Add receive-time timestamping mode

This directly uses the receive times of each packet.

src/lib.rs

@@ -32,6 +32,8 @@ pub enum TimestampMode {
     Timecode = 2,
     #[genum(name = "NDI Timestamp", nick = "timestamp")]
     Timestamp = 3,
+    #[genum(name = "Receive Time", nick = "receive-time")]
+    ReceiveTime = 4,
 }
 
 fn plugin_init(plugin: &gst::Plugin) -> Result<(), glib::BoolError> {

src/ndisrc/imp.rs

@@ -475,7 +475,10 @@ impl BaseSrcImpl for NdiSrc {
                 let settings = self.settings.lock().unwrap();
 
                 if let Some(latency) = state.current_latency {
-                    let min = if settings.timestamp_mode != TimestampMode::Timecode {
+                    let min = if matches!(
+                        settings.timestamp_mode,
+                        TimestampMode::ReceiveTimeTimecode | TimestampMode::ReceiveTimeTimestamp
+                    ) {
                         latency
                     } else {
                         gst::ClockTime::ZERO

src/receiver.rs

@@ -679,6 +679,7 @@ impl Receiver {
                     (receive_time + diff, duration)
                 }
             }
+            TimestampMode::ReceiveTime => (receive_time, duration),
         };
 
         gst_log!(