alsa, revid: reverted changes to revid and changed how ALSA implements Device

device/alsa/alsa.go

@@ -116,11 +116,11 @@ func (d *ALSA) Name() string {
 	return "ALSA"
 }
 
-// Set will take a Config struct, check the validity of the relevant fields
+// Setup will take a Config struct, check the validity of the relevant fields
 // and then performs any configuration necessary. If fields are not valid,
 // an error is added to the multiError and a default value is used.
 // It then initialises the ALSA device which can then be started, read from, and stopped.
-func (d *ALSA) Set(c config.Config) error {
+func (d *ALSA) Setup(c config.Config) error {
 	var errs device.MultiError
 	if c.SampleRate <= 0 {
 		errs = append(errs, errInvalidSampleRate)
@@ -185,6 +185,14 @@ func (d *ALSA) Set(c config.Config) error {
 	return nil
 }
 
+// Set exists to satisfy the implementation of the Device interface that revid uses.
+// Everything that would usually be in Set is in the Setup function.
+// This is because an ALSA device is different to other devices in that it
+// outputs binary non-packetised data and it requires a different configuration procedure.
+func (d *ALSA) Set(c config.Config) error {
+	return nil
+}
+
 // Start will start recording audio and writing to the ringbuffer.
 // Once an ALSA device has been stopped it cannot be started again. This is likely to change in future.
 func (d *ALSA) Start() error {

revid/audio_linux.go

@@ -41,7 +41,7 @@ func (r *Revid) setupAudio() error {
 
 	// Configure ALSA device.
 	r.cfg.Logger.Log(logger.Debug, "configuring input device")
-	err := r.input.Set(r.cfg)
+	err := d.Setup(r.cfg)
 	if err != nil {
 		r.cfg.Logger.Log(logger.Warning, "errors from configuring input device", "errors", err)
 	}

revid/revid.go

@@ -392,12 +392,6 @@ func (r *Revid) setupPipeline(mtsEnc func(dst io.WriteCloser, rate float64) (io.
 		}
 	}
 
-	// input.Set does not need to be called for InputAudio since it is called
-	// in setupAudio above, so we can return here.
-	if r.cfg.Input == config.InputAudio {
-		return nil
-	}
-
 	// Configure the input device. We know that defaults are set, so no need to
 	// return error, but we should log.
 	r.cfg.Logger.Log(logger.Debug, "configuring input device")