Merge pull request #15939 from alalek:ffmpeg_update_3.4
authorAlexander Alekhin <alexander.a.alekhin@gmail.com>
Tue, 19 Nov 2019 18:45:39 +0000 (18:45 +0000)
committerAlexander Alekhin <alexander.a.alekhin@gmail.com>
Tue, 19 Nov 2019 18:45:39 +0000 (18:45 +0000)

Trivial merge