save video as mp4

currently, PeTrack can save videos as *.avi (very large)

It would be awesome, if we could also save as *.mp4!!!

added enhancement feature labels

assigned to @t.schroedter

mentioned in merge request !151 (merged)

added Doing label

mentioned in merge request !178 (merged)

added Review/QA label and removed Doing label

added Doing label and removed Review/QA label

closed with merge request !178 (merged)

mentioned in commit 7bbc0351