Editing Variable Frame Rate Source Clips


Sometimes users report that Shotcut is not frame accurate. For example, they split a clip on a certain frame, but then later the split is not where they expected it. Or, they put a keyframe on a certain frame, but later the keyframe seems to be on a different frame. Also, sometimes people report that the audio and video out not in sync.

Symptoms like these can be caused by Variable Frame Rate (VFR) source clips. Some users report that VFR clips work in Shotcut if the VFR is subtle. Other clips, however, are completely unusable in Shotcut.

Identifying VFR Clips

Some programs will skip encoding frames as a way to reduce file size. Also, some devices will skip encoding frames if they do not have enough processing power to perform real time encoding. Typically, these clips can be identified by looking at the frame rate in the properties panel. If the clip frame rate does not match a standard frame rate, then it is probably VFR. If Shotcut is able to detect a VFR clip, it will add a “(variable)” tag after the frame rate. But Shotcut can not always detect VFR clips.

Converting VFR Clips

The best way to edit VFR clips is to convert them to a fixed frame rate. Follow these steps:

  1. Set the desired Video Mode in Shotcut (do not use Automatic). In particular, choose a frame rate for your project that meets your needs.
  2. Open the VFR clip
  3. If Shotcut detects the VFR, it may prompt you to convert. If not, click the “Convert…” button in the properties panel to open the conversion prompt.
  4. Click “OK” to start the conversion

After the conversion is complete, the clip will be replaced with the converted clip.