The "Premultiplied" setting for Alpha on the Image input node in the compositor doesn't seem to work correctly for png image with alpha #115014

Closed
opened 2023-11-16 20:48:49 +01:00 by T-112 · 2 comments

System Information
Operating system: macOS-13.6-arm64-arm-64bit 64 Bits
Graphics card: Metal API Apple M1 Pro 1.2

Blender Version
Broken: version: 4.0.0, branch: blender-v4.0-release, commit date: 2023-11-13 17:26, hash: 878f71061b8e
Worked: (don't know)

Short description of error
A png with alpha does not look correct when viewed using the compositor viewer node. Setting the Alpha to "Premultiplied" does not work, but using an Alpha Convert node does.

Exact steps for others to reproduce the error

  • Have a png image with alpha
  • Use an Image input node in the compositor with default settings
  • The image has a rough border with incorrect looking alpha when viewed via a viewer node in the compositor
    • The image has correct looking alpha when using the Image Editor to view it
  • In order to get correct looking alpha view the viewer node, I have to add an Alpha Convert node set to "To Premultiplied"
  • Setting the Alpha to "Premultiplied" on the Image input node gives a completely different and broken looking result
**System Information** Operating system: macOS-13.6-arm64-arm-64bit 64 Bits Graphics card: Metal API Apple M1 Pro 1.2 **Blender Version** Broken: version: 4.0.0, branch: blender-v4.0-release, commit date: 2023-11-13 17:26, hash: `878f71061b8e` Worked: (don't know) **Short description of error** A png with alpha does not look correct when viewed using the compositor viewer node. Setting the Alpha to "Premultiplied" does not work, but using an Alpha Convert node does. **Exact steps for others to reproduce the error** - Have a png image with alpha - Use an Image input node in the compositor with default settings - The image has a rough border with incorrect looking alpha when viewed via a viewer node in the compositor - The image has correct looking alpha when using the Image Editor to view it - In order to get correct looking alpha view the viewer node, I have to add an Alpha Convert node set to "To Premultiplied" - Setting the Alpha to "Premultiplied" on the Image input node gives a completely different and broken looking result
T-112 added the
Priority
Normal
Type
Report
Status
Needs Triage
labels 2023-11-16 20:48:50 +01:00
Member

Hi, thanks for the report. Yes, can confirm. But this appears to be fixed already in current main/4.1

Hi, thanks for the report. Yes, can confirm. But this appears to be fixed already in current main/4.1
Pratik Borhade added
Module
VFX & Video
Status
Confirmed
Interest
Compositing
and removed
Status
Needs Triage
labels 2023-11-17 06:12:29 +01:00
Member

Closing since this is already fixed in 4.1 which will be release soon.

Closing since this is already fixed in 4.1 which will be release soon.
Blender Bot added
Status
Archived
and removed
Status
Confirmed
labels 2024-03-11 10:05:24 +01:00
Sign in to join this conversation.
No Label
Interest
Alembic
Interest
Animation & Rigging
Interest
Asset Browser
Interest
Asset Browser Project Overview
Interest
Audio
Interest
Automated Testing
Interest
Blender Asset Bundle
Interest
BlendFile
Interest
Collada
Interest
Compatibility
Interest
Compositing
Interest
Core
Interest
Cycles
Interest
Dependency Graph
Interest
Development Management
Interest
EEVEE
Interest
EEVEE & Viewport
Interest
Freestyle
Interest
Geometry Nodes
Interest
Grease Pencil
Interest
ID Management
Interest
Images & Movies
Interest
Import Export
Interest
Line Art
Interest
Masking
Interest
Metal
Interest
Modeling
Interest
Modifiers
Interest
Motion Tracking
Interest
Nodes & Physics
Interest
OpenGL
Interest
Overlay
Interest
Overrides
Interest
Performance
Interest
Physics
Interest
Pipeline, Assets & IO
Interest
Platforms, Builds & Tests
Interest
Python API
Interest
Render & Cycles
Interest
Render Pipeline
Interest
Sculpt, Paint & Texture
Interest
Text Editor
Interest
Translations
Interest
Triaging
Interest
Undo
Interest
USD
Interest
User Interface
Interest
UV Editing
Interest
VFX & Video
Interest
Video Sequencer
Interest
Virtual Reality
Interest
Vulkan
Interest
Wayland
Interest
Workbench
Interest: X11
Legacy
Blender 2.8 Project
Legacy
Milestone 1: Basic, Local Asset Browser
Legacy
OpenGL Error
Meta
Good First Issue
Meta
Papercut
Meta
Retrospective
Meta
Security
Module
Animation & Rigging
Module
Core
Module
Development Management
Module
EEVEE & Viewport
Module
Grease Pencil
Module
Modeling
Module
Nodes & Physics
Module
Pipeline, Assets & IO
Module
Platforms, Builds & Tests
Module
Python API
Module
Render & Cycles
Module
Sculpt, Paint & Texture
Module
Triaging
Module
User Interface
Module
VFX & Video
Platform
FreeBSD
Platform
Linux
Platform
macOS
Platform
Windows
Priority
High
Priority
Low
Priority
Normal
Priority
Unbreak Now!
Status
Archived
Status
Confirmed
Status
Duplicate
Status
Needs Info from Developers
Status
Needs Information from User
Status
Needs Triage
Status
Resolved
Type
Bug
Type
Design
Type
Known Issue
Type
Patch
Type
Report
Type
To Do
No Milestone
No project
No Assignees
3 Participants
Notifications
Due Date
The due date is invalid or out of range. Please use the format 'yyyy-mm-dd'.

No due date set.

Dependencies

No dependencies set.

Reference: blender/blender#115014
No description provided.