Best way for Background processing in PHP based application

[Mixibiza]

I am working on a huge php application with Zend framework, in that project we need to process files and create thumbnails for images, videos, documents for which we are using imagemagick, ffmpeg, openoffice in background process. To make the process optimized and fast with minimum resources I am thinking of implementing this process using another language may be java or c.What you people suggest[*]Stick with PHP[*]Use Java[*]Use C