It must be the way the speakers are connected. Can the media player you are using select between channels (R or L) - I use VLC and it allows you to switch between Left and Right. If you can hear the audio by using the player to switch them it would be more convenient as a stopgap than demuxing the audio track and using an editor then muxing the audio back to the video.
I think you ve finally solved it.............. I got a file up in VLC hit left and the sound magically came up !
cant see the same left right setting in BS PLAYER which I use most mainly because of the p key that will take screen shots but VLC has a similar set up shift then s
I ve got my audio feed to this little music centre plugged into the headphone socket on the laptop I just unplugged it and played one of the vids with no sound.... You ve guessed it.......... the sound was there playing in the laptop ! So with a definite audio signal working in the laptop , you d think I d be able to plug into the headphone socket and get some sound in my music centre speakers..... but try as I may I cant Its as though its playing in the computor but not sending that signal to the headphone socket could there be some sound adjustment inside the laptop that might send a signal ? I ve got two input sockets on the music centre.... think they go direct one to the left speaker one to the right I ve tried both .......... not a peep !