What variable frame rate is and where it comes from
Variable frame rate means the frame rate changes over time within a file. A January 2019 Adobe Community FAQ written by an Adobe employee says VFR is common in footage from smartphones, webcams and screen recorders, naming tools such as NVIDIA ShadowPlay and OBS Studio as examples. [1] Editors built around a fixed timeline rate can play such files with audio gradually out of sync.
This guide is based on Adobe's FAQ and the MediaInfo and HandBrake documentation, not on our own editing tests. The Adobe source is a community FAQ rather than a formal help article, so menu names may have changed in later versions.
Detect it before you fix anything
MediaInfo is free, open-source software that displays technical data for video and audio files, including frame rate and codec. On 13 October 2026 its site listed versions for Windows, macOS, Android, iOS and many Linux distributions, plus a browser-based MediaInfoOnline. [2]
The Adobe FAQ describes checking the Frame Rate Mode field: Variable indicates VFR. It also says Premiere Pro 12.0.1 or later shows Variable Frame Rate Detected in a clip's Properties panel. [1]
- Open the original file in MediaInfo and note the frame rate mode and any minimum and maximum frame rates.
- In Premiere Pro, right-click the imported clip, choose Properties, and look for the VFR notice. [1]
- Record the result in your project notes so you know which clips need treatment.
Option one: let the editor preserve sync
The Adobe FAQ describes a Preserve Audio Sync setting, found by opening the clip in the Source Monitor and going to MPEG Source settings in the Effect Controls panel. It keeps audio and video aligned by adding or dropping video frames, which can make motion less smooth, and the FAQ says it is the default for VFR sources with audio. The alternative, Smooth Video Motion, keeps all frames but does not maintain sync. [1]
That is fine for a talking head where a dropped frame is invisible. It is weaker for screen recordings with fast cursor movement or scrolling, where duplicated frames can look like stutter.
Option two: convert to constant frame rate
The Adobe FAQ recommends transcoding VFR footage to constant frame rate before editing, especially for proxy, consolidate or transcode workflows, and notes that Preserve Audio Sync may not work with some files. It names HandBrake and Shutter Encoder as tools. [1]
HandBrake's frame rate documentation, marked as a draft, describes three behaviors. Same as Source with Variable Frame Rate copies the source timing without conversion. Same as Source with Constant Frame Rate keeps the detected rate and makes variable portions constant. A specific constant frame rate conforms the whole video to that rate, which the page says is not recommended except in special circumstances such as encoding for import into an NLE. [3]
| Approach | Keeps original timing | Main trade-off |
|---|---|---|
| Editor sync option | File untouched | Added or dropped frames; may fail on some files [1] |
| HandBrake, Same as Source, constant | No, new file | Re-encode time and generation loss |
| HandBrake, specific constant rate | No, new file | Converts the whole video to one chosen rate [3] |
Worked example: a fictional phone interview
This example is invented. A creator edits a 40-minute phone recording. By minute 30 the speaker's lips visibly lead the audio. MediaInfo shows Frame rate mode Variable with a range of rates. The editor's sync option fixes the talking head but the screen-share insert from the same session stutters.
The creator converts a copy of the screen-share clip with HandBrake to a constant frame rate matching the project, checks the new file in MediaInfo, replaces it in the timeline, and spot-checks sync at the start, middle and end. The original files stay archived.
Pitfalls and the no-purchase path
Never overwrite the original recording with the converted file. Conversion is a lossy re-encode, and you may need the source if the first conversion settings are wrong. Check the converted file's frame rate mode again rather than assuming the setting took effect.
Every tool named here is free, and the editor sync option costs nothing but a check. Buying a new editor will not fix VFR by itself; detection and a deliberate conversion step do. We have not verified recorder-side settings that prevent VFR at capture, so test your own recorder with MediaInfo before a long session.
Questions before you decide
Is audio drift always caused by variable frame rate?
No. It is one common cause in phone, webcam and screen recordings according to Adobe's FAQ, so confirm it with MediaInfo or the Properties panel before converting anything.
Which HandBrake setting should I use for editing?
HandBrake's documentation describes constant frame rate options and says converting to a specific rate is mainly for special cases such as NLE import. Match your project rate and check the result in MediaInfo.
Sources & verification
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- Adobe Community FAQ (Adobe employee): How to work with Variable Frame Rate (VFR) media in Premiere Pro, January 2019 Accessed 13 Oct 2026
- MediaArea: MediaInfo Accessed 13 Oct 2026
- HandBrake Documentation: Frame rate Accessed 13 Oct 2026
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