I am currenlty working on a set of classes to manipulate media files (basically video) - actually they are wrappers over command-line utilities ffmpeg and mencoder, but they support common interface so that any other backend is possible to use - you will only need to write a PHP-wrapper supporting the same interface, if you want to use, say, avidemux.

Features I have [almost] implemented:
- Read media-file information, such as used, codecs, bitrate, fps etc.
- Converting from one format to another (including flv - flash video to be viewed in a web-browser), with a possibility to convert only a selected part of original movie. Also you can change movie quality, pixel-size and other parameters.
- Snapshots generating (jpeg, but png could also be supported) - from an arbitrary position in the stream.

I am developing those classes as a part of my own web-tollkit - Naf (stands for Not A Framework). However, class-and-file-naming conventions are the same as in ZF, I also cover code with unit-tests (simpletest, but they can be easily converted to phpunit). Right now, I am heavily refactoring this code, so I can expect to have a useful version within Naf - in about a week. Then I hope I will be able to give a link to a SVN repositiory for those interested to download.

Questions and ideas are expceted in this thread, thanks.