[mythtv-users] poor sound, MythTV /PVR-250 & MPlayer

Mark Staudinger mark at mark.staudinger.net
Thu Dec 2 19:11:13 UTC 2004

Hi everyone. I've been running MythTV for a few weeks now and am running into 
a slight problem with the audio quality of my recordings.  Not so much when 
playing back recorded programs with MythTV (although it's there to some 
degree) but more so when playing files through MPlayer using MythVideo.

Some system details (I can provide more if need be): 

SuSE-9.0 based install, with kernel 2.4.24 from kernel.org.  Hardware is an 
MSI Hermes (Intel 845GV) with a Hauppauge PVR-250 card.
ivtv-0.1.9, using the firmware from "pvr250_22_inf.zip".
MythTV 0.16
MythVideo 0.16 
(Both MythTV and -Video are build from downloaded source, not CVS).
XFree86  4.3.3
MPlayer 1.0pre5-3.3.1 (built from source)
LAME 3.96.1 (built from source)

The gist of the problem is that recorded material from the PVR-250 has a 
faint sibilance and has a pretty "hot" high-end.  When playing back either a 
recorded show, or one that's been transcoded by MythTV, IN MythTV, it's not 

However, if I play the same file using MPlayer (whether untouched, transcoded 
by MythTV, or transcoded with MPlayer [either with -oac copy or -oac 
mp3lame]), the sibilance and sizzle is completely overblown and unlistenable.

It doesn't appear to be a volume issue, I've tried lowering the playback 
volume in MPlayer, as well as reducing the recording volume.  No dice.  I've 
also tried upping the recording settings (from 32KHz/192kbit to 
48KHz/256kbit), which made a marginal improvement.

This only manifests itself on material recorded with MythTV.  When playing 
back mpeg and avi files from other sources, sound is normal.

Also, when playing back MythTV-generated files (before or after encoding with 
mencoder) on my Win2000 box, the sound is comparable to watching the video in 
MythTV - a slight sibilance, but not horrendous.

I'm not sure where to begin with this.  Any pointers would be appreciated.  I 
guess knowing what's different in how MythTV and MPlayer play back/transcode 
sound might be a good place.


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