FCP incorrect frame order on playback or export if retimed compound clip contains trim or through edits

[joema4]

Apple Feedback Assistant ID: FB12048770

Description: If a timeline clip contains several trim or through edits, is made a compound clip, then that compound clip is retimed, the playback or exported frame order may be incorrect. It is more likely if retimed to 2x or higher but can happen if retimed to other values such as 60% or 80%.

Originally filed using MacOS Feedback Assistant, 10-March 2023, bug # FB12048770, reported to Apple Product Support as case 101955192401.

This is apparently of different origin than the previous bug FB10671041 (FCP incorrect frame order on M1 Max & Ultra if ProRes 422 clip contains certain Fx and is retimed and rendered to cache), which was unique to M1 Max and Ultra, and which was fixed on 10.6.4.

• Happens on Intel and Apple Silicon
• Versions tested: FCP 10.5.2 on Intel Ventura 13.2.1, 10.6.3 and FCP 10.6.5, 10.6.6 on Apple Silicon and Intel Mojave 10.6.3, Ventura 13.2.1, and Ventura 13.4.

Machines tested:

• M1 Ultra Mac Studio, 64-core GPU, 128GB RAM, 8TB SSD (Ventura 13.2.1, 13.4)
• M1 Max MacBook Pro 64GB RAM, 32-core GPU, 4TB SSD (Mojave 10.6.3)
• M2 Pro Mac Mini 10-core CPU, 19-core GPU, 32GB RAM, 4TB SSD (Ventura 13.2.1)
• 2019 MacBook Pro 16 10-core CPU, 8GB Radion Pro 5500M (Ventura 13.2.1)
• 2017 iMac 27 4-core CPU, 8GB Radeon Pro 580, 2TB SSD (Ventura 13.2.1)

STEPS TO REPRODUCE:

• Import the the test clip Clip2CloudsPR422.mov
• Import the project XML (either one, the v. 1.9 XML is for testing older FCP versions).
• Play the timeline
• Results: stuttery playback with incorrect frame order and/or duplicated frames. Frame anomalies are also seen in built-in timecode effect if placed on the compound clip.

NOTES:

• First noticed if retimed compound clip contains multicam clip with edits, however it's not isolated to MC clips. Suggest future testing of a potential fix include the multicam scenario for better coverage.

• Does not require a long clip or hundreds of through edits. Only a few edits will cause it.

• Is not limited to through edits, that is just the simplest case.

• Incorrect frame order can usually be seen immediately in timeline, however in some cases rendering the timeline via CTRL+R may be needed.

• Incorrect frame order persists in either ProRes 422 or H264 output file.

Files to reproduce, plus sample file of output: https://www.dropbox.com/sh/0zuft9w6ntnc9y1/AABoxl7w_p9joe5SEH3uuzbJa?dl=0

[latenitefilms]

This is PERFECT! Thank you!