In compression, "efficiency" usually means "compression level". If by "efficiency" you mean "speed", then yes, I think OP's approach can be much, much faster t

In compression, "efficiency" usually means "compression level". If by "efficiency" you mean "speed", then yes, I think OP's approach can be much, much faster than usual video compression approaches -- but this is true of all compression algorithms that don't compress very well. The fastest such algorithm -- leaving the input unchanged -- is infinitely fast, but achieves no compression at all.