[mythtv-users] Mythvideo performance

[Ryan Steffes]

>
> What's noticeable mean to you?  One or two seconds, or 5 seconds, or 10
> seconds, or ...


Average, 20 to 30 seconds, sometimes over minute.  It only does this the
first time I go into MythVideo, then seems faster until I haven't gone in a
while, then pauses again.  I'm assuming it has to do with disk access.  I
also get a similarly long delay when going into My Recordings but I always
blamed this on building previews, since it stutters (for lack of a better
word) when flipping past a newly recorded show.


> My current set up:
> > I've currently got a combine frontend/backend with a 400G video
> > partition spread across two drives using LVM.  It's a reiserfs
> partition.
> ...
> > As stated, there's approximately 350 video files.  Gallery mode is
> > important to me, for WAF.  She and I like to see the videos with
> > covers laid out as they might be on the shelf, and have it set to
> > display 8 at a time, which makes it easier to find a movie
>
> I get a noticeable delay of less than 2 seconds when entering into
> gallery view on my combined frontend/backend with 244 videos, but it's
> almost completely from reading the images for the 8 video posters I
> display per screen.  (In other words, my setup is almost identical to
> yours, and what's left of the performance problem is not inside Myth.)
>
> If entering the list view (loaded from the database--not from the
> filesystem) is fast, loading the posters is the (non-Myth) problem
> causing the delay.  If not, it could be the sorting or something else...
>
> Make sure you disable the setting:
>
> Video List browses files
> If set, this will cause the Video List screen to show all relevant files
> below the MythVideo starting directory whether they have been scanned or
> not.
>
> for the test.  Note, also, that there's an equivalent setting for the
> other 3 views.



I do have this on, because during the transition from DVDs to avis, I
occasionally just stuck a ripped vob in there and transcoded it later.  I'll
try with it off, and see if there is a difference.

> Also, I don't know if this is a problem or just an oddity, when I go
> > to play a movie, it kicks off two mplayer processes.
>
> Probably a bad player command...



Default player command is fairly straightforward:

mplayer -fs -zoom -quiet -vo xv %s -ao alsa:device=digital -ac hwac3, -alang
en

I did notice I had that command both for 'mythtv' and 'localhost'.  I
removed the entry for 'localhost' and will see if that bit changes.  I don't
think it's affecting anything, I just thought it was odd.

Since [6646] (which is part of MythTV 0.19, but not part of MythTV
> 0.18), MythVideo does an in-memory sort of videos to allow for removal
> of the initial articles (A |An |The ).  This causes some problems, so I
> wrote some patches to fix it, in #1354--which was committed in
> [9694]--and #1678--which is not committed.  The patch in #1678 would
> remove the in-memory sort from MythVideo (while allowing you to specify
> the sort key for each video).
>
> Also, in #1569, George Nassas wrote a patch which was made to speed up
> his MythVideo.  I don't know anything about the details of this patch,
> and I haven't used it, so I don't know how much it would help you (it
> still does an in-memory sort, but it makes other changes to speed things
> up).
>
> However, some of the changes in #1569 are incompatible with #1678.
> Therefore, you'd have to choose one or the other (or merge the changes).
>
> That being said, if you're compiling Myth yourself, you can apply one of
> these and see if it helps.  If you're not compiling Myth, it will be
> hard to determine if the problem is inside Myth or outside...
>
> #1678 - http://svn.mythtv.org/trac/ticket/1678 - use the patches
> *-mythvideo-titlesortkey_in_database.patch (but use
> mythplugins-mythvideo-titlesortkey_in_database-2.patch for
> mythplugins).  Note that this will change your video database schema, so
> if it's not accepted (or accepted after another change to the video
> database schema), you'll have to manually fix the database.
>
> #1569 - http://svn.mythtv.org/trac/ticket/1569 - the current patch is
> grabbag-2.diff.gz , but George will have to help you with it.



Thanks for these, if the other things don't work, I'll try the patch.  Do
you think going to a different distribution would effect my hardware
performance?  I don't see how it SHOULD, but there would be slightly
different drivers and such, I suppose, so possibly it could make a
difference.  My machine should be significantly more powerful than MythTV
needs, but it always seems to be struggling, particularly in the disk IO
area.  That doesn't make a ton of sense to me for just one PVR150.

Ryan
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