Videos should be always encoded before being put in the ZIM

[kelson42]

To secure the quality.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be now be reviewed manually. Thank you for your contributions.

[kelson42]

@rgaudin Might be for 1.2.0, not sure. Moving it and just posponed if not.

[benoit74]

I think we should only do this by default, and provide a switch to not reencode. E.g. for openzim/zim-requests#272, I plan to point to a file which is already in VP9, already in 480p, so I really so no reason to reencode aside loosing computing power / quality.