vlc does not play sound on mp4 files

[John Rose]

vlc 3.0.3 does not play sound for mp4 files (with audio as aac) on 4GB laptop upgraded from 16.04 to 18.04. The laptop used to play sound for these files under 16.04 with (I think) vlc 2.2.2 But the laptop plays sound Ok for video played on web sites with either Chromium or Firefox running. However, vlc 3.0.3 plays sound Ok on 8GB barebones with new install of 18.04. Thus, I'm not sure whether the problem is vlc 3.0.3 or some other package in 18.04.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: vlc 3.0.3-1-1ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-33.36-generic 4.15.18
Uname: Linux 4.15.0-33-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Aug 26 14:37:30 2018
InstallationDate: Installed on 2016-07-25 (762 days ago)
InstallationMedia: Ubuntu 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
SourcePackage: vlc
UpgradeStatus: Upgraded to bionic on 2018-08-21 (4 days ago)

[John Rose (johnaaronrose)]

Solution found. Whilst playing the mp4 file in vlc: in Settings->Sound->Applications, check that 'VLC Media Player' is shown as 'On' and that the level is 'above zero' (i.e. somewhere on th right)". As soon as I modified the level to be 'above zero' sound played. This also corrected no sound in Totem. What's confusing is that the volume shown by clicking the sound icon on the top right of the screen is shown as being to the level you set it at but there is no indication for
an app (e.g. vlc) which is playing. Ubuntu remember the sound setting for vlc if you quit vlc (when the Applications line for vlc is no longer displayed) and start it again. This makes it even more confusing.

[Sebastian Ramacher (s-ramacher)]

Seems like a bug in the gnome part controlling pulseaudio, but not like a vlc issue. Re-assigning to gnome since I don't know a better place for this bug.