Hikvision : how to delete old mp4 records on NAS ?

[dvb 0]

Hi,

 

I use several Hikvicions cameras (DS-2CD2732F-IS and DS-2CD2232-I5) sin 2014.

I have a lot of mp4 records, then I need to clean NAS partition.

 

There is no command like "delete old records" on setup page, and it I can deleted via telnet : "Permission denied".

 

How do you delete old records on NAS to save workspace ?

Thank you.