[mythtv-commits] Ticket #12193: OSD & Audio Channels do not change when audio switches from 2.0 to 5.1

[MythTV]

#12193: OSD & Audio Channels do not change when audio switches from 2.0 to 5.1
-------------------------------------------------+-------------------------
 Reporter:  JohnLBergqvist@…                     |          Owner:
     Type:  Bug Report - General                 |  jyavenard
 Priority:  major                                |         Status:  closed
Component:  MythTV - Audio Output                |      Milestone:  unknown
 Severity:  medium                               |        Version:
 Keywords:                                       |  0.27-fixes
  osd,audio,freesat,surround,5.1,2.0,stereo      |     Resolution:  Works
                                                 |  for me
                                                 |  Ticket locked:  0
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Comment (by JohnLBergqvist@…):

 Replying to [comment:4 jyavenard]:
 > Replying to [comment:2 JohnLBergqvist@…]:
 > > I'll try and upload a sample tomorrow.
 > > My audio device is an HDMI port (ALSA) on my graphics card going to
 stereo speakers on a TV, without any upmixing. Unsure whether bit-
 streaming is enabled, how would I check that? Also if it's my amplifier
 that detects the change, why does it detect it every time on the XBMC
 frontend (which is playing the same LiveTV file through the mythbackend),
 but not in MythFrontend? Unless it's simply a flag in the audio which
 MythTV isn't looking for? (or doesn't look again after playback has
 started)
 >
 > Because we aren't XBMC?
 > Believe it or not, our Audio Framework is far more advanced in what it
 can handle and how it detects the device connected. And the behaviour is
 set to ensure you get the highest audio quality whatever the
 circumstances.
 >
 > If you are connected via HDMI to your TV and your TV is stereo only
 (usually, most are); all you can output is stereo. You do not want to
 output 5.1. Most TV do not downmix the audio from 5.1 down to stereo, they
 only play left and right. This is not what you want.
 >
 > At best your TV can handle stereo, and if you check the log you would
 see that myth retrieved that information over ELD on the hdmi connection
 that Stereo PCM is the best available. You can see those changes starting
 mythfrontend with:
 >
 > {{{
 > mythfrontend -v audio --loglevel=debug
 > }}}
 >
 >
 > So myth configure itself as stereo and output stereo.
 > When the stream change from stereo to 5.1, the 5.1 signal is downmixed
 to stereo and is output that way.
 >
 > This is what the OSD report. If you want to see the original audio
 signal settings, go into Menu -> Playback -> Playback Data. Top right
 corner would show the codec used and the number of channels.
 >
 > If you want myth to output 5.1, simply connect a device that can handle
 5.1.
 > Note that you can override this behaviour in the audio settings.
 Manually enter the audio device to use, if it's a custom device you can
 override the maximum amount of channels you can use
 >
 > That sample is way too big, I only need a few second worth, when the
 change actually occurs.
 >
 > If you do think that is wrong, read the ticket how to on how to submit a
 ticket and what to provide
 > include the output of mythfrontend --version
 >
 > and the unedited log of mythfrontend started with -v audio,playback
 --loglevel=debug
 But if this is the case, how come when I start watching (via the HDMI
 port) a program that's already in 5.1, the OSD and the channels stay as
 5.1...?

 Also although I usually watch a program via Stereo, I have connected a 5.1
 system up to it and the effect is still the same...


 {{{
 Mythfrontend Version:

 Please attach all output as a file in bug reports.
 MythTV Version : v0.27.1-16-gaa822f5-dirty
 MythTV Branch : fixes/0.27
 Network Protocol : 77
 Library API : 0.27.20140520-1
 QT Version : 4.8.6
 Options compiled in:
  linux profile use_hidesyms using_alsa using_oss using_pulse
 using_pulseoutput using_backend using_bindings_perl using_bindings_python
 using_bindings_php using_dvb using_firewire using_frontend using_hdhomerun
 using_ceton using_hdpvr using_ivtv using_joystick_menu using_libcrypto
 using_libdns_sd using_libxml2 using_libudf using_lirc using_mheg
 using_opengl using_opengl_video using_qtwebkit using_qtscript using_qtdbus
 using_taglib using_v4l2 using_x11 using_xrandr using_xv using_profiletype
 using_bindings_perl using_bindings_python using_bindings_php
 using_mythtranscode using_opengl using_vdpau using_ffmpeg_threads
 using_mheg using_libass using_libxml2 using_libudf
 }}}

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Ticket URL: <https://code.mythtv.org/trac/ticket/12193#comment:5>
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