If you want to try Opera 25 (unstable "developer" build), it is supposed to support a few more formats than 24 does. Opera does not have the rights to distribute proprietary codecs like H.264 for video and MP3 for audio; prior to version 25 they only supported formats that had freely distributable codes. With Opera 25 they are adding support for whatever codecs they find on your system.

The "developer" builds are available from the Desktop Team blog and install separately from the stable version.