[pulseaudio-discuss] Virtual audio cable - high cpu usage

[Sean Greenslade]

On Tue, Feb 02, 2021 at 10:40:51AM +0100, Renaud GHIA wrote:
> Hi,
> 
> Below the result of the command "pacmd list".
> Here without any change of resampling method.

This part here shows your ffmpeg client:

>     index: 1
> driver: <protocol-native.c>
> flags:
> state: RUNNING
> source: 2 <VACmic>
> volume: front-left: 65536 / 100% / 0.00 dB,   front-right: 65536 / 100% /
> 0.00 dB
>        balance 0.00
> muted: no
> current latency: 0.50 ms
> requested latency: 2000.00 ms
> sample spec: s16le 2ch 48000Hz
> channel map: front-left,front-right
>             Stereo
> resample method: speex-float-1

It seems like ffmpeg is requesting 48 kHz audio, so pulse is forced to
resample. If possible, can you try running your ffmpeg process with the
flag "-sample_rate 44100" and see if that reduces the CPU usage?

Everything else in your pulse chain is 44.1 kHz, so with that change
there should be no resampling at all.

--Sean