diff --git a/device/alsa/alsa.go b/device/alsa/alsa.go
index e4db1c31..970a325f 100644
--- a/device/alsa/alsa.go
+++ b/device/alsa/alsa.go
@@ -45,11 +45,10 @@ import (
 )
 
 const (
-	pkg               = "alsa: "
-	rbTimeout         = 100 * time.Millisecond
-	rbNextTimeout     = 2000 * time.Millisecond
-	rbLen             = 200
-	defaultSampleRate = 48000
+	pkg           = "alsa: "
+	rbTimeout     = 100 * time.Millisecond
+	rbNextTimeout = 2000 * time.Millisecond
+	rbLen         = 200
 )
 
 // "running" means the input goroutine is reading from the ALSA device and writing to the ringbuffer.
@@ -61,6 +60,23 @@ const (
 	stopped
 )
 
+const (
+	defaultSampleRate = 48000
+	defaultBitDepth   = 16
+	defaultChannels   = 1
+	defaultRecPeriod  = 1.0
+	defaultCodec      = codecutil.PCM
+)
+
+// Configuration field errors.
+var (
+	errInvalidSampleRate = errors.New("invalid sample rate, defaulting")
+	errInvalidChannels   = errors.New("invalid number of channels, defaulting")
+	errInvalidBitDepth   = errors.New("invalid bitdepth, defaulting")
+	errInvalidRecPeriod  = errors.New("invalid record period, defaulting")
+	errInvalidCodec      = errors.New("invalid audio codec, defaulting")
+)
+
 // An ALSA device holds everything we need to know about the audio input stream and implements io.Reader and device.AVDevice.
 type ALSA struct {
 	l      Logger        // Logger for device's routines to log to.
@@ -107,19 +123,24 @@ func (d *ALSA) Name() string {
 func (d *ALSA) Set(c config.Config) error {
 	var errs device.MultiError
 	if c.SampleRate <= 0 {
-		errs = append(errs, fmt.Errorf("invalid sample rate: %v", c.SampleRate))
+		errs = append(errs, errInvalidSampleRate)
+		c.SampleRate = defaultSampleRate
 	}
 	if c.Channels <= 0 {
-		errs = append(errs, fmt.Errorf("invalid number of channels: %v", c.Channels))
+		errs = append(errs, errInvalidChannels)
+		c.Channels = defaultChannels
 	}
 	if c.BitDepth <= 0 {
-		errs = append(errs, fmt.Errorf("invalid bitdepth: %v", c.BitDepth))
+		errs = append(errs, errInvalidBitDepth)
+		c.BitDepth = defaultBitDepth
 	}
 	if c.RecPeriod <= 0 {
-		errs = append(errs, fmt.Errorf("invalid recording period: %v", c.RecPeriod))
+		errs = append(errs, errInvalidRecPeriod)
+		c.RecPeriod = defaultRecPeriod
 	}
-	if !codecutil.IsValid(c.InputCodec) {
-		errs = append(errs, errors.New("invalid codec"))
+	if c.InputCodec != codecutil.ADPCM && c.InputCodec != codecutil.PCM {
+		errs = append(errs, errInvalidCodec)
+		c.InputCodec = defaultCodec
 	}
 	d.Config = Config{
 		SampleRate: c.SampleRate,
diff --git a/revid/config/config.go b/revid/config/config.go
index 52a1264c..9f6a776b 100644
--- a/revid/config/config.go
+++ b/revid/config/config.go
@@ -50,7 +50,6 @@ const (
 	InputAudio
 
 	// Outputs.
-	OutputAudio
 	OutputRTMP
 	OutputRTP
 	OutputHTTP
diff --git a/revid/config/variables.go b/revid/config/variables.go
index 0f0b6af5..12959c8d 100644
--- a/revid/config/variables.go
+++ b/revid/config/variables.go
@@ -40,20 +40,19 @@ import (
 // Default variable values.
 const (
 	// General revid defaults.
-	defaultInput           = InputRaspivid
-	defaultOutput          = OutputHTTP
-	defaultInputCodec      = codecutil.H264
-	defaultVerbosity       = logger.Error
-	defaultRTPAddr         = "localhost:6970"
-	defaultCameraIP        = "192.168.1.50"
-	defaultBurstPeriod     = 10 // Seconds
-	defaultMinFrames       = 100
-	defaultFrameRate       = 25
-	defaultWriteRate       = 25
-	defaultClipDuration    = 0
-	defaultAudioInputCodec = codecutil.ADPCM
-	defaultPSITime         = 2
-	defaultFileFPS         = 0
+	defaultInput        = InputRaspivid
+	defaultOutput       = OutputHTTP
+	defaultInputCodec   = codecutil.H264
+	defaultVerbosity    = logger.Error
+	defaultRTPAddr      = "localhost:6970"
+	defaultCameraIP     = "192.168.1.50"
+	defaultBurstPeriod  = 10 // Seconds
+	defaultMinFrames    = 100
+	defaultFrameRate    = 25
+	defaultWriteRate    = 25
+	defaultClipDuration = 0
+	defaultPSITime      = 2
+	defaultFileFPS      = 0
 
 	// Ring buffer defaults.
 	defaultRBCapacity     = 50000000 // => 50MB
@@ -138,6 +137,11 @@ var Variables = []struct {
 			}
 		},
 	},
+	{
+		Name:   "Channels",
+		Type_:  "uint",
+		Update: func(c *Config, v string) { c.Channels = parseUint("Channels", v, c) },
+	},
 	{
 		Name:   "Exposure",
 		Type_:  "enum:auto,night,nightpreview,backlight,spotlight,sports,snow,beach,verylong,fixedfps,antishake,fireworks",
@@ -243,14 +247,8 @@ var Variables = []struct {
 			switch c.InputCodec {
 			case codecutil.H264, codecutil.MJPEG, codecutil.PCM, codecutil.ADPCM:
 			default:
-				switch c.Input {
-				case OutputAudio:
-					c.LogInvalidField("InputCodec", defaultAudioInputCodec)
-					c.InputCodec = defaultAudioInputCodec
-				default:
-					c.LogInvalidField("InputCodec", defaultInputCodec)
-					c.InputCodec = defaultInputCodec
-				}
+				c.LogInvalidField("InputCodec", defaultInputCodec)
+				c.InputCodec = defaultInputCodec
 			}
 		},
 	},
@@ -449,6 +447,17 @@ var Variables = []struct {
 			c.RBWriteTimeout = lessThanOrEqual("RBWriteTimeout", c.RBWriteTimeout, 0, c, defaultRBWriteTimeout)
 		},
 	},
+	{
+		Name:  "RecPeriod",
+		Type_: "float",
+		Update: func(c *Config, v string) {
+			_v, err := strconv.ParseFloat(v, 64)
+			if err != nil {
+				c.Logger.Log(logger.Warning, fmt.Sprintf("invalid %s param", "RecPeriod"), "value", v)
+			}
+			c.RecPeriod = _v
+		},
+	},
 	{
 		Name:   "Rotation",
 		Type_:  "uint",
@@ -470,6 +479,11 @@ var Variables = []struct {
 			}
 		},
 	},
+	{
+		Name:   "SampleRate",
+		Type_:  "uint",
+		Update: func(c *Config, v string) { c.SampleRate = parseUint("SampleRate", v, c) },
+	},
 	{
 		Name:  "Saturation",
 		Type_: "int",