[mythtv-users] TrueHD titles causing video judder

[Nick Skarott]

On Sat, 2019-07-27 at 12:07 -0700, Neil Salstrom wrote:
> I've recently noticed that bluray titles (ripped to .mkv) will have
> significant video juddering / skipping when the TrueHD audio track is
> used.  Switching to the 5.1 track will stop the judder.  I don't see
> any issue when playing something with other high resolution audio
> formats (DTS-MA).
> 
> I've set the audio read ahead from the default 100ms to 500ms and saw
> no change.
> 
> I'm using a Nvidia GT 430 and driver version 340.107.
> 
> Mythtv version (compiled myself):
> 
> mythfrontend --version
> Please attach all output as a file in bug reports.
> MythTV Version : v30.0-68-ge094a02017
> MythTV Branch : fixes/30
> Network Protocol : 91
> Library API : 30.20181231-1
> QT Version : 5.9.5
> Options compiled in:
>  linux profile use_hidesyms using_alsa using_pulse using_backend
> using_bdjava using_bindings_perl using_bindings_python
> using_bindings_php using_dvb using_frontend using_hdhomerun
> using_vbox
> using_libcrypto using_libdns_sd using_libfftw3 using_libxml2
> using_lirc using_mheg using_opengl using_opengl_video
> using_opengl_themepainter using_qtwebkit using_qtscript using_qtdbus
> using_taglib using_v4l2 using_x11 using_xnvctrl
> using_xnvctrl_external
> using_libbluray_external using_xrandr using_xv using_profiletype
> using_bdjava using_bindings_perl using_bindings_python
> using_bindings_php using_fontconfig using_freetype2
> using_mythtranscode using_opengl using_vaapi2 using_vdpau
> using_ffmpeg_threads using_mheg using_libass using_libxml2
> using_libmp3lame
> 
> Log file from a play back with playback,audio flagged:
> 
> https://pastebin.com/z8dcxcCz
> 
> In this log there are two playbacks.  The first (using Shazam) is
> default with TrueHD.  The second time Shazam is played a few seconds
> in I switch to the 5.1 track.  The juddering video becomes smooth as
> soon as 5.1 is selected.
> 
> I've verified this behaviour with several different movies that have
> TrueHD and also movies with DTS-MA (and the DTS-MA titles play with
> no
> issues).
> 
> Has anyone else experienced this?
> 
> Thanks!
> 
> Neil
> 
Just a quick question regarding this, are the titles you have ripped
that use Dolby TrueHD Atmos enabled? I have had issues before with
TrueHD tracks that have Atmos metadata for object-based audio causing
judder as something goes a little iffy in the decode.

-Nick