[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
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 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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Changes (by jyavenard):

 * status:  infoneeded_new => closed
 * resolution:   => Works for me


Comment:

 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

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Ticket URL: <https://code.mythtv.org/trac/ticket/12193#comment:4>
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