audio: add API to build raw audio caps

gstreamer-audio/src/functions.rs

@@ -0,0 +1,105 @@
+// Copyright (C) 2020 Guillaume Desmottes <guillaume.desmottes@collabora.com>
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use glib;
+use glib::ToSendValue;
+use gst;
+
+use std::i32;
+
+pub fn audio_make_raw_caps(
+    formats: &[::AudioFormat],
+    layout: ::AudioLayout,
+) -> gst::caps::Builder<gst::caps::NoFeature> {
+    assert_initialized_main_thread!();
+
+    let formats: Vec<glib::SendValue> = formats
+        .iter()
+        .map(|f| match f {
+            ::AudioFormat::Encoded => panic!("Invalid encoded format"),
+            ::AudioFormat::Unknown => panic!("Invalid unknown format"),
+            _ => f.to_string().to_send_value(),
+        })
+        .collect();
+
+    let builder = gst::caps::Caps::builder("audio/x-raw")
+        .field("format", &gst::List::from_owned(formats))
+        .field("rate", &gst::IntRange::<i32>::new(1, i32::MAX))
+        .field("channels", &gst::IntRange::<i32>::new(1, i32::MAX));
+
+    match layout {
+        ::AudioLayout::Interleaved => builder.field("layout", &"interleaved"),
+        ::AudioLayout::NonInterleaved => builder.field("layout", &"non-interleaved"),
+        ::AudioLayout::__Unknown(_) => builder,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use gst;
+
+    #[test]
+    fn audio_caps() {
+        gst::init().unwrap();
+
+        let caps = audio_make_raw_caps(
+            &[::AudioFormat::S16be, ::AudioFormat::S16le],
+            ::AudioLayout::Interleaved,
+        )
+        .build();
+        assert_eq!(caps.to_string(), "audio/x-raw, format=(string){ S16BE, S16LE }, rate=(int)[ 1, 2147483647 ], channels=(int)[ 1, 2147483647 ], layout=(string)interleaved");
+
+        #[cfg(feature = "v1_18")]
+        {
+            use glib::translate::{from_glib_full, ToGlib};
+
+            /* audio_make_raw_caps() is a re-implementation so ensure it returns the same caps as the C API */
+            let c_caps = unsafe {
+                let formats: Vec<gst_audio_sys::GstAudioFormat> =
+                    [::AudioFormat::S16be, ::AudioFormat::S16le]
+                        .iter()
+                        .map(|f| f.to_glib())
+                        .collect();
+                let caps = gst_audio_sys::gst_audio_make_raw_caps(
+                    formats.as_ptr(),
+                    formats.len() as u32,
+                    gst_audio_sys::GST_AUDIO_LAYOUT_INTERLEAVED,
+                );
+                from_glib_full(caps)
+            };
+            assert_eq!(caps, c_caps);
+        }
+
+        let caps = audio_make_raw_caps(
+            &[::AudioFormat::S16be, ::AudioFormat::S16le],
+            ::AudioLayout::NonInterleaved,
+        )
+        .field("rate", &16000)
+        .field("channels", &2)
+        .build();
+        assert_eq!(
+            caps.to_string(),
+            "audio/x-raw, format=(string){ S16BE, S16LE }, rate=(int)16000, channels=(int)2, layout=(string)non-interleaved"
+        );
+    }
+
+    #[test]
+    #[should_panic(expected = "Invalid encoded format")]
+    fn audio_caps_encoded() {
+        gst::init().unwrap();
+        audio_make_raw_caps(&[::AudioFormat::Encoded], ::AudioLayout::Interleaved);
+    }
+
+    #[test]
+    #[should_panic(expected = "Invalid unknown format")]
+    fn audio_caps_unknown() {
+        gst::init().unwrap();
+        audio_make_raw_caps(&[::AudioFormat::Unknown], ::AudioLayout::Interleaved);
+    }
+}

gstreamer-audio/src/lib.rs

@@ -53,6 +53,8 @@ mod audio_channel_position;
 pub use audio_channel_position::*;
 #[cfg(any(feature = "v1_14", feature = "dox"))]
 mod audio_stream_align;
+mod functions;
+pub use functions::*;
 
 mod audio_decoder;
 pub use audio_decoder::AudioDecoderExtManual;