Parse frames from a decoder and push to pipewire

src/audio/codec.rs

@@ -1,35 +1,80 @@
 use std::{
+    collections::VecDeque,
     io::{Read, Write},
     process::{Child, ChildStdin, ChildStdout, Command, Stdio},
+    sync::mpsc::{channel, Receiver, Sender, TryRecvError},
+    thread,
 };
 
 use crate::utils::Error;
 
+const MAX_SAMPLE_BUFF: usize = 1_000_000;
+
 pub struct DecoderContext {
     process: Child,
-    encoded_in: ChildStdin,
-    frames_out: ChildStdout,
+    encoded_in: Sender<Vec<u8>>,
+    frames_out: Receiver<Vec<u8>>,
+    sample_buf: VecDeque<Vec<u8>>,
 }
 
-pub fn init() -> Result<DecoderContext, Error> {
+pub fn init(stride: usize, sample_rate: u32) -> Result<DecoderContext, Error> {
     let mut decoder = Command::new("ffmpeg")
         .args(["-hide_banner", "-i", "-", "-f", "s16le", "-"])
         .stdin(Stdio::piped())
         .stdout(Stdio::piped())
         .stderr(Stdio::null())
         .spawn()?;
-    let encoded_in = decoder.stdin.take().unwrap();
-    let frames_out = decoder.stdout.take().unwrap();
+    let (encoded_in, encoded_out) = channel::<Vec<u8>>();
+    let (frames_in, frames_out) = channel();
+    let mut ffmpeg_in = decoder.stdin.take().unwrap();
+    let mut ffmpeg_out = decoder.stdout.take().unwrap();
+    thread::spawn(move || loop {
+        if let Ok(chunk) = encoded_out.recv() {
+            ffmpeg_in.write_all(chunk.as_slice()).unwrap();
+        } else {
+            break;
+        }
+    });
+    thread::spawn(move || loop {
+        let mut frames = vec![0; stride * sample_rate as usize / 1000 * 10];
+        match ffmpeg_out.read_exact(frames.as_mut_slice()) {
+            Err(_) => break,
+            Ok(_) => (),
+        };
+        match frames_in.send(frames) {
+            Err(_) => break,
+            Ok(_) => (),
+        };
+    });
     Ok(DecoderContext {
         process: decoder,
         encoded_in,
         frames_out,
+        sample_buf: VecDeque::new(),
     })
 }
 
 impl DecoderContext {
     pub fn append_chunk(&mut self, chunk: Vec<u8>) -> Result<(), Error> {
-        self.encoded_in.write_all(chunk.as_slice())?;
+        self.encoded_in.send(chunk)?;
         Ok(())
     }
+
+    pub fn fetch_samples(&mut self) {
+        loop {
+            match self.frames_out.try_recv() {
+                Err(TryRecvError::Empty) => break,
+                Ok(frames) => self.sample_buf.push_back(frames),
+                Err(_) => unimplemented!(),
+            }
+        }
+    }
+
+    pub fn next_sample(&mut self) -> Vec<u8> {
+        if self.sample_buf.len() < 100 {
+            self.fetch_samples();
+        }
+
+        self.sample_buf.pop_front().unwrap_or(vec![0; 1920])
+    }
 }

src/audio/errors.rs

@@ -0,0 +1,16 @@
+#[derive(Debug)]
+pub enum AudioError {
+    PodUpdateError,
+}
+
+impl std::error::Error for AudioError {}
+
+impl std::fmt::Display for AudioError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::PodUpdateError => {
+                write!(f, "Error while reconfiguring the audio stream paramteres")
+            }
+        }
+    }
+}

src/audio/mod.rs

@@ -14,6 +14,7 @@ use crate::{config::Settings, player::PlayerEvent, utils::Error};
 
 pub enum AudioEvent {
     DecodeChunk(Vec<u8>),
+    DecoderInit(u32, u32),
 }
 
 pub struct SoundManager {
@@ -60,5 +61,6 @@ pub fn init(
 }
 
 mod codec;
+mod errors;
 mod pw;
 mod sound_mgr;

src/audio/pw.rs

@@ -11,7 +11,7 @@ use pipewire::{
     stream::{Stream, StreamFlags},
 };
 
-use crate::utils::{default_pw_pod, Error};
+use crate::utils::{new_pw_pod, Error};
 
 pub fn init(
     samples: std::sync::mpsc::Receiver<Vec<u8>>,
@@ -53,24 +53,24 @@ pub fn init(
                 };
                 let chunk = data.chunk_mut();
                 *chunk.offset_mut() = 0;
+                *chunk.stride_mut() = 4;
                 *chunk.size_mut() = n_iter as _;
             }
         })
         .register()?;
 
-    let default_audio = default_pw_pod();
-    let mut params = [Pod::from_bytes(&default_audio).unwrap()];
-    audio_source.connect(
+    let audio_source_ref = audio_source.clone();
+    let _receiver = pw_signal.attach(mainloop.loop_(), move |pod_bytes| {
+        let mut params = [Pod::from_bytes(&pod_bytes).unwrap()];
+        audio_source_ref.disconnect().unwrap();
+        audio_source_ref
+            .connect(
                 Direction::Output,
                 None,
                 StreamFlags::AUTOCONNECT | StreamFlags::ALLOC_BUFFERS | StreamFlags::MAP_BUFFERS,
                 &mut params,
-    );
-
-    let audio_source_ref = audio_source.clone();
-    let _receiver = pw_signal.attach(mainloop.loop_(), move |pod_bytes| {
-        let mut params = [Pod::from_bytes(&pod_bytes).unwrap()];
-        audio_source_ref.update_params(&mut params);
+            )
+            .unwrap();
     });
 
     mainloop.run();

src/audio/sound_mgr.rs

@@ -4,11 +4,16 @@ use std::{
         Arc,
     },
     thread,
+    time::{Duration, SystemTime},
 };
 
-use crate::{config::Settings, player::PlayerEvent, utils::Error};
+use crate::{
+    config::Settings,
+    player::PlayerEvent,
+    utils::{new_pw_pod, Error},
+};
 
-use super::{codec, pw, AudioEvent, SoundManager};
+use super::{codec, errors::AudioError, pw, AudioEvent, SoundManager};
 
 impl SoundManager {
     pub fn init(
@@ -30,7 +35,7 @@ impl SoundManager {
                 Ok(_) => (),
             };
         });
-        let decoder_context = codec::init()?;
+        let decoder_context = codec::init(4, 48000)?;
 
         Ok(SoundManager {
             settings,
@@ -45,8 +50,21 @@ impl SoundManager {
     }
     pub fn begin(&mut self) -> Result<(), Error> {
         loop {
+            let start = SystemTime::now();
             self.handle_events()?;
+            if self.playing {
+                self.push_samples()?;
             }
+            let time_elapsed = SystemTime::now().duration_since(start)?;
+            let time_rem = Duration::from_millis(9).saturating_sub(time_elapsed);
+            thread::sleep(time_rem);
+        }
+    }
+
+    fn push_samples(&mut self) -> Result<(), Error> {
+        let frame = self.decoder_context.next_sample();
+        self.sample_in.send(frame)?;
+        Ok(())
     }
 
     fn handle_events(&mut self) -> Result<(), Error> {
@@ -57,8 +75,21 @@ impl SoundManager {
         };
         match event {
             AudioEvent::DecodeChunk(chunk) => self.decoder_context.append_chunk(chunk)?,
+            AudioEvent::DecoderInit(sample_rate, channel_count) => {
+                self.decoder_context = codec::init(channel_count as usize * 2, sample_rate)?;
+                self.update_pw_stream(channel_count, sample_rate)?
+            }
             _ => unimplemented!(),
         }
         Ok(())
     }
+
+    fn update_pw_stream(&mut self, channel_count: u32, sample_rate: u32) -> Result<(), Error> {
+        let pod_bytes = new_pw_pod(sample_rate, channel_count);
+
+        match self.pw_signal_in.send(pod_bytes) {
+            Err(_) => Err(Box::new(AudioError::PodUpdateError)),
+            Ok(_) => Ok(()),
+        }
+    }
 }

src/player/mod.rs

@@ -24,7 +24,6 @@ pub enum PlayerEvent {
     UserQuit,
     PlayNext,
     AddAudioChunk(Vec<u8>),
-    AudioChunkQueued(u32),
 }
 
 pub struct Player {

src/player/player.rs

@@ -82,6 +82,7 @@ impl Player {
             self.player_chan_in
                 .send(PlayerEvent::UpdateCover(default_cover()))?;
         }
+        self.audio_chan.send(AudioEvent::DecoderInit(48000, 2))?;
         self.tui_root.metadata.update_metadata(song);
         self.fetch_audio_chunk()?;
 

src/utils.rs

@@ -1,8 +1,11 @@
 use image::DynamicImage;
 use pipewire::spa::{
-    param::audio::AudioInfoRaw,
+    param::audio::{AudioFormat, AudioInfoRaw, MAX_CHANNELS},
     pod::{serialize::PodSerializer, Object, Value},
-    sys::{SPA_PARAM_EnumFormat, SPA_TYPE_OBJECT_Format},
+    sys::{
+        SPA_PARAM_EnumFormat, SPA_TYPE_OBJECT_Format, SPA_AUDIO_CHANNEL_FL, SPA_AUDIO_CHANNEL_FR,
+        SPA_AUDIO_CHANNEL_MONO,
+    },
 };
 use rand::{distributions::Alphanumeric, thread_rng, Rng};
 use std::io::Cursor;
@@ -40,8 +43,18 @@ pub fn format_duration(secs: u32) -> String {
     }
 }
 
-pub fn default_pw_pod() -> Vec<u8> {
-    let audio_info = AudioInfoRaw::new();
+pub fn new_pw_pod(sample_rate: u32, channels: u32) -> Vec<u8> {
+    let mut audio_info = AudioInfoRaw::new();
+    audio_info.set_format(AudioFormat::S16LE);
+    audio_info.set_rate(sample_rate);
+    audio_info.set_channels(channels);
+    let mut pos = [0; MAX_CHANNELS];
+    if channels == 1 {
+        pos[0] = SPA_AUDIO_CHANNEL_MONO
+    } else {
+        (pos[0], pos[1]) = (SPA_AUDIO_CHANNEL_FL, SPA_AUDIO_CHANNEL_FR);
+    }
+    audio_info.set_position(pos);
     PodSerializer::serialize(
         Cursor::new(Vec::new()),
         &Value::Object(Object {