I have been looking on the vlc forum for some further answers to this issue, and began a thread over there at ( http://forum.videolan.org/viewtopic.php?f=13&t=102552
) which goes into more specific detail than this post.
They have been quite helpful, and it appears that, though vlc was running when my audio malfunctioned, it does look like it is more of a configuration issue with vlc vs. PulseAudio and ALSA.
Summing up some of what was discussed, I tried to bypass PulseAudio and use ALSA directly in a terminal with their suggested command of “vlc --aout alsa” and that brought up video and audio in vlc immediately. All I can see that it has changed in the vlc GUI prefs is in Tools => Preferences => All => Audio => Output Modules, it has changed from “Default” to “ALSA Audio Output”, and inside that it chooses “HDA Nvidia, Conexant Analog Default Audio Device”. I don't notice anything else.
I had always run vlc and SMPlayer with their default settings before with no problems. I switched SMPlayer from the 'oss' default (which used to work) to plain 'alsa' and then to 'pulse' and it now works with either setting, and Clementine and Amarok are still working.
But now with one instance of vlc running, I can no longer hear any flv or mp4 files in the browser from YouTube etc. When I quit vlc they come back – perhaps this is normal but I don't recall a conflict before. This does not happen with Amarok or Clementine. And if Amarok and Clementine are opened first, vlc will not play audio at the same time. SMPlayer will.
Also, since all this began, when headphones are plugged in they no longer automatically defeat the speakers' output, I have to do that manually in Phonon.
In addition, and more importantly, the audio signal in vlc using ALSA directly is now very “scratchy”, with high end distortion like a very worn vinyl LP. The same downloaded file played with SMPlayer, Amarok, or Clementine is clean and clear. Strange.
Bottom line to date is that vlc's audio is back if set to alsa, though annoyingly not clear, SMPlayer does have audio when set to pulse or alsa, and there seems to be a conflict with vlc and other media players and the browser. It would be very nice to have vlc back with clear audio since, A: I really like it, and B: it will play 'most anything. But for now I can see and hear my files again with the other apps.
Still working on this if anyone has an idea for further experimentation. I am not yet fully clear on how vlc, Pulse, and ALSA all play together happily...
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