[mythtv] render2019 comments

Mark Kendall mark.kendall at gmail.com
Mon Sep 30 07:24:11 UTC 2019


On Sun, 29 Sep 2019 at 20:51, Klaas de Waal <klaas.de.waal at gmail.com> wrote:
>
> As requested in the IRC, a quick test of the render-2019, now from the
> other side of the Channel.

Thanks Klass

> Test on my development system: Intel i7-7700, only built-in Intel
> graphics (no Nvidia card).

Is that a Kabylake processor? If so, the new VAAPI code has not been
tested with Kabylake. It may be fine but I have come across
differences with older chipsets (tested on Sandybridge, Ironlake and
Coffeelake).

> Software: Fedora 30 with LXDE desktop.
> Mythfrontend graphics setting: (Setup / Video / Playback / Current
> Video Playback Profile) VAAPI2 Normal
> Mythfrontend plays in a 1280x720 window on a 1900x1200 desktop.
> Content is 50Hz but monitor is 60Hz.
> This is for me the usual setting.
>
> Build: no problem.

Is VAAPI enabled?

> Mythfrontend startup error message:
> [AVHWDeviceContext @ 0x1422d00] Failed to initialise VAAPI connection:
> -1 (unknown libva error).
> Cannot load libcuda.so.1

As noted to John - there are some static checks that need cleaning up
but in your case they should just be informative - not sure why the
VAAPI check would fail if VAAPI is enabled though.

> Playback of recordings:
> MPEG2 SD, i50 OK
> H264 1080i50, playback OK but jump back/forward shows one frame
> out-of-order about 0.5 second after the start
> HEVC 1080p50 image not correct when panning, top of screen seems to
> lag and judder; bottom looks ok.
> Short time of blocking artefacts when jumping back and forth.
>
> Video playback profile changed to OpenGL High Quality
> MPEG2 SD, i50 OK and jumping back and forth now much faster than with
> the previous profile.
> H264 1080i50 OK, no out-of-order frames. Noticed also some lag/judder
> at top of screen.
> HEVC 1080p50 image not correct when panning, top of screen seems to
> lag and judder; bottom looks ok.
> Short time of blocking artefacts when jumping back and forth.
>
> Both profiles show interlacing artefacts (or lack of de-interlacing).

Again, you probably need to make sure your display profiles are set to
something reasonable for the new code - otherwise you will get
software decode and no deinterlacing.

The partial lag/judder at the top of the screen sounds like a classic
OpenGL sync to vblank issue - afaik sync to vblank should be enabled
by default on intel open source drivers - have you made any changes to
your desktop setup?

> Create new profile
> -> ffmpeg & opengl
> Change maxcpu from 1 to 4
> Change deinterlacer quality (single rate) from None to High quality
> Change deinterlacer quality (double rate) from None to High quality
> Same for:
> -> ffmpeg & opengl-yv12
> Everything else left default.
> Result (on all 3 content types): Interlacing is OK, other issues still present.
>
> Also: some tearing near the top but this is also present (although
> much less) in the master.

If you have tearing in master and the branch - you definitely have a
vsync issue.

A quick google gave me this:-

https://askubuntu.com/questions/240923/enable-sync-to-vblank-on-lxde-with-intel-video-card

Otherwise try forcing sync to vbank from the command line (intel/amd
driver environment variable) :

vblank_mode=1 mythfrontend -v playback

> About the GUI.
> Below the "Deinterlacer quality (single rate)" option are two lines
> "Prefer OpenGL deinterlacers" and "Prefer driver deinterlacers".
> These two lines are skipped over when "None" is the desired quality.
> This makes sense after a few moments but initially it surprised me.
> It would be great if it was possible to grey-out the not-applicable
> options, as was recommended in the OSF-Motif style guide of the
> previous century.
> N.B. I do not know how to do that or if it is even possible in the
> MythTV GUI. If I knew I would also use that in mythtv-setup.

I was expecting that feedback at some point:)

I didn't want to make the extra preferences another screen as it makes
the setup much more complicated and requires a lot more code.

There are 2 'states' that I found in the code for the checkboxes -
enabled and visible. The visible state doesn't seem to have been
designed for this purpose - as setting visible to true again does not
show the setting.

So I settled on enabled for now - and as you note, there is no code
(as far as I can see) to change the presentation state when the
setting is disabled. Like you, I was hoping it would grayed out (or
something similar).

Anyone familiar with the settings UI code have any ideas/suggestions?

> Hope that this is what was requested,

Absolutely!

Thanks
Mark


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