Tvheadend

Hi everyone!

Since I am completely stuck finding the cause of my htpc-trouble, I`ll describve it here, perhaps anyone has an idea :

Setup :

Toshiba Satellite A100-151 Laptop with stable current gentoo and rt-kernel 3.6.11
2 USB-Tuners (TeVii S660 and DeLock USB-2.0 DVB-C (DRXK))
Sony KV29LS60e 100Hz CRT-TV

The laptop is attached to the CRT-TV in my livingroom, from S-video to SCART.

My problem is :

As soon as I start watching SDTV on the TV in my livingroom, I cannot watch HDTV streams via LAN (errors in tvheadend, framedrops etc etc.). Parallel HDTV-streaming and recording another channel works fine though.
Both usb-tuners are connected to separate USB-Hosts (I bought an extra PCExpressCard to have an additional USB-Host). Each tuner works well if used "solo" or when recording and streaming simoultaneously, which also means it shouldn`t be a disk-io problem either .. checked anyhow, iotop shows nothing uncommon.
When watching SDTV on the TV, CPU is about 50% if I manually set xbmc (frontend) to use one specific cpu-core only via taskset and at ~30% if it may use both cores. I also manually changed processpriorities and niceness and stuff, but nothing helps.

My CRT TV works with native DVB-PAL, so I use 768x576@25i as resolution, so there should be no videoscaling and deinterlacer required (dvb-input = video-output), both is deactivated in xbmc also to get less cpuload. I also checked LAN bw, but since everything is connected via gbit-lan there is plenty of bandwidth free.

Since I have no idea left what else could be the reason, I currently suspect tvheadend to have some bug, I use a svn version, 3.5.201~g2a9ccdd.

TVHeadend debug shows up with following if I enable debug mode :

Jul 25 14:56:38.098 TS: DRXK DVB-C DVB-T/Unitymedia UPG Hessen: 458,000 kHz/Boomerang: MPEG2VIDEO @ #553: Continuity counter error, 11 duplicate log lines suppressed

Jul 25 14:56:38.639 TS: Montage Technology DS3000/TS2020/BetaDigital: 11,332,250 kHz Horizontal (Default (Port 0, Universal LNB))/Sky Action HD: H264 @ #511: Continuity counter error, 73 duplicate log lines suppressed

Output of lsusb :

Bus 001 Device 002: ID 1b80:e1cc Afatech
Bus 001 Device 003: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 008 Device 002: ID 9022:d660 TeVii Technology Ltd. DVB-S2 S660
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 006 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 008 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 04d8:fd08 Microchip Technology, Inc.
Bus 001 Device 005: ID 045e:0745 Microsoft Corp. Nano Transceiver v1.0 for Bluetooth