evt3 0.4.0

Fast EVT3 (EVT 3.0) decoder library for Prophesee and Metavision event cameras. Decodes .raw and HDF5 event data for event-based vision and neuromorphic research.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166

//! Benchmarks for EVT3 decoder performance.
//!
//! Run with: cargo bench

use criterion::{black_box, criterion_group, criterion_main, Criterion, Throughput};
use evt3::{ColumnarEventSink, Evt3Decoder};
use std::path::PathBuf;

const TEST_FILE_CANDIDATES: [&str; 2] = ["test_data/laser.raw", "../test_data/laser.raw"];

fn synthetic_bytes() -> Vec<u8> {
    let mut data = Vec::new();

    // Generate 100k synthetic events worth of data.
    for i in 0..100_000 {
        data.extend_from_slice(&0x8000u16.to_le_bytes());
        data.extend_from_slice(&((0x6000 | (i & 0x0FFF)) as u16).to_le_bytes());
        data.extend_from_slice(&((i & 0x07FF) as u16).to_le_bytes());
        data.extend_from_slice(&(0x2800u16 | ((i * 3) & 0x07FF) as u16).to_le_bytes());
    }

    data
}

fn synthetic_vector_bytes() -> Vec<u8> {
    let mut data = Vec::new();
    data.extend_from_slice(&0x8000u16.to_le_bytes());
    for i in 0..100_000_u32 {
        data.extend_from_slice(&(0x6000_u16 | (i & 0x0fff) as u16).to_le_bytes());
        data.extend_from_slice(&((i & 0x07ff) as u16).to_le_bytes());
        data.extend_from_slice(&(0x3000_u16 | ((i * 3) & 0x07ff) as u16).to_le_bytes());
        data.extend_from_slice(&(0x4001_u16 | ((i & 0x0f) << 4) as u16).to_le_bytes());
    }
    data
}

fn decode_file_benchmark(c: &mut Criterion) {
    let Some(test_path) = TEST_FILE_CANDIDATES
        .iter()
        .map(PathBuf::from)
        .find(|path| path.exists())
    else {
        eprintln!(
            "Benchmark skipped: test file not found in {:?}",
            TEST_FILE_CANDIDATES
        );
        return;
    };

    // Get file size for throughput calculation
    let file_size = std::fs::metadata(&test_path).unwrap().len();

    let mut group = c.benchmark_group("decode_file");
    group.throughput(Throughput::Bytes(file_size));

    group.bench_function("full_file", |b| {
        b.iter(|| {
            let mut decoder = Evt3Decoder::new();
            let result = decoder.decode_file(black_box(&test_path)).unwrap();
            black_box(result.cd_events.len())
        })
    });

    group.bench_function("full_file_columns", |b| {
        b.iter(|| {
            let result = Evt3Decoder::new()
                .decode_file_columns(black_box(&test_path))
                .unwrap();
            black_box(result.cd_events.len())
        })
    });

    group.finish();
}

fn decode_buffer_benchmark(c: &mut Criterion) {
    let data = synthetic_bytes();

    let words: Vec<u16> = data
        .chunks_exact(2)
        .map(|c| u16::from_le_bytes([c[0], c[1]]))
        .collect();

    let mut group = c.benchmark_group("decode_buffer");
    group.throughput(Throughput::Elements(words.len() as u64));

    group.bench_function("synthetic_100k_events", |b| {
        b.iter(|| {
            let mut decoder = Evt3Decoder::new();
            let mut cd_events = Vec::new();
            let mut trigger_events = Vec::new();
            decoder.decode_buffer(black_box(&words), &mut cd_events, &mut trigger_events);
            black_box(cd_events.len())
        })
    });

    group.finish();
}

fn decode_bytes_benchmark(c: &mut Criterion) {
    let data = synthetic_bytes();

    let mut group = c.benchmark_group("decode_bytes");
    group.throughput(Throughput::Bytes(data.len() as u64));

    group.bench_function("even_chunks", |b| {
        b.iter(|| {
            let mut decoder = Evt3Decoder::new();
            let mut cd_events = Vec::new();
            let mut trigger_events = Vec::new();

            for chunk in data.chunks(8192) {
                decoder
                    .decode_bytes(black_box(chunk), &mut cd_events, &mut trigger_events)
                    .unwrap();
            }

            decoder.finish_stream().unwrap();
            black_box(cd_events.len())
        })
    });

    group.bench_function("irregular_chunks", |b| {
        b.iter(|| {
            let mut decoder = Evt3Decoder::new();
            let mut cd_events = Vec::new();
            let mut trigger_events = Vec::new();

            for chunk in data.chunks(4095) {
                decoder
                    .decode_bytes(black_box(chunk), &mut cd_events, &mut trigger_events)
                    .unwrap();
            }

            decoder.finish_stream().unwrap();
            black_box(cd_events.len())
        })
    });

    group.finish();
}

fn decode_vector_benchmark(c: &mut Criterion) {
    let data = synthetic_vector_bytes();
    let mut group = c.benchmark_group("decode_vectors");
    group.throughput(Throughput::Bytes(data.len() as u64));

    group.bench_function("sparse_vector_masks", |b| {
        b.iter(|| {
            let mut decoder = Evt3Decoder::new();
            let mut sink = ColumnarEventSink::default();
            decoder.decode_bytes_into(black_box(&data), &mut sink);
            black_box(sink.cd.len())
        })
    });
    group.finish();
}

criterion_group!(
    benches,
    decode_file_benchmark,
    decode_buffer_benchmark,
    decode_bytes_benchmark,
    decode_vector_benchmark
);
criterion_main!(benches);