[mythtv] waiting for prebuffer...

[John Patrick Poet]

Doug Larrick wrote:

> John Patrick Poet wrote:
>
>> The pauses happen when the log says "prebuffering pause"/"prebuffer 
>> wait timed out..".
>>
>> I have seperate backend/frontend machines connected via gigabit 
>> ethernet.  The backend machine's load is usually arround 0.3 if I am 
>> watching and recording at the same time.
>>
>> Does "prebuffering pause" indicate that the backend is not sending 
>> data to the frontend quick enough?
>
>
> It's actually when the NVP is not getting enough frames from the 
> decoder, which can happen when the backend's not sending MPEG fast 
> enough, or when they're not being decoded fast enough.  What's the 
> load like on the frontend?
>
> Does it help at all if you uncomment the calls to run the decoder at 
> realtime priority?  (This is not a good idea in general -- sometimes 
> makes the videoout thread starved for cycles and jittery -- but if it 
> improves matters might indicate that the decoder thread's starved for 
> CPU).  Could the driver for your gigabit ethernet be hogging CPU for 
> longish periods?  Can you try to make the MTU smaller?


The typical load on the frontend is just a touch over 1, with between 40 
and 45% CPU.

I have had this problem since before you added the "realtime priority", 
so I don't think that has anything to do with it.

I need to some more testing, but it actually looks like lowering the MTU 
has solved the problem!  The problem is infrequent enough that I cannot 
be sure, but I have not seen a glitch in over an hour, now.

Thanks for the suggestion, I had not thought to do that.

John