handle invalid framerate, check for av-offset property

src/lib.rs

@@ -71,4 +71,6 @@ pub enum Error {
     Sync,
     #[error("failed to lock internal sync primitive")]
     Lock,
+    #[error("invalid framerate: {0}")]
+    Framerate(f64),
 }

src/video.rs

@@ -53,6 +53,7 @@ pub(crate) struct Internal {
     pub(crate) framerate: f64,
     pub(crate) duration: std::time::Duration,
     pub(crate) speed: f64,
+    pub(crate) sync_av: bool,
 
     pub(crate) frame: Arc<Mutex<Vec<u8>>>,
     pub(crate) upload_frame: Arc<AtomicBool>,
@@ -141,10 +142,12 @@ impl Internal {
 
     /// Syncs audio with video when there is (inevitably) latency presenting the frame.
     pub(crate) fn set_av_offset(&mut self, offset: Duration) {
+        if self.sync_av {
             self.source
                 .set_property("av-offset", -(offset.as_nanos() as i64));
         }
     }
+}
 
 /// A multimedia video loaded from a URI (e.g., a local file path or HTTP stream).
 pub struct Video(pub(crate) RefCell<Internal>);
@@ -220,6 +223,14 @@ impl Video {
             .map_err(|_| Error::Caps)?;
         let framerate = framerate.numer() as f64 / framerate.denom() as f64;
 
+        if framerate.is_nan()
+            || framerate.is_infinite()
+            || framerate < 0.0
+            || framerate.abs() < f64::EPSILON
+        {
+            return Err(Error::Framerate(framerate));
+        }
+
         let duration = std::time::Duration::from_nanos(
             pipeline
                 .query_duration::<gst::ClockTime>()
@@ -227,6 +238,8 @@ impl Video {
                 .unwrap_or(0),
         );
 
+        let sync_av = pipeline.has_property("av-offset", None);
+
         // NV12 = 12bpp
         let frame = Arc::new(Mutex::new(vec![
             0u8;
@@ -293,6 +306,7 @@ impl Video {
             framerate,
             duration,
             speed: 1.0,
+            sync_av,
 
             frame,
             upload_frame,