I've recently upgraded my living room ATV (which couldn't run Mythfrontend) to one of the new mini's and installed Mythfrontend along with Plex, XBMC, Boxee and Remote Buddy to control it all. I'm over all happy with the results except for Mythfrontend. I can't get decent picture quality no matter what I do if I try to do any fill to expand to fit the display. At default scaling, things are fine pretty much however I set the playback profile and deinterlacing. Once I try to do a fill, forget about it. Jumpy, terrible PQ (likely due to the deinterlacer being starved for fields) and all around unhappiness. The Mythbox plugin for XBMC (on the Mac) has actually decent PQ but has tons of other problems that to me make it pretty unusable. In my 'real' home theater, I have a Linux box running the HTPC and have silky smooth Mythtv video through VDPAU with scaling and deinterlacing not even breaking a sweat. However in the past, before VDPAU, I have used generic XV based control and it was still a world better than what I can get on the Mac with any profile I can come up with. Have any of you been able achieve good results with Mythfrontend for MacOS? I'd love to hear your settings.


Setup:

Mac Mini - 2.266MHz CPU - 2GB RAM 9400M
Snow Leopard
1080P LCD display using mini-dvi dongle to dvi-to-hdmi cable (audio separate via audio out)

-Trouble

I haven't looked in a while, but last I saw, the precompiled Myth front-end binary available for OS X was a PowerPC binary, meaning it runs under code translation with a severe performance penalty. Are you sure the version of the front-end you're running is Intel-native?

Eh. Nevermind. Looks like there are readily available Intel and UB builds listed on the Myth wiki:
http://www.mythtv.org/wiki/Myth_on_Mac_OS_X#Pre-built_Downloads

I have an nvidia-based Mac Mini I use as my frontend. I dual boot between Snow Leopard and Mythbuntu. I find that the video quality on Linux is much better than on the Mac side.

In Mac OS, the playback doesn't seem as smooth. This is especially true on my 720p stations, where I get a "judder" effect as frames are dropped. This may be related to the encoding from that station, but I do not see the same behavior when running Linux.

The settings I use:

Utilities/Setup -> Setup -> TV Settings -> Playback

- Extra audio buffering (had popping without this)
- One video profile for all resolutions:
Decoder: Standard
Max CPUs: 2
Video Renderer: quartz-blit
OSD Renderer: softblend
Primary Deinterlacer: Kernel
Fallback Deinterlacer: Linear Blend
- page 9/10: Scale video as necessary = enabled

Another note on this..

In order to get better playback, I have been trying to get the MythTV support in XBMC / Plex to work reliably. But, I haven't got them to work as well as MythFrontend. When they do work, the video quality is better than Myth.

Also, I have not yet tried the new 0.22 Mythfrontend release. But, I don't think it adds much of anything Mac-specific.

tji, Thanks. I was afraid of this, just thought maybe someone had a some secret setting that wasn't obvious. Looks like a Koala will be replacing a Snow Leopard ;) . I'm fine with Linux and love VDPAU but I will miss Netflix. That's the only thing I can't do in Linux :( Multiboot with rEFIt or Bootcamp brings WAF waaay down of course.



-Trouble

Are you using a 1080p display? There were issues in the past where the scaling would revert to software under certain conditions, related to the resolution dividing evenly and a lot of people had problems when displaying 1080p.

Some recommendations for isolating the issue:

- ssh in and run 'top'. If MythFrontEnd is taking a ton of CPU, scaling may be the issue.

- For a lot more detail on CPU usage, use the 'Shark' profiling app included with xCode. it will break down CPU usage into the internal functions using the CPU time.

- Run mythfrontend from an ssh session, with parameter "-v playback" to get a lot of debug output



I am still working on debugging mine. Last night I was watching NFL games, and at first playback was crap and it was spewing debug messages. Later, playback was 100% smooth, with no debug messages being output. I am not sure what changed.. it could have even been something with the video stream encoding.

Yes, I am using a 1080P display. I do remember that some early builds of .21 were missing mmx capability and that was affecting performance greatly but that's been 'fixed' for a while now. I'm sure it is using software scaling and that is what the issue is, or it's at least part of the issue. Running in the 'MacOS Hardware Acceleration' mode doesn't really seem to make much of a difference when scaling hits - Plus you can't use a deinterlacer with it which is a killer.

-Trouble

same boat here - running on pretty fast hardware but 720p playback seems to be dropping frames. strangely, 1080i content seemed okay.

my TV is overscanning and i've set mythfrontend to shrink the window down to compensate. might this have something to do with it?

has anyone discovered any mythfrontend settings in the last 106 days that might help? :)

> my TV is overscanning and i've set mythfrontend to shrink the window down to compensate. might this have something to do with it?

That was one of the issues in the past, re-sizing the video would make it drop out of hardware scaling and do it in software. If this is the issue, you should see the problems go away if you turn off the re-sizing.


For me, it seemed to be a subtler issue, like the MPEG encoding was not agreeing with the Mac decoder or something (just a guess, I didn't debug it enough to narrow it down).


I have been primarily using a Linux frontend (Acer AspireRevo with VDPAU support) so I haven't looked into my Mac issues any more. But, I should give it another shot, there is no reason to run multiple systems, I should be able to do it all from the Mac. If I find anything else, I'll post here.

> my TV is overscanning and i've set mythfrontend to shrink the window down to compensate. might this have something to do with it?

That was one of the issues in the past, re-sizing the video would make it drop out of hardware scaling and do it in software. If this is the issue, you should see the problems go away if you turn off the re-sizing.


For me, it seemed to be a subtler issue, like the MPEG encoding was not agreeing with the Mac decoder or something (just a guess, I didn't debug it enough to narrow it down).


I have been primarily using a Linux frontend (Acer AspireRevo with VDPAU support) so I haven't looked into my Mac issues any more. But, I should give it another shot, there is no reason to run multiple systems, I should be able to do it all from the Mac. If I find anything else, I'll post here.

thanks for the reply.

i'll try turning off the screen shrink and see what happens. this is a quad-core 3GHz machine though so i'd think software decoding would be OK. anyway assuming that works, i guess i have to look into switchresX to get rid of the overscan?

i can't tell if it's network-related, or hd homerun related, but mythbackend on osx completely corrupted a recording. it's as though it lost sync with the ATSC stream at some point and never recovered. i've never had that happen with my linux mythbackend using HD-2000s.

a second recording had a dropout in the middle that sounded similar, but it somehow recovered. replacing my linux myth box with the mac is not going to work out if this persists...