[mythtv-users] Both In progress HD recordings and Live Tv dropping frames on frontend.

[John]

On 14/05/14 10:46, Jean-Yves Avenard wrote:
> On 14 May 2014 05:06, John <reidjr at lineone.net> wrote:
>
>> I am intrigued by what the difference is between the frontend being in the
>>
>> kState_WatchingRecording rather than kState_WatchingPreRecorded, as I assume
>> it is the dBase activity of being in the former state that causes the issue.
>> As the backend shouldnt care if a frontend is watching somthing its
>> recording, nulling out that activity seems to make sense.
> as far as the FE is concerned, it makes no difference except that it
> will know if it needs to query the database for seek tables.
>
> your BE is obviously too busy to properly serve files while also recording
>
Thanks for your reply.

I think it is more subtle than that. I carried out some further tests 
after reading your reply.

I can record 4 simultaneous HD programmes on my backend and watch any 
one of them on the frontend on the same physical machine (Core2duo with 
intel graphics).

The revo Atom/Ion frontend can also watch a PRE-recorded stream from the 
backend while all 4 other programmes are being recorded.

If I try to watch an in-progress recording I get visible judder and 
dropped frames as per my initial post. This doese not apear to be better 
or worse if I am recording 1 or 4 programmes.

So there is something fundamentally different about playing an in 
progress recording which is causing the dropped frames, it is not the 
fact that the backend itself is busy with other tasks. It could be some 
sort of blocking of serving and recording the same stream of course, as 
suggested above, but mounting the backend root without barriers made no 
difference. I have tried logging with playback and database, but I cant 
diagnose the cause of the drops.

[An odd discovery, and potential red herring  is that turning off 
interlacing on the Atom frontend seems to stop the dropped frames for 
the in-progress recordings. The same recording ( when complete) can be 
watched with VDPAU Temporal 2x de-interlacing. ]


John