Demos can be recorded via the
record [filename] and
stop commands (where
[filename] is the real filename without extension, such as
I believe they are saved in the root TF2 directory although I'm not at a computer with TF2 on it to check. On Windows, this defaults to
C:\Program Files (x86)\Steam\steamapps\common\Team Fortress 2\tf\. The file will be
There is also a client plugin named p-rec that can be set up to auto-record demos if the game matches certain criteria. This is commonly used to record competitive matches by recording matches where mp_tournament is enabled. The current working version of p-rec for Team Fortress 2 is 2.0.5 (2.0.6 is broken). Once installed, typing
prec_info into the game console will tell you what the various options for it do.
And yes, it is possible to convert Demo files to videos. Since the replay update, TF2 can convert it directly to a .mov file.