[mythtv-users] Recorded material stutters, live TV is perfect. Why?

[Mark Knecht]

I'm flummoxed about 0.21 and all the stuttering problems we're having.
Here's the set of experiments I've done:

The system:

1) The backend - dedicated backend machine is an AMD Sempron 3200+,
with SATA drive & 512MB. hdparm -tT says 45MB/S. After a boot I'm
using 180MB of ram. No swapping has been reported.

2) Local frontend - underpowered 1.8GHz Celeron with 256MB, but shared
memory with the graphic controller so only about 185MB.

3) Remote frontend #1 across wireless network - AMD64 3000+ with 1GB memory.

4) Remote frontend #2 across wireless network - identical to local
frontend - 1.8GHz Sempron with 256MB.

The results:

1) On the local frontend I can run live TV or recorded material
without any stuttering.

2) On remote frontend #1 (the AMD64) I can run live TV without
stuttering but all recorded material stutters badly. The AMD64 is
running the SLIM profile.

3) On remote frontend #2 I have no problems. Live and recorded
material playback fine.

Prior to switching to 0.21 we had no problem with any machine. Since
switching to 0.21 my AMD64 machine is useless.

CPU usage on the backend is never more than 2% when it's only doing
playback. On the AMD64 CPU usage as reported by top is never more than
20%.

Here's the one that really bothers me: On the AMD64 I can play live TV
with a full system rebuild going on - compilers are running and CPU
usage as reported by top is 100%. Disk usage is intense at times. Live
TV is perfect. No stuttering. On the other hand with absolutely
nothing running on the AMD64 playback of recorded material stutters
all the time.

I cannot figure out where the weak link is.

Any ideas anyone?

Thanks,
Mark