[pulseaudio-tickets] [PulseAudio] #611: Flat Volume briefly increases volume of existing streams

[PulseAudio]

#611: Flat Volume briefly increases volume of existing streams
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  Reporter:  sladi        |       Owner:  lennart
      Type:  enhancement  |      Status:  new    
 Milestone:               |   Component:  daemon 
Resolution:               |    Keywords:         
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Changes (by Baughn):

 * cc: sveina at gmail.com (added)


Comment:

 The inverse effect occurs when a quiet stream stops playing: The device
 volume is increased a moment too soon, before the stream buffer is fully
 drained, which results in a moment of potentially ear-damaging noise.

 The (apparent) ideal solution would be to have the volume adjustments
 inline with the samples, to be automatically processed by the sound card.
 I very much doubt that this is possible.

 One compromise that would still be an improvement is to do the volume
 adjustment after the stream ends; however, this is not the best  possible
 solution. In general, sudden volume adjustments should never be made while
 a stream is playing, due to possible issues with creating harmonics that
 could even, theoretically, damage equipment. The latter is admittedly very
 unlikely in practice.

 A better solution would seem to be to gradually adjust the volume over a
 period of time; reducing the device volume while increasing the stream
 volume, and vice versa. While there's still a possibility of timing errors
 here, due to the low speed of the changes, it would hopefully not be
 noticable. Pulseaudio could still use an instant change before/after the
 stream plays in the cases where no other streams are simultaneously
 playing.

 Moral: In general, don't do sudden changes of the hardware volume while
 said hardware is in use, or if it was in use a moment ago; you may be
 mistaken about buffering.

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Ticket URL: <http://pulseaudio.org/ticket/611#comment:1>
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