MP3 Support (#14)

src/encoder/flac.rs

@@ -0,0 +1,52 @@
+use flacenc::bitsink::ByteSink;
+use flacenc::component::BitRepr;
+use flacenc::error::Verify;
+
+use super::execute_with_result;
+use super::EncodedStream;
+use super::Encoder;
+use super::Samples;
+
+#[derive(Debug)]
+pub struct FlacEncoder;
+
+#[async_trait::async_trait]
+impl Encoder for FlacEncoder {
+    async fn encode(&self, samples: Samples) -> anyhow::Result<EncodedStream> {
+        let source = flacenc::source::MemSource::from_samples(
+            &samples.samples,
+            samples.channels as usize,
+            samples.bits_per_sample as usize,
+            samples.sample_rate as usize,
+        );
+
+        let config = flacenc::config::Encoder::default()
+            .into_verified()
+            .map_err(|e| anyhow::anyhow!("Failed to verify encoder config: {:?}", e))?;
+
+        let (tx, rx) = tokio::sync::oneshot::channel();
+
+        rayon::spawn(execute_with_result(
+            move || {
+                let flac_stream = flacenc::encode_with_fixed_block_size(
+                    &config,
+                    source,
+                    config.block_size,
+                )
+                .map_err(|e| anyhow::anyhow!("Failed to encode flac: {:?}", e))?;
+
+                let mut byte_sink = ByteSink::new();
+                flac_stream
+                    .write(&mut byte_sink)
+                    .map_err(|e| anyhow::anyhow!("Failed to write flac stream: {:?}", e))?;
+
+                Ok(byte_sink.into_inner())
+            },
+            tx,
+        ));
+
+        let byte_sink: Vec<u8> = rx.await??;
+
+        Ok(EncodedStream::new(byte_sink))
+    }
+}