In order to upload a SSL certificate to PTC/PTZ/DL cameras, it must be in the PEM format.
To create this format, you will need your certificate, any intermediate certificates, and the CA root in a base-64 encoded format.
Additionally, you will need the private key in the PKCS#8 format(should be unencrypted).
Once you have gathered these components, combine them in the specified order to create the PEM format, and then proceed to upload it onto the camera web interface to enable HTTPS.
The format structure should be as follow:
-BEGIN PRIVATE KEY-
...................
-END PRIVATE KEY-
-BEGIN CERTIFICATE-
................
-END CERTIFICATE-