Fix aac.DecodeConfig sampleRate parsing

pkg/aac/aac.go

@@ -69,6 +69,8 @@ func DecodeConfig(b []byte) (objType, sampleFreqIdx, channels byte, sampleRate u
 	sampleFreqIdx = rd.ReadBits8(4)
 	if sampleFreqIdx == 0b1111 {
 		sampleRate = rd.ReadBits(24)
+	} else {
+		sampleRate = sampleRates[sampleFreqIdx]
 	}
 
 	channels = rd.ReadBits8(4)

pkg/aac/aac_test.go

@@ -41,3 +41,12 @@ func TestADTS(t *testing.T) {
 
 	require.Equal(t, src[:len(dst)], dst)
 }
+
+func TestEncodeConfig(t *testing.T) {
+	conf := EncodeConfig(TypeAACLC, 48000, 1, false)
+	require.Equal(t, "1188", hex.EncodeToString(conf))
+	conf = EncodeConfig(TypeAACLC, 16000, 1, false)
+	require.Equal(t, "1408", hex.EncodeToString(conf))
+	conf = EncodeConfig(TypeAACLC, 8000, 1, false)
+	require.Equal(t, "1588", hex.EncodeToString(conf))
+}