Peer rename + details box on Connectivity tab; Add band dialog fixes

Add band dialog (from testing feedback):
 * Tab order is now Start, End, Gain, OK, Cancel (OK was after Cancel).
 * Gain box takes decimals like 1.5 (half-dB steps); parametric list shows one decimal.
 * The two frequency boxes start empty — nothing prepopulated to mislead; both required on OK.

New Connectivity-tab feature (held for next release):
 * Rename peer (Alt+M) opens a dialog to give a peer a friendly name, with a Clear custom name
   button. Names are keyed by the peer's MACHINE NAME (stable across restarts, IP changes and
   networks), stored machine-wide in AppConfig.PeerFriendlyNames, and resolved everywhere a peer
   shows: both peer lists (via PeerListItem.DisplayNameProvider), the volume/pan/EQ list, the
   status line and split-recording filenames. Manual-by-IP peers with no announced name fall back
   to keying by address.
 * Peer details (Alt+E): a read-only box for the highlighted connected peer showing name, machine
   name, IP, connected-for, link health + ping, what they're sending, and whether they're
   receiving our audio. "Sending: 2 devices on ASIO at 48 kHz, Opus" is derived from the live
   receive streams — each stream is one device and its lane gives WASAPI vs ASIO — so NO protocol
   change and no new privacy exposure. AudioReceiver.ActiveFormatsFromAddress added for this.

Manual updated (readme.html + MANUAL.md). Build clean; --selftest passes; deployed to both test
folders. Held for next release.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/RemSound.App/AddBandDialog.cs

@@ -1,22 +1,25 @@
+using System.Globalization;
 using RemSound.Core;
 
 namespace RemSound.App;
 
 /// <summary>Modal dialog for adding one parametric EQ band. The user sets a start frequency, an end
 /// frequency and a gain; all three are spin-or-type boxes that refuse non-numbers and clamp to range.
-/// While the dialog is open it previews the in-progress band live (so the peer's sound changes as the
-/// values move); OK keeps the band, Cancel/Escape drops it and reverts the preview.</summary>
+/// The two frequency boxes start EMPTY (no prepopulated value to mislead the user); the gain defaults
+/// to a gentle boost. While the dialog is open it previews the in-progress band live (so the peer's
+/// sound changes as the values move); OK keeps the band, Cancel/Escape drops it and reverts.</summary>
 internal sealed class AddBandDialog : Form
 {
     private readonly NumericUpDown startFreq = new()
     {
         Minimum = (decimal)PeerEqBands.ParametricMinHz,
         Maximum = (decimal)PeerEqBands.ParametricMaxHz,
-        Value = 200,
+        Value = (decimal)PeerEqBands.ParametricMinHz,
         Increment = 10,
         DecimalPlaces = 0,
         Width = 120,
         TextAlign = HorizontalAlignment.Right,
+        TabIndex = 0,
         AccessibleName = "Start frequency in Hertz (Alt+S)",
     };
 
@@ -24,11 +27,12 @@ internal sealed class AddBandDialog : Form
     {
         Minimum = (decimal)PeerEqBands.ParametricMinHz,
         Maximum = (decimal)PeerEqBands.ParametricMaxHz,
-        Value = 2000,
+        Value = (decimal)PeerEqBands.ParametricMinHz,
         Increment = 10,
         DecimalPlaces = 0,
         Width = 120,
         TextAlign = HorizontalAlignment.Right,
+        TabIndex = 1,
         AccessibleName = "End frequency in Hertz (Alt+E)",
     };
 
@@ -37,27 +41,24 @@ internal sealed class AddBandDialog : Form
         Minimum = -(decimal)PeerEqBands.MaxGainDb,
         Maximum = (decimal)PeerEqBands.MaxGainDb,
         Value = 3,
-        Increment = 1,
-        DecimalPlaces = 0,
+        Increment = 0.5m,       // allow half-dB steps; typing any value like 1.5 works too
+        DecimalPlaces = 1,
         Width = 120,
         TextAlign = HorizontalAlignment.Right,
+        TabIndex = 2,
         AccessibleName = "Gain in dB (Alt+G)",
     };
 
     private readonly Action<ParametricBand?>? livePreview;
+    private ParametricBand? resultBand;
     private bool accepted;
 
     /// <summary>The band the user built, valid only when <see cref="Form.ShowDialog()"/> returned OK.</summary>
-    public ParametricBand Result => new()
-    {
-        StartHz = (float)startFreq.Value,
-        EndHz = (float)endFreq.Value,
-        GainDb = (float)gainDb.Value,
-    };
+    public ParametricBand Result => resultBand ?? new ParametricBand();
 
     /// <param name="livePreview">Called with the in-progress band on every value change so the caller
-    /// can apply it to the peer in real time, and with null when the dialog is cancelled/closed so the
-    /// caller reverts to the saved shaping.</param>
+    /// can apply it to the peer in real time, and with null when the band is incomplete or the dialog
+    /// is cancelled/closed so the caller reverts to the saved shaping.</param>
     public AddBandDialog(Action<ParametricBand?>? livePreview = null)
     {
         this.livePreview = livePreview;
@@ -84,29 +85,39 @@ internal sealed class AddBandDialog : Form
         AddRow(grid, 1, "&End frequency in Hz (Alt+E)", endFreq);
         AddRow(grid, 2, "&Gain in dB (Alt+G)", gainDb);
 
-        var okButton = new Button { Text = "OK", AutoSize = true, DialogResult = DialogResult.None };
-        var cancelButton = new Button { Text = "Cancel", AutoSize = true, DialogResult = DialogResult.Cancel };
+        var okButton = new Button { Text = "OK", AutoSize = true, DialogResult = DialogResult.None, TabIndex = 0 };
+        var cancelButton = new Button { Text = "Cancel", AutoSize = true, DialogResult = DialogResult.Cancel, TabIndex = 1 };
         okButton.Click += (_, _) => TryAccept();
 
+        // OK before Cancel, in both tab order and left-to-right layout.
         var buttonRow = new FlowLayoutPanel
         {
             Dock = DockStyle.Fill,
-            FlowDirection = FlowDirection.RightToLeft,
+            FlowDirection = FlowDirection.LeftToRight,
             AutoSize = true,
+            TabIndex = 3,
         };
-        buttonRow.Controls.Add(cancelButton);
         buttonRow.Controls.Add(okButton);
+        buttonRow.Controls.Add(cancelButton);
         grid.Controls.Add(buttonRow, 1, 3);
 
         Controls.Add(grid);
         AcceptButton = okButton;
         CancelButton = cancelButton;
 
-        startFreq.ValueChanged += (_, _) => Preview();
-        endFreq.ValueChanged += (_, _) => Preview();
-        gainDb.ValueChanged += (_, _) => Preview();
+        foreach (var box in new[] { startFreq, endFreq, gainDb })
+        {
+            box.ValueChanged += (_, _) => Preview();
+            box.TextChanged += (_, _) => Preview();
+        }
 
-        Shown += (_, _) => { startFreq.Focus(); Preview(); };
+        Shown += (_, _) =>
+        {
+            // Blank the two frequency boxes so nothing is prepopulated; the user must enter both.
+            startFreq.Text = "";
+            endFreq.Text = "";
+            startFreq.Focus();
+        };
     }
 
     // The mnemonic hint is embedded in each NumericUpDown's AccessibleName; the label carries the
@@ -114,41 +125,72 @@ internal sealed class AddBandDialog : Form
     private static void AddRow(TableLayoutPanel grid, int row, string labelText, NumericUpDown box)
     {
         var label = new Label { Text = labelText, AutoSize = true, Anchor = AnchorStyles.Left, Margin = new Padding(0, 6, 8, 0) };
-        // A plain Label with '&' wires the mnemonic to the next control in tab order (the box).
         grid.Controls.Add(label, 0, row);
         grid.Controls.Add(box, 1, row);
     }
 
-    private ParametricBand Current() => new()
+    private static bool TryReadHz(NumericUpDown box, out float hz)
     {
-        StartHz = (float)startFreq.Value,
-        EndHz = (float)endFreq.Value,
-        GainDb = (float)gainDb.Value,
-    };
+        hz = 0f;
+        var t = box.Text.Trim();
+        if (t.Length == 0) return false;
+        if (!float.TryParse(t, NumberStyles.Float, CultureInfo.CurrentCulture, out hz)) return false;
+        return hz >= PeerEqBands.ParametricMinHz && hz <= PeerEqBands.ParametricMaxHz;
+    }
 
-    private void Preview() => livePreview?.Invoke(Current());
+    private bool TryReadDb(out float db)
+    {
+        db = 0f;
+        var t = gainDb.Text.Trim();
+        if (t.Length == 0) return false;
+        if (!float.TryParse(t, NumberStyles.Float, CultureInfo.CurrentCulture, out db)) return false;
+        db = Math.Clamp(db, -PeerEqBands.MaxGainDb, PeerEqBands.MaxGainDb);
+        return true;
+    }
+
+    private void Preview()
+    {
+        if (TryReadHz(startFreq, out float s) && TryReadHz(endFreq, out float e) && e > s)
+            livePreview?.Invoke(new ParametricBand { StartHz = s, EndHz = e, GainDb = TryReadDb(out float d) ? d : 0f });
+        else
+            livePreview?.Invoke(null);   // incomplete / invalid → nothing to preview
+    }
 
     private void TryAccept()
     {
-        if (endFreq.Value <= startFreq.Value)
+        if (!TryReadHz(startFreq, out float s) || !TryReadHz(endFreq, out float e))
         {
-            var page = new TaskDialogPage
-            {
-                Caption = "Add EQ band",
-                Heading = "End frequency must be higher than start",
-                Text = $"The end frequency ({endFreq.Value:0} Hz) must be higher than the start frequency ({startFreq.Value:0} Hz). Adjust one of them and try again.",
-                Icon = TaskDialogIcon.Warning,
-                Buttons = { TaskDialogButton.OK },
-            };
-            TaskDialog.ShowDialog(this, page);
+            Warn("Enter both frequencies",
+                $"Enter a start and an end frequency, each between {PeerEqBands.ParametricMinHz:0} and {PeerEqBands.ParametricMaxHz:0} Hz.");
+            startFreq.Focus();
+            return;
+        }
+        if (e <= s)
+        {
+            Warn("End frequency must be higher than start",
+                $"The end frequency ({e:0} Hz) must be higher than the start frequency ({s:0} Hz). Adjust one of them and try again.");
             endFreq.Focus();
             return;
         }
+        resultBand = new ParametricBand { StartHz = s, EndHz = e, GainDb = TryReadDb(out float d) ? d : 0f };
         accepted = true;
         DialogResult = DialogResult.OK;
         Close();
     }
 
+    private void Warn(string heading, string text)
+    {
+        var page = new TaskDialogPage
+        {
+            Caption = "Add EQ band",
+            Heading = heading,
+            Text = text,
+            Icon = TaskDialogIcon.Warning,
+            Buttons = { TaskDialogButton.OK },
+        };
+        TaskDialog.ShowDialog(this, page);
+    }
+
     protected override void OnFormClosing(FormClosingEventArgs e)
     {
         base.OnFormClosing(e);

src/RemSound.App/MainForm.cs

@@ -268,6 +268,9 @@ public sealed class MainForm : Form
     private readonly CheckedListBox rememberedPeersList = new() { CheckOnClick = true, Width = 430, Height = 90, AccessibleName = "Remembered peers (Alt+R)" };
     private readonly Label rememberedPeersStatus = new() { AutoSize = true, Text = "No remembered peer selected." };
     private readonly Button manualAddButton = new() { Text = "Add peer by IP (Alt+&A)", AutoSize = true, AccessibleName = "Add peer by IP" };
+    // Read-only details for the peer highlighted in the connected list, and a button to give it a name.
+    private readonly TextBox peerDetailsBox = new() { Multiline = true, ReadOnly = true, Width = 430, Height = 132, ScrollBars = ScrollBars.Vertical, AccessibleName = "Peer details (Alt+E)" };
+    private readonly Button renamePeerButton = new() { Text = "Rena&me peer (Alt+M)", AutoSize = true, AccessibleName = "Rename peer" };
     // Per-profile "pin to exact addresses" toggle (#17). When ticked, RefreshKnownPeers skips the
     // discovered-peer merge and the address-follow, so the profile's peers stay exactly as the user set.
     private readonly AccessibleCheckBox lockPeerAddressesBox = new()
@@ -419,6 +422,12 @@ public sealed class MainForm : Form
     // Display labels for selected peers so we can render them in the dialog list even when
     // discovery has temporarily lost sight of them ("Foo (192.168.1.5) — offline").
     private readonly Dictionary<Guid, string> selectedPeerLabels = [];
+    // Custom friendly names, keyed by peer identity (machine name, else address). Loaded from AppConfig
+    // (machine-wide) at startup and mirrored back on rename. Resolved to display names everywhere a peer
+    // shows — connected/discovered lists, the volume/pan/EQ list, the status line, split recordings.
+    private Dictionary<string, string> peerFriendlyNames = new(StringComparer.OrdinalIgnoreCase);
+    // When each connected peer (by per-run InstanceId) first went healthy — for the "connected for" line.
+    private readonly Dictionary<Guid, DateTime> peerConnectedSinceUtc = [];
 
     // Anti-thrash state for the discovery-driven endpoint follow (see the peer-rebuild loop). A peer
     // reachable at two addresses at once (a VPN address AND a LAN address, say) announces from both,
@@ -842,6 +851,11 @@ public sealed class MainForm : Form
                 .Select(kv => (kv.Value.Address, selectedPeerLabels.GetValueOrDefault(kv.Key, kv.Value.Address.ToString())))
                 .ToList();
 
+        // Load the machine-wide friendly-name book and make every peer list resolve display names
+        // through it. Set before any list is built so names show from the first render.
+        peerFriendlyNames = new Dictionary<string, string>(AppConfig.Load().PeerFriendlyNames ?? new(), StringComparer.OrdinalIgnoreCase);
+        PeerListItem.DisplayNameProvider = ResolvePeerDisplayName;
+
         // --- Set accessibility names ---
         // For these four controls the keyboard shortcut is included explicitly in both the
         // visible label (set in BuildLayout) and the AccessibleName, instead of relying on the
@@ -2974,13 +2988,24 @@ public sealed class MainForm : Form
         // Preferences dialog (File → Preferences, Ctrl+P) as the last two items.
 
         // === Layout ===
-        // 6 rows: 0–2 the three peer lists, 3 manual-add, 4 the lock-to-fixed-addresses toggle, 5 status.
-        panel.RowCount = 6;
+        // 8 rows: 0 connected peers, 1 the details box + 2 rename button (both about the highlighted
+        // connected peer), 3–4 discovered & remembered lists, 5 manual-add, 6 the lock toggle, 7 status.
+        panel.RowCount = 8;
         FormLayoutRows.AddCheckedListRow(panel, 0, "Connected peers (Alt+&C)", connectedPeersList, connectedPeersStatus, FocusListControl);
-        FormLayoutRows.AddCheckedListRow(panel, 1, "Discovered peers (Alt+&D)", discoveredPeersList, discoveredPeersStatus, FocusListControl);
-        FormLayoutRows.AddCheckedListRow(panel, 2, "Remembered peers (Alt+&R)", rememberedPeersList, rememberedPeersStatus, FocusListControl);
-        panel.Controls.Add(new Label { Text = "Manual peer", AutoSize = true, Anchor = AnchorStyles.Left }, 0, 3);
-        panel.Controls.Add(manualAddButton, 1, 3);
+
+        // Details of, and a rename for, the peer highlighted in the connected list above.
+        var detailsLabel = new MnemonicLabel { Text = "Peer d&etails (Alt+E)", AutoSize = true, Anchor = AnchorStyles.Left, MnemonicTarget = peerDetailsBox };
+        detailsLabel.Click += (_, _) => peerDetailsBox.Focus();
+        panel.Controls.Add(detailsLabel, 0, 1);
+        panel.Controls.Add(peerDetailsBox, 1, 1);
+        renamePeerButton.Click += (_, _) => OnRenamePeer();
+        panel.Controls.Add(renamePeerButton, 1, 2);
+        connectedPeersList.SelectedIndexChanged += (_, _) => UpdatePeerDetails();
+
+        FormLayoutRows.AddCheckedListRow(panel, 3, "Discovered peers (Alt+&D)", discoveredPeersList, discoveredPeersStatus, FocusListControl);
+        FormLayoutRows.AddCheckedListRow(panel, 4, "Remembered peers (Alt+&R)", rememberedPeersList, rememberedPeersStatus, FocusListControl);
+        panel.Controls.Add(new Label { Text = "Manual peer", AutoSize = true, Anchor = AnchorStyles.Left }, 0, 5);
+        panel.Controls.Add(manualAddButton, 1, 5);
 
         lockPeerAddressesBox.Checked = settings.LoadLockPeerAddresses();
         lockPeerAddressesBox.CheckedChanged += (_, _) =>
@@ -2989,14 +3014,15 @@ public sealed class MainForm : Form
             MarkProfileDirty();
             logFile.Event($"lock peer addresses: {(lockPeerAddressesBox.Checked ? "on" : "off")}");
         };
-        panel.Controls.Add(lockPeerAddressesBox, 0, 4);
+        panel.Controls.Add(lockPeerAddressesBox, 0, 6);
         panel.SetColumnSpan(lockPeerAddressesBox, 2);
 
         // Connection status readout — last row, tab-into-able.
         var statusLabel = new MnemonicLabel { Text = "Connection status (Alt+&S)", AutoSize = true, Anchor = AnchorStyles.Left, MnemonicTarget = statusReadout };
         statusLabel.Click += (_, _) => statusReadout.Focus();
-        panel.Controls.Add(statusLabel, 0, 5);
-        panel.Controls.Add(statusReadout, 1, 5);
+        panel.Controls.Add(statusLabel, 0, 7);
+        panel.Controls.Add(statusReadout, 1, 7);
+        UpdatePeerDetails();
 
         // Initial render so the box has content the moment the user tabs into it.
         RefreshStatusReadout();
@@ -3495,12 +3521,19 @@ public sealed class MainForm : Form
 
     // dB spoken as words — most NVDA users run with punctuation off and would never hear a "+" sign,
     // so a boost must say "plus". ("minus" comes through on its own, but we spell both for symmetry.)
+    // The graphic sliders read whole dB; the parametric list keeps up to one decimal (e.g. 1.5 dB).
     private static string FormatGainDb(float db)
     {
         if (MathF.Abs(db) < 0.5f) return "flat";
         return db > 0 ? $"plus {db:0} dB" : $"minus {MathF.Abs(db):0} dB";
     }
 
+    private static string FormatGainDbPrecise(float db)
+    {
+        if (MathF.Abs(db) < 0.05f) return "flat";
+        return db > 0 ? $"plus {db:0.#} dB" : $"minus {MathF.Abs(db):0.#} dB";
+    }
+
     /// <summary>Whether a given peer is shaped right now: the profile-wide master switch AND that peer's
     /// own tick (per-peer bypass) both have to be on.</summary>
     private bool ShapingActiveFor(string? key)
@@ -3649,7 +3682,7 @@ public sealed class MainForm : Form
     private sealed class ParametricBandItem(ParametricBand band)
     {
         public ParametricBand Band { get; } = band;
-        public override string ToString() => $"{Band.StartHz:0} Hz to {Band.EndHz:0} Hz, {FormatGainDb(Band.GainDb)}";
+        public override string ToString() => $"{Band.StartHz:0} Hz to {Band.EndHz:0} Hz, {FormatGainDbPrecise(Band.GainDb)}";
     }
 
     /// <summary>Send-side controls: codec + packet size on row 0, lock-to-audio-clock on
@@ -4189,11 +4222,145 @@ public sealed class MainForm : Form
                 ? RoundToFive(rtt)
                 : null;
 
+            // Keep the friendly-name label fresh for the pan/EQ list, status line and recordings, and
+            // track when this peer first went healthy for the "connected for" line.
+            selectedPeerLabels[item.Peer.InstanceId] = ResolvePeerDisplayName(item.Peer);
+            if (isHealthy) { if (!peerConnectedSinceUtc.ContainsKey(item.Peer.InstanceId)) peerConnectedSinceUtc[item.Peer.InstanceId] = DateTime.UtcNow; }
+            else peerConnectedSinceUtc.Remove(item.Peer.InstanceId);
+
             if (item.ToString() != prevText)
             {
                 connectedPeersList.RefreshItemPublic(i);
             }
         }
+        UpdatePeerDetails();
+    }
+
+    // === Peer identity, friendly names, and the details box ===
+
+    /// <summary>The stable key a friendly name is stored under: the peer's machine name when it's a real
+    /// name, otherwise its address (the manual-by-IP case, where Name equals the address string).</summary>
+    private static string PeerIdentityKey(PeerAnnouncement peer)
+    {
+        var addr = peer.Address.ToString();
+        return string.IsNullOrWhiteSpace(peer.Name) || peer.Name == addr ? addr : peer.Name;
+    }
+
+    /// <summary>The name to show for a peer: its custom friendly name if set, else its machine name
+    /// (which for a manual-by-IP peer is the address). Used by every peer list via
+    /// <see cref="PeerListItem.DisplayNameProvider"/>.</summary>
+    private string ResolvePeerDisplayName(PeerAnnouncement peer)
+        => peerFriendlyNames.TryGetValue(PeerIdentityKey(peer), out var custom) && !string.IsNullOrWhiteSpace(custom)
+            ? custom
+            : peer.Name;
+
+    private PeerListItem? SelectedConnectedPeer() => SafeSelectedItem(connectedPeersList) as PeerListItem;
+
+    /// <summary>Refreshes the read-only details box for whichever peer is highlighted in the connected
+    /// list. Runs on selection change and each status tick (so "connected for" and ping stay live).</summary>
+    private void UpdatePeerDetails()
+    {
+        var item = SelectedConnectedPeer();
+        renamePeerButton.Enabled = item is not null;
+        var text = item is null ? "Select a connected peer to see its details." : BuildPeerDetailsText(item);
+        if (peerDetailsBox.Text != text) peerDetailsBox.Text = text;
+    }
+
+    private string BuildPeerDetailsText(PeerListItem item)
+    {
+        var peer = item.Peer;
+        var lines = new List<string>();
+        var display = ResolvePeerDisplayName(peer);
+        var machine = string.IsNullOrWhiteSpace(peer.Name) || peer.Name == peer.Address.ToString() ? null : peer.Name;
+
+        if (!string.Equals(display, machine, StringComparison.Ordinal) && !string.Equals(display, peer.Address.ToString(), StringComparison.Ordinal))
+            lines.Add($"Name: {display}");
+        lines.Add($"Machine name: {machine ?? "(unknown — added by address)"}");
+        lines.Add($"Address: {peer.Address}");
+
+        if (peerConnectedSinceUtc.TryGetValue(peer.InstanceId, out var since))
+            lines.Add($"Connected for: {DescribeDuration(DateTime.UtcNow - since)}");
+
+        if (item.Status.Connected)
+            lines.Add(item.Status.RttMs is { } rtt ? $"Link: healthy, ping {rtt} ms" : "Link: healthy");
+        else
+            lines.Add("Link: not connected");
+
+        lines.Add("Sending: " + DescribeSending(peer));
+        lines.Add("Receiving your audio: " + (item.Status.Sending ? "yes" : "no"));
+
+        return string.Join(Environment.NewLine, lines);
+    }
+
+    /// <summary>"2 devices on ASIO at 48 kHz, Opus" — built from the live receive streams (each stream is
+    /// one capture device; its lane tells us WASAPI vs ASIO). Falls back gracefully when we're not
+    /// receiving that peer.</summary>
+    private string DescribeSending(PeerAnnouncement peer)
+    {
+        var formats = receiver.ActiveFormatsFromAddress(peer.Address);
+        if (formats.Count == 0)
+            return peer.CanSend ? "yes — turn on Receive audio to see the details" : "no";
+
+        string deviceWord = formats.Count == 1 ? "1 device" : $"{formats.Count} devices";
+
+        var apis = formats.Select(f => f.Lane == RenderRoute.AsioLane ? "ASIO" : "WASAPI").Distinct().OrderBy(a => a).ToList();
+        string apiPart = apis.Count == 1 ? $" on {apis[0]}" : $" on {string.Join(" and ", apis)}";
+
+        var rates = formats.Select(f => f.SampleRate).Distinct().ToList();
+        string ratePart = rates.Count == 1 ? $" at {rates[0]} Hz" : "";
+
+        var codecs = formats.Select(f => ((AudioTransportCodec)f.Codec) == AudioTransportCodec.Opus ? "Opus" : "PCM").Distinct().ToList();
+        string codecPart = codecs.Count == 1 ? $", {codecs[0]}" : "";
+
+        return $"{deviceWord}{apiPart}{ratePart}{codecPart}";
+    }
+
+    private static string DescribeDuration(TimeSpan d)
+    {
+        if (d.TotalSeconds < 60) return $"{(int)d.TotalSeconds} seconds";
+        if (d.TotalMinutes < 60) return $"{(int)d.TotalMinutes} minute{((int)d.TotalMinutes == 1 ? "" : "s")}";
+        int hours = (int)d.TotalHours;
+        int mins = d.Minutes;
+        return mins == 0 ? $"{hours} hour{(hours == 1 ? "" : "s")}" : $"{hours} hour{(hours == 1 ? "" : "s")} {mins} minute{(mins == 1 ? "" : "s")}";
+    }
+
+    private void OnRenamePeer()
+    {
+        var item = SelectedConnectedPeer();
+        if (item is null) return;
+        var peer = item.Peer;
+        var key = PeerIdentityKey(peer);
+        var machineForDisplay = string.IsNullOrWhiteSpace(peer.Name) || peer.Name == peer.Address.ToString()
+            ? peer.Address.ToString()
+            : peer.Name;
+        peerFriendlyNames.TryGetValue(key, out var current);
+
+        using var dlg = new RenamePeerDialog(machineForDisplay, current);
+        if (dlg.ShowDialog(this) != DialogResult.OK) return;
+        ApplyFriendlyName(key, dlg.FriendlyName);
+    }
+
+    /// <summary>Store (or clear) a peer's friendly name in the machine-wide book, persist it, and
+    /// refresh every place a peer name shows.</summary>
+    private void ApplyFriendlyName(string identityKey, string? name)
+    {
+        if (string.IsNullOrWhiteSpace(name)) peerFriendlyNames.Remove(identityKey);
+        else peerFriendlyNames[identityKey] = name.Trim();
+
+        try
+        {
+            var cfg = AppConfig.Load();
+            cfg.PeerFriendlyNames = new Dictionary<string, string>(peerFriendlyNames, StringComparer.OrdinalIgnoreCase);
+            cfg.Save();
+        }
+        catch (Exception ex) { logFile.Event($"peer rename: failed to save friendly name: {ex.Message}"); }
+
+        // Refresh everywhere: connected/discovered lists rebuild their labels, the pan/EQ list re-reads
+        // its peer names, and the details box updates.
+        lastPanEqPeerSignature = "";
+        SyncAllPeerLists();
+        RefreshPanEqPeerList();
+        UpdatePeerDetails();
     }
 
     private void SyncDiscoveredList()
@@ -5872,7 +6039,7 @@ public sealed class MainForm : Form
         foreach (var (id, oldEndpoint) in selectedPeerEndpoints.ToList())
         {
             if (!knownPeers.TryGetValue(id, out var peer)) continue;
-            selectedPeerLabels[id] = peer.Name;
+            selectedPeerLabels[id] = ResolvePeerDisplayName(peer);
 
             var newEndpoint = new IPEndPoint(peer.Address, peer.AudioPort);
             // Same address, or the one we're on is still healthy: nothing to do — and reset the
@@ -5912,7 +6079,7 @@ public sealed class MainForm : Form
     private void SelectPeer(PeerAnnouncement peer, bool fromProfileRestore)
     {
         selectedPeerEndpoints[peer.InstanceId] = new IPEndPoint(peer.Address, peer.AudioPort);
-        selectedPeerLabels[peer.InstanceId] = peer.Name;
+        selectedPeerLabels[peer.InstanceId] = ResolvePeerDisplayName(peer);
         logFile.Event($"peer selected: {peer.Name} {peer.Address}:{peer.AudioPort}");
         InvalidateAutoTuneHistory();
         PushAllowedReceiveSenders();

src/RemSound.App/MainFormChoices.cs

@@ -63,6 +63,11 @@ internal sealed class PeerLineStatus
 
 internal sealed class PeerListItem
 {
+    /// <summary>Optional resolver mapping a peer to the display name to show — e.g. a user-set friendly
+    /// name. Set once by MainForm. When null (or it returns the machine name) behaviour is unchanged,
+    /// so this covers the connected AND discovered lists in one place.</summary>
+    public static Func<PeerAnnouncement, string>? DisplayNameProvider;
+
     public PeerAnnouncement Peer { get; }
     public PeerLineStatus Status { get; } = new();
 
@@ -79,7 +84,8 @@ internal sealed class PeerListItem
         // Base label: "hostname (ip)" for discovered peers, just "ip" for manual-by-IP entries
         // (where hostname equals the IP address). Avoids "192.168.1.95 (192.168.1.95)" duplication.
         var addr = Peer.Address.ToString();
-        var basePart = Peer.Name == addr ? addr : $"{Peer.Name} ({addr})";
+        var name = DisplayNameProvider?.Invoke(Peer) ?? Peer.Name;
+        var basePart = name == addr ? addr : $"{name} ({addr})";
 
         if (!Status.Connected)
         {

src/RemSound.App/RenamePeerDialog.cs

@@ -0,0 +1,84 @@
+namespace RemSound.App;
+
+/// <summary>Modal dialog for giving a peer a friendly name. Shows the machine name for reference, a
+/// text box for the custom name, and a "Clear custom name" button that wipes it back to the machine
+/// name. OK (or Clear) returns DialogResult.OK; the caller reads <see cref="FriendlyName"/> — null
+/// meaning "no custom name" (cleared or left blank). Cancel/Escape makes no change.</summary>
+internal sealed class RenamePeerDialog : Form
+{
+    private readonly TextBox nameBox = new()
+    {
+        Width = 260,
+        TabIndex = 0,
+        AccessibleName = "Friendly name (Alt+N)",
+    };
+
+    /// <summary>The chosen name, valid only when ShowDialog returned OK. Null = no custom name.</summary>
+    public string? FriendlyName { get; private set; }
+
+    public RenamePeerDialog(string machineName, string? currentCustomName)
+    {
+        Text = "Rename peer";
+        StartPosition = FormStartPosition.CenterParent;
+        FormBorderStyle = FormBorderStyle.FixedDialog;
+        MinimizeBox = false;
+        MaximizeBox = false;
+        ShowInTaskbar = false;
+        ClientSize = new Size(380, 170);
+
+        nameBox.Text = currentCustomName ?? "";
+
+        var grid = new TableLayoutPanel
+        {
+            Dock = DockStyle.Fill,
+            Padding = new Padding(12),
+            ColumnCount = 2,
+            RowCount = 3,
+        };
+        grid.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
+        grid.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
+
+        var machineLabel = new Label
+        {
+            Text = $"Machine name: {machineName}",
+            AutoSize = true,
+            Anchor = AnchorStyles.Left,
+            Margin = new Padding(0, 0, 0, 8),
+        };
+        grid.Controls.Add(machineLabel, 0, 0);
+        grid.SetColumnSpan(machineLabel, 2);
+
+        // Plain label with '&' wires the mnemonic to the next control in tab order (the text box).
+        var nameLabel = new Label { Text = "Friendly &name (Alt+N)", AutoSize = true, Anchor = AnchorStyles.Left, Margin = new Padding(0, 4, 8, 0) };
+        grid.Controls.Add(nameLabel, 0, 1);
+        grid.Controls.Add(nameBox, 1, 1);
+
+        var clearButton = new Button { Text = "&Clear custom name (Alt+C)", AutoSize = true, AccessibleName = "Clear custom name", TabIndex = 1 };
+        var okButton = new Button { Text = "OK", AutoSize = true, DialogResult = DialogResult.OK, TabIndex = 2 };
+        var cancelButton = new Button { Text = "Cancel", AutoSize = true, DialogResult = DialogResult.Cancel, TabIndex = 3 };
+
+        clearButton.Click += (_, _) =>
+        {
+            FriendlyName = null;
+            DialogResult = DialogResult.OK;
+            Close();
+        };
+        okButton.Click += (_, _) =>
+        {
+            var t = nameBox.Text.Trim();
+            FriendlyName = t.Length == 0 ? null : t;   // blank box = clear, same as the Clear button
+        };
+
+        var buttonRow = new FlowLayoutPanel { Dock = DockStyle.Fill, FlowDirection = FlowDirection.LeftToRight, AutoSize = true, TabIndex = 2 };
+        buttonRow.Controls.Add(clearButton);
+        buttonRow.Controls.Add(okButton);
+        buttonRow.Controls.Add(cancelButton);
+        grid.Controls.Add(buttonRow, 1, 2);
+
+        Controls.Add(grid);
+        AcceptButton = okButton;
+        CancelButton = cancelButton;
+
+        Shown += (_, _) => { nameBox.Focus(); nameBox.SelectAll(); };
+    }
+}