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| 1 | +use std::ffi::c_void; |
| 2 | + |
| 3 | +const ST_SETTING_USE_QUICKSEEK: i32 = 2; |
| 4 | +const MIN_RATE: f64 = 0.25; |
| 5 | +const MAX_RATE: f64 = 4.0; |
| 6 | +const RECEIVE_CHUNK_FRAMES: usize = 4096; |
| 7 | + |
| 8 | +unsafe extern "C" { |
| 9 | + fn frkb_soundtouch_create() -> *mut c_void; |
| 10 | + fn frkb_soundtouch_destroy(handle: *mut c_void); |
| 11 | + fn frkb_soundtouch_set_channels(handle: *mut c_void, channels: u32); |
| 12 | + fn frkb_soundtouch_set_sample_rate(handle: *mut c_void, sample_rate: u32); |
| 13 | + fn frkb_soundtouch_set_tempo(handle: *mut c_void, tempo: f64); |
| 14 | + fn frkb_soundtouch_set_pitch(handle: *mut c_void, pitch: f64); |
| 15 | + fn frkb_soundtouch_set_rate(handle: *mut c_void, rate: f64); |
| 16 | + fn frkb_soundtouch_set_setting(handle: *mut c_void, setting_id: i32, value: i32); |
| 17 | + fn frkb_soundtouch_put_samples(handle: *mut c_void, samples: *const f32, num_samples: u32); |
| 18 | + fn frkb_soundtouch_receive_samples( |
| 19 | + handle: *mut c_void, |
| 20 | + output: *mut f32, |
| 21 | + max_samples: u32, |
| 22 | + ) -> u32; |
| 23 | + fn frkb_soundtouch_flush(handle: *mut c_void); |
| 24 | +} |
| 25 | + |
| 26 | +fn clamp_rate(value: f64) -> f64 { |
| 27 | + if value.is_finite() && value > 0.0 { |
| 28 | + value.clamp(MIN_RATE, MAX_RATE) |
| 29 | + } else { |
| 30 | + 1.0 |
| 31 | + } |
| 32 | +} |
| 33 | + |
| 34 | +pub(crate) struct SoundTouchHandle(*mut c_void); |
| 35 | + |
| 36 | +unsafe impl Send for SoundTouchHandle {} |
| 37 | + |
| 38 | +impl SoundTouchHandle { |
| 39 | + pub(crate) fn new(channels: u32, sample_rate: u32, tempo: f64) -> Option<Self> { |
| 40 | + let handle = unsafe { frkb_soundtouch_create() }; |
| 41 | + if handle.is_null() { |
| 42 | + return None; |
| 43 | + } |
| 44 | + unsafe { |
| 45 | + frkb_soundtouch_set_channels(handle, channels); |
| 46 | + frkb_soundtouch_set_sample_rate(handle, sample_rate); |
| 47 | + frkb_soundtouch_set_tempo(handle, tempo); |
| 48 | + frkb_soundtouch_set_pitch(handle, 1.0); |
| 49 | + frkb_soundtouch_set_rate(handle, 1.0); |
| 50 | + frkb_soundtouch_set_setting(handle, ST_SETTING_USE_QUICKSEEK, 1); |
| 51 | + } |
| 52 | + Some(Self(handle)) |
| 53 | + } |
| 54 | + |
| 55 | + pub(crate) fn put_samples(&mut self, samples: &[f32], num_samples: usize) { |
| 56 | + if samples.is_empty() || num_samples == 0 { |
| 57 | + return; |
| 58 | + } |
| 59 | + unsafe { frkb_soundtouch_put_samples(self.0, samples.as_ptr(), num_samples as u32) } |
| 60 | + } |
| 61 | + |
| 62 | + pub(crate) fn receive_samples(&mut self, output: &mut [f32], max_samples: usize) -> usize { |
| 63 | + if output.is_empty() || max_samples == 0 { |
| 64 | + return 0; |
| 65 | + } |
| 66 | + unsafe { frkb_soundtouch_receive_samples(self.0, output.as_mut_ptr(), max_samples as u32) as usize } |
| 67 | + } |
| 68 | + |
| 69 | + pub(crate) fn flush(&mut self) { |
| 70 | + unsafe { frkb_soundtouch_flush(self.0) } |
| 71 | + } |
| 72 | +} |
| 73 | + |
| 74 | +impl Drop for SoundTouchHandle { |
| 75 | + fn drop(&mut self) { |
| 76 | + if !self.0.is_null() { |
| 77 | + unsafe { frkb_soundtouch_destroy(self.0) } |
| 78 | + self.0 = std::ptr::null_mut(); |
| 79 | + } |
| 80 | + } |
| 81 | +} |
| 82 | + |
| 83 | +pub(crate) fn process_interleaved_f32( |
| 84 | + samples: &[f32], |
| 85 | + sample_rate: u32, |
| 86 | + channels: usize, |
| 87 | + tempo: f64, |
| 88 | +) -> Result<Vec<f32>, String> { |
| 89 | + let safe_channels = channels.max(1); |
| 90 | + if sample_rate == 0 { |
| 91 | + return Err("sample_rate is 0".to_string()); |
| 92 | + } |
| 93 | + if samples.is_empty() { |
| 94 | + return Ok(Vec::new()); |
| 95 | + } |
| 96 | + let safe_tempo = clamp_rate(tempo); |
| 97 | + if (safe_tempo - 1.0).abs() <= 0.0001 { |
| 98 | + return Ok(samples.to_vec()); |
| 99 | + } |
| 100 | + let mut processor = SoundTouchHandle::new(safe_channels as u32, sample_rate, safe_tempo) |
| 101 | + .ok_or_else(|| "create soundtouch failed".to_string())?; |
| 102 | + processor.put_samples(samples, samples.len() / safe_channels); |
| 103 | + |
| 104 | + let mut output = Vec::<f32>::with_capacity( |
| 105 | + ((samples.len() as f64 / safe_tempo.max(0.01)) as usize).saturating_add(safe_channels * 1024), |
| 106 | + ); |
| 107 | + let mut chunk = vec![0.0_f32; safe_channels * RECEIVE_CHUNK_FRAMES]; |
| 108 | + |
| 109 | + loop { |
| 110 | + let received = processor.receive_samples(&mut chunk, RECEIVE_CHUNK_FRAMES); |
| 111 | + if received == 0 { |
| 112 | + break; |
| 113 | + } |
| 114 | + output.extend_from_slice(&chunk[..received * safe_channels]); |
| 115 | + } |
| 116 | + |
| 117 | + processor.flush(); |
| 118 | + |
| 119 | + loop { |
| 120 | + let received = processor.receive_samples(&mut chunk, RECEIVE_CHUNK_FRAMES); |
| 121 | + if received == 0 { |
| 122 | + break; |
| 123 | + } |
| 124 | + output.extend_from_slice(&chunk[..received * safe_channels]); |
| 125 | + } |
| 126 | + |
| 127 | + Ok(output) |
| 128 | +} |
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