My first thought is that if that data is important (and irreplaceable), get yourself a second level of backup. I would use an external drive. Taking it just one step further, store that drive in a safe place off site, such as at your office or in a safe deposit box. Do your daily backups to the file server, then once or twice a month, back that up to your external.
Seems rather a pricey solution if your main goal is to to have their transcoding. I'd do some research into other software to achieve the same thing that could be installed on either a Windows, Linux, or BSD file server. I'd also carefully read some reviews of the Synology, and pay attention to the transcoding limitations cited.