Merge pull request #226 from whentze/master

Implement `total_duration` for `FlacDecoder`

src/decoder/flac.rs

@@ -18,6 +18,7 @@ where
     bits_per_sample: u32,
     sample_rate: u32,
     channels: u16,
+    samples: Option<u64>,
 }
 
 impl<R> FlacDecoder<R>
@@ -43,6 +44,7 @@ where
             bits_per_sample: spec.bits_per_sample,
             sample_rate: spec.sample_rate,
             channels: spec.channels as u16,
+            samples: spec.samples,
         })
     }
 }
@@ -68,7 +70,9 @@ where
 
     #[inline]
     fn total_duration(&self) -> Option<Duration> {
-        None
+        // `samples` in FLAC means "inter-channel samples" aka frames
+        // so we do not divide by `self.channels` here.
+        self.samples.map(|s| Duration::from_micros(s * 1_000_000 / self.sample_rate as u64))
     }
 }
 

tests/flac_test.rs

@@ -0,0 +1,21 @@
+extern crate rodio;
+
+use rodio::Source;
+use std::{io::BufReader, time::Duration};
+
+#[test]
+fn test_flac_encodings() {
+    // 16 bit FLAC file exported from Audacity (2 channels, compression level 5)
+    let file = std::fs::File::open("tests/audacity16bit_level5.flac").unwrap();
+    let mut decoder = rodio::Decoder::new(BufReader::new(file)).unwrap();
+    assert!(decoder.any(|x| x != 0)); // File is not just silence
+    assert_eq!(decoder.total_duration(), Some(Duration::from_secs(3))); // duration is calculated correctly
+
+    // 24 bit FLAC file exported from Audacity (2 channels, various compression levels)
+    for level in &[0, 5, 8] {
+        let file = std::fs::File::open(format!("tests/audacity24bit_level{}.flac", level)).unwrap();
+        let mut decoder = rodio::Decoder::new(BufReader::new(file)).unwrap();
+        assert!(decoder.any(|x| x != 0));
+        assert_eq!(decoder.total_duration(), Some(Duration::from_secs(3)));
+    }
+}