FFmpeg Opus audio codec supports up to 256 kbps, not 320.

[aknotwell]

Operating System Info

Windows 11

Other OS

No response

OBS Studio Version

32.0.0

OBS Studio Version (Other)

No response

OBS Studio Log URL

https://obsproject.com/logs/4SmMmetrlR4yaIca

OBS Studio Crash Log URL

No response

Expected Behavior

Tried to stream using WHIP, which only supports the FFmpeg Opus codec, but was unable to do an error. After further testing, I realized that any audio bitrate above 256 kbps, is unsupported by OBS. when the FFmpeg Opus codec is being used.

Current Behavior

Prevents stream/recording from starting giving this error: Failed to open AAC codec: Invalid Argument. If I had to guess, this means OBS is defaulting back to AAC for 320 kbps, but then some argument fails because Opus is being used.

Steps to Reproduce

1. In either record / stream tabs choose the FFmpeg Opus audio codec. I recommend using record because for streaming you have to switch your stream method to WHIP specifically.
2. Change audio output channels to be >256 kbps.
   3.Click record / stream.
   ...

Anything else we should know?

No response

[thebitbrine]

Found the issue and opened a PR to fix it: #12765

The problem is the Opus encoder was using the same bitrate settings as AAC (which goes up to 1024 kbps), but FFmpeg's libopus caps out at 256 kbps per channel. When you tried to use anything above 256, it'd fail with that confusing "Failed to open AAC codec" error.

The fix adds a separate properties function for Opus with the correct 64-256 kbps range. Also fixed the error message to actually show which codec failed instead of always saying "AAC codec".