bbx_file/readers/
wav.rs

1//! WAV file reader via wavers.
2
3use std::path::Path;
4
5use bbx_dsp::{
6    buffer::{AudioBuffer, Buffer},
7    reader::Reader,
8    sample::Sample,
9};
10use wavers::Wav;
11
12/// A WAV file reader implementing [`Reader`].
13///
14/// Loads the entire WAV file into memory on construction, providing
15/// sample data via the `read_channel` method.
16pub struct WavFileReader<S: Sample> {
17    channel_buffers: Vec<AudioBuffer<S>>,
18    sample_rate: f64,
19    num_channels: usize,
20    num_samples: usize,
21}
22
23impl<S: Sample> WavFileReader<S> {
24    /// Create a `WavFileReader` for an audio file located
25    /// at the specified file path.
26    pub fn from_path(file_path: &str) -> Result<Self, Box<dyn std::error::Error>> {
27        let mut reader: Wav<f32> = Wav::from_path(Path::new(file_path))?;
28
29        let sample_rate = reader.sample_rate() as f64;
30        let num_channels = reader.n_channels() as usize;
31        let num_samples = reader.n_samples();
32
33        let mut channels = Vec::with_capacity(num_channels);
34        for _ in 0..num_channels {
35            channels.push(AudioBuffer::new(num_samples));
36        }
37
38        for (channel_index, channel) in reader.channels().enumerate() {
39            for (sample_index, sample) in channel.iter().enumerate() {
40                channels[channel_index][sample_index] = S::from_f64(*sample as f64);
41            }
42        }
43
44        Ok(Self {
45            channel_buffers: channels,
46            sample_rate,
47            num_channels,
48            num_samples,
49        })
50    }
51}
52
53impl<S: Sample> Reader<S> for WavFileReader<S> {
54    fn sample_rate(&self) -> f64 {
55        self.sample_rate
56    }
57
58    fn num_channels(&self) -> usize {
59        self.num_channels
60    }
61
62    fn num_samples(&self) -> usize {
63        self.num_samples
64    }
65
66    fn read_channel(&self, channel_index: usize) -> &[S] {
67        self.channel_buffers[channel_index].as_slice()
68    }
69}
70
71#[cfg(test)]
72mod tests {
73    use std::io::BufWriter;
74
75    use hound::{SampleFormat, WavSpec, WavWriter};
76    use tempfile::NamedTempFile;
77
78    use super::*;
79
80    fn create_test_wav(sample_rate: u32, num_channels: u16, samples: &[Vec<f32>]) -> NamedTempFile {
81        let temp_file = NamedTempFile::new().unwrap();
82        let spec = WavSpec {
83            channels: num_channels,
84            sample_rate,
85            bits_per_sample: 32,
86            sample_format: SampleFormat::Float,
87        };
88
89        let mut writer = WavWriter::new(BufWriter::new(temp_file.reopen().unwrap()), spec).unwrap();
90
91        let num_samples = samples[0].len();
92        for i in 0..num_samples {
93            for channel in samples {
94                writer.write_sample(channel[i]).unwrap();
95            }
96        }
97        writer.finalize().unwrap();
98
99        temp_file
100    }
101
102    #[test]
103    fn test_wav_reader_mono_f32() {
104        let samples = vec![vec![0.0, 0.5, 1.0, -0.5, -1.0]];
105        let temp_file = create_test_wav(44100, 1, &samples);
106
107        let reader = WavFileReader::<f32>::from_path(temp_file.path().to_str().unwrap()).unwrap();
108
109        assert_eq!(reader.num_channels(), 1);
110        assert_eq!(reader.num_samples(), 5);
111        assert_eq!(reader.sample_rate(), 44100.0);
112
113        let channel = reader.read_channel(0);
114        for (i, &expected) in samples[0].iter().enumerate() {
115            assert!(
116                (channel[i] - expected).abs() < 1e-6,
117                "Sample {} mismatch: {} vs {}",
118                i,
119                channel[i],
120                expected
121            );
122        }
123    }
124
125    #[test]
126    fn test_wav_reader_mono_f64() {
127        let samples = vec![vec![0.0, 0.25, 0.75, -0.25, -0.75]];
128        let temp_file = create_test_wav(48000, 1, &samples);
129
130        let reader = WavFileReader::<f64>::from_path(temp_file.path().to_str().unwrap()).unwrap();
131
132        assert_eq!(reader.num_channels(), 1);
133        assert_eq!(reader.num_samples(), 5);
134        assert_eq!(reader.sample_rate(), 48000.0);
135
136        let channel = reader.read_channel(0);
137        for (i, &expected) in samples[0].iter().enumerate() {
138            assert!((channel[i] - expected as f64).abs() < 1e-6, "Sample {} mismatch", i);
139        }
140    }
141
142    #[test]
143    fn test_wav_reader_stereo_f32() {
144        let left = vec![0.1, 0.2, 0.3, 0.4, 0.5];
145        let right = vec![-0.1, -0.2, -0.3, -0.4, -0.5];
146        let samples = vec![left.clone(), right.clone()];
147        let temp_file = create_test_wav(44100, 2, &samples);
148
149        let reader = WavFileReader::<f32>::from_path(temp_file.path().to_str().unwrap()).unwrap();
150
151        assert_eq!(reader.num_channels(), 2);
152        // wavers.n_samples() returns total samples across all channels
153        assert_eq!(reader.num_samples(), 10);
154
155        let left_channel = reader.read_channel(0);
156        let right_channel = reader.read_channel(1);
157
158        for i in 0..5 {
159            assert!((left_channel[i] - left[i]).abs() < 1e-6, "Left sample {} mismatch", i);
160            assert!(
161                (right_channel[i] - right[i]).abs() < 1e-6,
162                "Right sample {} mismatch",
163                i
164            );
165        }
166    }
167
168    #[test]
169    fn test_wav_reader_sample_rate() {
170        let samples = vec![vec![0.0; 10]];
171
172        let temp_22050 = create_test_wav(22050, 1, &samples);
173        let reader = WavFileReader::<f32>::from_path(temp_22050.path().to_str().unwrap()).unwrap();
174        assert_eq!(reader.sample_rate(), 22050.0);
175
176        let temp_96000 = create_test_wav(96000, 1, &samples);
177        let reader = WavFileReader::<f32>::from_path(temp_96000.path().to_str().unwrap()).unwrap();
178        assert_eq!(reader.sample_rate(), 96000.0);
179    }
180
181    #[test]
182    fn test_wav_reader_invalid_path() {
183        let result = WavFileReader::<f32>::from_path("/nonexistent/path/audio.wav");
184        assert!(result.is_err());
185    }
186}
bbx_file/readers/wav.rs

bbx_file/readers/
wav.rs
