Mailing List Archive

Ticket #13369: Playback issues with 30Hz display
#13369: Playback issues with 30Hz display
--------------------------------------+--------------------------
Reporter: paulsd | Owner: (none)
Type: Bug Report - General | Status: new
Priority: minor | Milestone: needs_triage
Component: MythTV - General | Version: v29.1
Severity: medium | Keywords:
Ticket locked: 0 |
--------------------------------------+--------------------------
I'm using MythTV 2:29.1+fixes.20180414.329c235-0ubuntu3 in Ubuntu 18.04.

I recently got a new 4K TV. This TV has one HDMI 2.0a port (which
supports 4K@60Hz), and three HDMI 1.4 ports (which only support 4K@30Hz).
If I connect my MythTV box to the HDMI 2.0a port and configure X to
display at 4K@60Hz, then everything works fine. Unfortunately, only the
HDMI 2.0a port on the TV supports ARC, so this port needs to be connected
to my stereo system instead of my MythTV box. If I connect my MythTV box
to an HDMI 1.4 port and configure X to display at 1K@60Hz, then everything
works fine.

However, if I connect my MythTV box to an HDMI 1.4 port and configure X to
display at 4K@30Hz, then Recordings work fine, but LiveTV playback doesn't
work. Specifically, LiveTV video is played at half speed, and only brief
clips of audio are occasionally played. The same symptom occurs using any
of the accelerated Playback Profiles (my system only supports OpenGL and
VAAPI, so I can't test VDPAU). LiveTV plays at half speed even if audio
is disabled (by setting the 'Audio output device' to NULL in the frontend
settings).

If I use a non-accelerated Playback Profile at 4K@30Hz, then LiveTV plays
properly, but I have other problems (video tearing and high CPU usage).
In addition, if audio is disabled (by setting the 'Audio output device' to
NULL in the frontend settings), then LiveTV still works as expected, but
Recordings play back at double speed.

So, something is clearly different about the display refresh rate handling
for LiveTV vs Recordings, and both are wrong in some cases.

--
Ticket URL: <https://code.mythtv.org/trac/ticket/13369>
MythTV <http://www.mythtv.org>
MythTV Media Center
Re: Ticket #13369: Playback issues with 30Hz display [ In reply to ]
#13369: Playback issues with 30Hz display
----------------------------------+------------------------------
Reporter: paulsd | Owner: (none)
Type: Bug Report - General | Status: new
Priority: minor | Milestone: needs_triage
Component: MythTV - General | Version: v29.1
Severity: medium | Resolution:
Keywords: | Ticket locked: 0
----------------------------------+------------------------------
Changes (by paulsd):

* Attachment "mythtv_logs.tar.bz2" added.

Tarball containing `mythtv -v playback` logs for many permutations of
settings

--
Ticket URL: <https://code.mythtv.org/trac/ticket/13369>
MythTV <http://www.mythtv.org>
MythTV Media Center
Re: Ticket #13369: Playback issues with 30Hz display [ In reply to ]
#13369: Playback issues with 30Hz display
----------------------------------+------------------------------
Reporter: paulsd | Owner: (none)
Type: Bug Report - General | Status: new
Priority: minor | Milestone: needs_triage
Component: MythTV - General | Version: v29.1
Severity: medium | Resolution:
Keywords: | Ticket locked: 0
----------------------------------+------------------------------

Comment (by paulsd):

In the log tarball, mythtv_logs/30hz_opengl_noaudio_live.log and
mythtv_logs/30hz_opengl_audio_live.log show half-speed (30fps vs 60fps)
video playback, and mythtv_logs/30hz_noopengl_noaudio_rec.log shows
double-speed (120fps vs 60fps) video playback. The other logs all played
back at the expected speed (60fps).

I also stumbled across https://forum.mythtv.org/viewtopic.php?t=1220 which
looks like another report of this same issue.

--
Ticket URL: <https://code.mythtv.org/trac/ticket/13369#comment:1>
MythTV <http://www.mythtv.org>
MythTV Media Center
Re: Ticket #13369: Playback issues with 30Hz display [ In reply to ]
#13369: Playback issues with 30Hz display
----------------------------------+-------------------------------
Reporter: paulsd | Owner: Peter Bennett
Type: Bug Report - General | Status: assigned
Priority: minor | Milestone: needs_triage
Component: MythTV - General | Version: v29.1
Severity: medium | Resolution:
Keywords: | Ticket locked: 0
----------------------------------+-------------------------------
Changes (by Peter Bennett):

* owner: (none) => Peter Bennett
* status: new => assigned


--
Ticket URL: <https://code.mythtv.org/trac/ticket/13369#comment:2>
MythTV <http://www.mythtv.org>
MythTV Media Center
Re: Ticket #13369: Playback issues with 30Hz display [ In reply to ]
#13369: Playback issues with 30Hz display
----------------------------------+-------------------------------
Reporter: paulsd | Owner: Peter Bennett
Type: Bug Report - General | Status: assigned
Priority: minor | Milestone: needs_triage
Component: MythTV - General | Version: v29.1
Severity: medium | Resolution:
Keywords: | Ticket locked: 0
----------------------------------+-------------------------------

Comment (by Peter Bennett):

I am unable to recreate this with v29 or latest master. I tried OpenGL
slim. Live TV as well as recordings play fine on a 4K display with an HDMI
1.4 running at 30HZ 3840x2160.

Is this interlaced content? Check your deinterlacer - I was using Linear
blend.

Try pressing pause while in Live TV for a few seconds, then unpause.

There is a fix for the pause-unpause issue fix in v30.

--
Ticket URL: <https://code.mythtv.org/trac/ticket/13369#comment:3>
MythTV <http://www.mythtv.org>
MythTV Media Center