[pulseaudio-discuss] When multiple sink inputs are connected to a same sink, how are the audio streams are mixed?

[Colin Guthrie]

'Twas brillig, and Lin, Mengdong at 29/05/11 04:57 did gyre and gimble:
> When multiple sink inputs are connected to a same sink, how are the
> audio streams of different formats are mixed?
> 
>  
> 
> E.g. A Bluetooth sink is connected to 2 sink input streams, how does the
> sink handle different audio formats such as sampling frequency? E.g. one
> sink input is 44100HZ stereo (music player) and the other is 16000HZ
> mono (Gtalk)? Is pulseaudio or the Bluetooth headset handle the mixing?

All the mixing is handled in PulseAudio (at least this is how it works
for other things and while I don't know the bluetooth code well, I
presume it's the same).

We always resample to the device's sample rate, then mix the streams
together.

In git master we also support passthrough now. When passthrough is used
(e.g. mp3 to the BT device) then only one stream at a time is used.

Col

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Colin Guthrie
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http://colin.guthr.ie/

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