Format Conversion When Finishing Mixed-Format Sequences

Final Cut Pro supports mixed-format sequences, which is very convenient when you need to perform the offline edit of a project that incorporates a wide variety of source material. For example, it’s common to mix high definition (HD) and standard definition (SD) clips in documentary programs. More extreme examples include programs that incorporate archival footage in different broadcast standards with different frame rates, such as programs that combine PAL and NTSC footage.

In some cases, you can mix formats and finish your program using the original media without problems. However, certain combinations of mismatched media attributes can cause trouble when the time comes to finish and output your project. This section illustrates how you should handle different combinations of clips in mixed-format sequences to avoid problems.

Which media attributes can safely differ from the sequence settings?

The following clip characteristics can differ from those of the sequence without causing problems.

  • Codec: You can freely mix clips using any codecs that are compatible with Final Cut Pro, as long as their frame rates, interlacing, and frame size are appropriate to the sequence. However, keep in mind that some broadcasters have specific requirements about what percentage of a program can use source footage in a highly compressed digital format such as HDV or AVCHD.
  • Aspect ratio: Final Cut Pro lets you mix footage with different aspect ratios (for example, mixing footage with 3:4 and 16:9 aspect ratios), including anamorphic footage. Depending on the combination of sequence and media frame sizes, Final Cut Pro automatically letterboxes (places horizontal bars at the top and bottom of the screen) or pillarboxes (places vertical bars at the left and right of the screen) clips as necessary to fit them into the available width and height of the frame.
  • Bit depth: You can mix clips with any bit depth Final Cut Pro supports. Typical bit depths for video include 8-bit and 10-bit.
  • Frame size: If you set the Motion Filtering Quality pop-up menu (in the Video Processing tab of the Sequence Settings window) to Best, the scaling in Final Cut Pro is sufficient for modest enlargements and for shrinking higher-resolution clips down to smaller frame sizes. This means you’re in good shape if you’re editing HD clips into an SD sequence, as long as the frame rate and interlacing match all the other clips. However, if you’re editing SD clips into an HD sequence, you may want to consider using Compressor to upscale your media for the best results, as described later in this section.
Which media attributes should not differ from the sequence settings?

If you’re preparing a sequence for finishing, the following clip characteristics should match those of the sequence to ensure seamless mastering and output.

  • Frame rate: This is the most important clip characteristic that should match that of the sequence. Although you can freely mix frame rates during offline editing, it’s not ideal to rely on Final Cut Pro to retime the frame rates of clips that don’t match the sequence frame rate if you plan to output a high-quality master.
  • Interlacing: Although you can freely mix progressive and interlaced clips during the offline edit, you typically need to output to one format or the other when you create a program’s final master. Final Cut Pro is not the best environment for converting one field-handling standard to the other.
What is the best way to do format conversion using Compressor?

If you have one or more clips in your sequence whose frame rates, scanning methods (interlaced or progressive), or frame sizes don’t match, you can use Compressor to do a standards conversion of the mismatched clips. Compressor can use optical flow analysis to create high-quality conversions, but you have to choose the appropriate settings for your preset in the Inspector. With these settings chosen, processing times are high, but the results are worth it.

For more information, see the Compressor documentation. To briefly summarize, if you’re doing standards conversion, turn on Frame Controls in the Frame Controls tab of the Inspector, and choose the following options.

  • Resize Filter pop-up menu: For the highest-quality result when resizing smaller-resolution clips to a larger frame size, choose “Best (Statistical prediction).” You’ll select the actual frame size to convert the clip to (along with cropping and pixel aspect ratio conversion options, if necessary) in the Geometry section of the Inspector.
  • Output Fields and Deinterlace pop-up menus: If you need to deinterlace a clip or introduce interlacing to a clip, choose the standard you require from the Output Fields pop-up menu, and then choose “Best (Motion compensated)” from the Deinterlace pop-up menu. Additional options, including the Adaptive Details checkbox and the Anti-alias and Details Level sliders, let you adjust the way the final result is processed. If you’re converting a telecined film clip with interlacing, choose Reverse Telecine instead to remove the 3:2 pull-down.
  • Rate Conversion pop-up menu: If you’re changing the frame rate, choose “Best (High quality motion compensated),” and then choose a conversion method from the “of source” pop-up menu, to the right of the “Set Duration to” field.