diff --git a/Cargo.toml b/Cargo.toml
index f1867c3..4950d0b 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,8 +10,9 @@ crate-type = ["cdylib"]
 [dependencies]
 anyhow = "1.0.79"
 byteorder = "1.5.0"
+futures-util = "0.3.30"
 numpy = "0.21.0"
-ogg = "0.9.1"
+ogg = { version = "0.9.1", features = ["async"] }
 opus = "0.3.0"
 pyo3 = "0.21.0"
 rayon = "1.8.1"
@@ -19,6 +20,7 @@ rubato = "0.15.0"
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0.113"
 symphonia = { version = "0.5.4", features = ["all"] }
+tokio = { version = "1.39.3", features = ["full"] }
 
 [profile.release]
 debug = true
diff --git a/py_src/sphn/__init__.pyi b/py_src/sphn/__init__.pyi
index 9bafa3a..018e892 100644
--- a/py_src/sphn/__init__.pyi
+++ b/py_src/sphn/__init__.pyi
@@ -42,6 +42,13 @@ def read_opus_bytes(bytes):
     """
     pass
 
+@staticmethod
+def resample(pcm, src_sample_rate, dst_sample_rate):
+    """
+    Resamples some pcm data.
+    """
+    pass
+
 @staticmethod
 def write_opus(filename, data, sample_rate):
     """
@@ -112,3 +119,31 @@ class FileReader:
         The sample rate as an int.
         """
         pass
+
+class OpusStreamReader:
+    def __init__(sample_rate):
+        pass
+
+    def append_bytes(self, data):
+        """
+        Write some ogg/opus bytes to the current stream.
+        """
+        pass
+
+    def read_pcm(self):
+        """
+        Get some pcm data out of the stream.
+        """
+        pass
+
+class OpusStreamWriter:
+    def __init__(sample_rate):
+        pass
+
+    def append_pcm(self, pcm):
+        """ """
+        pass
+
+    def read_bytes(self):
+        """ """
+        pass
diff --git a/src/lib.rs b/src/lib.rs
index 5347024..9dcc96e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -325,9 +325,85 @@ fn read_opus_bytes(bytes: Vec<u8>, py: Python) -> PyResult<(PyObject, u32)> {
     Ok((data, sample_rate))
 }
 
+#[pyclass]
+struct OpusStreamWriter {
+    inner: opus::StreamWriter,
+    sample_rate: u32,
+}
+
+#[pymethods]
+impl OpusStreamWriter {
+    #[new]
+    fn new(sample_rate: u32) -> PyResult<Self> {
+        let inner = opus::StreamWriter::new(sample_rate).w()?;
+        Ok(Self { inner, sample_rate })
+    }
+
+    fn __str__(&self) -> String {
+        format!("OpusStreamWriter(sample_rate={})", self.sample_rate)
+    }
+
+    fn append_pcm(&mut self, pcm: numpy::PyReadonlyArray1<f32>) -> PyResult<()> {
+        let pcm = pcm.as_array();
+        match pcm.as_slice() {
+            None => {
+                let pcm = pcm.to_vec();
+                self.inner.append_pcm(&pcm).w()?
+            }
+            Some(pcm) => self.inner.append_pcm(pcm).w()?,
+        };
+        Ok(())
+    }
+
+    fn read_bytes(&mut self) -> PyResult<PyObject> {
+        let bytes = self.inner.read_bytes().w()?;
+        let bytes = Python::with_gil(|py| pyo3::types::PyBytes::new_bound(py, &bytes).into_py(py));
+        Ok(bytes)
+    }
+}
+
+#[pyclass]
+struct OpusStreamReader {
+    inner: opus::StreamReader,
+    sample_rate: u32,
+}
+
+#[pymethods]
+impl OpusStreamReader {
+    #[new]
+    fn new(sample_rate: u32) -> PyResult<Self> {
+        let inner = opus::StreamReader::new(sample_rate).w()?;
+        Ok(Self { inner, sample_rate })
+    }
+
+    fn __str__(&self) -> String {
+        format!("OpusStreamReader(sample_rate={})", self.sample_rate)
+    }
+
+    /// Write some ogg/opus bytes to the current stream.
+    fn append_bytes(&mut self, data: &[u8]) -> PyResult<()> {
+        self.inner.append(data).w()
+    }
+
+    // TODO(laurent): maybe we should also have a pyo3_async api here.
+    /// Get some pcm data out of the stream.
+    fn read_pcm(&mut self) -> PyResult<PyObject> {
+        let pcm_data = self.inner.read_pcm().w()?;
+        Python::with_gil(|py| match pcm_data {
+            None => Ok(py.None()),
+            Some(data) => {
+                let data = numpy::PyArray1::from_vec_bound(py, data.to_vec()).into_py(py);
+                Ok(data)
+            }
+        })
+    }
+}
+
 #[pymodule]
 fn sphn(_py: Python, m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_class::<FileReader>()?;
+    m.add_class::<OpusStreamReader>()?;
+    m.add_class::<OpusStreamWriter>()?;
     m.add_function(wrap_pyfunction!(durations, m)?)?;
     m.add_function(wrap_pyfunction!(read, m)?)?;
     m.add_function(wrap_pyfunction!(write_wav, m)?)?;
diff --git a/src/opus.rs b/src/opus.rs
index 55fa48e..6650f5c 100644
--- a/src/opus.rs
+++ b/src/opus.rs
@@ -5,6 +5,7 @@ use anyhow::Result;
 // https://opus-codec.org/docs/opus_api-1.2/group__opus__encoder.html#ga4ae9905859cd241ef4bb5c59cd5e5309
 const OPUS_ENCODER_FRAME_SIZE: usize = 960;
 const OPUS_SAMPLE_RATE: u32 = 48000;
+const OPUS_ALLOWED_FRAME_SIZES: [usize; 6] = [120, 240, 480, 960, 1920, 2880];
 
 /// See https://www.opus-codec.org/docs/opusfile_api-0.4/structOpusHead.html
 #[allow(unused)]
@@ -198,3 +199,140 @@ pub fn write_ogg_stereo<W: std::io::Write>(
         write_ogg_48khz(w, &pcm, sample_rate, true)
     }
 }
+
+struct BufferStream(std::sync::mpsc::Sender<Vec<u8>>);
+
+impl std::io::Write for BufferStream {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        if self.0.send(buf.to_vec()).is_err() {
+            return Err(std::io::Error::new(
+                std::io::ErrorKind::NotConnected,
+                "opus stream writer error".to_string(),
+            ));
+        };
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+
+pub struct StreamWriter {
+    pw: ogg::PacketWriter<'static, BufferStream>,
+    encoder: opus::Encoder,
+    out_encoded: Vec<u8>,
+    total_data: u64,
+    rx: std::sync::mpsc::Receiver<Vec<u8>>,
+}
+
+impl StreamWriter {
+    pub fn new(sample_rate: u32) -> Result<Self> {
+        if sample_rate != 48000 && sample_rate != 24000 {
+            anyhow::bail!("sample-rate has to be 48000 or 24000, got {sample_rate}")
+        }
+        let encoder =
+            opus::Encoder::new(sample_rate, opus::Channels::Mono, opus::Application::Voip)?;
+        let (tx, rx) = std::sync::mpsc::channel();
+        let mut pw = ogg::PacketWriter::new(BufferStream(tx));
+        let out_encoded = vec![0u8; 50_000];
+        let mut head = Vec::new();
+        write_opus_header(&mut head, 1u8, sample_rate)?;
+        pw.write_packet(head, 42, ogg::PacketWriteEndInfo::EndPage, 0)?;
+        let mut tags = Vec::new();
+        write_opus_tags(&mut tags)?;
+        pw.write_packet(tags, 42, ogg::PacketWriteEndInfo::EndPage, 0)?;
+        Ok(Self { pw, encoder, out_encoded, total_data: 0, rx })
+    }
+
+    pub fn append_pcm(&mut self, pcm: &[f32]) -> Result<()> {
+        if !OPUS_ALLOWED_FRAME_SIZES.contains(&pcm.len()) {
+            anyhow::bail!(
+                "pcm length has to match an allowed frame size {OPUS_ALLOWED_FRAME_SIZES:?}, got {}", pcm.len()
+            )
+        }
+
+        let size = self.encoder.encode_float(pcm, &mut self.out_encoded)?;
+        let msg = self.out_encoded[..size].to_vec();
+        self.total_data += pcm.len() as u64;
+        self.pw.write_packet(msg, 42, ogg::PacketWriteEndInfo::EndPage, self.total_data)?;
+        Ok(())
+    }
+
+    pub fn read_bytes(&mut self) -> Result<Vec<u8>> {
+        match self.rx.try_recv() {
+            Ok(data) => Ok(data),
+            Err(std::sync::mpsc::TryRecvError::Empty) => Ok(vec![]),
+            Err(std::sync::mpsc::TryRecvError::Disconnected) => {
+                anyhow::bail!("opus stream writer disconnected")
+            }
+        }
+    }
+}
+
+pub struct StreamReader {
+    pr: ogg::reading::async_api::PacketReader<tokio::io::DuplexStream>,
+    decoder: opus::Decoder,
+    tx: tokio::io::DuplexStream,
+    runtime: tokio::runtime::Runtime,
+    pcm_buf: Vec<f32>,
+}
+
+// The StreamReader implementation uses tokio under the hood, this is a bit of a bummer and comes
+// from the ogg crate PacketReader non-async api requiring Seek on its input stream (and so not
+// having to keep much inner state), the async version just requires read so is more adapted to
+// what we want to provide here.
+impl StreamReader {
+    pub fn new(sample_rate: u32) -> Result<Self> {
+        if sample_rate != 48000 && sample_rate != 24000 {
+            anyhow::bail!("sample-rate has to be 48000 or 24000, got {sample_rate}")
+        }
+        // TODO(laurent): look whether there is a more adapted channel type.
+        let (tx, rx) = tokio::io::duplex(100_000);
+        let decoder = opus::Decoder::new(sample_rate, opus::Channels::Mono)?;
+        let pr = ogg::reading::async_api::PacketReader::new(rx);
+        // TODO(laurent): consider spawning a thread so that the process happens in the background.
+        let runtime = tokio::runtime::Runtime::new()?;
+        let pcm_buf = vec![0f32; 24_000 * 10];
+        Ok(Self { pr, decoder, tx, runtime, pcm_buf })
+    }
+
+    pub fn append(&mut self, data: &[u8]) -> Result<()> {
+        use tokio::io::AsyncWriteExt;
+
+        self.runtime.block_on({
+            // Maybe we should wait for a bit of time here to allow for the PacketReader to do some
+            // processing.
+            self.tx.write_all(data)
+        })?;
+        Ok(())
+    }
+
+    /// Returns None at the end of the stream and an empty slice if no data is currently available.
+    pub fn read_pcm(&mut self) -> Result<Option<&[f32]>> {
+        use futures_util::StreamExt;
+        use std::future::Future;
+
+        let waker = futures_util::task::noop_waker();
+        let mut cx = futures_util::task::Context::from_waker(&waker);
+        let mut next = self.pr.next();
+        let next = std::pin::Pin::new(&mut next);
+        let result = match next.poll(&mut cx) {
+            std::task::Poll::Ready(None) => None,
+            std::task::Poll::Ready(Some(packet)) => {
+                let packet = packet?;
+                if packet.data.starts_with(b"OpusHead") || packet.data.starts_with(b"OpusTags") {
+                    todo!();
+                }
+                let bytes_read = self.decoder.decode_float(
+                    &packet.data,
+                    &mut self.pcm_buf,
+                    /* Forward Error Correction */ false,
+                )?;
+                Some(&self.pcm_buf[..bytes_read])
+            }
+            std::task::Poll::Pending => Some(&self.pcm_buf[..0]),
+        };
+        Ok(result)
+    }
+}
diff --git a/test/stream.py b/test/stream.py
new file mode 100644
index 0000000..171ac67
--- /dev/null
+++ b/test/stream.py
@@ -0,0 +1,30 @@
+import sphn
+
+filename = "bria.mp3"
+data, sr = sphn.read(filename)
+print(data.shape, sr)
+
+data = sphn.resample(data, sr, 24000)
+print(data.shape)
+
+stream_writer = sphn.OpusStreamWriter(24000)
+# This must be an allowed value among 120, 240, 480, 960, 1920, and 2880.
+packet_size = 960
+for lo in range(0, data.shape[-1], packet_size):
+    up = lo + packet_size
+    packet = data[0, lo:up]
+    print(packet.shape)
+    if packet.shape[-1] != packet_size:
+        break
+    stream_writer.append_pcm(packet)
+
+with open("myfile.opus", "wb") as fobj:
+    while True:
+        opus = stream_writer.read_bytes()
+        if len(opus) == 0:
+            break
+        fobj.write(opus)
+
+data_roundtrip, sr_roundtrip = sphn.read_opus("myfile.opus")
+print(data_roundtrip.shape, sr_roundtrip)
+sphn.write_opus("myfile2.opus", data_roundtrip, sr_roundtrip)