analyze_audio/
analyze_audio.rs

1use nes_sim::{ControllerState, FrontendInput, FrontendRuntime};
2use std::env;
3use std::fs;
4use std::io::{BufWriter, Write};
5use std::path::Path;
6
7fn main() {
8    let rom_path = env::args().nth(1).expect("Usage: analyze_audio <rom-path>");
9    let rom = fs::read(&rom_path).expect("Failed to read ROM");
10    let mut runtime = FrontendRuntime::from_rom_bytes(&rom).expect("Failed to load ROM");
11
12    let input = FrontendInput {
13        controller1: ControllerState::new(),
14        ..Default::default()
15    };
16
17    // 运行几秒收集样本
18    let mut all_samples = Vec::new();
19    for _ in 0..300 {
20        let snapshot = runtime.step(input);
21        all_samples.extend_from_slice(snapshot.audio.samples);
22    }
23
24    // 分析
25    let min = all_samples.iter().cloned().reduce(f32::min).unwrap();
26    let max = all_samples.iter().cloned().reduce(f32::max).unwrap();
27    let avg = all_samples.iter().sum::<f32>() / all_samples.len() as f32;
28
29    // 计算方差（噪声水平）
30    let variance =
31        all_samples.iter().map(|&x| (x - avg).powi(2)).sum::<f32>() / all_samples.len() as f32;
32    let std_dev = variance.sqrt();
33
34    // 统计接近静音的样本
35    let near_zero_count = all_samples.iter().filter(|&&x| x.abs() < 1e-6).count();
36    let near_zero_ratio = near_zero_count as f32 / all_samples.len() as f32;
37
38    println!("=== 音频样本分析 ===");
39    println!("样本总数: {}", all_samples.len());
40    println!("最小值: {:.6}", min);
41    println!("最大值: {:.6}", max);
42    println!("平均值: {:.6}", avg);
43    println!("标准差 (噪声水平): {:.6}", std_dev);
44    println!(
45        "接近静音的样本 (<1e-6): {} ({:.2}%)",
46        near_zero_count,
47        near_zero_ratio * 100.0
48    );
49
50    // 找出典型静音期间的噪声范围
51    let mut silent_samples: Vec<f32> = all_samples
52        .iter()
53        .filter(|&&x| x.abs() < 0.001)
54        .copied()
55        .collect();
56    silent_samples.sort_by(|a, b| a.abs().partial_cmp(&b.abs()).unwrap());
57    if silent_samples.len() > 100 {
58        let quiet_max = silent_samples[silent_samples.len() / 2 + 50]; // 取中位数附近的最大值
59        println!("静音期间典型噪声范围: ±{:.6}", quiet_max);
60    }
61
62    // 保存所有样本供可视化（默认最多保存 10 秒）
63    let sample_rate = runtime.snapshot().audio.sample_rate;
64    let max_samples = (sample_rate as usize) * 10; // 最多 10 秒
65    let wav_samples = &all_samples[..max_samples.min(all_samples.len())];
66    let wav_path = Path::new(&rom_path).with_extension("wav");
67    write_wav(&wav_path, wav_samples, sample_rate);
68    println!(
69        "已保存 {} 个样本 (约 {:.1} 秒) 到: {}",
70        wav_samples.len(),
71        wav_samples.len() as f32 / sample_rate as f32,
72        wav_path.display()
73    );
74}
75
76fn write_wav(path: &Path, samples: &[f32], sample_rate: u32) {
77    let file = fs::File::create(path).expect("Failed to create WAV file");
78    let mut writer = BufWriter::new(file);
79
80    // WAV header
81    let sample_count = samples.len() as u32;
82    let byte_count = sample_count * 2; // 16-bit mono
83
84    writer.write_all(b"RIFF").unwrap();
85    writer.write_all(&(36 + byte_count).to_le_bytes()).unwrap();
86    writer.write_all(b"WAVE").unwrap();
87    writer.write_all(b"fmt ").unwrap();
88    writer.write_all(&16u32.to_le_bytes()).unwrap(); // fmt chunk size
89    writer.write_all(&1u16.to_le_bytes()).unwrap(); // PCM
90    writer.write_all(&1u16.to_le_bytes()).unwrap(); // mono
91    writer.write_all(&sample_rate.to_le_bytes()).unwrap();
92    writer.write_all(&(sample_rate * 2).to_le_bytes()).unwrap(); // byte rate
93    writer.write_all(&2u16.to_le_bytes()).unwrap(); // block align
94    writer.write_all(&16u16.to_le_bytes()).unwrap(); // bits per sample
95    writer.write_all(b"data").unwrap();
96    writer.write_all(&byte_count.to_le_bytes()).unwrap();
97
98    // samples
99    for &sample in samples {
100        let sample_i16 = (sample.clamp(-1.0, 1.0) * 32767.0) as i16;
101        writer.write_all(&sample_i16.to_le_bytes()).unwrap();
102    }
103}
analyze_audio/analyze_audio.rs

analyze_audio/
analyze_audio.rs
