I am attempting to build my first PVR and have one issue that I haven’t been able to find a solution to. I am using a 1.7 P4 on an 850 based Intel bord with 512mb, 60GB, Nvidia FX5900u, Sound Blaster Audigy2, Intel pro 1000mt, Haumppauge PVR250 and a Haumppauge wintv-go (fusion878a) and am running KnoppMyth R5A16. The problem I am having is getting the sound to function properly on the 878 card.

I would like to run a cable from the line out on the 878 to the line in on the audigy, but alsamixer –V capture doesn’t list line and no other adjustments allow sound from line. Alsamixer dose show line, but it is a direct pass-through which makes the sound come too early. Alsamixer –V capture dose show controls for mic so I hooked up the 878 to the microphone input. The problem with the mic is that the PCM under capture goes to 100% every time I change a channel or pause and when the PCM under capture is on, there is a loop causing a echo effect. There also is a crackling sound when using the mic capture that is not present when I listen to the pvr250 or to the 878 directly.

I am still searching for a solution, but if anyone knows what I am doing wrong, I would appreciate the advice.

I don't have time to search right now but I know this exact problem has been covered here on these forums perhaps searching for audigy

_________________
Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

I have been searching for two days now, and have not seen this issue mentioned. There were similar issues, and I have tried everything related with no success. I have also upgraded to ALSA 1.0.9b which didn’t help.

You may have seen the answer and not even realized it... This is the usual muting issue covered in dozens of threads and the MythTV documentation here:
http://www.mythtv.org/docs/mythtv-HOWTO-7.html

Line In sounds like it is doing exactly what it's supposed to, providing sound input for capture in sync with the video capture. However you don't want to listen to that, so you should mute it. The sound out which is in sync with the video playback comes from the PCM feed.

BTW - Note the distinction here between capture and playback. Watching live TV with MythTV is a convenient fiction. You're actually watching playback of a temporary recording. This is how pausing or rewinding live TV works. Once you wrap your head around this and all it's consequences the sound issue will become much clearer.

I think I may have done poorly trying to describe the problem, so I will try again with some screenshots (left unscaled for legibility).

I am semi-aware of how MythTV works and know about the delay caused by using line in to listen directly to the capture card. I only made reference to it in attempt to demonstrate that line playback dose work, and the capture card outputs to it with clear audio.

The problem is multi part, I have line muted as shown below, but it is not listed under capture. Mic is listed under capture so I am attempting to use it instead of line. When I enable mic in playback, the audio is clear but delayed as it should be. If I mute mic playback and enable mic capture, I have two issues.

The first issue is that when pcm capture is enabled, a loopback occurs causing a echo. I can turn pcm capture volume to 0 and the echo goes away, but whenever I pause or change channels, pcm capture returns to 100% bringing back the echo.

The second issue is that with pcm capture at 0 and audio coming through in sync with video, the audio is choppy.

PLAYBACK
http://anscv.com/images/alsamixer/alsamixer.JPG
CAPTURE
http://anscv.com/images/alsamixer/alsamixercapture.JPG

The bad news is that this may be a problem with the card or the drivers. I'd suggest a deep search here since I remember a widely reported problem with one of the current SB cards several months ago. The next step over there is to head over to the ALSA fourms and ask there. Frankly I'd have to do the same research myself...

I did a quick search and saw a couple of threads about very similar problems with audigy cards, unfortunately none of them had any solutions.

_________________
Have a question search the forum and have a look at the KnoppMythWiki.

Xsecrets

i went to utilities/setup -> setup -> general
and unchecked "use internal volume controls" and now my echo is gone
i checked and saw that i had the same thing when playing tv.
pcm capture would jump to 80 then 0 when not playing.

hope this helps!