[mythtv-users] Ceton Based Recordings Failing

Thu Jul 12 17:00:44 UTC 2018

> On Jul 12, 2018, at 12:53 PM, Peter Bennett <pb.mythtv at gmail.com> wrote:
> 
> 
> 
> On 07/12/2018 07:24 AM, Craig Huff wrote:
>> I replaced my PVR-500 tuners awhile ago with a Ceton 6 ETH InfiniTV.  I was having trouble with recordings that acted like they had dropped packets of data.  The advice I got was to increase network stack buffers.  That seemed to clear things up for awhile, but the problem has cropped up again.
>> 
>> Here are the values I changed and their current values:
>> net.core.rmem_max=1048576
>> net.core.rmem_default=1048576
>> net.ipv4.udp_rmem_min=1048576
>> 
>> and here are typical error messages from the mythbackend.log:
>> Jul 11 21:54:05 penguin mythbackend: mythbackend[2603]: E CetonStreamHandler recorders/dtvrecorder.cpp:855 (FindH264Keyframes) DTVRec[1]: PES start code not found in TS packet with PUSI set
>> Jul 11 21:54:10 penguin mythbackend: mythbackend[2603]: E CetonStreamHandler recorders/dtvrecorder.cpp:881 (FindH264Keyframes) DTVRec[1]: PES packet headers overflow to next TS packet, aborting keyframe search
>> Jul 11 21:54:10 penguin mythbackend: mythbackend[2603]: E CetonStreamHandler mpeg/mpegstreamdata.cpp:364 (AssemblePSIP) MPEGStream[1](0x7f005401def0): Error: offset>181, pes length & current cannot be queried
>> 
>> If I recall correctly other issues that were discussed as possible causes for this behavior included the Ceton getting too warm/hot and network architecture.
>> 
>> To keep the Ceton unit as cool as possible, I have it resting on top of a 140mm fan which is propped up on rubber feet providing good airflow up through the Ceton.  My recording setup is in an upstairs area beside the stairwell railing.  The stairs are open to air circulation on both floors.  Despite air conditioning, the air temperature around my MythTV system can be about 75 F into the evening before coming back down.  At the moment, it is 68 F ambient and the tuners are reporting temperatures just under 104 F.  I am currently recording a program and, while it appears to be working, I am seeing errors logged like the last of the three listed above.  These occur at intervals as short as 16 seconds or as long as 3+ minutes.
>> 
>> I have the backend and the Ceton connected to an 8-port Trendnet Gigabit Switch along with other devices including a daisy chain to another one.  As I understand it, anything other than traffic on this particular switch should be irrelevant because it is a switch, not a simple hub.  I am not certain what grade of ethernet cables I used to connect the backend and the Ceton to the switch, but it seems likely that they are Cat 3.
>> 
>> If I have provided enough information to point to what is causing my problems, I would appreciate any advice on fixing them.  If more information is needed, you have but to tell me what you need (and if arcane, where to find it).
>> 
>> Thank you for any assistance you can provide.
>> 
>> --
>> Craig.
>> 
> I have used a Ceton eth-6 for several years without this type of problem.
> I suggest checking the coax cable from the cable company. Make sure it is tight and that there is no bad connector. I suggest if possible replace it with a new cable to see if that helps. Also you could try Cat 5e or Cat 6 ethernet cable. Since you have a gigabit switch you can support gigabit speed. If you are recording several channels at the same time you will need gigabit speed.
> 
> I had a problem like this years ago with a HD Homerun Prime, and eventually found that the router it was going through was dropping packets. If all else fails you may want to try a different switch or router, to eliminate the switch as being a possible cause.
> 
> Peter

1 more thing to try is swapping out the wall wart power supply .   New power supplies fix a lot of ills, particularly with the HDHR tuners. Maybe you could have a problem with the one feeding the ceton. I also had oddness recently and had to power off and power ‘reboot’ one of the gigabit switches I have. Or power off power on the ceton itself.

Jay

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