vse group strips expanding in length on cancelled movement #101098

New Issue

System Information
Operating system: Linux-5.19.8-arch1-1-x86_64-with-glibc2.36 64 Bits
Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 515.65.01

Blender Version
Broken: version: 3.3.1 Release Candidate, branch: master, commit date: 2022-09-12 18:27, hash: 19ae71c113
broken in 3.4.0 as well

Short description of error

Peek 2022-09-15 18-42.mp4

Cancelling movement on a group strip in the VSE makes it expand in length. This does not happen every time but in a solid 40% of cases, with bigger movements increasing the likelihood.

Exact steps for others to reproduce the error

open new file with video editing template
create color (or other) strip
ctrl+g it into a grouped strip
start movement with g, wiggle mouse around
cancel movement with right mouse button

**System Information** Operating system: Linux-5.19.8-arch1-1-x86_64-with-glibc2.36 64 Bits Graphics card: NVIDIA GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 515.65.01 **Blender Version** Broken: version: 3.3.1 Release Candidate, branch: master, commit date: 2022-09-12 18:27, hash: `19ae71c113` broken in 3.4.0 as well **Short description of error** [Peek 2022-09-15 18-42.mp4](https://archive.blender.org/developer/F13496300/Peek_2022-09-15_18-42.mp4) Cancelling movement on a group strip in the VSE makes it expand in length. This does not happen every time but in a solid 40% of cases, with bigger movements increasing the likelihood. **Exact steps for others to reproduce the error** 1. open new file with video editing template 2. create color (or other) strip 3. ctrl+g it into a grouped strip 4. start movement with g, wiggle mouse around 5. cancel movement with right mouse button

Added subscriber: @paperbenni

Added subscriber: @iss

Changed status from 'Needs Triage' to: 'Needs User Info'

Can't reproduce the issue here. Can you upload .blend file?

Changed status from 'Needs User Info' to: 'Confirmed'

Sorry, I was testing in 2.93.. Can reproduce in 3.4.

This is caused by clamping handle translation to strip bounds, but the issue is, that if both handles are moved and step is bigger than strip length, it will fail.

Since function SEQ_time_update_meta_strip_range() is still needed, it would be possible to inline part of SEQ_time_*_handle_frame_set() without clamping. problem is, that this will happen at every place where both handles are moved at the same time, so in SEQ_transform_translate_sequence() as well. Flag to skip clamping could be implemented, but I don't quite like such flags. Also would violate my principle, that API functions should not result in invalid state.

So solution could be to have function that translates one or both handles. This way it would be possible to skip clamping if both handles are moved. Also it would clean up code where handle_set(seq, handle_get(seq) + x) is used as such code is not best to read.

As bugfix, I will implement SEQ_time_translate_handles() for both handles at once, this can be backported to LTS, and then will look at code if I see only one handle being moved, so I can add enum for SEQ_time_translate_handles() to select which handle.

This is caused by clamping handle translation to strip bounds, but the issue is, that if both handles are moved and step is bigger than strip length, it will fail. Since function `SEQ_time_update_meta_strip_range()` is still needed, it would be possible to inline part of `SEQ_time_*_handle_frame_set()` without clamping. problem is, that this will happen at every place where both handles are moved at the same time, so in `SEQ_transform_translate_sequence()` as well. Flag to skip clamping could be implemented, but I don't quite like such flags. Also would violate my principle, that API functions should not result in invalid state. So solution could be to have function that translates one or both handles. This way it would be possible to skip clamping if both handles are moved. Also it would clean up code where `handle_set(seq, handle_get(seq) + x)` is used as such code is not best to read. As bugfix, I will implement `SEQ_time_translate_handles()` for both handles at once, this can be backported to LTS, and then will look at code if I see only one handle being moved, so I can add enum for `SEQ_time_translate_handles()` to select which handle.

This issue was referenced by 41527ea89c

This issue was referenced by 41527ea89c7ab99737c8ba598f649d20bd7df972

This issue was referenced by d4a763d363

This issue was referenced by d4a763d363f14ae4de9411652d3556df2abcce21

Changed status from 'Confirmed' to: 'Resolved'

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vse group strips expanding in length on cancelled movement #101098