Quicktime Play X terminal commands - for your user pleasure!

Disable rounded corners

Code:
defaults write com.apple.QuickTimePlayerX MGCinematicWindowDebugForceNoRoundedCorners 1
Never show titlebar/controller

Code:
defaults write com.apple.QuickTimePlayerX MGUIVisibilityNeverAutoshow 1
Always show titlebar/controller

Code:
defaults write com.apple.QuickTimePlayerX MGUIVisibilityNeverAutohide 1
Never show the titlebar

Code:
defaults write com.apple.QuickTimePlayerX MGCinematicWindowDebugForceNoTitlebar 1
Autoplay movies on open

Code:
defaults write com.apple.QuickTimePlayerX MGPlayMovieOnOpen 1
Automatically show subtitles and closed captioning on open

Code:
defaults write com.apple.QuickTimePlayerX MGEnableCCAndSubtitlesOnOpen 1
Keep playing full-screen even when you command-tab out of QT

Code:
defaults write com.apple.QuickTimePlayerX MGFullScreenExitOnAppSwitch 0
Allow simultaneous recordings

Code:
defaults write com.apple.QuickTimePlayerX MGAllowMultipleSimultaneousRecordings 1
Unknown
I don't know exactly what these do, or they don't seem to have an effect when I enable them but here you go:

Code:
defaults write com.apple.QuickTimePlayerX MGTimeIntervalBeforeShowingLoadingUI
defaults write com.apple.QuickTimePlayerX MGUseForkedDecoder
defaults write com.apple.QuickTimePlayerX MGEnableMediumQualityAudioRendering
defaults write com.apple.QuickTimePlayerX MGDisableQuickTimeX
defaults write com.apple.QuickTimePlayerX MGShowFrameworkVersions
defaults write com.apple.QuickTimePlayerX MGEnableWWDC2009KeynoteBehavior
defaults write com.apple.QuickTimePlayerX MGCinematicWindowUseWindowShapeForRoundedCorners
defaults write com.apple.QuickTimePlayerX MGCinematicWindowTitleAlwaysHasActiveAppearance
defaults write com.apple.QuickTimePlayerX MGTimelineDisableAudioTrackForVideoMovies
defaults write com.apple.QuickTimePlayerX MGTimelineShowSlientRangesWithModifierKey