[mythtv-users] MythTV and Pulseaudio

[Another Sillyname]

2009/12/21 Another Sillyname <anothersname at googlemail.com>:
> 2009/12/21 Ross Campbell <ross.campbell at gmail.com>:
>> On Sun, Dec 20, 2009 at 2:21 PM, Brian J. Murrell <brian at interlinx.bc.ca> wrote:
>>> I'd argue this Pulseaudio and
>>> Mythtv discussion is far more on topic that most of the (OT at least)
>>> chatter that goes on on this list.
>>
>> It is... For better or worse, Linux distros are doing deep integration
>> of pulseaudio in the desktop environments, and the simple "disable
>> pulse audio by doing X" is turning into this mess:
>> http://ubuntu-ky.ubuntuforums.org/showthread.php?p=8284273 with a
>> batch of caveats and broken pieces that some people like me may
>> actually care about.
>>
>> Myth disables pulseaudio on startup and if you exec any programs that
>> expect to use pulse for sound, they may or may not fall back to
>> another sound server. Example: emulator works from commandline, hangs
>> when exec'ed from mythgame due to which version of libsdl1.2debian-*
>> is installed (hint: libsdl1.2debian-pulseaudio is the "correct one"
>> for ubuntu, but that causes no sound and a hang on exit of sdlmame or
>> presumably any app that uses sdl for sound...! install
>> libsdl1.2debian-all and apps that use sdl for sound will be able to
>> fall back to alsa).
>>
>> I presume the experimental pulseaudio patch that allows the flag below
>> made it into 0.22, right?
>>
>>   EXPERIMENTALLY_ALLOW_PULSE_AUDIO=1 mythfrontend
>>
>> Read a post somewhere suggesting that myth should only disable
>> pulseaudio when the internal player is playing something back... and
>> re-enable it when it's done. That would at least ensure that any 3rd
>> party apps exec'ed from inside myth wouldn't have any sound issues...
>> barring actual pulseaudio support, that's a better workaround IMHO.
>>
>> I know all the details behind the linux sound server holy wars and
>> don't want to incite a riot. Personally, I wish jackd had won, but it
>> didn't... and my days of having the free time to hack together my own
>> massively customized linux distribution are drawing to a close. The
>> relevant point is that not just ignoring pulseaudio as a supported
>> soundserver, but DISABLING IT by default seems like it is only going
>> to create more issues as time goes by.
>>
>> I sincerely hope the pulseaudio devs,  mythtv devs, and ubuntu devs
>> can all get together and map out the functionality requirements, and
>> code changed to make pulseaudio work with myth out of the box in the
>> future.
>>
>> -Ross
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>> mythtv-users at mythtv.org
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>>
>
> Sorry I have to throw my 2c in here.
>
> Myth DOES NOT disable pulse by default.
>
> I run a Fedora 11 frontend, with MythTV 0.22-1 from rpmfusion on top of it.
>
> I have Pulseaudio 9.15-17 installed and alsa-plugins-pulseaudio
> 1.0.21-2 also installed.
>
> My sound setup in mythtv is
>
> Audio Output Device ALSA:Default
>
> Passthrough Output Device ALSA:iec958:{ AESO 0x02 }
>
> Max Audio Channels Stereo
>
> Upmix Passive
>
> Enable AC3 to SPDIF passthrough --> Checked
>
> Enable DTS to SPDIF passthrough --> Unchecked
>
> Aggressive Sound Card Buffering --> Unchecked
>
> ------  Next Page
>
> Use Internal Volume Controls --> Unchecked
>
> ---------------------------------------
>
> I output ALL my audio to an external amplifier via a SPDIF connection.
>
> ---------------------------------------
>
> I also have pulseaudio-module-lirc installed
>
> The reason I know for certain that pulse is NOT getting turned off is
> I added the following to my lircrc file to control the volume....
>
> begin pulseaudio
>
> begin
>     remote = mceusb
>     prog = pulseaudio
>     button = VolUp
>     config = volume-up
> end
>
> begin
>     remote = SonyBDRemote
>     prog = pulseaudio
>     button = l1
>     config = volume-up
> end
>
> begin
>     remote = mceusb
>     prog = pulseaudio
>     button = VolDown
>     config = volume-down
> end
>
> begin
>     remote = SonyBDRemote
>     prog = pulseaudio
>     button = l2
>     config = volume-down
> end
>
> begin
>      remote = mceusb
>      prog = pulseaudio
>      button = Mute
>      config = mute-toggle
> end
>
> begin
>      remote = SonyBDRemote
>      prog = pulseaudio
>      button = l3
>      config = mute-toggle
> end
>
> end pulseaudio
>
> As all my audio outputs via SPDIF this used to mean I had to use two
> remotes, one to control myth and my normal amp remote to control my
> volume, frankly this was a pain in the ar*e.
>
> The above configuration allowed me to control all the volumes (except
> full Dolby) using my mythtv remote.
>
> There is no audio delay except in the first second or so when you
> start to play a new avi and it has to sync the audio and the picture.
>
> The path for the audio output is as follows....
>
> MythTV -->  ALSA  -->  Pulseaudio.
>
> It all works fine and without problems.
>

Just as a footnote....

This also solved my 'mono sound not output by myth problem' as
previously ALSA and the amplifier would fall out if mono sound was
output (basically no sound output).

As Pulseaudio remaps all mono to 'fake' stereo (i.e. the mono signal
is sent to both channels) I can now also listen to Radio 5 Live and
watch CNN off satellite and hear the sound without an issue.

Regards