Mixing frame rates – Apple Final Cut Express 4 User Manual
Page 924
924
When Are Clips Automatically Conformed to a Sequence?
Most of the time, Final Cut Express automatically conforms clips when you edit them
into a sequence. This makes it simple to mix video with different resolutions, aspect
ratios, and field dominances. However, there are certain cases where Final Cut Express
does not conform your clip:
 If the dimensions of the edited clip are smaller than those of the sequence, the value
of the clip’s Scale parameter is increased only if the “Always scale clips to sequence
size” option in the User Preferences window is selected.
 When you edit or paste a clip that contains Scale or Aspect Ratio parameter
keyframes into a sequence, Final Cut Express does not change these parameter
settings to fit the clip into the sequence. This allows you to preserve any Scale or
Aspect Ratio parameter keyframes you added to your clip to create a motion effect.
To automatically conform edited or pasted clips whose image dimensions are
smaller than the sequence dimensions:
1
Choose Final Cut Express > User Preferences, then click the Editing tab.
2
Select “Always scale clips to sequence size,” then click OK.
3
Edit one or more clips into your sequence.
Each edited clip’s Scale and Aspect Ratio parameter settings are adjusted automatically
so that the clip’s size matches the sequence dimensions.
Mixing Frame Rates
Clips with any Final Cut Express–supported frame rate can be added to a sequence and
played back in real time. Depending on whether the clip frame rate is faster or slower
than that of the sequence, Final Cut Express skips or repeats frames of the sequence clip.
If a clip and sequence have matching frame rates:
Each frame of the clip’s media file is played back in the sequence. No frame rate
conversion occurs, even when the clip and sequence codecs don’t match. Ideally, your
clip and sequence frame rates should always match.
If a clip’s media file frame rate is slower than the sequence frame rate:
Final Cut Express repeats frames of the clip’s media file as necessary to create the
appearance of playback at the sequence frame rate. The repeating pattern is not
necessarily compatible with standard pull-down or frame duplication patterns of other
formats. In cases with interlaced footage (such as a PAL clip within an NTSC sequence),
fields are sometimes doubled (instead of frames) to avoid field stuttering.