I spent hours googling, downloading video converters, etc, when all I wanted to do was play some saved DVR footage from a Swann DVR. I was taken several times to this forum and saw many threads with the questions unanswered.
The Swann DVR model I was trying to view saves files in .264 extensions. So I called them and they gave me the location to download the player which you will not find on their website.
http://swann.com/downloads/drivers/DVR_2600/PlayBack_V1_0_1_15.exe
I know some other DVRs also save in 264 format and this player might work for them too.