[mythtv] fixes/31 branch created!

[Mark Kendall]

On Wed, 19 Feb 2020 at 16:59, Mike Bibbings <mike.bibbings at gmail.com> wrote:
> Ran some tests on Pi2 and Pi4 master at commit 4e0da5033
>
> Using your recommended settings LiveTV and recorded playback are looking
> good for both Pi2 and Pi4.
>
> On occasion Pi4 LiveTV shows MPEG-2 ffmpeg   Deint None instead of 2x
> GLSL Onefield.

I suspect I'm going to get a lot of reports of this :(

The default behaviour is now to assume progressive material and only
switch on deinterlacing when interlaced frames are seen.

The main reason for the switch is that FFmpeg is very good these days
at detecting the interlaced flags properly and there are fewer false
positives this way.

There appear to be a number of UK SD channels that have 'mixed'
content. Whether they are genuinely progressive, interlaced or mixed,
I'm not sure - but regardless, it often takes anything from a few
seconds to a few minutes for deinterlacing to actually turn on.

I'm not ruling out an issue with the deinterlacing/video profile code
but I do see this behavour a lot on UK Freeview - without any obvious
loss of quality.

> mythfrontend started by QT_QPA_PLATFORM=eglfs mythfrontend at console.
>
> It looks like something in drm/fkms/kernel is reading edid from the
> connected hdmi device and deciding to ignore settings for hdmi_group and
> hdmi_mode in /boot/config.txt.

You probably want this:-

https://doc.qt.io/qt-5/embedded-linux.html#display-output

and this line is probably key:-

When mode is not defined, the system's preferred mode is chosen. The
accepted values for mode are: off, current, preferred, skip,
widthxheight, widthxheight at vrefresh, or a modeline string.

In summary, you need to create a config file for Qt to read. That
should get the correct mode at startup. If you enable video mode
switching in mythtv settings, it should switch the refresh rate for
you as well (if needed, not really an issue if you are just watching
broadcast 50Hz content).

I can't test right now - but fingers crossed that should do the trick:)

regards
Mark