add the option to record audio and video calls

Add the option to record video and audio calls.

Where once the video/audio call start it should show the option to record and once the call is ended it can processes the video/audio and post them in the group or channel.

And from where user can further download the video/audio if they want.

I know storing all the data on servers would be insane, so what you can do is auto delete the data after 30 days. 

Update

Regarding the privacy issues there can a user settings created "Ask me to start recording"

By enabling it everytime someone from group starts a video/audio call recording a notification will sent to all those people who have enabled this settings.

Asking for approval to start recording.

If they do not wish to get recorded they can deny it and the video/audio call recording request will be canceled.

To successfully start recording the video/audio call all the members of the call with the settings enable should approve for the recording request.

I could only think of this possible way to get over with privacy issue.