[mythtv-commits] Ticket #7517: Separate Volume control from Audio Output

MythTV mythtv at cvs.mythtv.org
Sat Nov 7 20:42:26 UTC 2009

#7517: Separate Volume control from Audio Output
 Reporter:  mythtv@…               |       Owner:  jyavenard
     Type:  enhancement            |      Status:  new      
 Priority:  minor                  |   Milestone:  unknown  
Component:  MythTV - Audio Output  |     Version:  unknown  
 Severity:  medium                 |     Mlocked:  0        
 The existing implementation for controlling audio volume from within
 MythTV is associated with the Audio Output system. The attached patches
 aim to separate the functionality of adjusting audio volume from the
 playback of audio content.

 I feel that the proposed volume control implementation contained within
 the attached patches provides a number of improvements:

  * Volume Control Enumeration - The system provides user-friendly names
 within the Audio setup pages of MythFrontend.

  * Volume Control State Externalised - The system relies on the state of
 the volume control being stored externally. This approach simplifies
 scenarios such as changing channels whilst muted, which previously
 required special handling within the code.

  * Volume Control State Change Events - Any user interface component (e.g.
 the volume OSD) can be connected to the volume control interface so that
 it can be displayed whenever the volume control state changes. This
 approach correctly handles scenarios where the volume control may be
 modified by a means other than MythTV keypresses (e.g. if there are
 hardware controls for the volume). This follows more of a "model", "view",
 "controller" architecture.

 With the exception of the software volume control implementation all
 interfaces target system level volume controls. Normally such controls
 should not be modified by an application, however as the primary intention
 of MythTV is to take control of the whole PC, these implementations
 provide the best results.

 In order to provide device enumeration, these patches increase the minimum
 required version of OSS to be version 4 or greater. This makes it
 incompatible with OSS version 3, which is currently shipped with the linux

 For correct operation, the patches attached to Ticket #6662 should also be

Ticket URL: <http://svn.mythtv.org/trac/ticket/7517>
MythTV <http://www.mythtv.org/>

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