[mythtv-users] LiveTV Stutters - Recordings are Perfect

[David Hofstra]

I'm a long-time MythTV user, but I've only ever used Myth to watch
recordings (not to watch live-tv).  I've always used my DirecTV box for
LiveTV as it was easier for the WAF.

I recently purchased a HDHomerun Prime, and switched from DirecTV to
Xfinity.   I found that the Xfinity box on-screen guide is unbearable to
watch LiveTV... ughh  So, I'm trying to use MythTV to watch LiveTV and
ditch the Xfinity box altogether.

Problem:   Recordings playback wonderfully 100% on my frontend (and have
for years).  LiveTV stutters about 10 times per hour, and about once per
day it fails.   It almost always stutters a few seconds after the channel
change, which I hear is to be expected, but then it continues to stutter
every so many minutes.

A)  When LiveTV fails, it fails with 'video buffering failed too many times'
B)  When LiveTV stutters, I see a bunch of the following in the frontend
terminal (infact, I see this when it doesn't stutter also)
     -RingBuf(<filename>): Waited 0.2 seconds for data to become
available... 15720 < 32768
     -RingBuf(<filename>): Taking too long to be allowed to read..

I have a Geforce 210 @1024MB running 295.40 and it is using VDPAU normal
settings on mythbuntu (OS 12.04)

Here's what I have tried so far:

1)  Replaced network cables to HDHomerun Prime as well as to the frontend.
2)  Replaced the hard-drive in the frontend.
3)  Moved the LiveTV recording group directory to a faster RAID5 drive set
on the backend (previously on home directory)
4)  Stopped upmixing stereo to 5.1
5)  I tried both streaming using the myth:// protocol, and also having the
liveTV directory on the NFS share directly.
6)  I tried using every window manager known to man
7)  Upgraded to the newest 0.25 mythtv-fixes, which updates to a new
version virtually every day
8)  I have one other frontend with a Geforce 6150, and while it doesn't
seem to stutter, the HDTV tearing is so horrible, I cannot really tell if
this box has the same problem or not.
9)  I've increased the HD ringbuffer size in the backend-setup
10)  Some folks note that if you pause LiveTV for a few seconds, then the
stuttering stops.   This also seems to work for me, but I hate to have to
pause LiveTV every time I change the channel.

Does anyone have any other thoughts, or notice something I have not tried
after looking the above over?  Why/How could Recordings be so perfect, and
LiveTV be so horrible????  Any suggestions appreciated.
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