[mythtv-users] Glitchy HDHR Recordings

[Richard Shaw]

On Fri, Sep 25, 2009 at 12:03 PM, James Orr <james.orr7 at gmail.com> wrote:
> I have a master backend with 2 PVR-250s connected to it, and a slave backend
> which records from an HD HomeRun.
>
> Now that fall is here with the new TV shows, things are getting busy and
> I've had a couple situations where I am recording 4 programs at once.
>
> If I'm recording two HD programs only, everything is fine.
>
> If I'm recording two HD programs plus one SD program, everything is fine.
>
> If I'm recording two HD programs and two SD programs, the HD programs become
> extremely glitchy with lots of artifacts and large green blocks and
> stuttering, only barely watchable and occaisionally completely unwatchable.
> This seems to start a few minutes after the programs started recording, the
> first few minutes are fine.
>
> For example on Monday, it recorded Heroes, House, How I Met Your Mother and
> one other hour long show I forget which.  A few minutes into both House and
> Heroes the recordings became glitchy and this lasted half an hour, until How
> I Met Your Mother ended.
>
> I suspected it might be something to do with commercial flagging so I went
> in to mythtv-setup and set it so that it will only flag recordings recorded
> on the same backend, AND restricted the job queue to run only between
> midnight and 7:00 PM (avoiding prime-time hours when I'm most likely to be
> recording that many things), but this didn't help at all.
>
> What I don't really understand is why having the master backend record
> something affects how the slave backend is doing it's recording if there's
> no jobs running at the same time (i.e. the slave backend comm flagging
> something on the master or vice versa).
>
> Also, I have my storage folders setup so that both backends only record to
> local drives.
>
> Fortunately most of the shows recorded on the PVRs are on the cable networks
> and thus have many repeats so for now I can tell it not to record any
> showing at the same time as two HD recordings but this isn't a good long
> term solution and doesn't help much with the WAF either :).

This is purely a guess, but does your master backend also the mysql
server? If so, is your database on the same physical drive as your
recordings? The only reason I can think of this happening is that
there is some lag in updating the index info in your database when
recording 4 programs at once.

Does transcoding with index rebuilding help? e.g. "mythranscode
--buildindex ..."[1]

Richard

[1] http://www.mythtv.org/wiki/Mythtranscode