[mythtv-users] Jitter / Stutter problem but only on recorded playback live TV smooth

Richard S anewbeginning2004 at hotmail.com
Sat Jan 17 17:14:30 EST 2004


Thank you in advance ALL !!!

Problem I have is with jitter/stutter on playback of recordings.

Everything was working smooth for a day or so then my recordings seem to 
jitter/stutter even ones that were previously good.

I copied one over to another PC and played it with mplayer and it played 
fine on mplayer but had jitter/stutter on mythtv playback.

I then looked at live TV on the mythtv box and that was still smooth just 
the recordings I have play with jitter/stutter.

I have on occasion had live TV jitter but if I pause for say 10 seconds its 
smooth from then on unless I change channels (just an observation and seems 
like others have seen this also)

Next I started a recording and watched it while recording and it was smooth 
just like the live TV was.

After it was finished recording I watched it and it had jitter/stutter.

I then reboot the system and now the recordings play smooth.

My system:

Epox8kta (KT133 chipset)
Duron 1.2ghz
Nvidia geforce2 GTS 32 meg (used with NVTV for output to TV)
PVR-250 (not sure what rev)
I have tested my system under full CPU load and video load and is stable and 
temps are quite good all less than 50'C.
PSU Antec True power 380 watt
Creative labs live Value

Software:
OS is gentoo and I am using X (startx& to start environment)
Using mythtv CVS from 1/7/2004
Using IVTV 0.1.9 from 1/13/2004 (what a great advance)

Few performance numbers:
Using "top" command

CPU while recording only 2%
CPU while recording and watching 34%
CPU watching a recording only 33%

memory usage looks normal best I can tell and swap is working fine

Using hdparm -t /dev/hda

DMA is enabled
run while recording 31 mb/sec
run while recording and watching 31 mb/sec
run system idle 42 mb/sec
run watching a recording 31 mb/sec

Settings:

Jitter enabled (always bad if not enabled)
A/V sync enabled (always bad if not enabled)
Audio buffer (seems to be the same set or not)

I certainly do not understand the software, sorry I just hope I have given 
some useful information so that someone may be able to help me solve this 
problem.

It seems that my system problem is with the playback not the record 
capability.

It also seems like there is something different with how the mythtv plays 
back a recording vs watching live TV or watching a recording while it is 
recording (just a guess).

The key here seems to be that a reboot clears things up at least temporarily 
kinda like there is a buffering problem that gets worse with time like what 
a memory leak does to systems such that a reboot fixes the problem for a 
while.

Any ideas? greatly appreciated.

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