[mythtv] [mythtv-commits] Ticket #8798: DD5.1 does not play correctly when timestretch is enabled.

[Jean-Yves Avenard]

Hi

On 29 August 2010 17:17, BP <lists at qucae.com> wrote:
> MythTV wrote:
>>
>> #8798: DD5.1 does not play correctly when timestretch is enabled.
>>
>> -----------------------------------+----------------------------------------
>>  Reporter:  jpoet                  |           Owner:  jyavenard
>> Type:  defect                 |          Status:  closed      Priority:
>>  minor                  |       Milestone:  unknown    Component:  MythTV -
>> Audio Output  |         Version:  Unspecified
>>  Severity:  medium                 |      Resolution:  invalid
>> Keywords:  AC3 DD5.1 timestretch  |   Ticket locked:  0
>>  -----------------------------------+----------------------------------------
>> Changes (by jyavenard):
>>
>>  * status:  assigned => closed
>>  * resolution:  => invalid
>>
>>
>> Comment:
>>
>>  That option isn't active by default.
>>  It shouldn't even be available for spdif (option is either greyed out, or
>>  not displayed at all).
>>  This option is only available if the audio device reports supporting more
>>  than 2 channels. If it reports more than 2 for the spdif port, it's an
>>  ALSA bug
>>
>>  I'd be interested to see the log again with -v audio ; it now shows in
>> the
>>  log the number of channels supported for each audio device
>>
>
> For me, the option is greyed out, but checked/enabled.  Time stretch has
> been broken for me since the audio changes that introduced that
> configuration.
>
> Thanks to this ticket pointing the right direction, I was able to make time
> strech work again by directly setting MultiChannelPCM to 0 in the settings
> table of the database (also unchecks the greyed out setting for LPCM).  All
> my frontends had MultiChannelPCM set to 1.  As the option is greyed out,
> there was no means I could find through the settings UI to disable LPCM.
>
> Without knowing how it got enabled, perhaps the Audio settings page should
> disable LPCM as part of greying out the option?  Having to hack the database
> if it gets enabled for some reason is not the best option.  Or at least the
> "dirty fix" mentioned in comment 6.
>
> I could also see a potential issue if someone changes sound cards for a
> given hostname from one which had support to one that does not thus getting
> them stuck with this setting enabled.

If the option is greyed, it isn't used, no matter the settings in the database.

Intrigued by your report, I just looked at the code again, and the
same code used to decide if it should be greyed out or not, is the
same as the one deciding to send LPCM or not.

e.g. if the LPCM field is greyed or unchecked then myth won't attempt
to send lpcm.