[mythtv-users] audio issue using Internal player

Marius Schrecker marius at schrecker.org
Fri Dec 4 07:34:12 UTC 2009

>>>On Thu, Dec 3, 2009 at 12:37 AM, Marius Schrecker <marius at schrecker.org> wrote:

 >>>I wrote to the list a while back about a motorboating noise I sometimes get. At the time I hadn't isolated when it happens, and couldn't stop the behaviour without a >>>complete cold reboot (unloading modules doesn't help).

>>>I use digital passthrough with my onboard Nforce4.
>>>The problem occurs when I abruptly end playback from the internal player, it's as if the audio stream isn't correctly ended and the audio hardware goes into a >>>feedback loop. Using mplayer or xine, I don't have this issue, so they must have a mechanism for rounding off the audio stream.I also notice that the clicks and pops >>>when I chance audio codec or format are much, much queiter in mplayer and xine than using Internal.

>>>The solution to the problem is also much simpler than I thought. I just have to feed the sound system a new stream, and the loop stops.
>>>Does anyone know if this is a known issue?Can I end every playback from Internal by playing a short, empty audio stream? If so, how?

>>I have this happen occasionally.  I can't remember what I do to stop it but maybe it is just turn off the TV.  I do not know if this is a known issue and I have a little old >>version of Myth, Mythbuntu 8.04 LTS.  I have done only a few updates and only to solve a specific problem. If you find out there is an update to fix this please post in >>this thread.


>http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users On Thu Dec  3 16:51 , Aaron <aaron at rb303.net> wrote:Heh, I never thought of it as sounding like a motor boat, >but now that you say it, it really does. I have this issue as well on a nForce 630 chipset. It does only happen occasionally so I just thought it was the cheap internal >sound card. Now that I think of it, this also happened in Windows every once and a while, but I narrowed that
>down to bad drivers. I removed the bad drivers and it went away.One thing I have noticed, it only does it on DTS tracks (DD/AC3 seem fine).I have noticed it does it in >Myth more than anything else. I installed XBMC, and have had 0 audio issues since I tried it. DTS crackling is totally gone, so it the motor boating wind down.
>I use Toslink SPDIF out to my Yamaha receiver.AaronOn Thu, Dec 3, 2009 at 9:56 AM, Allen Edwards

Sounds like we're all suffering from the same issue: Nvidia chipset and toslink out.  Now that you mention DTS, that could well be the case, though I haven't done a proper analysis of that. As I stated, I don't have the issue with mplayer or xine, and the loud pops from the Internal when changing codec or starting/stopping a stream do indicate that the start/end handling isn't as good using Internal.

Anyway, as stated, the workaround is just to feed a new soundstream to the system, and the question was how to do that automagically.

Cheers again


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