Sequencer: Add Scene Strip Volume property #112597

20kdc · 2023-09-19T20:17:13+02:00

20kdc commented

2023-09-19 20:17:13 +02:00

Problem

Presently, it is not possible to alter a scene strip's volume independent of that scene.

Case A

This can be annoying if, for example, there is contextual audio involved that should not always be present, or would be duplicated, in the outer scene.

Take as an example a music-synced production prepared in the Sequencer. The scenes may look like this:

Video (MainWork, then EndCard)
MainWork (various 3D scenes and sequencer business, along with the actual audio)
Credits (refers to MainWork, but silently, while having separate audio)

Credits may even refer to MainWork multiple times at different points, which would cause duplicated audio.

However, while editing MainWork, the audio is important for synchronization. In addition, some 3D scenes may be "built around" specific musical moments and thus carry their own references to the music.

Case B

Keyframing scene volume from a Sequencer scene strip does not act in an "unsurprising" way.

My tests on Blender 3.6 and main (as of the base commit of this PR) indicate that the keyframes are in fact added, but they are added on the timeline of the target scene, without accounting for the frame offset / etc. Seeking produces nearly no feedback whatsoever, except the possible lighting of the keyframe indicator.

Proposal

The property to directly control scene strip volume exists, and in my testing, works fine including animation.

As such, exposing this property and adding UI for it should solve the problem. (I have yet to test pan, see TODO)

Notably, this only required exposing the data in RNA and UI. It doesn't alter sequencer.cc or such. (It also appears that someone had already been laying the groundwork for this change there.)

Alternatives

It may be a potential idea to have a method of marking a strip as "not visible from outside". This doesn't help if trying to keyframe volume, but would generally allow for (for example) in-VSE "helper sounds" to be suppressed while allowing sound effects to remain exported.
A "Volume Control" effect strip would allow for a more general-purpose approach to managing sound volume. (Apparently, as of very recently, an "Equalizer" strip modifier has been added. However, this modifier can't be applied to scene strip audio.)
Volume/pan control may be merged into the basic set of strip attributes in the same way that Transform has been.

Limitations

It is possible that there are side effects to this implementation that I am not aware of, i.e. some situation in which the audio will not properly handle the "recursive multiplication". However, it seems that the Sequencer audio implementation is a relatively consistent "audio graph", and testing hasn't shown any issues, so I don't think this is likely.

User Interface

The current UI retains Scene Volume for compatibility, but adds Strip Volume in a separate panel.

TODO

I'm unsure of how to add panning into this nicely, as the Sound Strip code from which this is sourced (in scripts/startup/bl_ui/space_sequencer.py) is both unspecific enough to be kind of a duplication and also specific enough for deduplication to be difficult. A particularly acute problem is that scenes are not necessarily mono, so the effects are uncertain.
- Answer: Panning doesn't work for scene strips anyway. Therefore exposing it from the RNA was removed from the PR as of b232a17c5e .
Animated scene strip volume does not update the UI properly, though this also applies to other properties such as the transform.
- This kind of seems like it's the result of something elsewhere.
There may be particularly nebulous reasons not to do this that I am not aware of.
- Nobody has brought any up.
Given that animated scene volume (as opposed to strip volume) from the VSE appears to not function in any expected way, it may be an idea to remove it entirely. The property still exists at its regular location as part of a Scene's properties.
- Done
~~Figure out what Failed to add relation "Sequence Scene Audio -> Sequencer" and Could not find op_from: ComponentKey(SCScene.001, AUDIO) are about.~~ Part of an unrelated, separate issue.

## Problem Presently, it is not possible to alter a scene strip's volume independent of that scene. ### Case A This can be annoying if, for example, there is contextual audio involved that should not always be present, or would be duplicated, in the outer scene. Take as an example a music-synced production prepared in the Sequencer. The scenes may look like this: * Video (MainWork, then EndCard) * MainWork (various 3D scenes and sequencer business, along with the actual audio) * Credits (refers to MainWork, but silently, while having separate audio) Credits may even refer to MainWork multiple times at different points, which would cause duplicated audio. However, while editing MainWork, the audio is important for synchronization. In addition, some 3D scenes may be "built around" specific musical moments and thus carry their own references to the music. ### Case B Keyframing scene volume from a Sequencer scene strip does not act in an "unsurprising" way. My tests on Blender 3.6 and main (as of the base commit of this PR) indicate that the keyframes are in fact added, but they are added on the timeline of the target scene, without accounting for the frame offset / etc. Seeking produces nearly no feedback whatsoever, except the possible lighting of the keyframe indicator. ## Proposal The property to directly control scene strip volume exists, and in my testing, works fine including animation. As such, exposing this property and adding UI for it should solve the problem. (I have yet to test pan, see TODO) Notably, this only required exposing the data in RNA and UI. It doesn't alter `sequencer.cc` or such. (It also appears that someone had already been laying the groundwork for this change there.) ## Alternatives * It may be a potential idea to have a method of marking a strip as "not visible from outside". This doesn't help if trying to keyframe volume, but would generally allow for (for example) in-VSE "helper sounds" to be suppressed while allowing sound effects to remain exported. * A "Volume Control" effect strip would allow for a more general-purpose approach to managing sound volume. (Apparently, as of very recently, an "Equalizer" strip modifier has been added. However, this modifier can't be applied to scene strip audio.) * Volume/pan control may be merged into the basic set of strip attributes in the same way that Transform has been. ## Limitations * It is possible that there are side effects to this implementation that I am not aware of, i.e. some situation in which the audio will not properly handle the "recursive multiplication". However, it seems that the Sequencer audio implementation is a relatively consistent "audio graph", and testing hasn't shown any issues, so I don't think this is likely. ## User Interface The current UI retains Scene Volume for compatibility, but adds Strip Volume in a separate panel. ![image](/attachments/e6b44c68-7504-4132-9896-93b1d358f7fa) ## TODO * ~~I'm unsure of how to add panning into this nicely, as the Sound Strip code from which this is sourced (in `scripts/startup/bl_ui/space_sequencer.py`) is both unspecific enough to be kind of a duplication and also specific enough for deduplication to be difficult. A particularly acute problem is that scenes are not necessarily mono, so the effects are uncertain.~~ * Answer: Panning doesn't work for scene strips anyway. Therefore exposing it from the RNA was removed from the PR as of b232a17c5eb7877b6e4a63cceea5cce616f26df8 . * Animated scene strip volume does not update the UI properly, though this also applies to other properties such as the transform. * This kind of seems like it's the result of something elsewhere. * There may be particularly nebulous reasons *not* to do this that I am not aware of. * Nobody has brought any up. * ~~Given that animated scene volume (as opposed to strip volume) from the VSE appears to not function in any expected way, it may be an idea to remove it entirely. The property still exists at its regular location as part of a Scene's properties.~~ * Done * ~~Figure out what `Failed to add relation "Sequence Scene Audio -> Sequencer"` and `Could not find op_from: ComponentKey(SCScene.001, AUDIO)` are about.~~ Part of an unrelated, separate issue.

image.png

16 KiB

20kdc added 2 commits 2023-09-19 20:17:22 +02:00

c424e64f23 RNA: Expose audio properties of Scene Sequencer strips

4d7a9fd5ed UI: Sequencer: Add scene strip volume property to UI

Iliya Katushenock added the

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