[mythtv-users] Alternative to zbox for a frontend

Paul Gardiner lists at glidos.net
Thu Sep 14 21:52:47 UTC 2017

On 13/09/2017 16:16, Peter Bennett wrote:
 > On 09/13/2017 10:21 AM, Paul Gardiner wrote:
 >> Turns out I was misinterpreting what I was seeing. tvservice seems to
 >> be showing that the pi is picking up the 50Hz prefered mode of my tv.
 >> The problem is performance. SD runs perfectly, but with 1080i25
 >> content frames are dropped - I'd guess about 1 in 4 or 5 because the
 >> result is so much like running at the wrong frame rate. Strangely some
 >> 720p24 isn't quite perfect either although in that case it depends on
 >> the scene and some parts are perfectly smooth (that's with the screen
 >> mode changed to 24Hz).
 >> I'm pretty sure I've applied every optimisation you list, besides
 >> trying greater than 256MB gpu mem. Perhaps I need to get a Pi 3.
 > You never said what version of MythTV you are using - the 0.27 version
 > for Raspberry Pi was an unofficial release and is missing many
 > optimizations, so hopefully you are on 0.28 or 29.

I'm usingh 0.28.

 > Verify the mpeg2 license (vcgencmd codec_enabled MPG2).
 > You could try running with -v playback to see if it is dropping frames
 > or there is some other problem.

Yeah, that's enabled. I thought it must be: my first run was before my 
license was delivered and playback was very lumpy.

 > Completely smooth video may not be achievable at this time. See ticket
 > at https://code.mythtv.org/trac/ticket/12907
 > I use it for 1080i and 1080p at 30 fps on a pi2. If it is not 100%
 > smooth all the time it does not worry me or my wife.

It's such a shame. It's so close. Most of the 1080i content we get here 
isn't truly interlaced and the results for that are not quite perfect 
but acceptable. True interlaced content though is noticeably less smooth 
than on my zbox.

 > If you have done all of the performance steps I recommended, I don't
 > think that a Pi 3 will make that much of an improvement. Perhaps you
 > notice these things more than I do.

I might give a pi 3 a try, given they're so cheap, but I think you are 
corrrect. It looks like the pi 3, although faster with the default set 
up, cannot be overclocked much past the pi 2.

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