Add appsink example

examples/src/bin/appsink.rs

@@ -0,0 +1,96 @@
+extern crate gstreamer as gst;
+use gst::*;
+extern crate gstreamer_app as gst_app;
+use gst_app::*;
+
+extern crate glib;
+use glib::*;
+
+use std::u64;
+use std::i16;
+use std::i32;
+
+fn main() {
+    gst::init().unwrap();
+
+    let pipeline = gst::Pipeline::new(None);
+    let src = gst::ElementFactory::make("audiotestsrc", None).unwrap();
+    let sink = gst::ElementFactory::make("appsink", None).unwrap();
+
+    pipeline.add_many(&[&src, &sink]).unwrap();
+    gst::Element::link_many(&[&src, &sink]).unwrap();
+
+    let appsink = sink.clone().dynamic_cast::<AppSink>().unwrap();
+    appsink.set_caps(&Caps::new_simple(
+        "audio/x-raw",
+        &[
+            (&"format", &"S16BE"),
+            (&"layout", &"interleaved"),
+            (&"channels", &(1i32)),
+            (&"rate", &IntRange::<i32>::new(1, i32::MAX)),
+        ],
+    ));
+
+    appsink.set_callbacks(AppSinkCallbacks::new(
+        /* eos */
+        |_| {},
+        /* new_preroll */
+        |_| FlowReturn::Ok,
+        /* new_samples */
+        |appsink| {
+            let sample = match appsink.pull_sample() {
+                None => return FlowReturn::Eos,
+                Some(sample) => sample,
+            };
+
+            let buffer = sample.get_buffer().unwrap();
+            assert_eq!(buffer.get_size() % 2, 0);
+            let map = buffer.map_read().unwrap();
+            let data = map.as_slice();
+            let sum: f64 = data.chunks(2)
+                .map(|sample| {
+                    let u: u16 = ((sample[0] as u16) << 8) | (sample[1] as u16);
+                    let f = (u as i16 as f64) / (i16::MAX as f64);
+                    f * f
+                })
+                .sum();
+            let rms = (sum / ((data.len() / 2) as f64)).sqrt();
+            println!("rms: {}", rms);
+
+            FlowReturn::Ok
+        },
+    ));
+
+    assert_ne!(
+        pipeline.set_state(gst::State::Playing),
+        gst::StateChangeReturn::Failure
+    );
+
+    let bus = pipeline.get_bus().unwrap();
+
+    loop {
+        let msg = match bus.timed_pop(u64::MAX) {
+            None => break,
+            Some(msg) => msg,
+        };
+
+        match msg.view() {
+            MessageView::Eos(..) => break,
+            MessageView::Error(err) => {
+                println!(
+                    "Error from {}: {} ({:?})",
+                    msg.get_src().get_path_string(),
+                    err.get_error(),
+                    err.get_debug()
+                );
+                break;
+            }
+            _ => (),
+        }
+    }
+
+    assert_ne!(
+        pipeline.set_state(gst::State::Null),
+        gst::StateChangeReturn::Failure
+    );
+}

gstreamer-app/src/lib.rs

@@ -36,3 +36,5 @@ pub use auto::traits::*;
 
 mod app_src;
 mod app_sink;
+pub use app_src::AppSrcCallbacks;
+pub use app_sink::AppSinkCallbacks;