Hello, I’ve also been having trouble finding a good solution for this.
QuickTime does not record lossless RGB video.
ScreenFlow has the same problem, albeit to a far lesser extent. It’s not free and its export options all have flaws.
There’s CamTwist + Syphon Recorder, but CT is a performance hog at times.
SyphonInject + Syphon Recorder may also cause performance issues based on the source.
v002 Screen Capture doesn’t seem to work on Yosemite.
Desktop to Syphon isn’t behaving correctly when I set my origins and capture resolution.
Syphoner is not free and it’s broken on Yosemite.
ffmpeg has a frame rate bug with AV Foundation capture.
High performance lossless RGB recording on OS X seems to be really hard to come by.