screenshare: advanced in-app streaming controls + hwdec toggle

Add a local-only "Screen sharing" section to Settings plus a per-call quality
picker on the Share control: in-app control over how a share is encoded
(quality/bitrate/framerate/max-height/max-viewers/software-x264, + extra
pixelpass args) and how it's played back (mpv/vlc, hardware decode, buffering,
cache, + extra mpv args). Settings live in AppConfig.screen_share (all
serde-defaulted, so old configs load unchanged) and become pixelpass host CLI
flags / mpv args at share/view launch.

Hardware decode defaults OFF, which also fixes the frozen-frame-with-audio bug:
forcing --hwdec=auto stalled some viewers' HW decoder on frame 1 while audio
kept playing.

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

src/app/mod.rs

@@ -4,7 +4,10 @@ use crate::audio::clip_player::{
 };
 use crate::audio::eq::{EQ_GAIN_DB_MAX, EQ_GAIN_DB_MIN, EqSettings};
 use crate::audio::{AudioDevice, enumerate_audio_devices};
-use crate::config::{AppConfig, AudioProfile, NetworkMode, RecordingMode, RoomLayout};
+use crate::config::{
+    AppConfig, AudioProfile, NetworkMode, RecordingMode, RoomLayout, ShareBuffering, SharePlayer,
+    ShareQuality,
+};
 use crate::core::{
     CoreController,
     messages::{CoreCommand, UiEvent},
@@ -60,18 +63,20 @@ pub enum SettingsCategory {
     Profile,
     Appearance,
     Network,
+    Advanced,
     Notifications,
     Games,
 }
 
 impl SettingsCategory {
-    const ALL: [SettingsCategory; 8] = [
+    const ALL: [SettingsCategory; 9] = [
         SettingsCategory::Audio,
         SettingsCategory::Hotkeys,
         SettingsCategory::Recording,
         SettingsCategory::Profile,
         SettingsCategory::Appearance,
         SettingsCategory::Network,
+        SettingsCategory::Advanced,
         SettingsCategory::Notifications,
         SettingsCategory::Games,
     ];
@@ -84,6 +89,7 @@ impl SettingsCategory {
             SettingsCategory::Profile => "Profile",
             SettingsCategory::Appearance => "Appearance",
             SettingsCategory::Network => "Network",
+            SettingsCategory::Advanced => "Advanced",
             SettingsCategory::Notifications => "Notifications",
             SettingsCategory::Games => "Games",
         }
@@ -97,6 +103,7 @@ impl SettingsCategory {
             SettingsCategory::Profile => "Avatar and identity",
             SettingsCategory::Appearance => "Layout and theme",
             SettingsCategory::Network => "Relay and privacy mode",
+            SettingsCategory::Advanced => "Screen sharing",
             SettingsCategory::Notifications => "Chimes and sounds",
             SettingsCategory::Games => "Detection, presence, backgrounds",
         }
@@ -109,6 +116,176 @@ impl std::fmt::Display for SettingsCategory {
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ShareMaxHeightChoice {
+    Source,
+    P720,
+    P1080,
+    P1440,
+}
+
+impl ShareMaxHeightChoice {
+    const ALL: [ShareMaxHeightChoice; 4] = [
+        ShareMaxHeightChoice::Source,
+        ShareMaxHeightChoice::P720,
+        ShareMaxHeightChoice::P1080,
+        ShareMaxHeightChoice::P1440,
+    ];
+
+    fn from_config(value: Option<u32>) -> Self {
+        match value {
+            Some(720) => ShareMaxHeightChoice::P720,
+            Some(1080) => ShareMaxHeightChoice::P1080,
+            Some(1440) => ShareMaxHeightChoice::P1440,
+            _ => ShareMaxHeightChoice::Source,
+        }
+    }
+
+    fn to_config(self) -> Option<u32> {
+        match self {
+            ShareMaxHeightChoice::Source => None,
+            ShareMaxHeightChoice::P720 => Some(720),
+            ShareMaxHeightChoice::P1080 => Some(1080),
+            ShareMaxHeightChoice::P1440 => Some(1440),
+        }
+    }
+}
+
+impl std::fmt::Display for ShareMaxHeightChoice {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            ShareMaxHeightChoice::Source => "Source",
+            ShareMaxHeightChoice::P720 => "720p",
+            ShareMaxHeightChoice::P1080 => "1080p",
+            ShareMaxHeightChoice::P1440 => "1440p",
+        })
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ShareFramerateChoice {
+    Preset,
+    Fps15,
+    Fps24,
+    Fps30,
+    Fps60,
+}
+
+impl ShareFramerateChoice {
+    const ALL: [ShareFramerateChoice; 5] = [
+        ShareFramerateChoice::Preset,
+        ShareFramerateChoice::Fps15,
+        ShareFramerateChoice::Fps24,
+        ShareFramerateChoice::Fps30,
+        ShareFramerateChoice::Fps60,
+    ];
+
+    fn from_config(value: Option<u32>) -> Self {
+        match value {
+            Some(15) => ShareFramerateChoice::Fps15,
+            Some(24) => ShareFramerateChoice::Fps24,
+            Some(30) => ShareFramerateChoice::Fps30,
+            Some(60) => ShareFramerateChoice::Fps60,
+            _ => ShareFramerateChoice::Preset,
+        }
+    }
+
+    fn to_config(self) -> Option<u32> {
+        match self {
+            ShareFramerateChoice::Preset => None,
+            ShareFramerateChoice::Fps15 => Some(15),
+            ShareFramerateChoice::Fps24 => Some(24),
+            ShareFramerateChoice::Fps30 => Some(30),
+            ShareFramerateChoice::Fps60 => Some(60),
+        }
+    }
+}
+
+impl std::fmt::Display for ShareFramerateChoice {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            ShareFramerateChoice::Preset => "Preset default",
+            ShareFramerateChoice::Fps15 => "15 fps",
+            ShareFramerateChoice::Fps24 => "24 fps",
+            ShareFramerateChoice::Fps30 => "30 fps",
+            ShareFramerateChoice::Fps60 => "60 fps",
+        })
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ShareMaxViewersChoice {
+    Auto,
+    One,
+    Two,
+    Three,
+    Four,
+    Five,
+    Six,
+    Seven,
+    Eight,
+}
+
+impl ShareMaxViewersChoice {
+    const ALL: [ShareMaxViewersChoice; 9] = [
+        ShareMaxViewersChoice::Auto,
+        ShareMaxViewersChoice::One,
+        ShareMaxViewersChoice::Two,
+        ShareMaxViewersChoice::Three,
+        ShareMaxViewersChoice::Four,
+        ShareMaxViewersChoice::Five,
+        ShareMaxViewersChoice::Six,
+        ShareMaxViewersChoice::Seven,
+        ShareMaxViewersChoice::Eight,
+    ];
+
+    fn from_config(value: Option<u32>) -> Self {
+        match value {
+            Some(1) => ShareMaxViewersChoice::One,
+            Some(2) => ShareMaxViewersChoice::Two,
+            Some(3) => ShareMaxViewersChoice::Three,
+            Some(4) => ShareMaxViewersChoice::Four,
+            Some(5) => ShareMaxViewersChoice::Five,
+            Some(6) => ShareMaxViewersChoice::Six,
+            Some(7) => ShareMaxViewersChoice::Seven,
+            Some(8) => ShareMaxViewersChoice::Eight,
+            _ => ShareMaxViewersChoice::Auto,
+        }
+    }
+
+    fn to_config(self) -> Option<u32> {
+        match self {
+            ShareMaxViewersChoice::Auto => None,
+            ShareMaxViewersChoice::One => Some(1),
+            ShareMaxViewersChoice::Two => Some(2),
+            ShareMaxViewersChoice::Three => Some(3),
+            ShareMaxViewersChoice::Four => Some(4),
+            ShareMaxViewersChoice::Five => Some(5),
+            ShareMaxViewersChoice::Six => Some(6),
+            ShareMaxViewersChoice::Seven => Some(7),
+            ShareMaxViewersChoice::Eight => Some(8),
+        }
+    }
+}
+
+impl std::fmt::Display for ShareMaxViewersChoice {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            ShareMaxViewersChoice::Auto => "Auto",
+            ShareMaxViewersChoice::One => "1",
+            ShareMaxViewersChoice::Two => "2",
+            ShareMaxViewersChoice::Three => "3",
+            ShareMaxViewersChoice::Four => "4",
+            ShareMaxViewersChoice::Five => "5",
+            ShareMaxViewersChoice::Six => "6",
+            ShareMaxViewersChoice::Seven => "7",
+            ShareMaxViewersChoice::Eight => "8",
+        })
+    }
+}
+
+const SHARE_CACHE_MB_OPTIONS: [u32; 8] = [1, 2, 4, 8, 16, 32, 64, 128];
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 enum HomeLayoutMode {
     FocusedEmpty,
@@ -379,6 +556,18 @@ pub enum AppMessage {
     NetworkModeSelected(NetworkMode),
     AudioProfileSelected(AudioProfile),
     RecordingModeSelected(RecordingMode),
+    ScreenShareQualitySelected(ShareQuality),
+    ScreenSharePlayerSelected(SharePlayer),
+    ScreenShareBufferingSelected(ShareBuffering),
+    ScreenShareMaxHeightSelected(ShareMaxHeightChoice),
+    ScreenShareFramerateSelected(ShareFramerateChoice),
+    ScreenShareMaxViewersSelected(ShareMaxViewersChoice),
+    ScreenShareCacheMbSelected(u32),
+    ScreenShareBitrateChanged(String),
+    ToggleScreenShareForceSoftwareEncode(bool),
+    ToggleScreenShareHardwareDecode(bool),
+    ScreenShareExtraMpvArgsChanged(String),
+    ScreenShareExtraHostArgsChanged(String),
     /// Choose the friends presence posture (W7): invisible / normal / discoverable.
     PresenceModeSelected(PresenceMode),
     /// Friends list (W7 P5): add-form edits, add, remove, and local rename.
@@ -537,6 +726,8 @@ pub enum AppMessage {
     /// Select which app's audio to share in the picker: `Some(name)` for one app,
     /// `None` for the whole desktop ("All system audio").
     SelectShareAudioApp(Option<String>),
+    /// Session-only quality preset for the next share start.
+    SelectShareQualityOverride(ShareQuality),
     /// Confirm the picker: start the share with the currently selected audio app.
     ConfirmShareScreen,
     /// Watch a peer's screen share, identified by their pixelpass ticket.
@@ -761,6 +952,8 @@ pub struct AppState {
     /// The picker's current selection: `Some(name)` = capture that app's audio,
     /// `None` = "All system audio" (whole desktop; may echo the call).
     share_audio_selection: Option<String>,
+    /// Session-only quality override for the next screen-share start.
+    share_quality_selection: ShareQuality,
     /// A share start is in flight: `ConfirmShareScreen` was sent but the core
     /// hasn't yet replied with `ScreenShareStarted`/an error. Blocks reopening
     /// the picker (and re-confirming) during that startup window. Cleared on
@@ -871,6 +1064,7 @@ impl AppState {
         self.share_picker_open = false;
         self.share_audio_apps.clear();
         self.share_audio_selection = None;
+        self.share_quality_selection = self.config.screen_share.quality;
         self.share_starting = false;
         self.share_audio_dropped = false;
         self.share_audio_app_active = false;
@@ -975,6 +1169,7 @@ impl Default for AppState {
         let (clip_player, clip_status) = ClipPlayer::new(config.clip_volume);
         let (music_player, music_status) = ClipPlayer::new(config.music_volume);
         let music_broadcasting = config.music_broadcast;
+        let share_quality_selection = config.screen_share.quality;
         let music_playlist = config
             .music_playlist
             .iter()
@@ -1049,6 +1244,7 @@ impl Default for AppState {
             share_picker_open: false,
             share_audio_apps: Vec::new(),
             share_audio_selection: None,
+            share_quality_selection,
             share_starting: false,
             share_audio_dropped: false,
             share_audio_app_active: false,
@@ -1563,6 +1759,7 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
                 // so the picker can't be reopened during the startup window.
                 state.share_picker_open = true;
                 state.share_audio_selection = None;
+                state.share_quality_selection = state.config.screen_share.quality;
                 state.share_audio_apps.clear();
                 let _ = state.controller.send(CoreCommand::ListAudioApps);
             }
@@ -1573,6 +1770,9 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
         AppMessage::SelectShareAudioApp(app) => {
             state.share_audio_selection = app;
         }
+        AppMessage::SelectShareQualityOverride(quality) => {
+            state.share_quality_selection = quality;
+        }
         AppMessage::ConfirmShareScreen => {
             // Only a confirm from an open picker starts a share; a stray confirm
             // (or one arriving while a start is already in flight) is ignored, so
@@ -1581,14 +1781,21 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
                 state.share_picker_open = false;
                 state.share_starting = true;
                 let audio_app = state.share_audio_selection.clone();
-                let _ = state
+                let settings = state.config.screen_share.clone();
-                    .controller
+                let quality = state.share_quality_selection;
-                    .send(CoreCommand::StartScreenShare { audio_app });
+                let _ = state.controller.send(CoreCommand::StartScreenShare {
+                    audio_app,
+                    settings,
+                    quality,
+                });
                 state.status_message = "Starting screen share…".to_string();
             }
         }
         AppMessage::WatchShare(ticket) => {
-            let _ = state.controller.send(CoreCommand::ViewShare(ticket));
+            let settings = state.config.screen_share.clone();
+            let _ = state
+                .controller
+                .send(CoreCommand::ViewShare { ticket, settings });
             state.status_message = "Opening screen share…".to_string();
         }
         AppMessage::ToggleMutePressed => {
@@ -2064,6 +2271,61 @@ fn update(state: &mut AppState, message: AppMessage) -> Task<AppMessage> {
             // Takes effect on the next recording start.
             let _ = state.controller.send(CoreCommand::SetRecordingMode(mode));
         }
+        AppMessage::ScreenShareQualitySelected(quality) => {
+            state.config.screen_share.quality = quality;
+            state.share_quality_selection = quality;
+            state.config.save();
+        }
+        AppMessage::ScreenSharePlayerSelected(player) => {
+            state.config.screen_share.player = player;
+            state.config.save();
+        }
+        AppMessage::ScreenShareBufferingSelected(buffering) => {
+            state.config.screen_share.buffering = buffering;
+            state.config.save();
+        }
+        AppMessage::ScreenShareMaxHeightSelected(choice) => {
+            state.config.screen_share.max_height = choice.to_config();
+            state.config.save();
+        }
+        AppMessage::ScreenShareFramerateSelected(choice) => {
+            state.config.screen_share.framerate = choice.to_config();
+            state.config.save();
+        }
+        AppMessage::ScreenShareMaxViewersSelected(choice) => {
+            state.config.screen_share.max_viewers = choice.to_config();
+            state.config.save();
+        }
+        AppMessage::ScreenShareCacheMbSelected(cache_mb) => {
+            state.config.screen_share.cache_mb = cache_mb;
+            state.config.save();
+        }
+        AppMessage::ScreenShareBitrateChanged(value) => {
+            let trimmed = value.trim();
+            if trimmed.is_empty() {
+                state.config.screen_share.bitrate_mbps = None;
+                state.config.save();
+            } else if let Ok(mbps) = trimmed.parse::<u32>() {
+                state.config.screen_share.bitrate_mbps = Some(mbps);
+                state.config.save();
+            }
+        }
+        AppMessage::ToggleScreenShareForceSoftwareEncode(enabled) => {
+            state.config.screen_share.force_software_encode = enabled;
+            state.config.save();
+        }
+        AppMessage::ToggleScreenShareHardwareDecode(enabled) => {
+            state.config.screen_share.hardware_decode = enabled;
+            state.config.save();
+        }
+        AppMessage::ScreenShareExtraMpvArgsChanged(args) => {
+            state.config.screen_share.extra_mpv_args = args;
+            state.config.save();
+        }
+        AppMessage::ScreenShareExtraHostArgsChanged(args) => {
+            state.config.screen_share.extra_host_args = args;
+            state.config.save();
+        }
         AppMessage::PresenceModeSelected(mode) => {
             state.config.presence_mode = mode;
             state.config.save();
@@ -3166,6 +3428,30 @@ fn presence_mode_hint(mode: PresenceMode) -> &'static str {
     }
 }
 
+fn share_quality_hint(quality: ShareQuality) -> &'static str {
+    match quality {
+        ShareQuality::Auto => "Use pixelpass bandwidth pre-flight; falls back to Medium.",
+        ShareQuality::Low => "Lower bandwidth: up to 480p, about 1 Mbps.",
+        ShareQuality::Medium => "Balanced preset: up to 720p, about 2.5 Mbps.",
+        ShareQuality::High => "Sharper preset: up to 1080p, about 4 Mbps.",
+        ShareQuality::Source => "Native source resolution, about 6 Mbps.",
+    }
+}
+
+fn share_player_hint(player: SharePlayer) -> &'static str {
+    match player {
+        SharePlayer::Mpv => "Try mpv first, then VLC if mpv is unavailable.",
+        SharePlayer::Vlc => "Try VLC first, then mpv if VLC is unavailable.",
+    }
+}
+
+fn share_buffering_hint(buffering: ShareBuffering) -> &'static str {
+    match buffering {
+        ShareBuffering::LowLatency => "Small buffers for interactive screen sharing.",
+        ShareBuffering::Smooth => "Larger mpv cache/readahead for steadier playback.",
+    }
+}
+
 /// Formats a call duration as `m:ss` (or `h:mm:ss` past an hour).
 fn format_duration(total_secs: u64) -> String {
     let h = total_secs / 3600;
@@ -4759,6 +5045,135 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
         // Spacing between one category and the next.
         let section_gap = 18.0;
 
+        let screen_share = &state.config.screen_share;
+        let screen_share_bitrate = screen_share
+            .bitrate_mbps
+            .map(|v| v.to_string())
+            .unwrap_or_default();
+        let screen_share_section = column![
+            column![
+                text("Host encoding").size(13).color(color_subtext),
+                row![
+                    column![
+                        text("Quality").size(12).color(color_subtext),
+                        pick_list(
+                            &ShareQuality::ALL[..],
+                            Some(screen_share.quality),
+                            AppMessage::ScreenShareQualitySelected,
+                        ).width(iced::Length::Fill),
+                        text(share_quality_hint(screen_share.quality)).size(11).color(color_subtext),
+                    ].spacing(4).width(iced::Length::Fill),
+                    column![
+                        text("Max resolution").size(12).color(color_subtext),
+                        pick_list(
+                            &ShareMaxHeightChoice::ALL[..],
+                            Some(ShareMaxHeightChoice::from_config(screen_share.max_height)),
+                            AppMessage::ScreenShareMaxHeightSelected,
+                        ).width(iced::Length::Fill),
+                        text("Source keeps the captured display height.").size(11).color(color_subtext),
+                    ].spacing(4).width(iced::Length::Fill),
+                ].spacing(16).width(iced::Length::Fill),
+                row![
+                    column![
+                        text("Framerate").size(12).color(color_subtext),
+                        pick_list(
+                            &ShareFramerateChoice::ALL[..],
+                            Some(ShareFramerateChoice::from_config(screen_share.framerate)),
+                            AppMessage::ScreenShareFramerateSelected,
+                        ).width(iced::Length::Fill),
+                        text("Preset default lets pixelpass choose.").size(11).color(color_subtext),
+                    ].spacing(4).width(iced::Length::Fill),
+                    column![
+                        text("Bitrate Mbps").size(12).color(color_subtext),
+                        context_input("preset default", &screen_share_bitrate)
+                            .on_input(AppMessage::ScreenShareBitrateChanged)
+                            .style(t_style)
+                            .padding(8)
+                            .width(iced::Length::Fill),
+                        text("Blank uses the quality preset.").size(11).color(color_subtext),
+                    ].spacing(4).width(iced::Length::Fill),
+                ].spacing(16).width(iced::Length::Fill),
+                row![
+                    column![
+                        text("Max viewers").size(12).color(color_subtext),
+                        pick_list(
+                            &ShareMaxViewersChoice::ALL[..],
+                            Some(ShareMaxViewersChoice::from_config(screen_share.max_viewers)),
+                            AppMessage::ScreenShareMaxViewersSelected,
+                        ).width(iced::Length::Fill),
+                        text("Auto uses pixelpass' connection-aware recommendation.").size(11).color(color_subtext),
+                    ].spacing(4).width(iced::Length::Fill),
+                    column![
+                        checkbox(screen_share.force_software_encode)
+                            .label("Force software encode")
+                            .on_toggle(AppMessage::ToggleScreenShareForceSoftwareEncode),
+                        text("Passes --no-hwencode to pixelpass.").size(11).color(color_subtext),
+                    ].spacing(8).width(iced::Length::Fill),
+                ].spacing(16).width(iced::Length::Fill),
+            ].spacing(10).width(iced::Length::Fill),
+            vertical_space(section_gap),
+            column![
+                text("Viewer playback").size(13).color(color_subtext),
+                row![
+                    column![
+                        text("Player").size(12).color(color_subtext),
+                        pick_list(
+                            &SharePlayer::ALL[..],
+                            Some(screen_share.player),
+                            AppMessage::ScreenSharePlayerSelected,
+                        ).width(iced::Length::Fill),
+                        text(share_player_hint(screen_share.player)).size(11).color(color_subtext),
+                    ].spacing(4).width(iced::Length::Fill),
+                    column![
+                        text("Buffering").size(12).color(color_subtext),
+                        pick_list(
+                            &ShareBuffering::ALL[..],
+                            Some(screen_share.buffering),
+                            AppMessage::ScreenShareBufferingSelected,
+                        ).width(iced::Length::Fill),
+                        text(share_buffering_hint(screen_share.buffering)).size(11).color(color_subtext),
+                    ].spacing(4).width(iced::Length::Fill),
+                ].spacing(16).width(iced::Length::Fill),
+                row![
+                    column![
+                        text("Cache MB").size(12).color(color_subtext),
+                        pick_list(
+                            &SHARE_CACHE_MB_OPTIONS[..],
+                            Some(screen_share.cache_mb),
+                            AppMessage::ScreenShareCacheMbSelected,
+                        ).width(iced::Length::Fill),
+                        text("Used as mpv demuxer cache size.").size(11).color(color_subtext),
+                    ].spacing(4).width(iced::Length::Fill),
+                    column![
+                        checkbox(screen_share.hardware_decode)
+                            .label("Hardware video decode")
+                            .on_toggle(AppMessage::ToggleScreenShareHardwareDecode),
+                        text("Adds --hwdec=auto to mpv. Off avoids the known frame-freeze bug.").size(11).color(color_subtext),
+                    ].spacing(8).width(iced::Length::Fill),
+                ].spacing(16).width(iced::Length::Fill),
+            ].spacing(10).width(iced::Length::Fill),
+            vertical_space(section_gap),
+            column![
+                text("Extra mpv args").size(12).color(color_subtext),
+                context_input("--no-osc --vd-lavc-threads=2", &screen_share.extra_mpv_args)
+                    .on_input(AppMessage::ScreenShareExtraMpvArgsChanged)
+                    .style(t_style)
+                    .padding(8)
+                    .width(iced::Length::Fill),
+                text("⚠ Advanced — may break playback").size(11).color(color_yellow),
+                text("Extra pixelpass args").size(12).color(color_subtext),
+                context_input("--relay https://relay.example/", &screen_share.extra_host_args)
+                    .on_input(AppMessage::ScreenShareExtraHostArgsChanged)
+                    .style(t_style)
+                    .padding(8)
+                    .width(iced::Length::Fill),
+                text("⚠ Advanced — may break playback").size(11).color(color_yellow),
+            ].spacing(6).width(iced::Length::Fill),
+            text("Applies the next time you start or watch a screen share. These are local preferences only.").size(11).color(color_subtext),
+        ]
+        .spacing(10)
+        .width(iced::Length::Fill);
+
         // One recording-mode radio with a hover tooltip explaining it. (iced's
         // pick_list can't host per-option tooltips, so the modes are radios.)
         let mode_radio = |mode: RecordingMode, label: &'static str| -> Element<'_, AppMessage> {
@@ -5082,6 +5497,13 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
             .spacing(10)
             .width(iced::Length::Fill)
             .into(),
+            SettingsCategory::Advanced => column![
+                section_header("Screen sharing"),
+                screen_share_section,
+            ]
+            .spacing(10)
+            .width(iced::Length::Fill)
+            .into(),
             SettingsCategory::Notifications => column![
                 section_header("Notifications & Sounds"),
                 column![
@@ -6479,11 +6901,29 @@ fn view(state: &AppState) -> Element<'_, AppMessage> {
                 } else {
                     AppMessage::OpenPixelpassHelp
                 };
-                button(btn_content(share_kind, share_label, share_fg))
+                let share_button = button(btn_content(share_kind, share_label, share_fg))
                     .on_press(share_press)
                     .style(b_style(share_bg, share_hover, share_fg, 8.0))
                     .padding(14)
+                    .width(iced::Length::Fill);
+                let share_control: Element<'_, AppMessage> = if state.self_sharing {
+                    share_button.into()
+                } else {
+                    row![
+                        share_button,
+                        pick_list(
+                            &ShareQuality::ALL[..],
+                            Some(state.share_quality_selection),
+                            AppMessage::SelectShareQualityOverride,
+                        )
+                        .width(iced::Length::Fixed(112.0)),
+                    ]
+                    .spacing(8)
+                    .align_y(iced::alignment::Vertical::Center)
                     .width(iced::Length::Fill)
+                    .into()
+                };
+                share_control
             },
         ];
 
@@ -8703,6 +9143,10 @@ mod tests {
         assert!(!state.share_picker_open);
         assert!(state.share_audio_apps.is_empty());
         assert!(state.share_audio_selection.is_none());
+        assert_eq!(
+            state.share_quality_selection,
+            state.config.screen_share.quality
+        );
         assert!(!state.share_starting);
         assert!(!state.share_audio_dropped);
         assert!(!state.share_audio_app_active);
@@ -9198,12 +9642,14 @@ mod tests {
                 "Profile",
                 "Appearance",
                 "Network",
+                "Advanced",
                 "Notifications",
                 "Games"
             ]
         );
         assert_eq!(SettingsCategory::Audio.hint(), "Devices, mic gate, echo");
         assert_eq!(SettingsCategory::Profile.hint(), "Avatar and identity");
+        assert_eq!(SettingsCategory::Advanced.hint(), "Screen sharing");
         assert_eq!(
             SettingsCategory::Games.hint(),
             "Detection, presence, backgrounds"

src/config.rs

@@ -168,6 +168,139 @@ impl std::fmt::Display for NetworkMode {
     }
 }
 
+/// Pixelpass host quality preset for screen shares. `Auto` leaves pixelpass free
+/// to choose from its bandwidth pre-flight; fixed presets are passed as CLI flags.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum ShareQuality {
+    #[default]
+    Auto,
+    Low,
+    Medium,
+    High,
+    Source,
+}
+
+impl ShareQuality {
+    pub const ALL: [ShareQuality; 5] = [
+        ShareQuality::Auto,
+        ShareQuality::Low,
+        ShareQuality::Medium,
+        ShareQuality::High,
+        ShareQuality::Source,
+    ];
+}
+
+impl std::fmt::Display for ShareQuality {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            ShareQuality::Auto => "Auto",
+            ShareQuality::Low => "Low",
+            ShareQuality::Medium => "Medium",
+            ShareQuality::High => "High",
+            ShareQuality::Source => "Source",
+        })
+    }
+}
+
+/// Preferred local player for watching a peer's screen share.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum SharePlayer {
+    #[default]
+    Mpv,
+    Vlc,
+}
+
+impl SharePlayer {
+    pub const ALL: [SharePlayer; 2] = [SharePlayer::Mpv, SharePlayer::Vlc];
+}
+
+impl std::fmt::Display for SharePlayer {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            SharePlayer::Mpv => "mpv",
+            SharePlayer::Vlc => "VLC",
+        })
+    }
+}
+
+/// Local player buffering posture for screen-share playback.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
+#[serde(rename_all = "snake_case")]
+pub enum ShareBuffering {
+    #[default]
+    LowLatency,
+    Smooth,
+}
+
+impl ShareBuffering {
+    pub const ALL: [ShareBuffering; 2] = [ShareBuffering::LowLatency, ShareBuffering::Smooth];
+}
+
+impl std::fmt::Display for ShareBuffering {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            ShareBuffering::LowLatency => "Low latency",
+            ShareBuffering::Smooth => "Smooth",
+        })
+    }
+}
+
+fn default_screen_share_cache_mb() -> u32 {
+    2
+}
+
+/// Local-only screen-share preferences. Host fields become pixelpass host CLI
+/// flags; viewer fields shape local mpv/VLC launch. None/empty/default values
+/// deliberately let pixelpass/player defaults stand.
+#[derive(Debug, Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct ScreenShareSettings {
+    #[serde(default)]
+    pub quality: ShareQuality,
+    #[serde(default)]
+    pub bitrate_mbps: Option<u32>,
+    #[serde(default)]
+    pub framerate: Option<u32>,
+    #[serde(default)]
+    pub max_height: Option<u32>,
+    #[serde(default)]
+    pub max_viewers: Option<u32>,
+    #[serde(default)]
+    pub force_software_encode: bool,
+    #[serde(default)]
+    pub extra_host_args: String,
+    #[serde(default)]
+    pub player: SharePlayer,
+    #[serde(default)]
+    pub hardware_decode: bool,
+    #[serde(default)]
+    pub buffering: ShareBuffering,
+    #[serde(default = "default_screen_share_cache_mb")]
+    pub cache_mb: u32,
+    #[serde(default)]
+    pub extra_mpv_args: String,
+}
+
+impl Default for ScreenShareSettings {
+    fn default() -> Self {
+        Self {
+            quality: ShareQuality::default(),
+            bitrate_mbps: None,
+            framerate: None,
+            max_height: None,
+            max_viewers: None,
+            force_software_encode: false,
+            extra_host_args: String::new(),
+            player: SharePlayer::default(),
+            hardware_decode: false,
+            buffering: ShareBuffering::default(),
+            cache_mb: default_screen_share_cache_mb(),
+            extra_mpv_args: String::new(),
+        }
+    }
+}
+
 fn default_true() -> bool {
     true
 }
@@ -369,6 +502,9 @@ pub struct AppConfig {
     /// Empty / unset = look it up on `$PATH`. Hand-editable; no Settings UI yet.
     #[serde(default)]
     pub pixelpass_path: Option<String>,
+    /// Local-only host/player controls for screen sharing.
+    #[serde(default)]
+    pub screen_share: ScreenShareSettings,
     /// Recently-joined rooms (W7), most-recent-first. Purely local UI state for a
     /// one-click rejoin; never sent over the wire. De-duped by room topic and
     /// capped (see `recents`). Defaulted empty so older configs upgrade cleanly.
@@ -474,6 +610,7 @@ impl Default for AppConfig {
             sound_mic_toggle_enabled: true,
             sound_reconnect_failed_enabled: true,
             pixelpass_path: None,
+            screen_share: ScreenShareSettings::default(),
             recents: Vec::new(),
             peer_eq: HashMap::new(),
             peer_pan: HashMap::new(),
@@ -803,6 +940,14 @@ mod tests {
         assert!(deserialized.custom_sound_self_leave.is_none());
         assert!(deserialized.custom_sound_mic_toggle.is_none());
         assert!(deserialized.custom_sound_reconnect_failed.is_none());
+        assert_eq!(deserialized.screen_share, ScreenShareSettings::default());
+        assert_eq!(deserialized.screen_share.quality, ShareQuality::Auto);
+        assert_eq!(deserialized.screen_share.player, SharePlayer::Mpv);
+        assert_eq!(
+            deserialized.screen_share.buffering,
+            ShareBuffering::LowLatency
+        );
+        assert_eq!(deserialized.screen_share.cache_mb, 2);
         // Configs predating the per-sound flags (W6) enable every chime, so an
         // upgrade is silent-change-free.
         for sound in Sound::ALL {

src/core/messages.rs

@@ -1,4 +1,4 @@
-use crate::config::{AudioProfile, NetworkMode, RecordingMode};
+use crate::config::{AudioProfile, NetworkMode, RecordingMode, ScreenShareSettings, ShareQuality};
 use crate::friends::Friend;
 use crate::network::PeerState;
 use crate::presence::{FriendPresence, PresenceMode};
@@ -119,13 +119,18 @@ pub enum CoreCommand {
     /// whole desktop audio (the legacy behavior).
     StartScreenShare {
         audio_app: Option<String>,
+        settings: ScreenShareSettings,
+        quality: ShareQuality,
     },
     /// Stop sharing our screen: kill the pixelpass host and clear the presence
     /// ticket. No-op when not sharing.
     StopScreenShare,
     /// Watch a peer's screen share: spawn a pixelpass viewer for `ticket` and
     /// open it in a local player.
-    ViewShare(String),
+    ViewShare {
+        ticket: String,
+        settings: ScreenShareSettings,
+    },
     /// Mint a fresh persistent identity (W7), discarding the old one. Takes effect
     /// on the next room join (the endpoint is rebuilt then). The core replies with
     /// an updated [`UiEvent::IdentityStatus`].
@@ -244,9 +249,16 @@ pub fn delivery_class(cmd: &CoreCommand) -> DeliveryClass {
         }
         | CoreCommand::SetPixelpassPath(_)
         | CoreCommand::ListAudioApps
-        | CoreCommand::StartScreenShare { audio_app: _ }
+        | CoreCommand::StartScreenShare {
+            audio_app: _,
+            settings: _,
+            quality: _,
+        }
         | CoreCommand::StopScreenShare
-        | CoreCommand::ViewShare(_)
+        | CoreCommand::ViewShare {
+            ticket: _,
+            settings: _,
+        }
         | CoreCommand::RegenerateIdentity
         | CoreCommand::AddFriend {
             id: _,
@@ -325,9 +337,16 @@ pub fn coalesce_key(cmd: &CoreCommand) -> Option<CoalesceKey> {
         }
         | CoreCommand::SetPixelpassPath(_)
         | CoreCommand::ListAudioApps
-        | CoreCommand::StartScreenShare { audio_app: _ }
+        | CoreCommand::StartScreenShare {
+            audio_app: _,
+            settings: _,
+            quality: _,
+        }
         | CoreCommand::StopScreenShare
-        | CoreCommand::ViewShare(_)
+        | CoreCommand::ViewShare {
+            ticket: _,
+            settings: _,
+        }
         | CoreCommand::RegenerateIdentity
         | CoreCommand::AddFriend {
             id: _,

src/core/mod.rs

@@ -3123,7 +3123,11 @@ async fn run_core_loop(
                     .await;
             }
 
-            CoreCommand::StartScreenShare { audio_app } => {
+            CoreCommand::StartScreenShare {
+                audio_app,
+                settings,
+                quality,
+            } => {
                 let Some(session) = &mut active_session else {
                     let _ = ui_tx
                         .send(UiEvent::Error(
@@ -3173,7 +3177,15 @@ async fn run_core_loop(
                     });
                     tx
                 });
-                match crate::screenshare::spawn_host(&bin, audio_app.as_deref(), notices).await {
+                match crate::screenshare::spawn_host(
+                    &bin,
+                    audio_app.as_deref(),
+                    &settings,
+                    quality,
+                    notices,
+                )
+                .await
+                {
                     Ok((child, ticket)) => {
                         crate::log_msg("Screen share host started");
                         session.screenshare_host = Some(child);
@@ -3211,7 +3223,7 @@ async fn run_core_loop(
                 let _ = ui_tx.send(UiEvent::ScreenShareStopped).await;
             }
 
-            CoreCommand::ViewShare(ticket) => {
+            CoreCommand::ViewShare { ticket, settings } => {
                 let bin = match crate::screenshare::pixelpass_path(pixelpass_override.as_deref()) {
                     Some(b) => b,
                     None => {
@@ -3239,7 +3251,7 @@ async fn run_core_loop(
                         crate::log_msg("Screen share viewer replaced (re-watch)");
                     }
                 }
-                match crate::screenshare::spawn_viewer(&bin, &ticket).await {
+                match crate::screenshare::spawn_viewer(&bin, &ticket, &settings).await {
                     Ok(child) => {
                         crate::log_msg("Screen share viewer started");
                         if let Some(session) = &mut active_session {

src/screenshare/mod.rs

@@ -21,6 +21,8 @@ use std::time::Duration;
 use tokio::io::{AsyncBufReadExt, BufReader};
 use tokio::process::{Child, Command};
 
+use crate::config::{ScreenShareSettings, ShareBuffering, SharePlayer, ShareQuality};
+
 /// The binary we shell out to. Looked up on `$PATH` unless a config override
 /// points elsewhere.
 const PIXELPASS_BIN: &str = "pixelpass";
@@ -139,7 +141,11 @@ fn json_u32(v: &serde_json::Value, key: &str) -> u32 {
 /// otherwise rejects hyphen-leading option values). The name is locally chosen
 /// (our own enumeration / the user's pick), not peer-supplied, but is still
 /// sanitized via [`sanitize_app_name`] before reaching here. Pure: no I/O.
-pub fn host_args(audio_app: Option<&str>) -> Vec<String> {
+pub fn host_args(
+    audio_app: Option<&str>,
+    settings: &ScreenShareSettings,
+    quality: ShareQuality,
+) -> Vec<String> {
     let mut args = vec![
         "--host".to_string(),
         "--output".to_string(),
@@ -149,9 +155,44 @@ pub fn host_args(audio_app: Option<&str>) -> Vec<String> {
         args.push(format!("--app={name}"));
         args.push("--strict-audio".to_string());
     }
+    if quality != ShareQuality::Auto {
+        args.push(format!("--quality={}", pixelpass_quality(quality)));
+    }
+    if let Some(height) = settings.max_height {
+        args.push(format!("--max-height={height}"));
+    }
+    if let Some(mbps) = settings.bitrate_mbps {
+        args.push(format!("--bitrate={}", mbps.saturating_mul(1000)));
+    }
+    if let Some(fps) = settings.framerate {
+        args.push(format!("--framerate={fps}"));
+    }
+    if settings.force_software_encode {
+        args.push("--no-hwencode".to_string());
+    }
+    if let Some(max) = settings.max_viewers {
+        args.push(format!("--max-viewers={max}"));
+    }
+    args.extend(split_extra_args(&settings.extra_host_args));
     args
 }
 
+fn pixelpass_quality(quality: ShareQuality) -> &'static str {
+    match quality {
+        ShareQuality::Auto => "auto",
+        ShareQuality::Low => "low",
+        ShareQuality::Medium => "medium",
+        ShareQuality::High => "high",
+        ShareQuality::Source => "source",
+    }
+}
+
+/// Split user-supplied advanced argv text into separate tokens. Peerspeak does
+/// not depend on a shell lexer, so quoted values are not interpreted here.
+fn split_extra_args(raw: &str) -> impl Iterator<Item = String> + '_ {
+    raw.split_whitespace().map(str::to_string)
+}
+
 /// Validate a locally-chosen audio app name before it becomes a `--app` value:
 /// trim, reject empty / overlong, and reject names carrying control characters
 /// (newlines etc.) that have no place in a real `application.name`. `None` means
@@ -320,15 +361,17 @@ pub fn is_available(config_override: Option<&str>) -> bool {
 /// whole desktop sink, which avoids the call-loopback echo (A23). The child keeps
 /// running (streaming to viewers) until killed or dropped; remaining stdout is
 /// drained in a background task so a full pipe can't stall the host. We do
-/// **not** pass `--max-viewers`: pixelpass bandwidth-measures its own safe cap,
+/// not pass encode/viewer overrides unless the local settings explicitly ask for
-/// protecting the sharer's uplink, and refuses extras with `viewer_refused`.
+/// them, so pixelpass keeps its own defaults in the common case.
 pub async fn spawn_host(
     bin: &Path,
     audio_app: Option<&str>,
+    settings: &ScreenShareSettings,
+    quality: ShareQuality,
     notices: Option<tokio::sync::mpsc::UnboundedSender<PixelpassEvent>>,
 ) -> std::io::Result<(Child, String)> {
     let mut child = Command::new(bin)
-        .args(host_args(audio_app))
+        .args(host_args(audio_app, settings, quality))
         .stdin(Stdio::null())
         .stdout(Stdio::piped())
         // Capture stderr (not null): pixelpass prints its startup precondition
@@ -428,10 +471,14 @@ pub fn pixelpass_failure_detail(stderr: &str) -> String {
 }
 
 /// Spawn a pixelpass viewer for `ticket`, wait for it to connect, and open the
-/// stream in a local player (mpv, falling back to vlc). Returns the live viewer
+/// stream in a local player (mpv/VLC in the configured order, then fallback).
-/// child so the caller can kill it on room-leave; it also self-exits when the
+/// Returns the live viewer child so the caller can kill it on room-leave; it also
-/// player window closes (its tunnel ends).
+/// self-exits when the player window closes (its tunnel ends).
-pub async fn spawn_viewer(bin: &Path, ticket: &str) -> std::io::Result<Child> {
+pub async fn spawn_viewer(
+    bin: &Path,
+    ticket: &str,
+    settings: &ScreenShareSettings,
+) -> std::io::Result<Child> {
     let mut child = Command::new(bin)
         .args(viewer_args(ticket))
         .stdin(Stdio::null())
@@ -465,7 +512,7 @@ pub async fn spawn_viewer(bin: &Path, ticket: &str) -> std::io::Result<Child> {
         }
     };
 
-    if let Err(e) = launch_player(&url) {
+    if let Err(e) = launch_player(&url, settings) {
         let _ = child.kill().await;
         return Err(e);
     }
@@ -556,20 +603,24 @@ fn event_for_log(ev: &PixelpassEvent) -> String {
 /// decodes, ignoring audio timestamps, which makes a shared *video* drift
 /// progressively out of sync with its audio. Pacing to the audio clock costs a
 /// little latency (negligible for pointing at a desktop) and keeps a shared
-/// video in sync.
+/// video in sync. We also leave hwdec at the `low-latency` default (software
-fn launch_player(url: &str) -> std::io::Result<()> {
+/// decode): forcing `--hwdec=auto` froze some viewers on frame 1 while audio
-    const MPV_ARGS: &[&str] = &[
+/// kept playing.
-        "--profile=low-latency",
+fn launch_player(url: &str, settings: &ScreenShareSettings) -> std::io::Result<()> {
-        "--hwdec=auto",
+    let mpv_args = mpv_args(settings);
-        "--audio-buffer=0.2",
+    let vlc_args = vlc_args();
-        "--demuxer-max-bytes=2M",
+    let first = match settings.player {
-        "--demuxer-readahead-secs=0.5",
+        SharePlayer::Mpv => ("mpv", &mpv_args),
-    ];
+        SharePlayer::Vlc => ("vlc", &vlc_args),
-    const VLC_ARGS: &[&str] = &["--network-caching=200", "--live-caching=200"];
+    };
+    let second = match settings.player {
+        SharePlayer::Mpv => ("vlc", &vlc_args),
+        SharePlayer::Vlc => ("mpv", &mpv_args),
+    };
 
-    let child = match spawn_player("mpv", MPV_ARGS, url) {
+    let child = match spawn_player(first.0, first.1, url) {
         Ok(c) => c,
-        Err(_) => spawn_player("vlc", VLC_ARGS, url).map_err(|_| {
+        Err(_) => spawn_player(second.0, second.1, url).map_err(|_| {
             std::io::Error::new(
                 std::io::ErrorKind::NotFound,
                 "no media player found — install mpv or vlc to watch screen shares",
@@ -583,7 +634,35 @@ fn launch_player(url: &str) -> std::io::Result<()> {
     Ok(())
 }
 
-fn spawn_player(bin: &str, args: &[&str], url: &str) -> std::io::Result<Child> {
+pub fn mpv_args(settings: &ScreenShareSettings) -> Vec<String> {
+    let mut args = Vec::new();
+    match settings.buffering {
+        ShareBuffering::LowLatency => {
+            args.push("--profile=low-latency".to_string());
+            args.push("--audio-buffer=0.2".to_string());
+            args.push("--demuxer-readahead-secs=0.5".to_string());
+        }
+        ShareBuffering::Smooth => {
+            args.push("--cache=yes".to_string());
+            args.push("--demuxer-readahead-secs=2".to_string());
+        }
+    }
+    args.push(format!("--demuxer-max-bytes={}M", settings.cache_mb));
+    if settings.hardware_decode {
+        args.push("--hwdec=auto".to_string());
+    }
+    args.extend(split_extra_args(&settings.extra_mpv_args));
+    args
+}
+
+fn vlc_args() -> Vec<String> {
+    vec![
+        "--network-caching=200".to_string(),
+        "--live-caching=200".to_string(),
+    ]
+}
+
+fn spawn_player(bin: &str, args: &[String], url: &str) -> std::io::Result<Child> {
     Command::new(bin)
         .args(args)
         .arg(url)
@@ -627,7 +706,11 @@ mod tests {
     fn host_args_without_app_shares_whole_desktop() {
         // No app selected → no --app flag → pixelpass keeps its default
         // (whole-desktop) audio capture.
-        assert_eq!(host_args(None), vec!["--host", "--output", "json"]);
+        let settings = ScreenShareSettings::default();
+        assert_eq!(
+            host_args(None, &settings, ShareQuality::Auto),
+            vec!["--host", "--output", "json"]
+        );
     }
 
     #[test]
@@ -635,8 +718,9 @@ mod tests {
         // The chosen app rides in the `--app=<name>` single-token form so a
         // name beginning with `-` can never be reparsed as a flag (A23), plus
         // `--strict-audio` so pixelpass never falls back to whole-desktop audio.
+        let settings = ScreenShareSettings::default();
         assert_eq!(
-            host_args(Some("Firefox")),
+            host_args(Some("Firefox"), &settings, ShareQuality::Auto),
             vec![
                 "--host",
                 "--output",
@@ -647,7 +731,7 @@ mod tests {
         );
         // The hyphen-leading name is still bound to --app as a single token;
         // --strict-audio is the trailing flag.
-        let args = host_args(Some("-rm -rf"));
+        let args = host_args(Some("-rm -rf"), &settings, ShareQuality::Auto);
         assert_eq!(args[3], "--app=-rm -rf");
         assert_eq!(args[4], "--strict-audio");
     }
@@ -656,11 +740,84 @@ mod tests {
     fn host_args_blank_or_control_app_is_dropped() {
         // An empty / whitespace / control-laden selection is sanitized away,
         // falling back to whole-desktop capture rather than a broken flag.
-        assert_eq!(host_args(Some("   ")), vec!["--host", "--output", "json"]);
+        let settings = ScreenShareSettings::default();
         assert_eq!(
-            host_args(Some("bad\nname")),
+            host_args(Some("   "), &settings, ShareQuality::Auto),
             vec!["--host", "--output", "json"]
         );
+        assert_eq!(
+            host_args(Some("bad\nname"), &settings, ShareQuality::Auto),
+            vec!["--host", "--output", "json"]
+        );
+    }
+
+    #[test]
+    fn host_args_apply_screen_share_settings_and_extra_args_last() {
+        let settings = ScreenShareSettings {
+            bitrate_mbps: Some(5),
+            framerate: Some(60),
+            max_height: Some(1080),
+            max_viewers: Some(4),
+            force_software_encode: true,
+            extra_host_args: "--relay https://relay.example --verbose".to_string(),
+            ..ScreenShareSettings::default()
+        };
+
+        assert_eq!(
+            host_args(Some("Firefox"), &settings, ShareQuality::High),
+            vec![
+                "--host",
+                "--output",
+                "json",
+                "--app=Firefox",
+                "--strict-audio",
+                "--quality=high",
+                "--max-height=1080",
+                "--bitrate=5000",
+                "--framerate=60",
+                "--no-hwencode",
+                "--max-viewers=4",
+                "--relay",
+                "https://relay.example",
+                "--verbose",
+            ]
+        );
+    }
+
+    #[test]
+    fn mpv_args_default_matches_low_latency_software_decode() {
+        assert_eq!(
+            mpv_args(&ScreenShareSettings::default()),
+            vec![
+                "--profile=low-latency",
+                "--audio-buffer=0.2",
+                "--demuxer-readahead-secs=0.5",
+                "--demuxer-max-bytes=2M",
+            ]
+        );
+    }
+
+    #[test]
+    fn mpv_args_smooth_hwdecode_and_extra_args_last() {
+        let settings = ScreenShareSettings {
+            hardware_decode: true,
+            buffering: ShareBuffering::Smooth,
+            cache_mb: 16,
+            extra_mpv_args: "--no-osc --vd-lavc-threads=2".to_string(),
+            ..ScreenShareSettings::default()
+        };
+
+        assert_eq!(
+            mpv_args(&settings),
+            vec![
+                "--cache=yes",
+                "--demuxer-readahead-secs=2",
+                "--demuxer-max-bytes=16M",
+                "--hwdec=auto",
+                "--no-osc",
+                "--vd-lavc-threads=2",
+            ]
+        );
     }
 
     #[test]