Hello Johan, I believe I see the same problem on our thin clients, and I have a theory what makes the sound break. I believe that the problem is related to the sample rate of the sound you try to play.
Regarding your experiments with a DVB stream and youtube, I'd expect that the DVB stream comes with 48 kHz audio sampling rate, while the youtube video had 44.1 kHz? I can completely reproduce your results with two sample audio files, one with 44.1 kHz and one with 48 kHz sample rate. Here is what I see: Test1: - I boot up the thin client and open the 44.1 kHz file, it works. Test 2: - I boot up the thin client and open the 48 kHz file. From what the player shows, it appears to play, but I have no sound. - I close that file and open the 44.1 kHz file (the one that worked fine in test 1), and have no sound either. - Sound will not come back until I reboot the client. Test 3: - I boot up the thin client and open the 44.1 kHz file. I have sound. - I keep this file playing (endless loop). In parallel I open the 48 kHz file. I have sound, both files play together. In short, my theory is that 48 kHz playback breaks pulseaudio on LTSP clients. So why does test 3 work? When you first play a 44.1 kHz audio stream and in parallel open a 48 kHz stream, I believe pulseaudio will sample down the second stream to 44.1 kHz to mix it into the already playing stream. That's why audio works in test 3, and that also constitutes a workaround. Workaround: Tell your users to open up a 44.1 kHz youtube video, start to play and pause it, keep the browser window open. After that sound will work and stay up, no matter what file they play. This is really just a workaround, but our users were very thankful having it (we use LTSP in classrooms, and the difference of having or not having sound can well break or make a teacher's complete lesson...) In any case, it would be much better to really fix the problem. So, Johan, I'd ask you to confirm my three test cases above. I can supply two sample mp3 files if you need, please give me a note. It will be no difference what software you use for playback, as long as it uses pulseaudio (VLC is fine). If you confirm the test, we need some pulseaudio or LTSP developer to (a) find the reason, and/or (b) tell us if pulseaudio can be set up to generally downsample all audio to 44.1 kHz on our clients. Looking forward to seeing your results, best regards, Rüdiger On 13.04.2014 07:37, Johan Kragsterman wrote: > The results are strange.... > > If I start with VLC, directly after the newly booted client, and > ltsp-localapps pulseaudio -nC: > > ltsp-localapps vlc: > > VLC recieving dvb streams from my TV-server(mumudvb) doesn't play any sound, > though it displays that sound is in the stream, and it lets me choose the > local sound device to use(Just a note: This works perfect on a normal > workstation). > > If I start with google-chrome, and youtube, directly after the newly booted > client, and ltsp-localapps pulseaudio -nC: > > It seem to work fine with the sound, though the video quality is not fine. > > If I start VLC AFTER I started google-chrome/youtube where the sound is > already working, sound is actually working on vlc as well, though NOT in all > channels...!?!!? > So, I don't really know what I'm doing here, just doing experiments, and > reports back to list. > > But any hints here would be appreciated, and a strategy for solving this > would be fine! -- Dr. Rüdiger Kupper <k...@kg-fds.de> Kepler-Gymnasium Freudenstadt
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