mltframework / mltframework/shotcut

Stabilization filter causes stuttering on VFR (or converted VFR to CFR) videos

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Dominant language
C++
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Description

OS and Version (please complete the following information):

  • Operating System: Windows 10 (22H2 19045.5487)
  • Shotcut Version: 25.05.11

Describe the bug
Whenever duplicated frames are present such as from VFR or converted VFR into CFR videos, the stabilization filter also "stabilizes" the duplicated frames and smoothes them. Causing weird stuttering and jitter in the output.

Steps To Reproduce

  1. Start Shotcut
  2. Add a video with duplicated frames (VFR video for best results).
  3. Apply stabilization filter
  4. See stuttering on any filter settings.

Expected behavior
Stabilization should exclude the analysis and smoothing of duplicated frames that have not been changed since previous frame.

Screenshots

https://github.com/user-attachments/assets/2adb7611-abf1-4a2e-883f-068410a7ae2d

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

No source files or tests are identified in the issue. Reproduce the problem in Shotcut with a VFR or converted VFR video and the stabilization filter, then trace the stabilization filter's frame analysis and smoothing behavior. Done means duplicated unchanged frames are excluded and the stabilized output no longer stutters or jitters.

Written by the indexing model from the issue text.

Assessment

Domain
audio-video-rtc
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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