Capturing Audio using amixer(Processor I am using is IMX8MP)

[saksham98123]

Hello,

I have a pdm microphone connected to the board.

I am using the amixer driver and it has been loaded without errors. Now I having some trouble capturing the audio.

saksham98123_0-1623180007436.png

I have also tried the following command:

gst-launch-1.0 -v alsasrc device=plughw:1,0 ! queue ! audioconvert ! audio/x-raw, rate=16000 ! vorbisenc ! oggmux ! filesink location=alsasrc.ogg

the ouput of the above command:

saksham98123_1-1623180007459.png

After the above command the dmesg | grep micfil output:

saksham98123_2-1623180007490.png

Using amixer sset Channel_ID I can change the decibel level.

What amixer command should I use to go about capturing the audio? How would I know which audio device to use?

[igorpadykov]

Hi Saksham

for amixer usage one can look at sect.7.5 Audio Mixer (AUDMIX)   i.MX Linux Reference Manual​

and examples in

https://source.codeaurora.org/external/imx/imx-test/tree/test/mxc_amix_test?h=lf-5.10.y_1.0.0

Best regards
igor

[saksham98123]

HI Igor,

Thanks for getting back to me, the manual you have referred me to look at I have went over it and I haven't found anything concrete please provide further guidance.

Secondly I was hoping you can give me more in site on the error:

[116004.923246] fsl-micfil-dai 30ca0000.micfil: ASoC: can't open component 30ca0000.micfil: -6
[116032.879723] fsl-micfil-dai 30ca0000.micfil: ASoC: can't open component 30ca0000.micfil: -6
[116440.582560] fsl-micfil-dai 30ca0000.micfil: ASoC: can't open component 30ca0000.micfil: -6

Does the error above indicate a problem with the device tree or the driver not being loaded properly? I am starting to believe this might not have anything to do with capturing audio but the driver not being able to load properly.

Cheers

Saksham Nanda

[igorpadykov]

Hi Saksham

what bsp and dts used in the case, one can look at below (compatible = "fsl,imx8mp-micfil"; compatible = "fsl,imx-audio-micfil"; model = "imx-audio-micfil";)

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8mp-evk.d...

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8mp.dtsi?...

One can try to debug it using sect.7.6.4.2 Source Code Structure i.MX Linux Reference Manual​

https://source.codeaurora.org/external/imx/linux-imx/tree/sound/soc/fsl/fsl_micfil.c?h=imx_5.4.70_2....

Best regards
igor