Difference between revisions of "Developer:Davaar:VolumeService"

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= Architecture Overview =
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See http://www.openhome.org/wiki/Av:Developer:VolumeService
The Volume Service provides a means of controlling various settings which affect the product's volume (signal amplitude) measured at the output channels. A product may have one or more output channels. Balance or Fade settings may result in different volumes at each output. In the Mute state, all output channels are reduced to zero volume.
 
 
 
==Volume==
 
Volume is an adjustable setting that controls the loudness of the audio at the output channels of the product. Volume can be set to an absolute value or incremented/decremented in single steps. The maximum Volume setting is defined by the current value of '''VolumeLimit'''. The minimum Volume setting is zero. If an attempt is made to set the Volume above VolumeLimit, the Volume will be set to the '''VolumLimit'''. If an attempt is made to set the Volume above '''VolumeMax''', an error will  be reported.
 
 
 
== Volume Limit ==
 
VolumeLimit specifies the upper limit of the Volume. Any attempt to set Volume above the VolumeLimit will reset Volume to the value of VolumeLimit. If VolumeLimit is changed, Volume is checked and automatically reduced if necessary. The maximum VolumeLimit setting is defined by the '''VolumeMax''' Characteristic.
 
 
 
==Balance==
 
Balance is an adjustable setting that specifies the '''bias''' in volume between the '''left and right''' output channels of the product. Balance can be set to an absolute value or incremented/decremented in single steps. The maximum Balance setting is defined by the '''BalanceMax''' Characteristic. The minimum Balance setting is defined by ('''-BalanceMax''') .
 
 
 
==Fade==
 
Fade is an adjustable setting that specifies the '''bias''' in volume between the '''front and rear''' output channels of the products. Fade can be set to an absolute value or incremented/decremented in single steps. The maximum Fade setting is defined by the '''FadeMax''' Characteristic. The minimum Fade setting is defined by ('''-FadeMax''') .
 
 
 
==Mute==
 
Mute is an adjustable state that determines if the output channels of the product are muted or not. When muted, all output channels of the product are silent.
 
 
 
 
 
==Characterstics==
 
Each product has '''six''' read only values that define its volume Characteristics.
 
====VolumeMax====
 
VolumeMax defines the absolute maximum Volume setting.
 
 
 
====VolumeUnity====
 
VolumeUnity defines the value of Volume that will result in unity system gain (ie ''output amplitude'' = ''input amplitude'').
 
 
 
====VolumeSteps====
 
VolumeSteps defines the number of step increments required to increase the Volume from zero to VolumeMax.
 
====VolumeMilliDbPerStep====
 
VolumeMilliDbPerStep defines the size of each volume step in '''binary milli decibels''' (bmdB). [''1024bmdB = 1dB'']
 
 
 
====BalanceMax====
 
BalanceMax defines the maximum Balance setting. The minimum Balance setting is (-BalanceMax)
 
====FadeMax====
 
FadeMax defines the maximum Fade setting. The minimum Fade setting is (-FadeMax)
 
 
 
 
 
=Actions=
 
 
 
=== Volume ===
 
The Volume action reports the current Volume setting.
 
 
 
=== SetVolume===
 
The SetVolume action provides a means of setting the Volume to an absolute value.
 
 
 
=== Volume Inc===
 
The VolumeInc action provides a means of increasing the Volume by 1.
 
=== Volume Dec ===
 
The VolumeDec action provides a means of decreasing the Volume by 1.
 
=== VolumeLimit ===
 
The VolumeLimit action reports the current VolumeLimit setting.
 
=== Balance ===
 
The Balance action reports the current Balance setting.
 
=== SetBalance ===
 
The SetBalance action provides a means of setting the Balance to a specific value.
 
 
 
=== BalanceInc===
 
The BalanceInc action provides a means of increasing the Balance by 1.
 
=== BalanceDec ===
 
The BalanceDec action provides a means of decreasing the Balance by 1.
 
=== Fade ===
 
The Fade action reports the current Fade setting of the product.
 
==== SetFade ====
 
The SetFade action provides a means of setting the Fade to a specific value.
 
=== FadeInc===
 
The FadeInc action provides a means of increasing the Fade by 1.
 
 
 
=== FadeDec ===
 
The FadeDec action provides a means of decreasing the Fade by 1.
 
=== Mute ===
 
The Mute action reports the current Mute state of the product.
 
=== SetMute ===
 
The SetMute action provides a means of setting the Mute state.
 
 
 
=== Characteristics ===
 
The Characteristics action returns all '''six''' characteristic values of the product.
 
 
 
= API Reference =
 
 
 
[http://oss.linn.co.uk/trac/browser/Main/LibUpnpCil/Services/Openhome/Volume1.xml Volume Service Description (XML)]
 
 
 
= Migration Guide =
 
The Volume service replaces the '''Preamp''' service that existed in Cara. All preamp actions relating to configuration have been removed as part of the migration to the Volume service. The exception to this is the '''VolumeLimit''' action. This remains to allow reporting of the current value of VolumeLimit.
 
 
 
The domain for the Cara Preamp service was '''linn.co.uk'''. The domain for the Volume service is '''av.openhome.org'''.
 
 
 
 
 
== Actions ==
 
 
 
=== Changed Actions ===
 
====Volume====
 
The arguments have changed their names as follows:
 
*aVolume -> Value
 
=== SetVolume===
 
The arguments have changed their names as follows:
 
*aVolume -> Value
 
===Balance===
 
The arguments have changed their names as follows:
 
*aBalance -> Value
 
===SetBalance===
 
The arguments have changed their names as follows:
 
*aBalance -> Value
 
 
 
===Mute===
 
The arguments have changed their names as follows:
 
*aMute -> Value
 
===SetMute===
 
The arguments have changed their names as follows:
 
*aMute -> Value
 
 
 
===VolumeLimit===
 
The arguments have changed their names as follows:
 
*aVolumeLimit -> Value
 
 
 
=== New Actions ===
 
*Fade
 
*SetFade
 
*FadeInc
 
*FadeDec
 
*BalanceInc
 
*BalanceDec
 
*Characteristics
 
 
 
=== Obsolete Actions ===
 
 
 
*SetVolumeLimit
 
*SetStartupVolume
 
*StartupVolume
 
*SetStartupVolumeEnabled
 
*StartupVolumeEnabled
 

Revision as of 13:35, 24 March 2015