f8/sdk/fidl/fuchsia.media.sessions2/README.md - reference-docs - Git at Google

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 # fuchsia.media.sessions2

 <div class="fidl-version-div"><span class="fidl-attribute fidl-version">Added: 7</span></div>

 ## **PROTOCOLS**

 ## ActiveSession {#ActiveSession}
 *Defined in [fuchsia.media.sessions2/discovery.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=184)*
 <p>A protocol for watching the current active media session on the device.</p>
 <p>The currently active media session is the most recent existing media session
 to announce a &quot;Playing&quot; state on the local device, even if it is now paused.</p>

 ### WatchActiveSession {#ActiveSession.WatchActiveSession}

 <p>Watches the active session. The first request will be answered immediately
 with the current active session. Always leave a request hanging to receive
 a reply when the active session changes.</p>

 #### Request {#ActiveSession.WatchActiveSession_Request}

 &lt;EMPTY&gt;


 #### Response {#ActiveSession.WatchActiveSession_Response}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>session</code></td>
             <td>
                 <code><a class='link' href='#SessionControl'>SessionControl</a>?</code>
             </td>
         </tr>
 </table>

 ## Discovery {#Discovery}
 *Defined in [fuchsia.media.sessions2/discovery.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=146)*
 <p><code>Discovery</code> observes the collection of published media sessions
 and connects clients to them.</p>

 ### ConnectToSession {#Discovery.ConnectToSession}

 <p>Connects to a <code>SessionControl</code> for <code>session_id</code> if present. Drops the
 given channel otherwise.</p>

 #### Request {#Discovery.ConnectToSession_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>session_id</code></td>
             <td>
                 <code><a class='link' href='#SessionId'>SessionId</a></code>
             </td>
         </tr>
         <tr>
             <td><code>session_control_request</code></td>
             <td>
                 <code>request&lt;<a class='link' href='#SessionControl'>SessionControl</a>&gt;</code>
             </td>
         </tr>
 </table>


 ### WatchSessions {#Discovery.WatchSessions}

 <p>Connects a session watcher configured with the given options.</p>

 #### Request {#Discovery.WatchSessions_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>watch_options</code></td>
             <td>
                 <code><a class='link' href='#WatchOptions'>WatchOptions</a></code>
             </td>
         </tr>
         <tr>
             <td><code>session_watcher</code></td>
             <td>
                 <code><a class='link' href='#SessionsWatcher'>SessionsWatcher</a></code>
             </td>
         </tr>
 </table>


 ## ObserverDiscovery {#ObserverDiscovery}
 *Defined in [fuchsia.media.sessions2/discovery.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=164)*
 <p><code>ObserverDiscovery</code> observes the collection of published media sessions
 and connects clients to them for observation without playback controls.</p>

 ### ConnectToSession {#ObserverDiscovery.ConnectToSession}

 <p>Connects to a <code>SessionObserver</code> for <code>session_id</code> if present. Drops the
 given channel otherwise.</p>

 #### Request {#ObserverDiscovery.ConnectToSession_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>session_id</code></td>
             <td>
                 <code><a class='link' href='#SessionId'>SessionId</a></code>
             </td>
         </tr>
         <tr>
             <td><code>session_request</code></td>
             <td>
                 <code>request&lt;<a class='link' href='#SessionObserver'>SessionObserver</a>&gt;</code>
             </td>
         </tr>
 </table>


 ### WatchSessions {#ObserverDiscovery.WatchSessions}

 <p>Connects a session watcher configured with the given options.</p>

 #### Request {#ObserverDiscovery.WatchSessions_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>watch_options</code></td>
             <td>
                 <code><a class='link' href='#WatchOptions'>WatchOptions</a></code>
             </td>
         </tr>
         <tr>
             <td><code>sessions_watcher</code></td>
             <td>
                 <code><a class='link' href='#SessionsWatcher'>SessionsWatcher</a></code>
             </td>
         </tr>
 </table>


 ## Player {#Player}
 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=307)*
 <p><code>Player</code> is a handle for a media player. Unsupported commands are
 no-ops.  Consult <code>PlaybackCapabilities</code>, sent by to learn which
 commands are supported.</p>

 ### BindVolumeControl {#Player.BindVolumeControl}

 <p>Binds to the session's volume control for control and notifications. If this method is not
 supported as indicated by the absence of the <code>HAS_GAIN_CONTROL</code> flag in
 <code>PlayerCapabilities</code>, the channel handle passed as <code>volume_control_request</code> is closed
 by the service.</p>

 #### Request {#Player.BindVolumeControl_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>volume_control_request</code></td>
             <td>
                 <code>request&lt;<a class='link' href='../fuchsia.media.audio/'>fuchsia.media.audio</a>/<a class='link' href='../fuchsia.media.audio/#VolumeControl'>VolumeControl</a>&gt;</code>
             </td>
         </tr>
 </table>


 ### NextItem {#Player.NextItem}

 <p>Changes media to the next item (e.g. next song in playlist). If this method is not
 supported as indicated by the absence of the <code>CHANGE_TO_NEXT_ITEM</code> flag in
 <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#Player.NextItem_Request}

 &lt;EMPTY&gt;


 ### Pause {#Player.Pause}

 <p>Pauses playback and retains position in media. If this method is not supported as indicated
 by the absence of the <code>PAUSE</code> flag in <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#Player.Pause_Request}

 &lt;EMPTY&gt;


 ### Play {#Player.Play}

 <p>Plays media. If this method is not supported as indicated by the absence of the <code>PLAY</code>
 flag in <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#Player.Play_Request}

 &lt;EMPTY&gt;


 ### PrevItem {#Player.PrevItem}

 <p>Changes media to the previous item. If this method is not
 supported as indicated by the absence of the <code>CHANGE_TO_PREV_ITEM</code> flag in
 <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#Player.PrevItem_Request}

 &lt;EMPTY&gt;


 ### Seek {#Player.Seek}

 <p>Seeks to a specific position in media. Implementations are free to
 enter an error state if the position is out of bounds. <code>position</code>
 is an offset from the beginning of the media. If this method is not supported as indicated
 by the absence of the <code>SEEK</code> flag in <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#Player.Seek_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>position</code></td>
             <td>
                 <code><a class='link' href='../zx/'>zx</a>/<a class='link' href='../zx/#duration'>duration</a></code>
             </td>
         </tr>
 </table>


 ### SetPlaybackRate {#Player.SetPlaybackRate}

 <p>Sets the playback rate of the media. This will not change the playback mode. If this method
 is not supported as indicated by the absense of the <code>SET_PLAYBACK_RATE</code> flag in
 <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#Player.SetPlaybackRate_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>playback_rate</code></td>
             <td>
                 <code>float32</code>
             </td>
         </tr>
 </table>


 ### SetRepeatMode {#Player.SetRepeatMode}

 <p>Sets repeat mode to any of the supported repeat modes.
 Whether this method takes effect depends on the <code>PlayerCapabilities</code> and <code>repeat_mode</code>:</p>
 <ul>
 <li><a class='link' href='#OFF'>OFF</a> is always supported.</li>
 <li><a class='link' href='#GROUP'>GROUP</a> requires the <code>REPEAT_GROUPS</code> capability, and is otherwise ignored.</li>
 <li><a class='link' href='#SINGLE'>SINGLE</a> requires the <code>REPEAT_SINGLE</code> capability, and is otherwise ignored.</li>
 </ul>

 #### Request {#Player.SetRepeatMode_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>repeat_mode</code></td>
             <td>
                 <code><a class='link' href='#RepeatMode'>RepeatMode</a></code>
             </td>
         </tr>
 </table>


 ### SetShuffleMode {#Player.SetShuffleMode}

 <p>Sets shuffle mode. If this method is not supported as indicated by the absence of the
 <code>SHUFFLE</code> flag in <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#Player.SetShuffleMode_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>shuffle_on</code></td>
             <td>
                 <code>bool</code>
             </td>
         </tr>
 </table>


 ### SkipForward {#Player.SkipForward}

 <p>Skips forward in media by the player's default skip amount. If this method is not supported
 as indicated by the absence of the <code>SKIP_FORWARD</code> flag in <code>PlayerCapabilities</code>, this method
 does nothing.</p>

 #### Request {#Player.SkipForward_Request}

 &lt;EMPTY&gt;


 ### SkipReverse {#Player.SkipReverse}

 <p>Skips in reverse in media by the player's default skip amount. If this method is not
 supported as indicated by the absence of the <code>SKIP_REVERSE</code> flag in <code>PlayerCapabilities</code>,
 this method does nothing.</p>

 #### Request {#Player.SkipReverse_Request}

 &lt;EMPTY&gt;


 ### Stop {#Player.Stop}

 <p>Stops playback. The session should close.</p>

 #### Request {#Player.Stop_Request}

 &lt;EMPTY&gt;


 ### WatchInfoChange {#Player.WatchInfoChange}

 <p>Gets the net player info change using the hanging get pattern.</p>

 #### Request {#Player.WatchInfoChange_Request}

 &lt;EMPTY&gt;


 #### Response {#Player.WatchInfoChange_Response}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>player_info_delta</code></td>
             <td>
                 <code><a class='link' href='#PlayerInfoDelta'>PlayerInfoDelta</a></code>
             </td>
         </tr>
 </table>

 ## PlayerControl {#PlayerControl}
 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=24)*
 <p>Controls for a media player. <code>PlayerCapabilities</code> expresses which of the methods in this
 protocol are supported by the player. Because capabilties are dynamic, and a client cannot
 always know what capabilities will be supported when the method call reaches the service,
 calling a method that is not supported is simply ignored. In general, clients should not
 expect methods to work unless the player indicates sustained support.</p>

 ### BindVolumeControl {#PlayerControl.BindVolumeControl}

 <p>Binds to the session's volume control for control and notifications. If this method is not
 supported as indicated by the absence of the <code>HAS_GAIN_CONTROL</code> flag in
 <code>PlayerCapabilities</code>, the channel handle passed as <code>volume_control_request</code> is closed
 by the service.</p>

 #### Request {#PlayerControl.BindVolumeControl_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>volume_control_request</code></td>
             <td>
                 <code>request&lt;<a class='link' href='../fuchsia.media.audio/'>fuchsia.media.audio</a>/<a class='link' href='../fuchsia.media.audio/#VolumeControl'>VolumeControl</a>&gt;</code>
             </td>
         </tr>
 </table>


 ### NextItem {#PlayerControl.NextItem}

 <p>Changes media to the next item (e.g. next song in playlist). If this method is not
 supported as indicated by the absence of the <code>CHANGE_TO_NEXT_ITEM</code> flag in
 <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#PlayerControl.NextItem_Request}

 &lt;EMPTY&gt;


 ### Pause {#PlayerControl.Pause}

 <p>Pauses playback and retains position in media. If this method is not supported as indicated
 by the absence of the <code>PAUSE</code> flag in <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#PlayerControl.Pause_Request}

 &lt;EMPTY&gt;


 ### Play {#PlayerControl.Play}

 <p>Plays media. If this method is not supported as indicated by the absence of the <code>PLAY</code>
 flag in <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#PlayerControl.Play_Request}

 &lt;EMPTY&gt;


 ### PrevItem {#PlayerControl.PrevItem}

 <p>Changes media to the previous item. If this method is not
 supported as indicated by the absence of the <code>CHANGE_TO_PREV_ITEM</code> flag in
 <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#PlayerControl.PrevItem_Request}

 &lt;EMPTY&gt;


 ### Seek {#PlayerControl.Seek}

 <p>Seeks to a specific position in media. Implementations are free to
 enter an error state if the position is out of bounds. <code>position</code>
 is an offset from the beginning of the media. If this method is not supported as indicated
 by the absence of the <code>SEEK</code> flag in <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#PlayerControl.Seek_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>position</code></td>
             <td>
                 <code><a class='link' href='../zx/'>zx</a>/<a class='link' href='../zx/#duration'>duration</a></code>
             </td>
         </tr>
 </table>


 ### SetPlaybackRate {#PlayerControl.SetPlaybackRate}

 <p>Sets the playback rate of the media. This will not change the playback mode. If this method
 is not supported as indicated by the absense of the <code>SET_PLAYBACK_RATE</code> flag in
 <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#PlayerControl.SetPlaybackRate_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>playback_rate</code></td>
             <td>
                 <code>float32</code>
             </td>
         </tr>
 </table>


 ### SetRepeatMode {#PlayerControl.SetRepeatMode}

 <p>Sets repeat mode to any of the supported repeat modes.
 Whether this method takes effect depends on the <code>PlayerCapabilities</code> and <code>repeat_mode</code>:</p>
 <ul>
 <li><a class='link' href='#OFF'>OFF</a> is always supported.</li>
 <li><a class='link' href='#GROUP'>GROUP</a> requires the <code>REPEAT_GROUPS</code> capability, and is otherwise ignored.</li>
 <li><a class='link' href='#SINGLE'>SINGLE</a> requires the <code>REPEAT_SINGLE</code> capability, and is otherwise ignored.</li>
 </ul>

 #### Request {#PlayerControl.SetRepeatMode_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>repeat_mode</code></td>
             <td>
                 <code><a class='link' href='#RepeatMode'>RepeatMode</a></code>
             </td>
         </tr>
 </table>


 ### SetShuffleMode {#PlayerControl.SetShuffleMode}

 <p>Sets shuffle mode. If this method is not supported as indicated by the absence of the
 <code>SHUFFLE</code> flag in <code>PlayerCapabilities</code>, this method does nothing.</p>

 #### Request {#PlayerControl.SetShuffleMode_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>shuffle_on</code></td>
             <td>
                 <code>bool</code>
             </td>
         </tr>
 </table>


 ### SkipForward {#PlayerControl.SkipForward}

 <p>Skips forward in media by the player's default skip amount. If this method is not supported
 as indicated by the absence of the <code>SKIP_FORWARD</code> flag in <code>PlayerCapabilities</code>, this method
 does nothing.</p>

 #### Request {#PlayerControl.SkipForward_Request}

 &lt;EMPTY&gt;


 ### SkipReverse {#PlayerControl.SkipReverse}

 <p>Skips in reverse in media by the player's default skip amount. If this method is not
 supported as indicated by the absence of the <code>SKIP_REVERSE</code> flag in <code>PlayerCapabilities</code>,
 this method does nothing.</p>

 #### Request {#PlayerControl.SkipReverse_Request}

 &lt;EMPTY&gt;


 ### Stop {#PlayerControl.Stop}

 <p>Stops playback. The session should close.</p>

 #### Request {#PlayerControl.Stop_Request}

 &lt;EMPTY&gt;


 ## Publisher {#Publisher}
 *Defined in [fuchsia.media.sessions2/publisher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/publisher.fidl;l=23)*
 <p><code>Publisher</code> publishes media players so they may be discovered and
 controlled by clients who have permission to do so.</p>

 ### Publish {#Publisher.Publish}


 #### Request {#Publisher.Publish_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>player</code></td>
             <td>
                 <code><a class='link' href='#Player'>Player</a></code>
             </td>
         </tr>
         <tr>
             <td><code>registration</code></td>
             <td>
                 <code><a class='link' href='#PlayerRegistration'>PlayerRegistration</a></code>
             </td>
         </tr>
 </table>


 #### Response {#Publisher.Publish_Response}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>session_id</code></td>
             <td>
                 <code><a class='link' href='#SessionId'>SessionId</a></code>
             </td>
         </tr>
 </table>

 ## SessionControl {#SessionControl}
 *Defined in [fuchsia.media.sessions2/discovery.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=52)*
 <p>Controls a media session and views its status.</p>
 <p>The channel will close if the media session is stopped.</p>

 ### BindVolumeControl {#SessionControl.BindVolumeControl}

 <p>Binds to the session's volume control for control and notifications.</p>

 #### Request {#SessionControl.BindVolumeControl_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>volume_control_request</code></td>
             <td>
                 <code>request&lt;<a class='link' href='../fuchsia.media.audio/'>fuchsia.media.audio</a>/<a class='link' href='../fuchsia.media.audio/#VolumeControl'>VolumeControl</a>&gt;</code>
             </td>
         </tr>
 </table>


 ### NextItem {#SessionControl.NextItem}

 <p>Changes media to the next item (e.g. next song in playlist).</p>

 #### Request {#SessionControl.NextItem_Request}

 &lt;EMPTY&gt;


 ### Pause {#SessionControl.Pause}

 <p>Pauses playback and retains position in media</p>

 #### Request {#SessionControl.Pause_Request}

 &lt;EMPTY&gt;


 ### Play {#SessionControl.Play}

 <p>Plays media.</p>

 #### Request {#SessionControl.Play_Request}

 &lt;EMPTY&gt;


 ### PrevItem {#SessionControl.PrevItem}

 <p>Changes media to the previous item.</p>

 #### Request {#SessionControl.PrevItem_Request}

 &lt;EMPTY&gt;


 ### Seek {#SessionControl.Seek}

 <p>Seeks to a specific position in media. Implementations are free to
 enter an error state if the position is out of bounds. <code>position</code>
 is an offset from the beginning of the media.</p>

 #### Request {#SessionControl.Seek_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>position</code></td>
             <td>
                 <code><a class='link' href='../zx/'>zx</a>/<a class='link' href='../zx/#duration'>duration</a></code>
             </td>
         </tr>
 </table>


 ### SetPlaybackRate {#SessionControl.SetPlaybackRate}

 <p>Sets the playback rate of the media. This will not change the
 playback mode.</p>

 #### Request {#SessionControl.SetPlaybackRate_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>playback_rate</code></td>
             <td>
                 <code>float32</code>
             </td>
         </tr>
 </table>


 ### SetRepeatMode {#SessionControl.SetRepeatMode}

 <p>Sets repeat mode to any of the supported repeat modes.</p>

 #### Request {#SessionControl.SetRepeatMode_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>repeat_mode</code></td>
             <td>
                 <code><a class='link' href='#RepeatMode'>RepeatMode</a></code>
             </td>
         </tr>
 </table>


 ### SetShuffleMode {#SessionControl.SetShuffleMode}

 <p>Sets shuffle mode.</p>

 #### Request {#SessionControl.SetShuffleMode_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>shuffle_on</code></td>
             <td>
                 <code>bool</code>
             </td>
         </tr>
 </table>


 ### SkipForward {#SessionControl.SkipForward}

 <p>Skips forward in media by the player's default skip amount.</p>

 #### Request {#SessionControl.SkipForward_Request}

 &lt;EMPTY&gt;


 ### SkipReverse {#SessionControl.SkipReverse}

 <p>Skips in reverse in media by the player's default skip amount.</p>

 #### Request {#SessionControl.SkipReverse_Request}

 &lt;EMPTY&gt;


 ### Stop {#SessionControl.Stop}

 <p>Stops playback. The session should close.</p>

 #### Request {#SessionControl.Stop_Request}

 &lt;EMPTY&gt;


 ### WatchStatus {#SessionControl.WatchStatus}

 <p>Watches the session status. Leave a request hanging to receive a reply when
 the session status changes. The first request will be answered immediately with
 the current state.</p>

 #### Request {#SessionControl.WatchStatus_Request}

 &lt;EMPTY&gt;


 #### Response {#SessionControl.WatchStatus_Response}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>session_info_delta</code></td>
             <td>
                 <code><a class='link' href='#SessionInfoDelta'>SessionInfoDelta</a></code>
             </td>
         </tr>
 </table>

 ## SessionObserver {#SessionObserver}
 *Defined in [fuchsia.media.sessions2/discovery.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=101)*
 <p>Views a media session's status.</p>
 <p>The channel will close if the media session is stopped.</p>

 ### WatchStatus {#SessionObserver.WatchStatus}

 <p>Watches the session status. Leave a request hanging to receive a reply when
 the session status changes. The first request will be answered immediately with
 the current state.</p>

 #### Request {#SessionObserver.WatchStatus_Request}

 &lt;EMPTY&gt;


 #### Response {#SessionObserver.WatchStatus_Response}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>session_info_delta</code></td>
             <td>
                 <code><a class='link' href='#SessionInfoDelta'>SessionInfoDelta</a></code>
             </td>
         </tr>
 </table>

 ## SessionsWatcher {#SessionsWatcher}
 *Defined in [fuchsia.media.sessions2/discovery.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=121)*
 <p><code>SessionsWatcher</code> watches the collection of published sessions.</p>

 ### SessionRemoved {#SessionsWatcher.SessionRemoved}

 <p>Called by the registry service when a session is removed from the registered
 collection.</p>
 <p><code>SessionsWatcher</code> must reply to acknlowledge receipt of the session removal.
 Delinquent watchers who do not reply will eventually be disconnected.</p>

 #### Request {#SessionsWatcher.SessionRemoved_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>session_id</code></td>
             <td>
                 <code><a class='link' href='#SessionId'>SessionId</a></code>
             </td>
         </tr>
 </table>


 #### Response {#SessionsWatcher.SessionRemoved_Response}

 &lt;EMPTY&gt;

 ### SessionUpdated {#SessionsWatcher.SessionUpdated}

 <p>Called by the registry service when a session is updated. On first connection,
 this will be called as many times as needed to communicate the state of the
 world.</p>
 <p><code>SessionsWatcher</code> must reply to acknowledge receipt of the session info delta.
 Delinquent watchers who do not reply will eventually be disconnected.</p>

 #### Request {#SessionsWatcher.SessionUpdated_Request}

 <table>
     <tr><th>Name</th><th>Type</th></tr>
         <tr>
             <td><code>session_id</code></td>
             <td>
                 <code><a class='link' href='#SessionId'>SessionId</a></code>
             </td>
         </tr>
         <tr>
             <td><code>session_info_delta</code></td>
             <td>
                 <code><a class='link' href='#SessionInfoDelta'>SessionInfoDelta</a></code>
             </td>
         </tr>
 </table>


 #### Response {#SessionsWatcher.SessionUpdated_Response}

 &lt;EMPTY&gt;


 ## **STRUCTS**

 ### ImageSizeVariant  {#ImageSizeVariant data-text="ImageSizeVariant"}
 *Defined in [fuchsia.media.sessions2/images.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/images.fidl;l=17)*
 <p>A variant of an image at a specific size.</p>

 <table>
     <tr><th>Field</th><th>Type</th><th>Description</th><th>Default</th></tr>
         <tr id="ImageSizeVariant.url">
             <td><code>url</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.url/'>fuchsia.url</a>/<a class='link' href='../fuchsia.url/#Url'>Url</a></code>
             </td>
             <td></td>
             <td>No default</td>
         </tr>
         <tr id="ImageSizeVariant.width">
             <td><code>width</code></td>
             <td>
                 <code>uint32</code>
             </td>
             <td></td>
             <td>No default</td>
         </tr>
         <tr id="ImageSizeVariant.height">
             <td><code>height</code></td>
             <td>
                 <code>uint32</code>
             </td>
             <td></td>
             <td>No default</td>
         </tr>
 </table>


 ## **ENUMS**

 ### ContentType [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#ContentType data-text="ContentType"}
 Type: <code>uint32</code>

 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=97)*
 <p>The type of content playing back, which should be set to the largest
 applicable value.</p>

 <table>
     <tr><th>Name</th><th>Value</th><th>Description</th></tr>
         <tr id="ContentType.OTHER">
 <td><h3 id="ContentType.OTHER" class="add-link hide-from-toc">OTHER</h3></td>
             <td><code>1</code></td>
             <td><p>Content does not qualify for any of the other values.</p>
 </td>
         </tr>
         <tr id="ContentType.AUDIO">
 <td><h3 id="ContentType.AUDIO" class="add-link hide-from-toc">AUDIO</h3></td>
             <td><code>2</code></td>
             <td><p>Audio-only content that does not qualify as music.</p>
 </td>
         </tr>
         <tr id="ContentType.VIDEO">
 <td><h3 id="ContentType.VIDEO" class="add-link hide-from-toc">VIDEO</h3></td>
             <td><code>3</code></td>
             <td><p>Video-only or audio-video content that does not qualify as a TV show or a movie.</p>
 </td>
         </tr>
         <tr id="ContentType.MUSIC">
 <td><h3 id="ContentType.MUSIC" class="add-link hide-from-toc">MUSIC</h3></td>
             <td><code>4</code></td>
             <td><p>Audio-only content generally recognized as music.</p>
 </td>
         </tr>
         <tr id="ContentType.TV_SHOW">
 <td><h3 id="ContentType.TV_SHOW" class="add-link hide-from-toc">TV_SHOW</h3></td>
             <td><code>5</code></td>
             <td><p>Audio-video content that is part of a television or streaming series.</p>
 </td>
         </tr>
         <tr id="ContentType.MOVIE">
 <td><h3 id="ContentType.MOVIE" class="add-link hide-from-toc">MOVIE</h3></td>
             <td><code>6</code></td>
             <td><p>Audio-video content consisting of a feature film.</p>
 </td>
         </tr>
 </table>

 ### Error [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#Error data-text="Error"}
 Type: <code>uint32</code>

 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=184)*

 <table>
     <tr><th>Name</th><th>Value</th><th>Description</th></tr>
         <tr id="Error.OTHER">
 <td><h3 id="Error.OTHER" class="add-link hide-from-toc">OTHER</h3></td>
             <td><code>1</code></td>
             <td></td>
         </tr>
 </table>

 ### InterruptionBehavior [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#InterruptionBehavior data-text="InterruptionBehavior"}
 Type: <code>uint32</code>

 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=251)*
 <p>The behavior enforced on the player when it is
 interrupted, such as by an alarm.</p>
 <p>Interruptions are detected using the player's usage.</p>
 <p>By default the interruption behavior is <code>NONE</code>.</p>

 <table>
     <tr><th>Name</th><th>Value</th><th>Description</th></tr>
         <tr id="InterruptionBehavior.NONE">
 <td><h3 id="InterruptionBehavior.NONE" class="add-link hide-from-toc">NONE</h3></td>
             <td><code>0</code></td>
             <td><p>Interruptions have no effect on the player
 and it may continue in spite of reduced audibility.</p>
 </td>
         </tr>
         <tr id="InterruptionBehavior.PAUSE">
 <td><h3 id="InterruptionBehavior.PAUSE" class="add-link hide-from-toc">PAUSE</h3></td>
             <td><code>1</code></td>
             <td><p>With this behavior, when playback is interrupted, the player
 will be paused until the interruption is over, so the user
 does not miss any content.</p>
 </td>
         </tr>
 </table>

 ### MediaImageType [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#MediaImageType data-text="MediaImageType"}
 Type: <code>uint32</code>

 *Defined in [fuchsia.media.sessions2/images.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/images.fidl;l=8)*

 <table>
     <tr><th>Name</th><th>Value</th><th>Description</th></tr>
         <tr id="MediaImageType.ARTWORK">
 <td><h3 id="MediaImageType.ARTWORK" class="add-link hide-from-toc">ARTWORK</h3></td>
             <td><code>0</code></td>
             <td><p>Artwork for the playing media.</p>
 </td>
         </tr>
         <tr id="MediaImageType.SOURCE_ICON">
 <td><h3 id="MediaImageType.SOURCE_ICON" class="add-link hide-from-toc">SOURCE_ICON</h3></td>
             <td><code>1</code></td>
             <td><p>An icon for the source of the playing media (e.g. the player or
 streaming service).</p>
 </td>
         </tr>
 </table>

 ### PlayerState [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#PlayerState data-text="PlayerState"}
 Type: <code>uint32</code>

 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=166)*
 <p>State of a media player.</p>

 <table>
     <tr><th>Name</th><th>Value</th><th>Description</th></tr>
         <tr id="PlayerState.IDLE">
 <td><h3 id="PlayerState.IDLE" class="add-link hide-from-toc">IDLE</h3></td>
             <td><code>0</code></td>
             <td><p>The initial state of a session if there is no associated media.</p>
 </td>
         </tr>
         <tr id="PlayerState.PLAYING">
 <td><h3 id="PlayerState.PLAYING" class="add-link hide-from-toc">PLAYING</h3></td>
             <td><code>1</code></td>
             <td><p>The player is playing.</p>
 </td>
         </tr>
         <tr id="PlayerState.PAUSED">
 <td><h3 id="PlayerState.PAUSED" class="add-link hide-from-toc">PAUSED</h3></td>
             <td><code>2</code></td>
             <td><p>The player is paused.</p>
 </td>
         </tr>
         <tr id="PlayerState.BUFFERING">
 <td><h3 id="PlayerState.BUFFERING" class="add-link hide-from-toc">BUFFERING</h3></td>
             <td><code>3</code></td>
             <td><p>The player would be playing, but is temporarily paused for buffering.</p>
 </td>
         </tr>
         <tr id="PlayerState.ERROR">
 <td><h3 id="PlayerState.ERROR" class="add-link hide-from-toc">ERROR</h3></td>
             <td><code>4</code></td>
             <td><p>The player cannot recover from this state and will close.</p>
 </td>
         </tr>
 </table>

 ### RepeatMode [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#RepeatMode data-text="RepeatMode"}
 Type: <code>uint32</code>

 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=189)*
 <p>Modes of repeating playback of the current media.</p>

 <table>
     <tr><th>Name</th><th>Value</th><th>Description</th></tr>
         <tr id="RepeatMode.OFF">
 <td><h3 id="RepeatMode.OFF" class="add-link hide-from-toc">OFF</h3></td>
             <td><code>0</code></td>
             <td><p>No repeat.</p>
 </td>
         </tr>
         <tr id="RepeatMode.GROUP">
 <td><h3 id="RepeatMode.GROUP" class="add-link hide-from-toc">GROUP</h3></td>
             <td><code>1</code></td>
             <td><p>Repeat the relevant group of media (e.g. playlist).</p>
 </td>
         </tr>
         <tr id="RepeatMode.SINGLE">
 <td><h3 id="RepeatMode.SINGLE" class="add-link hide-from-toc">SINGLE</h3></td>
             <td><code>2</code></td>
             <td><p>Repeat the currently playing media.</p>
 </td>
         </tr>
 </table>


 ## **TABLES**

 ### MediaImage  {#MediaImage data-text="MediaImage"}


 *Defined in [fuchsia.media.sessions2/images.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/images.fidl;l=24)*
 <p>An image for playing media.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="MediaImage.image_type">
 <td><h3 id="MediaImage.image_type" class="add-link hide-from-toc">1</h3></td>
             <td><code>image_type</code></td>
             <td>
                 <code><a class='link' href='#MediaImageType'>MediaImageType</a></code>
             </td>
             <td></td>
         </tr>
         <tr id="MediaImage.sizes">
 <td><h3 id="MediaImage.sizes" class="add-link hide-from-toc">2</h3></td>
             <td><code>sizes</code></td>
             <td>
                 <code>vector&lt;<a class='link' href='#ImageSizeVariant'>ImageSizeVariant</a>&gt;[16]</code>
             </td>
             <td><p>Available variants of the image.</p>
 </td>
         </tr>
 </table>

 ### PlayerCapabilities  {#PlayerCapabilities data-text="PlayerCapabilities"}


 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=239)*
 <p>Describes the capabilities of a player.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="PlayerCapabilities.flags">
 <td><h3 id="PlayerCapabilities.flags" class="add-link hide-from-toc">1</h3></td>
             <td><code>flags</code></td>
             <td>
                 <code><a class='link' href='#PlayerCapabilityFlags'>PlayerCapabilityFlags</a></code>
             </td>
             <td><p>Indicates which capabilities are supported by the player. See <code>PlayerControl</code> for
 details.</p>
 </td>
         </tr>
 </table>

 ### PlayerInfoDelta  {#PlayerInfoDelta data-text="PlayerInfoDelta"}


 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=264)*
 <p>When emitted, fields that have changed should be set.
 The first emission to a new client should be a snapshot.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="PlayerInfoDelta.local">
 <td><h3 id="PlayerInfoDelta.local" class="add-link hide-from-toc">1</h3></td>
             <td><code>local</code></td>
             <td>
                 <code>bool</code>
             </td>
             <td><p>Whether the entry point for the media into our device network is the
 local machine; this should be true if this is the device streaming
 from a music service, but false or omitted if this machine is just
 receiving an audio stream to act as a speaker.</p>
 <p>If omitted, the value is unchanged. Initially, this value is <code>true</code>.</p>
 </td>
         </tr>
         <tr id="PlayerInfoDelta.player_status">
 <td><h3 id="PlayerInfoDelta.player_status" class="add-link hide-from-toc">2</h3></td>
             <td><code>player_status</code></td>
             <td>
                 <code><a class='link' href='#PlayerStatus'>PlayerStatus</a></code>
             </td>
             <td><p>The status of the player.</p>
 <p>If omitted, all constituent values are unchanged. If a field within <code>PlayerStatus</code> is
 omitted, its value is unchanged. Initial values are indicated for each field in
 <code>player_status</code>.</p>
 </td>
         </tr>
         <tr id="PlayerInfoDelta.metadata">
 <td><h3 id="PlayerInfoDelta.metadata" class="add-link hide-from-toc">3</h3></td>
             <td><code>metadata</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.media/'>fuchsia.media</a>/<a class='link' href='../fuchsia.media/#Metadata'>Metadata</a></code>
             </td>
             <td><p>The metadata of the playing media.</p>
 <p>If omitted, the metadata is unchanged. Initially, there is no metadata.</p>
 </td>
         </tr>
         <tr id="PlayerInfoDelta.media_images">
 <td><h3 id="PlayerInfoDelta.media_images" class="add-link hide-from-toc">4</h3></td>
             <td><code>media_images</code></td>
             <td>
                 <code>vector&lt;<a class='link' href='#MediaImage'>MediaImage</a>&gt;[16]</code>
             </td>
             <td><p>The images associated with the playing media.</p>
 <p>If omitted, the media images are unchanged. An empty
 vector indicates that there are no media images, which is also the initial state.</p>
 </td>
         </tr>
         <tr id="PlayerInfoDelta.player_capabilities">
 <td><h3 id="PlayerInfoDelta.player_capabilities" class="add-link hide-from-toc">5</h3></td>
             <td><code>player_capabilities</code></td>
             <td>
                 <code><a class='link' href='#PlayerCapabilities'>PlayerCapabilities</a></code>
             </td>
             <td><p>The capabilities of the player.</p>
 <p>If omitted, the capabilities are unchanged. Initially, the player is assumed to have no
 capabilities.</p>
 </td>
         </tr>
         <tr id="PlayerInfoDelta.interruption_behavior">
 <td><h3 id="PlayerInfoDelta.interruption_behavior" class="add-link hide-from-toc">6</h3></td>
             <td><code>interruption_behavior</code></td>
             <td>
                 <code><a class='link' href='#InterruptionBehavior'>InterruptionBehavior</a></code>
             </td>
             <td><p>The behavior the player would like to engage in when interrupted
 by something, such as an alarm.</p>
 <p>If omitted, the behavior is unchanged. Initially, the value is <code>NONE</code>.</p>
 </td>
         </tr>
 </table>

 ### PlayerRegistration  {#PlayerRegistration data-text="PlayerRegistration"}


 *Defined in [fuchsia.media.sessions2/publisher.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/publisher.fidl;l=11)*
 <p>All information required by the media session registry service to
 register a player so that clients may observe its status and control
 it.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="PlayerRegistration.domain">
 <td><h3 id="PlayerRegistration.domain" class="add-link hide-from-toc">1</h3></td>
             <td><code>domain</code></td>
             <td>
                 <code><a class='link' href='#Domain'>Domain</a></code>
             </td>
             <td><p>The domain on which the player exists. Unset if it is the native
 Fuchsia domain.</p>
 </td>
         </tr>
         <tr id="PlayerRegistration.usage">
 <td><h3 id="PlayerRegistration.usage" class="add-link hide-from-toc">2</h3></td>
             <td><code>usage</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.media/'>fuchsia.media</a>/<a class='link' href='../fuchsia.media/#AudioRenderUsage'>AudioRenderUsage</a></code>
             </td>
             <td><p>The usage of the player's audio output. By default, this is assumed
 to be MEDIA.</p>
 </td>
         </tr>
 </table>

 ### PlayerStatus  {#PlayerStatus data-text="PlayerStatus"}


 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=119)*
 <p>Status of a media player.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="PlayerStatus.duration">
 <td><h3 id="PlayerStatus.duration" class="add-link hide-from-toc">1</h3></td>
             <td><code>duration</code></td>
             <td>
                 <code><a class='link' href='../zx/'>zx</a>/<a class='link' href='../zx/#duration'>duration</a></code>
             </td>
             <td><p>Total duration of playing media.</p>
 <p>If this value is omitted, the duration is unknown, not applicable or unchanged. Initially,
 the duration is assumed to be unknown.</p>
 </td>
         </tr>
         <tr id="PlayerStatus.is_live">
 <td><h3 id="PlayerStatus.is_live" class="add-link hide-from-toc">8</h3></td>
             <td><code>is_live</code></td>
             <td>
                 <code>bool</code>
             </td>
             <td><p>Whether the playing media is live (such as television or a live stream).</p>
 <p>If this field is omitted, the value is unchanged. Initially, the value is false.</p>
 </td>
         </tr>
         <tr id="PlayerStatus.player_state">
 <td><h3 id="PlayerStatus.player_state" class="add-link hide-from-toc">2</h3></td>
             <td><code>player_state</code></td>
             <td>
                 <code><a class='link' href='#PlayerState'>PlayerState</a></code>
             </td>
             <td><p>State of the player.</p>
 <p>If this field is omitted, the value is unchanged. Initially, the value is <code>IDLE</code>.</p>
 </td>
         </tr>
         <tr id="PlayerStatus.timeline_function">
 <td><h3 id="PlayerStatus.timeline_function" class="add-link hide-from-toc">3</h3></td>
             <td><code>timeline_function</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.media/'>fuchsia.media</a>/<a class='link' href='../fuchsia.media/#TimelineFunction'>TimelineFunction</a></code>
             </td>
             <td><p>A playback function that describes the position and rate of
 play through the media as a function of <code>CLOCK_MONOTONIC</code>.</p>
 <p>If this field is omitted, the value is unchanged. Initially, <code>reference_delta</code> is 1 and
 the remaining constituent fields are 0.</p>
 </td>
         </tr>
         <tr id="PlayerStatus.repeat_mode">
 <td><h3 id="PlayerStatus.repeat_mode" class="add-link hide-from-toc">4</h3></td>
             <td><code>repeat_mode</code></td>
             <td>
                 <code><a class='link' href='#RepeatMode'>RepeatMode</a></code>
             </td>
             <td><p>Repeat mode of the player.</p>
 <p>If this field is omitted, the value is unchanged. Initially, the value is <code>NONE</code>.</p>
 </td>
         </tr>
         <tr id="PlayerStatus.shuffle_on">
 <td><h3 id="PlayerStatus.shuffle_on" class="add-link hide-from-toc">5</h3></td>
             <td><code>shuffle_on</code></td>
             <td>
                 <code>bool</code>
             </td>
             <td><p>Shuffle mode of the player.</p>
 <p>If this field is omitted, the value is unchanged. Initially, the value is false.</p>
 </td>
         </tr>
         <tr id="PlayerStatus.content_type">
 <td><h3 id="PlayerStatus.content_type" class="add-link hide-from-toc">6</h3></td>
             <td><code>content_type</code></td>
             <td>
                 <code><a class='link' href='#ContentType'>ContentType</a></code>
             </td>
             <td><p>The type of content playing back.</p>
 <p>If this field is omitted, the value is unchanged. Initially, the value is <code>OTHER</code>.</p>
 </td>
         </tr>
         <tr id="PlayerStatus.error">
 <td><h3 id="PlayerStatus.error" class="add-link hide-from-toc">7</h3></td>
             <td><code>error</code></td>
             <td>
                 <code><a class='link' href='#Error'>Error</a></code>
             </td>
             <td><p>An error the player may have encountered.</p>
 <p>This field is omitted unless there is an error. Once an error is indicated, it cannot
 be rescinded.</p>
 </td>
         </tr>
 </table>

 ### SessionInfoDelta  {#SessionInfoDelta data-text="SessionInfoDelta"}


 *Defined in [fuchsia.media.sessions2/discovery.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=13)*
 <p>SessionInfoDelta holds a description of a media session.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="SessionInfoDelta.domain">
 <td><h3 id="SessionInfoDelta.domain" class="add-link hide-from-toc">1</h3></td>
             <td><code>domain</code></td>
             <td>
                 <code><a class='link' href='#Domain'>Domain</a></code>
             </td>
             <td><p>The domain on which the session takes place. A domain identifies a set of
 mutually compatible media targets and sessions; sessions on a domain may
 be played back on targets of the same domain.</p>
 <p>This field is always present.</p>
 </td>
         </tr>
         <tr id="SessionInfoDelta.is_local">
 <td><h3 id="SessionInfoDelta.is_local" class="add-link hide-from-toc">2</h3></td>
             <td><code>is_local</code></td>
             <td>
                 <code>bool</code>
             </td>
             <td><p>Whether the source of the media playback is on this device.</p>
 <p>This field is present only if known.</p>
 </td>
         </tr>
         <tr id="SessionInfoDelta.is_locally_active">
 <td><h3 id="SessionInfoDelta.is_locally_active" class="add-link hide-from-toc">3</h3></td>
             <td><code>is_locally_active</code></td>
             <td>
                 <code>bool</code>
             </td>
             <td><p>If this is <code>true</code>, the playback is taking place local to the device.
 Playing on the device speaker is local, playing on a remote speaker
 is not. This is only set when the session is playing back; a paused
 session is not active.</p>
 <p>This field is always present.</p>
 </td>
         </tr>
         <tr id="SessionInfoDelta.player_status">
 <td><h3 id="SessionInfoDelta.player_status" class="add-link hide-from-toc">4</h3></td>
             <td><code>player_status</code></td>
             <td>
                 <code><a class='link' href='#PlayerStatus'>PlayerStatus</a></code>
             </td>
             <td><p>The status of the player.</p>
 <p>This field is always present.</p>
 </td>
         </tr>
         <tr id="SessionInfoDelta.metadata">
 <td><h3 id="SessionInfoDelta.metadata" class="add-link hide-from-toc">5</h3></td>
             <td><code>metadata</code></td>
             <td>
                 <code><a class='link' href='../fuchsia.media/'>fuchsia.media</a>/<a class='link' href='../fuchsia.media/#Metadata'>Metadata</a></code>
             </td>
             <td><p>Metadata describing the media session.</p>
 <p>This field is always present.</p>
 </td>
         </tr>
         <tr id="SessionInfoDelta.media_images">
 <td><h3 id="SessionInfoDelta.media_images" class="add-link hide-from-toc">6</h3></td>
             <td><code>media_images</code></td>
             <td>
                 <code>vector&lt;<a class='link' href='#MediaImage'>MediaImage</a>&gt;</code>
             </td>
             <td><p>Images associated with the media or its source.</p>
 <p>This field is always present.</p>
 </td>
         </tr>
         <tr id="SessionInfoDelta.player_capabilities">
 <td><h3 id="SessionInfoDelta.player_capabilities" class="add-link hide-from-toc">7</h3></td>
             <td><code>player_capabilities</code></td>
             <td>
                 <code><a class='link' href='#PlayerCapabilities'>PlayerCapabilities</a></code>
             </td>
             <td><p>The capabilities the player of the media implements.</p>
 <p>This field is always present.</p>
 </td>
         </tr>
 </table>

 ### WatchOptions  {#WatchOptions data-text="WatchOptions"}


 *Defined in [fuchsia.media.sessions2/discovery.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=113)*
 <p>Options that specify which sessions are watched when watching the collection.</p>
 <p>The watched set is the set of sessions which satisfies all options.</p>

 <table>
     <tr><th>Ordinal</th><th>Field</th><th>Type</th><th>Description</th></tr>
         <tr id="WatchOptions.only_active">
 <td><h3 id="WatchOptions.only_active" class="add-link hide-from-toc">1</h3></td>
             <td><code>only_active</code></td>
             <td>
                 <code>bool</code>
             </td>
             <td><p>Watch only the active session. Watches all if not set.</p>
 </td>
         </tr>
         <tr id="WatchOptions.allowed_sessions">
 <td><h3 id="WatchOptions.allowed_sessions" class="add-link hide-from-toc">2</h3></td>
             <td><code>allowed_sessions</code></td>
             <td>
                 <code>vector&lt;uint64&gt;[1000]</code>
             </td>
             <td><p>Watch only sessions with these allowlisted ids. Watches all if not set.</p>
 </td>
         </tr>
 </table>


 ## **BITS**

 ### PlayerCapabilityFlags [strict](/fuchsia-src/reference/fidl/language/language.md#strict-vs-flexible){:.fidl-attribute} {#PlayerCapabilityFlags}
 Type: <code>uint32</code>

 *Defined in [fuchsia.media.sessions2/player.fidl](https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=200)*

 <table>
     <tr><th>Name</th><th>Value</th><th>Description</th></tr>
         <tr id="PlayerCapabilityFlags.PLAY">
 <td><h3 id="PlayerCapabilityFlags.PLAY" class="add-link hide-from-toc">PLAY</h3></td>
             <td>1</td>
             <td><p>If set, the player can <code>Play()</code>.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.PAUSE">
 <td><h3 id="PlayerCapabilityFlags.PAUSE" class="add-link hide-from-toc">PAUSE</h3></td>
             <td>4</td>
             <td><p>If set, the player can <code>Pause()</code>.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.SEEK">
 <td><h3 id="PlayerCapabilityFlags.SEEK" class="add-link hide-from-toc">SEEK</h3></td>
             <td>8</td>
             <td><p>If set, the player can <code>Seek()</code>.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.SKIP_FORWARD">
 <td><h3 id="PlayerCapabilityFlags.SKIP_FORWARD" class="add-link hide-from-toc">SKIP_FORWARD</h3></td>
             <td>16</td>
             <td><p>If set, the player can <code>SkipForward()</code>.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.SKIP_REVERSE">
 <td><h3 id="PlayerCapabilityFlags.SKIP_REVERSE" class="add-link hide-from-toc">SKIP_REVERSE</h3></td>
             <td>32</td>
             <td><p>If set, the player can <code>SkipReverse()</code>.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.SHUFFLE">
 <td><h3 id="PlayerCapabilityFlags.SHUFFLE" class="add-link hide-from-toc">SHUFFLE</h3></td>
             <td>64</td>
             <td><p>If set, the player can shuffle media.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.CHANGE_TO_NEXT_ITEM">
 <td><h3 id="PlayerCapabilityFlags.CHANGE_TO_NEXT_ITEM" class="add-link hide-from-toc">CHANGE_TO_NEXT_ITEM</h3></td>
             <td>128</td>
             <td></td>
         </tr>
         <tr id="PlayerCapabilityFlags.CHANGE_TO_PREV_ITEM">
 <td><h3 id="PlayerCapabilityFlags.CHANGE_TO_PREV_ITEM" class="add-link hide-from-toc">CHANGE_TO_PREV_ITEM</h3></td>
             <td>256</td>
             <td></td>
         </tr>
         <tr id="PlayerCapabilityFlags.HAS_GAIN_CONTROL">
 <td><h3 id="PlayerCapabilityFlags.HAS_GAIN_CONTROL" class="add-link hide-from-toc">HAS_GAIN_CONTROL</h3></td>
             <td>512</td>
             <td><p>If set, the player can <code>BindGainControl()</code>.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.REPEAT_GROUPS">
 <td><h3 id="PlayerCapabilityFlags.REPEAT_GROUPS" class="add-link hide-from-toc">REPEAT_GROUPS</h3></td>
             <td>1024</td>
             <td><p>If set, the player can repeat groups.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.REPEAT_SINGLE">
 <td><h3 id="PlayerCapabilityFlags.REPEAT_SINGLE" class="add-link hide-from-toc">REPEAT_SINGLE</h3></td>
             <td>2048</td>
             <td><p>If set, the player can repeat single media items.</p>
 </td>
         </tr>
         <tr id="PlayerCapabilityFlags.SET_PLAYBACK_RATE">
 <td><h3 id="PlayerCapabilityFlags.SET_PLAYBACK_RATE" class="add-link hide-from-toc">SET_PLAYBACK_RATE</h3></td>
             <td>4096</td>
             <td><p>If set, the player can accept playback rate changes.</p>
 </td>
         </tr>
 </table>


 ## **TYPE ALIASES**

 <table>
     <tr><th>Name</th><th>Value</th><th>Description</th></tr>
         <tr id="Domain">
             <td><a href="https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/player.fidl;l=17">Domain</a></td>
             <td>
                 <code>string</code>[<code>1000</code>]</td>
             <td><p>A domain identifies the ecosystem in which the session takes place.</p>
 <p>Domains should take the form of</p>
 <pre><code>`domain://&lt;unique name for protocol&gt;.version`
 </code></pre>
 <p>The <code>|</code> symbol is reserved and should not be used in a domain string.</p>
 </td>
         </tr>
         <tr id="SessionId">
             <td><a href="https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/fidl/fuchsia.media.sessions2/discovery.fidl;l=10">SessionId</a></td>
             <td>
                 <code>uint64</code></td>
             <td></td>
         </tr>
 </table>