Modify frame rate and duration in Compressor
You can modify the properties of applied or custom presets to set the frame rate of your output and modify the duration of a transcoded file.
Note: If you modify the properties of an applied preset in the output row of a job, the modifications apply to only that output. If you modify the properties of a custom preset, your modifications are saved for future use.
Set the frame rate
In Compressor, select an applied or custom preset.
In the Video Properties section of the Video inspector, do one of the following:
Click the “Frame rate” pop-up menu, then choose an option.
Automatic, the default value, matches the frame rate of the transcoded file to that of the source file if possible. If the source file’s frame rate isn’t supported within the limitations of the transcode presets, Compressor picks the best match.
You can also choose any of several commonly used frame rates, including 23.976 fps, 24 fps, and so on. Presets that use the Apple Devices, Image Sequence, MPEG-4, or Quicktime Movie formats support frame rates up to 120 fps.
Type a custom frame rate in the field to the right of the “Frame rate” pop-up menu.
Note: Some preset formats don’t permit custom frame rates.
Frame rate conversion can have a subtle or dramatic effect depending on how big a difference there is between the original and new frame rates, and also depending on the specific nature of the footage being converted. Footage with a lot of movement yields a much more visible change than footage with little movement in the frame.
Frame rate conversion may also add visible artifacts in the transcoded file; from stuttering (sometimes called “juddery”) playback, to repeated frames, ghost images, or other unnatural-looking elements. These effects can be somewhat mitigated by adjusting the method for retiming quality. See Set retiming and resizing quality in Compressor.
Adjust the duration of a transcoded file
In Compressor, select an applied or custom preset.
In the Retiming section of the General inspector, modify the Duration property in one of the following ways:
Enter a specific percentage of the source footage duration in the percentage field, or choose a preset value from the pop-up menu.
Note: Choosing a preset from this pop-up menu doesn’t change the frame rate of the output file. If you want to create a file at a frame rate other than the source’s original rate, see the previous task.
Click to select the button next to the timecode field and enter a specific duration for the outgoing file. The percentage field above automatically updates.
Note: This option is available only when you’re modifying an applied preset.
Click to select “Set so source frames play at [frame rate] fps.” The frame rate used in this option is the value set in the “Frame rate” property in the Video inspector.
Adjust the method for retiming quality as needed.
If the source media contains audio, retiming modifies the audio speed as well, thereby keeping audio and video in sync. Compressor also automatically corrects the pitch so the audio doesn’t sound artificially high or low.
Important: If you modify retiming properties in a preset that uses the QuickTime Movie format and choose “Enable audio pass-through” in the Audio inspector, the audio speed is not changed. Consequently, audio in the output file will not maintain sync with the video.
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