x264 Encoding Efficiency

I'm not exactly sure if it was updating Wirecast or iOS, but recently my CPU usage when streaming / recording with a x264 encoder has skyrocketed, resulting in dropped frames at a rate that makes the footage unwatchable. The identical settings worked just fine a few weeks ago. Even with more modest settings my computer struggles now.


MacBook Pro (Retina, 15-inch, Mid 2014); macOS Big Sur 11.3.1

Processor 2.8 GHz Quad-Core Intel Core i7

Memory 16GB 1600 MHz DDR3

Graphics Intel Iris Pro 1536 MB

Wirecast Version 14.2.0

Lowest Encoder Settings tried (CPU 80%):


Quality 3 (Very Fast Encoding - Default)

2500 kpbs

30 fps

Keyframe every 60 frames

Audio 128 kbps

Does anyone know what happened or a possible fix? The Apple H.264 works, but looks gross even at higher bitrates. I'd really like to go back to x264.



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  • There's no changes that I'm aware of that would increase CPU use over recent previous versions. 

    I've used Wirecast 14.2 on a 2013 15" MBP to go from one camera to Facebook using settings similar to yours and generally the CPU% is under 50%.

    You could try resetting Wirecast Preferences since if they become corrupted that can impact CPU use. Wirecast Help > Send Support Information, Reset Preferences button.

    Keep in mind anything and everything else you have running at that time will impact CPU use. Wirecast by default shows system CPU use.

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