[mythtv-users] MythTV Raspberry Pi2 frontend testers

Lawrence Rust lvr at softsystem.co.uk
Thu Nov 26 21:22:50 UTC 2015


On Tue, 2015-11-24 at 15:04 -0500, Peter Bennett (cats22) wrote:
> On 11/23/2015 06:09 AM, Lawrence Rust wrote:
> > On Sun, 2015-11-22 at 12:41 -0500, Peter Bennett (cats22) wrote:
> >> On 11/17/2015 02:24 PM, Lawrence Rust wrote:
> >>> If anyone would like to try it and provide some feedback then checkout
> >>> the fixes-0.27-rpi2 branch from here:
> >>> http://www.softsystem.co.uk/git/mythtv.git
> >>>
> >>>
> >> I have done some more testing and I now have this set up on my kitchen
> >> TV. It is working great and perfectly usable. Some issues I noticed:
> >>
> >> 1. Video is jerky and audio is interrupted when running stand alone
> >> (QT_QPA_PLATFORM=eglfs). It works fine (no jerkiness) under xwindows
> >> (QT_QPA_PLATFORM=xcb). So I am using it with xwindows. Following
> >> observations are in  that environment.
> > Are you using HDMI audio?  If so, this may be a bug that I need to look
> > at.
> >
> >> 2. If you try to compensate for tv overscan by making the picture
> >> smaller in /boot/config.txt or by using appearance setup in the mythtv
> >> frontend setup, the video is shown at the requested smaller size but the
> >> offset is not used, so a small video comes at the top left hand side of
> >> the screen instead of centered. This only affects video playback, the
> >> GUI menus and lists honor the settings correctly. You can make the video
> >> smaller using the zoom feature while playing and that works correctly.
> > I wasn't sure exactly how all the zooming, centring etc worked in Myth
> > so I took a best guess.  Following the existing NVidia and Xv code was
> > gruelling.   I will go back and check.
> >
> >> 3. If you pull up the menu while playing a recording (M key) or other
> >> OSD displays such as Info (I key), the video becomes jerky while the OSD
> >> is displayed.
> > This indicates that the OSD is falling back to CPU rendered softblend.
> > The opengl OSD uses EGL and requires Qt to run in EGLFS mode.
> >
> > I really need to find out why the EGLFS mode is jerky on some RPi's.  I
> > have 2 RPis and they both play smoothly in EGLFS mode with SD and 1080p
> > video.  I have these settings in /boot/config.txt:
> >
> > disable_overscan=1
> > hdmi_drive=2
> > # 1920x1080 @ 50Hz 16:9, clock:148MHz progressive 
> > hdmi_group=1
> > hdmi_mode=31
> >
> >> 4. Subtitles do not work. You can select them but they do not display.
> > I see subtitles on liveTV (BBC 1) and on DVD playback.  Maybe this is
> > something to do with the opengl OSD only being available with EGLFS
> > mode.  What happens if you select softblend in TV settings?
> >
> >> Great job. I hope we can get this in the official build. The above are
> >> minor issues and if they are restrictions that will be OK in my opinion.
> > My hope too.  Unfortunately, I've not had a lot of success in getting my
> > patches included.  I'll work at resolving the problems you identified.
> >
> > -- Lawrence Rust
> >
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> > MythTV Forums: https://forum.mythtv.org
> >
> Hi Lawrence
> 
> I am using analog audio in all cases.
> 
> I retested eglfs and compared it to xcb. I am using a 1080i recording.
> See attached file mediainfo.txt for info about it.
> 
> eglfs - Jerky playback on a 1280x1024 DVI screen and using analog audio.
> xcb - smooth playback, no jerkiness in this case
> 
> eglfs - smooth playback on an analog TV (I think it is treated as
> 720x480 by raspberry pi) composite with analog audio
> xcb - also smooth playback in this case
> 
> I have an old analog TV and the edges of the display disappear, so the
> GUI chops off at the left,right,top,bottom.
> 
> Overscan settings in config.txt fix this for most applications, but not
> for MythTV frontend.
> eglfs - overscan settings seem to be completely ignored.
> xcb - overscan settings are partially used, the width of picture is
> reduced but the position is still top left so you  lose the top and left
> of the GUI and get extra space at the bottom and right.
> 
> The other way of fixing the overscan is with the Front end Setup
> Appearance page where you can set the width and position of the GUI and
> whether playback should use the same settings.
> eglfs - picture size settings are honored but position settings are
> ignored, so that the top and left of the GUI are cut off and you get
> extra space at the bottom and right. If you set playback to use the same
> settings that is ignored, playback is still full screen with
> top,left,bottom,right cut off.
> xcb - picture size and position settings are honored so that the GUI is
> displayed perfectly. If you set playback to use the same settings, the
> size is honored but not the position so you get the top and left cut off
> and extra space at the bottom and right.
> 
> I have a remote that uses the keyboard media keys. I use the "Setup
> Keys" part of frontend setup to assign them appropriately.
> eglfs - One media keys is not detected at all (STOP) and the others work
> but with different codes from x-windows.
> xcb - All media keys work.
> 
> OSD
> eglfs - OSD works smoothly
> xcb - OSD causes jerkiness
> 
> Subtitles
> I am not seeing subtitles with either xcb or eglfs.
> With normal front end on a particular show I get a choice of ATSC CC1
> Subtitles or VBI CC1 subtitles. Either of these shows the same
> subtitles, I don't know why two are shown.
> With Raspberry Pi frontend I only see ATSC CC1 as a choice. Selecting it
> says "Subtitles enabled" but they never appear on the screen.
> 
> Because of the issues with the display cutting off and the media key for
> "stop" not working, xcb is preferable to me right now. I am using it
> with an analog TV so there is no jerkiness whether I use eglfs or xcb.
> 
> Attached is my config.txt file.
> 
> Let me know if there is anything I can do to help.
> 

Hi Peter,

Many thanks for your report and observations.  I will spend some time
this weekend to fathom these problems:

1. jerkiness with various source materials
2. platform (xcb/eglfs) variations
3. video playback position.

Hopefully I will have a revised branch & build early next week to test,
together with a 0.28/master variant too.

Thanks for your help.

BTW have you seen the Pi Zero?
https://www.raspberrypi.org/blog/raspberry-pi-zero/

Couldn't believe the price so I bought one!  Will see if that too can
run Myth :-)

-- Lawrence Rust



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