First attempt at audio playback with OGG Vorbis

ctru-rs/Cargo.toml

@@ -31,6 +31,7 @@ time = "0.3.7"
 tokio = { version = "1.16", features = ["rt", "time", "sync", "macros"] }
 cfg-if = "1.0.0"
 bytemuck = "1.12.3"
+lewton = "0.10.2"
 
 [features]
 default = ["romfs", "big-stack"]

ctru-rs/examples/ogg-audio.rs

@@ -0,0 +1,135 @@
+#![feature(allocator_api)]
+use ctru::linear::LinearAllocator;
+
+use ctru::prelude::*;
+use ctru::services::ndsp::{
+    wave::{WaveInfo, WaveStatus},
+    AudioFormat, Channel, InterpolationType, Ndsp, OutputMode,
+};
+
+use lewton::inside_ogg::OggStreamReader;
+use lewton::samples::InterleavedSamples;
+
+use std::fs::File;
+
+const CHANNEL_COUNT: usize = 2;
+// It should never get this big, but extra space is useful since we can't know the size beforehand
+// Read
+const AUDIO_WAVE_SIZE: usize = 4000 * CHANNEL_COUNT;
+
+fn setup_next_wave(
+    stream_reader: &mut OggStreamReader<File>,
+    channel: &Channel,
+    wave_info: &mut WaveInfo,
+) {
+    // Interleaved Dual Channel (Stereo PCM16)
+    match stream_reader
+        .read_dec_packet_generic::<InterleavedSamples<i16>>()
+        .unwrap()
+    {
+        Some(pck) => {
+            // A good way to handle the data would be to allocate it on LINEAR memory directly within `lewton`,
+            // but since that API isn't exposed (for its instability) a memcopy is needed either way.
+
+            let mut samples = pck.samples;
+            let raw_samples = bytemuck::cast_slice_mut::<_, u8>(samples.as_mut_slice());
+
+            // We need only the first part of the slice to clone the data over
+            let buf = wave_info.get_buffer_mut();
+            let (buf, _) = buf.split_at_mut(raw_samples.len());
+
+            buf.copy_from_slice(raw_samples);
+
+            // We change the sample_count of the WaveInfo so NDSP won't read the unused bytes
+            wave_info
+                .set_sample_count((samples.len() / pck.channel_count) as u32)
+                .unwrap();
+
+            channel.queue_wave(wave_info).unwrap();
+        }
+        None => return, // do nothing when the audio ends
+    }
+}
+
+fn main() {
+    ctru::init();
+    let gfx = Gfx::init().expect("Couldn't obtain GFX controller");
+    let hid = Hid::init().expect("Couldn't obtain HID controller");
+    let apt = Apt::init().expect("Couldn't obtain APT controller");
+    let _console = Console::init(gfx.top_screen.borrow_mut());
+
+    cfg_if::cfg_if! {
+        if #[cfg(not(all(feature = "romfs", romfs_exists)))] {
+            panic!("No RomFS was found, are you sure you included it?")
+        }
+    }
+
+    let _romfs = ctru::romfs::RomFS::init().unwrap();
+    let f = File::open("romfs:/music.ogg").unwrap();
+    let mut srr = OggStreamReader::new(f).unwrap();
+
+    println!("\nPress START to exit");
+    println!("Sample rate: {}", srr.ident_hdr.audio_sample_rate);
+
+    // If the audio is Mono or it has more channels than 2, it's incompatibile with this current setup
+    if srr.ident_hdr.audio_channels != 2 {
+        panic!(
+            "Audio file improperly modified: Number of channels incompatible with Stereo output"
+        );
+    }
+
+    // We setup the alternating buffers
+    let audio_data1 = Box::new_in([0u8; AUDIO_WAVE_SIZE], LinearAllocator);
+    let audio_data2 = audio_data1.clone();
+    let mut wave_info1 = WaveInfo::new(audio_data1, AudioFormat::PCM16Stereo, false);
+    let mut wave_info2 = WaveInfo::new(audio_data2, AudioFormat::PCM16Stereo, false);
+
+    // NDSP setup
+    let mut ndsp = Ndsp::init().expect("Couldn't obtain NDSP controller");
+    ndsp.set_output_mode(OutputMode::Stereo);
+
+    let channel_zero = ndsp.channel(0).unwrap();
+    channel_zero.set_interpolation(InterpolationType::Linear);
+    channel_zero.set_sample_rate(srr.ident_hdr.audio_sample_rate as f32);
+    channel_zero.set_format(AudioFormat::PCM16Stereo);
+
+    setup_next_wave(&mut srr, &channel_zero, &mut wave_info1);
+    setup_next_wave(&mut srr, &channel_zero, &mut wave_info2);
+
+    // Audio volume mix
+    let mut mix: [f32; 12] = [0f32; 12];
+    mix[0] = 0.8;
+    mix[1] = 0.8;
+    channel_zero.set_mix(&mix);
+
+    let mut altern = true; // true is wave_info1, false is wave_info2
+
+    // Main loop
+    while apt.main_loop() {
+        //Scan all the inputs. This should be done once for each frame
+        hid.scan_input();
+
+        if hid.keys_down().contains(KeyPad::KEY_START) {
+            break;
+        }
+
+        let current: &mut WaveInfo = if altern {
+            &mut wave_info1
+        } else {
+            &mut wave_info2
+        };
+
+        match current.get_status() {
+            WaveStatus::Free | WaveStatus::Done => {
+                setup_next_wave(&mut srr, &channel_zero, current);
+
+                altern = !altern;
+            }
+            _ => (),
+        }
+
+        // Flush and swap framebuffers
+        gfx.flush_buffers();
+        gfx.swap_buffers();
+    }
+}

ctru-rs/src/services/ndsp/mod.rs

@@ -43,6 +43,7 @@ pub enum NdspError {
     InvalidChannel(u8),               // channel id
     ChannelAlreadyInUse(u8),          // channel id
     WaveAlreadyQueued(u8),            // channel id
+    SampleCountOutOfBounds(u32, u32), // amount requested, maximum amount
 }
 
 pub struct Channel<'ndsp> {
@@ -288,7 +289,8 @@ impl fmt::Display for NdspError {
         match self {
             Self::InvalidChannel(id) => write!(f, "Audio Channel with id {id} doesn't exist. Valid channels have an id between 0 and 23."),
             Self::ChannelAlreadyInUse(id) => write!(f, "Audio Channel with id {id} is already being used. Drop the other instance if you want to use it here."),
-            Self::WaveAlreadyQueued(id) => write!(f, "The selected WaveInfo is already playing on channel {id}.")
+            Self::WaveAlreadyQueued(id) => write!(f, "The selected WaveInfo is already playing on channel {id}."),
+            Self::SampleCountOutOfBounds(samples_requested, max_samples) => write!(f, "The sample count requested is too big. Requested amount was {samples_requested} while the maximum sample count is {max_samples}."),
         }
     }
 }

ctru-rs/src/services/ndsp/wave.rs

@@ -1,4 +1,4 @@
-use super::AudioFormat;
+use super::{AudioFormat, NdspError};
 use crate::linear::LinearAllocator;
 
 /// Informational struct holding the raw audio data and playback info. This corresponds to [ctru_sys::ndspWaveBuf]
@@ -81,6 +81,42 @@ impl WaveInfo {
     pub(crate) fn set_channel(&mut self, id: u8) {
         self.played_on_channel = Some(id)
     }
+
+    /// Set the amount of samples to be read.
+    /// This function doesn't resize the internal buffer.
+    ///
+    /// # Note
+    ///
+    /// Operations of this kind are particularly usefulto allocate memory pools
+    /// for VBR (Variable BitRate) Formats, like OGG Vorbis.
+    ///
+    /// # Errors
+    ///
+    /// This function will return an error if the sample size exceeds the buffer's capacity
+    /// or if the WaveInfo is currently queued.
+    pub fn set_sample_count(&mut self, sample_count: u32) -> Result<(), NdspError> {
+        match self.get_status() {
+            WaveStatus::Playing | WaveStatus::Queued => {
+                return Err(NdspError::WaveAlreadyQueued(
+                    self.played_on_channel.unwrap(),
+                ));
+            }
+            _ => (),
+        }
+
+        let max_count: usize = self.buffer.len() / (self.audio_format.sample_size() as usize);
+
+        if sample_count > max_count as u32 {
+            return Err(NdspError::SampleCountOutOfBounds(
+                sample_count,
+                max_count as u32,
+            ));
+        }
+
+        self.raw_data.nsamples = sample_count;
+
+        Ok(())
+    }
 }
 
 impl TryFrom<u8> for WaveStatus {