[jimsiff]

I'm having problems with my SPDIF connection to my receiver. When I watch DVDs, archived videos, and rarely Live and Recorded TV in Myth, I get a lot of random audio drop outs. I can see my receiver switching from DD5.1 to DPLII if the signal drops for longer than a few seconds.


I'm running Mythbuntu 8.04. I'm using a Biostar TN720 mobo w/ AMD 5000+, a SPDIF header adapter mounted to an expansion slot cover, and a Blue Jeans Cable 6' 75 ohm coax digital audio cable connected to a Pioneer VSX-54TX receiver. I don't think the SPDIF connection is bad, because if I swtich xine to use stereo over SPDIF instead of AC3 DD5.1, audio is clean.


Any help, tips, or troubleshooting rsources would be greatly appreciated. This is driving me nuts, and I won't cancel DirecTV until the audio glitches are cleaned up.


Thanks,


Jim

 

[newlinux]

I'm by no means an expert in this area but I have a couple of questions:


1. Can you output consistent dolby digital playing the same files you have problems with back using mplayer, VLC or xine?


2. Can you play the stereo track from myth with these files through spdif without sound problems?


3. Do you get any errors from mythfrontend when you have these audio dropouts?

 

[jimsiff]



Quote:
Originally Posted by newlinux /forum/post/14285303


I'm by no means an expert in this area but I have a couple of questions:


1. Can you output consistent dolby digital playing the same files you have problems with back using mplayer, VLC or xine?


2. Can you play the stereo track from myth with these files through spdif without sound problems?


3. Do you get any errors from mythfrontend when you have these audio dropouts?

Good questions... I should have addressed those in my post. The problems occur whether I play the video files in Myth, or directly through mplayer, xine, or vlc.


Stereo tracks via SPDIF have static problems instead of outright drops.


There are some mixer errors in mythfrontend.log, but I'm not sure they mater (at least for DD & DTS), since SPDIF passthrough bypasses the sound chip and outputs the digital stream without any processing. I will run down these errors nonetheless. Hopefully it will help...


I have reduced the dropouts by about 80-90% by disabling "extended audio buffering" in TV Playback setup. That was from a tip from the mythtv-users mailing list.


I've got a few more tweaks to try, so hopefully I will get this thing nailed down soon.

 

[Rgb]

If you are using the motherboard audio, it could be a driver issue. See if there is an updated driver for the audio chipset on your mobo, which may require you to patch/recompile your kernel.


As a control measure, try a PCI sound card known to output SPDIF well in Linux, i.e. an older SB Live, the Chaintec AV710, or another card with a well supported chipset.

 

[Rgb]

Be sure to turn off the motherboard audio if you try a PCI sound card.


Also, for the Linux noobies- I had a large number of SPDIF issues (as well as video and general stability problems) on Win98SE and XP, too, until good drivers were available and the apps (powerDVD, MPC, ffdshow) were revved several times. It took at least 5-6 years (1998-2004) to stabilize and debug the Windows based media PC's. IMO, the Linux options are remarkably stable and usable if you are switching over, assuming you choose well supported parts (which goes the same for DIY Windows boxes).