On Nov 8, 2007 8:37 PM, Bob <<a href="mailto:mythtv@cox.net">mythtv@cox.net</a>> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div><div></div><div class="Wj3C7c">James Fidell wrote:<br>> I have everything working fine with normal stereo sound, so I thought<br>> I'd finally get around to trying to get AC3 passthrough working on my<br>> main front-end.
<br>><br>> I'm following the guidelines in the wiki at<br>><br>> <a href="http://mythtv.org/wiki/index.php/DigitalSoundHowTo" target="_blank">http://mythtv.org/wiki/index.php/DigitalSoundHowTo</a><br>>
<br>> <a href="http://mythtv.org/wiki/index.php/Configuring_Digital_Sound_with_AC3_and_SPDIF" target="_blank">http://mythtv.org/wiki/index.php/Configuring_Digital_Sound_with_AC3_and_SPDIF</a><br>><br>> but when testing with mplayer (using an ISO rip of a DVD) mplayer
<br>> spews a52 CRC errors, plays choppy sound and can't display the video<br>> properly either.<br>><br>> I've tried changing the mythtv config as suggested and playing the same<br>> iso back with the internal player but get no sound at all. In "normal"
<br>> stereo mode, playback is fine on both video and audio.<br>><br>> I think first I need to confirm that I can play back properly through<br>> the SPDIF connector outside mythtv. Is there another easy way to do
<br>> that?<br><br></div></div>Try speaker-test:<br><br><a href="http://alsa.opensrc.org/index.php/Speaker-test" target="_blank">http://alsa.opensrc.org/index.php/Speaker-test</a><br><br>There are a lot of options, more than the web page indicates. I was
<br>never able to get speaker test to make pink noise through 6 speakers,<br>but I do have surround sound working.</blockquote><div><br>Unfortunately, speaker-test doesn't have anything to do with S/PDIF or IEC958 passthrough. It can produce test sounds for two channels through a digital output just like for analog stereo output, but James Fidell said he already had regular stereo (I assume PCM) working.
<br><br>I found that configuring passthrough was much simpler than the Wiki describes. I believe all I had to do was to add "-afm hwac3" for mplayer and select "ALSA:iec958:{ AES0 0x02 }" in the "Passthrough output device:" listbox in the MythTV configuration. I have no idea what "{ AES0 0x02 }" means, but it seems to be correct for AC3 passthrough.
<br><br>Jonathan Rogers<br></div></div><br>