Extending left handle of a VSE multicam effect strip with snap creates frame stills #46678

New Issue

David Salvo · 2015-11-02T18:33:01+01:00

David Salvo commented

2015-11-02 18:33:01 +01:00

System Information
Mint 17.2, NVIDIA G92 [GeForce 9800 GT]

Blender Version
Broken: (example: 2.76, 1st release)
Worked: (broken for a while)

Short description of error
Extending left handle of a multicam effect strip with snap creates frame stills

Exact steps for others to reproduce the error

Add video to VSE timeline
Add multicam strip above video
Select LEFT multicam strip handle with right mouse button
Select any frame to the left of this handle
Snap selected handle to selected frame with SHIFT-S
Newly extended frames will display frame stills instead of video
NOTE: The still segment remains relative to the strip even as it is moved around. However, as soon as this handle is extended with either right mouse button or G for grab by even one frame, the strip will correct itself and play underlying video again.

**System Information** Mint 17.2, NVIDIA G92 [GeForce 9800 GT] **Blender Version** Broken: (example: 2.76, 1st release) Worked: (broken for a while) **Short description of error** Extending left handle of a multicam effect strip with snap creates frame stills **Exact steps for others to reproduce the error** - Add video to VSE timeline - Add multicam strip above video - Select LEFT multicam strip handle with right mouse button - Select any frame to the left of this handle - Snap selected handle to selected frame with SHIFT-S - Newly extended frames will display frame stills instead of video - NOTE: The still segment remains relative to the strip even as it is moved around. However, as soon as this handle is extended with either right mouse button or G for grab by even one frame, the strip will correct itself and play underlying video again.

David Salvo commented

2015-11-02 18:33:01 +01:00

Changed status to: 'Open'

David Salvo commented

2015-11-02 18:33:01 +01:00

Added subscriber: @slinkeepie

Sergey Sharybin commented

2015-11-03 12:23:56 +01:00

Added subscriber: @Sergey

Sergey Sharybin commented

2015-11-03 12:23:56 +01:00

Does the "Refresh Sequencer" button helps here? For me it shows black frames as it's actually expected.

Also, always attach the .blend file which demonstrates the issue.

Does the "Refresh Sequencer" button helps here? For me it shows black frames as it's actually expected. Also, always attach the .blend file which demonstrates the issue.

David Salvo commented

2015-11-03 20:25:19 +01:00

This comment was removed by @slinkeepie

*This comment was removed by @slinkeepie*

David Salvo commented

2015-11-07 21:11:38 +01:00

Hi Sergey,

Annoying I can't edit original description to make it a big clearer...

In your case what you tried should still bug out... one step I forgot to add was to make sure the multi-cam strip is set to source channel 1 (or whichever channel the video, or in the case of the test blend, colour strip, is on)

multicam-bug.blend

Hi Sergey, Annoying I can't edit original description to make it a big clearer... In your case what you tried should still bug out... one step I forgot to add was to make sure the multi-cam strip is set to source channel 1 (or whichever channel the video, or in the case of the test blend, colour strip, is on) [multicam-bug.blend](https://archive.blender.org/developer/F253687/multicam-bug.blend)

Bastien Montagne commented

2015-11-20 17:29:21 +01:00

Added subscribers: @Psy-Fi, @mont29

Bastien Montagne commented

2015-11-20 17:29:22 +01:00

OK, can confirm easily the issue with given file.

Problem comes from those new adjustment/multicam effect strips, they need a different caching management since (unlike pretty much any other movable strip), any editing, including full strip moving, should invalidate the whole cached data of it (both preprocess and final caches).

And to make things even more confusing, the start/startstill/startoffset/etc. also need extra care for those strips, calling BKE_sequence_single_fix() was missing in a few places, including snap operator (basically, there should never be any start/end still frames here…).

Attached patch (D1625) seems to fix things and work OK, but wouldn’t mind a second eye from @Sergey or @Psy-Fi here! Also, note that until you actually snap or move left or right handle of existing strips of that type, they can remain in 'invalid startstill state' (as in your demo file, where multicam strip has 15 start still frames), not sure it’s worth adding something in loader to fix this?

OK, can confirm easily the issue with given file. Problem comes from those new adjustment/multicam effect strips, they need a different caching management since (unlike pretty much any other movable strip), any editing, including full strip moving, should invalidate the whole cached data of it (both preprocess and final caches). And to make things even more confusing, the `start`/`startstill`/`startoffset`/etc. also need extra care for those strips, calling `BKE_sequence_single_fix()` was missing in a few places, including snap operator (basically, there should **never** be any start/end still frames here…). Attached patch ([D1625](https://archive.blender.org/developer/D1625)) seems to fix things and work OK, but wouldn’t mind a second eye from @Sergey or @Psy-Fi here! Also, note that until you actually snap or move left or right handle of existing strips of that type, they can remain in 'invalid startstill state' (as in your demo file, where multicam strip has 15 start still frames), not sure it’s worth adding something in loader to fix this?

blender-admin commented

2015-11-22 15:33:45 +01:00

This issue was referenced by 307f1e7d23

This issue was referenced by 307f1e7d2360de19d38a6b4c2e2b4323f505cf18

Bastien Montagne commented

2015-11-22 15:52:34 +01:00

Changed status from 'Open' to: 'Resolved'

Bastien Montagne closed this issue

2015-11-22 15:52:34 +01:00

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Extending left handle of a VSE multicam effect strip with snap creates frame stills #46678