diff --git a/revid/revid_test.go b/revid/revid_test.go
index 6f2fd6df..d88e4e9a 100644
--- a/revid/revid_test.go
+++ b/revid/revid_test.go
@@ -14,6 +14,8 @@ const raspividPath = "/usr/local/bin/raspivid"
 // Suppress all test logging, except for t.Errorf output.
 var silent bool
 
+// TestRaspivid tests that raspivid starts correctly.
+// It is intended to be run on a Raspberry Pi.
 func TestRaspivid(t *testing.T) {
 	if _, err := os.Stat(raspividPath); os.IsNotExist(err) {
 		t.Skip("Skipping TestRaspivid since no raspivid found.")
@@ -44,6 +46,7 @@ func TestRaspivid(t *testing.T) {
 // testLogger implements a netsender.Logger.
 type testLogger struct{}
 
+// SetLevel normally sets the logging level, but it is a no-op in our case.
 func (tl *testLogger) SetLevel(level int8) {
 }
 
@@ -56,8 +59,7 @@ func (tl *testLogger) Log(level int8, msg string, params ...interface{}) {
 	if !silent {
 		fmt.Printf("%s: %s\n", logLevels[level+1], msg)
 	}
-	if level >= 4 {
-		// Error or Fatal
+	if level == 5 {
 		buf := make([]byte, 1<<16)
 		size := runtime.Stack(buf, true)
 		fmt.Printf("%s\n", string(buf[:size]))