[mythtv-users] Ceton Based Recordings Failing
Peter Bennett
pb.mythtv at gmail.com
Thu Jul 12 16:53:53 UTC 2018
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
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