obsproject / obsproject/obs-studio

OBS Studio 28 breaks keyer in Decklink Output, performance in 4K extremely poor

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Dominant language
C
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Description

Operating System Info

macOS 12

Other OS

No response

OBS Studio Version

28.0.3

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/Ysc4v8pJc2ksZueX

OBS Studio Crash Log URL

No response

Expected Behavior

Key and Fill on Blackmagic hardware output when Keyer is enabled

Current Behavior

On OBS 28, this no longer works. Same image (or close to the same image) is output both on key and fill channels. Reverting to OBS 27 resolves this.

Steps to Reproduce
  1. Install Decklink or UltraStudio
  2. Switch to Video Color Format: RGB in Advanced settings, per Decklink Output instructions
  3. Enable Decklink output with a keyer enabled
  4. view separate key and fill feeds; they are virtually identical.
Anything else we should know?

No response

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reproducing the issue with OBS 28.0.3, Decklink or UltraStudio hardware, RGB video color format, and an enabled keyer, then compare the key and fill feeds with OBS 27. Review the Decklink Output instructions and the linked OBS log; done means separate key and fill output works again and 4K performance is no longer extremely poor.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
audio-video-rtc
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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