Use gstreamer-video API in appsrc example and make frame generation a bit more efficient

Cargo.lock

@@ -114,6 +114,7 @@ dependencies = [
  "gstreamer-app 0.1.0",
  "gstreamer-audio 0.1.0",
  "gstreamer-player 0.1.0",
+ "gstreamer-video 0.1.0",
  "gtk 0.1.3 (git+https://github.com/gtk-rs/gtk)",
  "send-cell 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-core 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",

examples/Cargo.toml

@@ -8,6 +8,7 @@ glib = { version = "0.1.3", git = "https://github.com/gtk-rs/glib" }
 gstreamer = { path = "../gstreamer" }
 gstreamer-app = { path = "../gstreamer-app" }
 gstreamer-audio = { path = "../gstreamer-audio" }
+gstreamer-video = { path = "../gstreamer-video" }
 gstreamer-player = { path = "../gstreamer-player", optional = true }
 gtk = { version = "0.1.3", git = "https://github.com/gtk-rs/gtk", features = ["v3_6"] }
 gio = { version = "0.1.3", git = "https://github.com/gtk-rs/gio" }

examples/src/bin/appsrc.rs

@@ -2,6 +2,7 @@ extern crate gstreamer as gst;
 use gst::*;
 extern crate gstreamer_app as gst_app;
 use gst_app::*;
+extern crate gstreamer_video as gst_video;
 
 extern crate glib;
 
@@ -30,15 +31,13 @@ fn create_pipeline() -> Result<(Pipeline, AppSrc), utils::ExampleError> {
     let appsrc = src.clone()
         .dynamic_cast::<AppSrc>()
         .expect("Source element is expected to be an appsrc!");
-    appsrc.set_caps(&Caps::new_simple(
+
-        "video/x-raw",
+    let info = gst_video::VideoInfo::new(gst_video::VideoFormat::Bgrx, WIDTH as u32, HEIGHT as u32)
-        &[
+        .fps(Fraction::new(2, 1))
-            ("format", &"BGRx"),
+        .build()
-            ("width", &(WIDTH as i32)),
+        .unwrap();
-            ("height", &(HEIGHT as i32)),
+
-            ("framerate", &Fraction::new(2, 1)),
+    appsrc.set_caps(&info.to_caps().unwrap());
-        ],
-    ));
     appsrc.set_property_format(Format::Time);
     appsrc.set_max_bytes(1);
     appsrc.set_property_block(true);
@@ -53,21 +52,25 @@ fn main_loop() -> Result<(), utils::ExampleError> {
         for i in 0..100 {
             println!("Producing frame {}", i);
 
-            // TODO: This is not very efficient
-            let mut vec = Vec::with_capacity(WIDTH * HEIGHT * 4);
             let r = if i % 2 == 0 { 0 } else { 255 };
             let g = if i % 3 == 0 { 0 } else { 255 };
             let b = if i % 5 == 0 { 0 } else { 255 };
 
-            for _ in 0..(WIDTH * HEIGHT) {
+            let mut buffer = gst::Buffer::with_size(WIDTH * HEIGHT * 4).unwrap();
-                vec.push(b);
+            {
-                vec.push(g);
+                let buffer = buffer.get_mut().unwrap();
-                vec.push(r);
+                buffer.set_pts(i * 500_000_000);
-                vec.push(0);
-            }
 
-            let mut buffer = Buffer::from_vec(vec).expect("Unable to create a Buffer");
+                let mut data = buffer.map_writable().unwrap();
-            buffer.get_mut().unwrap().set_pts(i * 500_000_000);
+
+                for p in data.as_mut_slice().chunks_mut(4) {
+                    assert_eq!(p.len(), 4);
+                    p[0] = b;
+                    p[1] = g;
+                    p[2] = r;
+                    p[3] = 0;
+                }
+            }
 
             if appsrc.push_buffer(buffer) != FlowReturn::Ok {
                 break;