (it’s the third from the left), and then select Custom from the Frame Controls pull-down menu (see “High Standards”). Next, set the Resize Filter menu to Best (Statistical Prediction). This changes the frame size from 480 pixels to 576 pixels using Optical Flow tracking. Set the Output Fields menu to Same As Source.
And here’s the most important (and the least intuitive) part: set the Deinterlace menu to Better (Motion Adaptive)—not Best. If you set Deinterlace to Best, the resulting video is overenhanced and filled with artifacts. It also takes much longer to render ( four times longer on my dual-2.5GHz G5). Using the Better setting, on the other hand, results in a great picture.
Finally, set Rate Conversion to Better (Motion Compensated). This setting changes the frame rate from 29.97 fps to 25 fps. When you’re done, click on Save As and give your customized preset the name NTSCtoPAL.
Return to the Batch window. Click on the Settings pull-down menu and choose your new NTSCtoPAL preset from the list. Delete the PAL DV session from the Batch window and click on Submit.
Converting from PAL to NTSC
There are two methods of converting from PAL to NTSC: traditional and Slow-PAL. The traditional method converts 25-fps PAL video to 29.97-fps NTSC video by creating new frames based on the pixel information in the existing frames (this is essentially the reverse of the NTSC-to-PAL process). This leaves the movie’s audio quality and run-time unaltered. And while the video quality isn’t as pristine as what you’ll get with the Slow-PAL method, it’s still quite good.
With the Slow-PAL method, on the other hand, the goal is to manipulate the video frames as little as possible—and thus end up with a better-looking video. You’ll use Apple’s Cinema Tools (included with Final Cut Studio) to change the frame rate from 25 fps to 23.98 fps before converting the video to the NTSC standard in Compressor. You’ll then use Final Cut to fill out the movie to 29.97 fps by strategically duplicating video fields (this process is similar to the telecine process used with film).
Although it’s more work, the Slow-PAL method results in excellent video quality—one reason most professional services use this method. The conversion process is also much faster. The downside is that the converted video runs roughly 4 percent slower than the original and the sound drops slightly in pitch (though few people will notice the difference).
The traditional method
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Slow-PAL Using Cinema Tools, conform your PAL video from 25 fps to 23.98 fps. |
To convert PAL to NTSC using the traditional method, follow the same process as for converting NTSC to PAL, but with one important change: choose Advanced Format Conversions: DV NTSC from the Settings pull-down menu. Then change the other menus as described previously, and save the custom preset as PALtoNTSC. Use the new preset for the conversion process.
The Slow-PAL method
If you’re willing to put in the extra work, I recommend the Slow-PALmethod.
Step 1 Launch Cinema Tools. You don’t need to build a database for this process, so disregard the database queries as the program starts. Choose Open Clip from the File menu and select the PAL movie you want to convert. It will load into a viewing window (see “Slow-PAL”). Click on the Conform button. When the Conform Clip dialog box appears, choose 23.98 from the Conform To pull-down menu. Then click on the Conform button in the dialog box. Conforming the video file changes the frame-rate data only of the QuickTime file, not of the video frames themselves. As a result, the finished movie file will run slightly longer.
Step 2 When Cinema Tools is done, drag the file into Compressor’s Batch window. From the Settings pull-down menu, select Advanced Format Conversions: DV NTSC. Open the Inspector window’s Frame Controls panel and set Resize Filter to Best (Statistical Prediction), set Output Fields to Same As Source or Progressive, and set Deinterlace to Better (Motion Adaptive). Then set Rate Conversion to Fast (Nearest Frame).
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Stretching to Fit To finish the Slow-PAL conversion process, import your movie into Final Cut Pro and set the Pulldown Pattern menu to 2:3:2:3. |
Step 3 While still in the Inspector window, click on the Encoder tab (the second button from the left), and then click on the Video Settings button. In the dialog box that appears, change the Frame Rate menu to Current and click on OK. Save the preset as Slow-PALtoNTSC and use it to submit your job.
Step 4 Since normal NTSC video runs at 29.97 fps, you now need to somehow add 6 frames (or 12 fields) of video per second. You do this by inserting a 3:2 cadence—a process that repeats one out of every four video fields. Evenly spreading out the repeated fields allows the video to remain smooth.
To do this, import the converted Slow-PAL clip into Final Cut Pro 5 and create a new sequence set to DV NTSC 48 kHz 23.98. Open the System Settings window’s Playback Control panel and set the Pulldown Pattern menu to 2:3:2:3 (see “Stretching to Fit”). Finally, output the video to a FireWire video deck (File: Edit To Tape). The result should be a superb NTSC product.
[ Anton Linecker is a writer and video technical advisor based in Los Angeles. ]