Regression: Loading a VSE .blend file created in older version into 3.6.0 loses information about video/audio clip cut lengths #110333

New Issue

System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GT 1030/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.67

Blender Version
Broken: version: 3.6.0, branch: blender-v3.6-release, commit date: 2023-06-27 08:08, hash: c7fc78b81ecb
Worked: tested on 3.0.0 and 3.1.0
Caused by c9be925f7d

Short description of error
Loading a .blend file with VSE data made in Blender 3.0.0 behaves unexpectedly when saved and opened in 3.6.0. The lengths of audio strips associated with videos are not retained. When loading the blend file in 3.6.0 the "Strip Start Offset" is reset to zero, thus making all of the start times of the audio strips incorrect.

Exact steps for others to reproduce the error

Open Blender 3.0.0 and start a blank VSE project.
Drag a video clip with audio into the timeline (I used an MKV clip recorded from OBS)
Use the "k" key to make some cuts to the clip.
move the new cuts vertically to make their start and ends easier to see.
Save the file as "test.blend"
Open the file in Blender 3.6.0
Observe that the start points of many of the audio clips are not correct.

Additional Info
I've included a ZIP file that contains a small .blend sample file, as well as a short 9 second .mkv screen recording necessary to demonstrate the bug. This .blend file was created in Blender 3.0.0.

I did not test further if this bug also occurs with pure audio files (such as .wav or .mp3) or if it only occurs with audio from video files. I tested with multiple MKV files generated by OBS, and all had this same issue.

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GT 1030/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 536.67 **Blender Version** Broken: version: 3.6.0, branch: blender-v3.6-release, commit date: 2023-06-27 08:08, hash: `c7fc78b81ecb` Worked: tested on 3.0.0 and 3.1.0 Caused by c9be925f7df29eb83f2bcac800bfcbe9882dbf15 **Short description of error** Loading a .blend file with VSE data made in Blender 3.0.0 behaves unexpectedly when saved and opened in 3.6.0. The lengths of audio strips associated with videos are not retained. When loading the blend file in 3.6.0 the "Strip Start Offset" is reset to zero, thus making all of the start times of the audio strips incorrect. **Exact steps for others to reproduce the error** - Open Blender 3.0.0 and start a blank VSE project. - Drag a video clip with audio into the timeline (I used an MKV clip recorded from OBS) - Use the "k" key to make some cuts to the clip. - move the new cuts vertically to make their start and ends easier to see. - Save the file as "test.blend" - Open the file in Blender 3.6.0 - Observe that the start points of many of the audio clips are not correct. **Additional Info** I've included a ZIP file that contains a small .blend sample file, as well as a short 9 second .mkv screen recording necessary to demonstrate the bug. This .blend file was created in Blender 3.0.0. I did not test further if this bug also occurs with pure audio files (such as .wav or .mp3) or if it only occurs with audio from video files. I tested with multiple MKV files generated by OBS, and all had this same issue.

Blender-vse-bug-test.zip

1.1 MiB

@iss might want to take a look at this one

Can confirm, quite recent regression introduced after 3.5 release

Broke between 54e397cc7830 - 654cfc06c591

Broke between `54e397cc7830 - 654cfc06c591`

Git bisect points to @iss 's commit: c9be925f7d :)

Git bisect points to @iss 's commit: c9be925f7df29eb83f2bcac800bfcbe9882dbf15 :)

In #107289 I had only files that are saved after versioning failed available, so normally I wouldn't attempt to fix such issue. Fortunately I can distinguish unaffected files.

Hi, this was my first bug report. I assume then that this fix will be added to the next update? How do I apply this fix?

I've never installed a patch/fix to any existing version of Blender before. Would I just download 3.6 installer and overwrite my existing 3.6 install when it releases? Or will Blender auto-update? If not, is there some way I can get a notification for when this fix is released?

Also, thanks for the hard work and quick responses.

Hi, this was my first bug report. I assume then that this fix will be added to the next update? How do I apply this fix? I've never installed a patch/fix to any existing version of Blender before. Would I just download 3.6 installer and overwrite my existing 3.6 install when it releases? Or will Blender auto-update? If not, is there some way I can get a notification for when this fix is released? Also, thanks for the hard work and quick responses.

Hi @James-28 , this will be available in the next release of 3.6.1 and it should already be available in 4.0 daily build. When it comes out just simply install over old version, or you can keep both version installed separately (downloading portable zip is also a good idea). Blender will not be self-updating. In #109399 you can check if this (#110333) has been backported, in which case the 3.6 daily build will include this fix.

Ok thanks! Yeah I have a few versions of Blender installed for different projects (2.80, 3.0, 3.6) but I wasn't sure if there was "backporting" (that's a new word to me) or how ever that works with the "LTS" versions.

I know 3.6 LTS stands for "long term support until June 2025" but does that "long term support" period also apply to subsequent sub-versions (3.6.1, 3.6.2, etc)? I'm just a little confused on what exactly the LTS refers to, the specific 3.6.0 release or the whole 3.6.x "family".

I've always found software versioning to be confusing, in general.

Ok thanks! Yeah I have a few versions of Blender installed for different projects (2.80, 3.0, 3.6) but I wasn't sure if there was "backporting" (that's a new word to me) or how ever that works with the "LTS" versions. I know 3.6 LTS stands for "long term support until June 2025" but does that "long term support" period also apply to subsequent sub-versions (3.6.1, 3.6.2, etc)? I'm just a little confused on what exactly the LTS refers to, the specific 3.6.0 release or the whole 3.6.x "family". I've always found software versioning to be confusing, in general.

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Regression: Loading a VSE .blend file created in older version into 3.6.0 loses information about video/audio clip cut lengths #110333