sdk-hwV1.3/target/allwinner/v851s3-fastboot_sl100_front/busybox-init-base-files/etc/asound.conf

hook_args.HookArgsDefault [
    {
        name "LINEOUT Switch"
        preserve true
        optional true
        value 1
    }
    {
        name "SPK Switch"
        preserve true
        optional true
        value 1
    }
    {
        name "LINEOUT Output Select"
        preserve true
        optional true
        value "differ" #value=1, "single" value=0
    }
#    {
#        name "LINEOUT volume"
#        preserve true
#        optional true
#        value 31
#    }
    {
        name "MIC1 Switch"
        preserve true
        optional true
        value 1
    }
    {
        name "MIC1 Input Select"
        preserve true
        optional true
        value "differ" #value=0, "single" value=1
    }
#    {
#        name "MIC1 gain volume"
#        preserve true
#        optional true
#        value 31
#    }
]

hook_args.HookArgsPlayback [
    {
        name "LINEOUT Switch"
        preserve true
        optional true
        value 1
    }
    {
        name "SPK Switch"
        preserve true
        optional true
        value 1
    }
    {
        name "LINEOUT Output Select"
        preserve true
        optional true
        value "differ"
    }
#    {
#        name "LINEOUT volume"
#        preserve true
#        optional true
#        value 31
#    }
]

hook_args.HookArgsCapture [
    {
        name "MIC1 Switch"
        preserve true
        optional true
        value 1
    }
    {
        name "MIC1 Input Select"
        preserve true
        optional true
        value "differ"
    }
#    {
#        name "MIC1 gain volume"
#        preserve true
#        optional true
#        value 31
#    }
]
pcm.!default {
    type hooks
    slave {
        pcm {
            type asym
            playback.pcm "hw:{CARD=audiocodec, DEV=0}"
            capture.pcm "hw:0,0"
        }
    }
    hooks.0 {
        type ctl_elems
        hook_args HookArgsDefault
    }
}

pcm.PlaybackRateDmix {
    @args [ SAMPLERATE CHNNUM PERIODSIZE ]
    @args.SAMPLERATE {
        type integer
        default 16000
    }
    @args.CHNNUM {
        type integer
        default 1
    }
    @args.PERIODSIZE {
        type integer
        default 256 #1024
    }
    type plug
    slave.pcm {
        type softvol
        slave.pcm {
            type hooks
            slave.pcm {
                type dmix
                ipc_key 1111
                ipc_perm 0666
                slave {
                    pcm "hw:0,0"
                    format S16_LE
                    rate        $SAMPLERATE
                    channels    $CHNNUM
                    period_size $PERIODSIZE
                    periods 4
                }
            }
            hooks.0 {
                type ctl_elems
                hook_args HookArgsPlayback
            }
        }
        control {
            name "Soft Volume Master"
            card audiocodec
            count 1
        }
        min_dB -26.0
        max_dB 25.0
        resolution 256
    }
    rate_converter "linear" #"speexrate"
}

#pcm.resample rely on alsa-plugin and libspeexdsp. Select them in menuconfig if we want to use plugin pcm.resample.
pcm.resample {
    type plug
    slave {
        pcm "hw:0,0"
        format S16_LE
        rate 16000
        channels 1
    }
    rate_converter "speexrate"
}

pcm.CaptureMic Capture1MicHard

# I2SRTX's I2S_SAMPLERATE and I2S_CHNNUM must be same to PlaybackRateDmix's SAMPLERATE and CHNNUM!
pcm.I2SRTX {
    @args [ I2S_SAMPLERATE I2S_CHNNUM ]
    @args.I2S_SAMPLERATE {
        type integer
        default 16000
    }
    @args.I2S_CHNNUM {
        type integer
        default 1
    }
    type hooks
    slave.pcm {
        type plug
        slave {
            pcm "hw:snddaudio0,0"
            channels $I2S_CHNNUM
            rate $I2S_SAMPLERATE
        }
    }
    hooks.0 {
        type ctl_elems
        hook_args [
            {
                name "loopback debug"
                preserve true
                optional true
                value 1
            }
        ]
    }
}

#pcm.CaptureI2SRX {
#    type hooks
#    slave.pcm "hw:snddaudio0,0"
#    hooks.0 {
#        type ctl_elems
#        hook_args [
#            {
#                name "loopback debug"
#                preserve true
#                optional true
#                value 1
#            }
#        ]
#    }
#}

#pcm_slave.slaveCap {
#    @args [ PCMID CHNNUM ]
#    @args.PCMID {
#        type string
#    }
#    @args.CHNNUM {
#        type integer
#    }
#    pcm $PCMID
#    channels $CHNNUM
#}

#pcm_slave.slaveMultiCapture {
#    pcm {
#        type multi
#        slaves {
#            a "slaveCap:CaptureMic,1"
#            b "slaveCap:CaptureI2SRX,1"
#        }
#        bindings {
#            0 {slave a channel 0}
#            1 {slave b channel 0}
#        }
#    }
#}

#pcm.CaptureDouble {
#    type plug
#    slave slaveMultiCapture
#    ttable.0.0 1
#    ttable.1.1 1
#}

#we define pcm capture plugin naming convention:
#pcm.Capture<n>Mic:<SampleRate>, <n>: the number of MIC. It can auto convert to indicated channels. <SampleRate>: set sample rate to Hardware PCM.
#pcm.Capture<n>MicPlusAec, if enable aec, add PlusAec. It forbids to auto convert to multi channels because of aec.
# ref to GenerateCaptureIdentifier() in [audio_hw.c]
#e.g.:
#pcm.Capture1Mic:16000
#pcm.Capture1MicPlusAec
#pcm.Capture2Mic:16000
#pcm.Capture2MicPlusAec
pcm.Capture1Mic {
    @args [ SAMPLERATE ]
    @args.SAMPLERATE {
        type integer
        default 16000
    }
    type hooks
    slave.pcm {
        type plug
        slave {
            pcm "hw:0,0"
            channels 1
            rate $SAMPLERATE
        }
    }
    hooks.0 {
        type ctl_elems
        hook_args HookArgsCapture
    }
}

pcm.Capture1MicHard {
    type hooks
    slave.pcm "hw:0,0"
    hooks.0 {
        type ctl_elems
        hook_args HookArgsCapture
    }
}
pcm.Capture1MicPlusAec {
    type route
    slave.pcm {
        type multi
        slaves {
            a {pcm Capture1MicHard channels 1}
            b {pcm I2SRTX channels 1}
        }
        bindings {
            0 {slave a channel 0}
            1 {slave b channel 0}
        }
    }
    ttable.0.0 1
    ttable.1.1 1
}

pcm.Capture2Mic {
    @args [ SAMPLERATE ]
    @args.SAMPLERATE {
        type integer
        default 16000
    }
    type hooks
    slave.pcm {
        type plug
        slave {
            pcm "hw:0,0"
            channels 2
            rate $SAMPLERATE
        }
    }
    hooks.0 {
        type ctl_elems
        hook_args [
            {
                name "MIC1 Switch"
                preserve true
                optional true
                value 1
            }
            {
                name "MIC1 Input Select"
                preserve true
                optional true
                value "differ"
            }
            {
                name "MIC2 Switch"
                preserve true
                optional true
                value 1
            }
            {
                name "MIC2 Input Select"
                preserve true
                optional true
                value "differ"
            }
        ]
    }
}

pcm.Capture2MicHard {
    type hooks
    slave.pcm "hw:0,0"
    hooks.0 {
        type ctl_elems
        hook_args [
            {
                name "MIC1 Switch"
                preserve true
                optional true
                value 1
            }
            {
                name "MIC1 Input Select"
                preserve true
                optional true
                value "differ"
            }
            {
                name "MIC2 Switch"
                preserve true
                optional true
                value 1
            }
            {
                name "MIC2 Input Select"
                preserve true
                optional true
                value "differ"
            }
        ]
    }
}
pcm.Capture2MicPlusAec {
    type route
    slave.pcm {
        type multi
        slaves {
            a {pcm Capture2MicHard channels 2}
            b {pcm I2SRTX channels 1}
        }
        bindings {
            0 {slave a channel 0}
            1 {slave a channel 1}
            2 {slave b channel 0}
        }
    }
    ttable.0.0 1
    ttable.1.1 1
    ttable.2.2 1
}

pcm.eq {
    type awequal
    slave.pcm "hw:0,0"
    config_file "/etc/awequal.conf"
    tuning_support true
    verbose true
}