Remove visual noise from avmedia

Change-Id: I2f2cccc75f902359fbe557333c0062b13d1e9e96
Reviewed-on: https://gerrit.libreoffice.org/8231
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>