Buffer overflows recording HDTV with saa7146 and mantis DVB-C tuners

Hello,

I've build a new VDR with h.264 xineliboutput plugin software decoding

and got a problem now with

buffer overruns and distorted recordings on all HD channels:

...
Nov  5 05:32:03 vdr2 vdr: [32753] ERROR: 47231 ring buffer overflows 
(8879240 bytes dropped)
Nov  5 05:32:09 vdr2 vdr: [32753] ERROR: 31042 ring buffer overflows 
(5835896 bytes dropped)
Nov  5 05:32:15 vdr2 vdr: [32753] ERROR: 47325 ring buffer overflows 
(8897100 bytes dropped)
Nov  5 05:32:21 vdr2 vdr: [32753] ERROR: 28306 ring buffer overflows 
(5321528 bytes dropped)
Nov  5 05:32:27 vdr2 vdr: [32753] ERROR: 14033 ring buffer overflows 
(2638204 bytes dropped)
...

This occurs with both saa7146 and mantis pci tuner cards.

This has not occured with the old VDR system using Broadcomm's crystalhd 
decoder in libxine.

LIVE TV works fine.

I've tried stable and testing minidvblinux.de VDR live systems to 
crosscheck, but same issue occurs.

If I increase the buffer for the saa7164 cards with module parameter 
it's getting worse and distorted picture and sound.

Any Ideas?

Increase VDR's buffer in source code?

What is the correct driver module debug parameter to provide a useful 
debog log?

Y
tom