Additions to Media Composer version 4 include:
• New "Mix & Match" capabilities let you mix video clips of any frame rate or field motion type regardless of the project’s type.... with no rendering necessary.
• New Expert Decompose Feature.
• Laptop editing enhancements for Time Code navigation and numeric trim value entry.
• Multicamera editing enhancements.
   
    
Get More Details:
+ Watch a video of the new Mix & Match video capabilities
+ Watch a video about the new Transition Preservation feature