ff-decode 0.14.1

Video and audio decoding - the Rust way
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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205

//! Integration tests for `ScopeAnalyzer` — vectorscope and RGB parade.
//!
//! These are pure-Rust pixel arithmetic functions, so no FFmpeg call is
//! required.  Tests use synthetic `VideoFrame` objects to verify measurable,
//! predictable output values.

use ff_decode::ScopeAnalyzer;
use ff_format::{PixelFormat, PooledBuffer, Timestamp, VideoFrame};

// ── Helpers ───────────────────────────────────────────────────────────────────

fn yuv420p_frame(w: u32, h: u32, y: u8, u: u8, v: u8) -> VideoFrame {
    let yp = PooledBuffer::standalone(vec![y; (w * h) as usize]);
    let up = PooledBuffer::standalone(vec![u; ((w / 2) * (h / 2)) as usize]);
    let vp = PooledBuffer::standalone(vec![v; ((w / 2) * (h / 2)) as usize]);
    VideoFrame::new(
        vec![yp, up, vp],
        vec![w as usize, (w / 2) as usize, (w / 2) as usize],
        w,
        h,
        PixelFormat::Yuv420p,
        Timestamp::default(),
        true,
    )
    .expect("test yuv420p frame")
}

fn yuv444p_frame(w: u32, h: u32, y: u8, u: u8, v: u8) -> VideoFrame {
    let yp = PooledBuffer::standalone(vec![y; (w * h) as usize]);
    let up = PooledBuffer::standalone(vec![u; (w * h) as usize]);
    let vp = PooledBuffer::standalone(vec![v; (w * h) as usize]);
    VideoFrame::new(
        vec![yp, up, vp],
        vec![w as usize, w as usize, w as usize],
        w,
        h,
        PixelFormat::Yuv444p,
        Timestamp::default(),
        true,
    )
    .expect("test yuv444p frame")
}

// ── vectorscope ───────────────────────────────────────────────────────────────

#[test]
fn vectorscope_neutral_yuv_frame_should_cluster_near_origin() {
    // U=128, V=128 → Cb=Cr=0 in centred coordinates → scatter near (0, 0).
    let frame = yuv420p_frame(8, 8, 128, 128, 128);
    let scatter = ScopeAnalyzer::vectorscope(&frame);
    assert!(
        !scatter.is_empty(),
        "vectorscope must return at least one point"
    );
    for (cb, cr) in &scatter {
        assert!(
            cb.abs() < 0.02,
            "neutral chroma Cb must be near 0; got {cb:.4}"
        );
        assert!(
            cr.abs() < 0.02,
            "neutral chroma Cr must be near 0; got {cr:.4}"
        );
    }
}

#[test]
fn vectorscope_yuv420p_sample_count_should_equal_quarter_of_pixel_count() {
    // 4:2:0 sub-sampling → chroma is one sample per 2×2 luma block.
    let frame = yuv420p_frame(8, 8, 128, 128, 128);
    let scatter = ScopeAnalyzer::vectorscope(&frame);
    assert_eq!(
        scatter.len(),
        8 * 8 / 4,
        "4:2:0 vectorscope must have w*h/4 samples"
    );
}

#[test]
fn vectorscope_yuv444p_sample_count_should_equal_pixel_count() {
    let frame = yuv444p_frame(6, 4, 128, 128, 128);
    let scatter = ScopeAnalyzer::vectorscope(&frame);
    assert_eq!(
        scatter.len(),
        6 * 4,
        "4:4:4 vectorscope must have exactly w*h samples"
    );
}

#[test]
fn vectorscope_all_values_should_be_in_normalised_range() {
    // Saturated blue: U=255 (max Cb), V=128 (neutral Cr)
    let frame = yuv444p_frame(4, 4, 100, 255, 128);
    let scatter = ScopeAnalyzer::vectorscope(&frame);
    for (cb, cr) in &scatter {
        assert!(
            *cb >= -1.0 && *cb <= 1.0,
            "Cb must be in [-1.0, 1.0]; got {cb:.4}"
        );
        assert!(
            *cr >= -1.0 && *cr <= 1.0,
            "Cr must be in [-1.0, 1.0]; got {cr:.4}"
        );
    }
}

#[test]
fn vectorscope_unsupported_format_should_return_empty() {
    let frame = VideoFrame::empty(4, 4, PixelFormat::Rgba).expect("test rgba frame");
    let scatter = ScopeAnalyzer::vectorscope(&frame);
    assert!(
        scatter.is_empty(),
        "vectorscope must return empty for RGBA input"
    );
}

// ── rgb_parade ────────────────────────────────────────────────────────────────

/// `rgb_parade` only supports YUV formats. A neutral grey YUV frame
/// (U=128, V=128) should produce equal R, G, B averages per column.
#[test]
fn rgb_parade_neutral_yuv_frame_should_have_equal_r_g_b_columns() {
    // U=128, V=128 = neutral chroma → R≈G≈B
    let frame = yuv420p_frame(8, 8, 128, 128, 128);
    let parade = ScopeAnalyzer::rgb_parade(&frame);

    assert_eq!(parade.r.len(), 8, "parade.r must have one vec per column");
    assert_eq!(parade.g.len(), 8, "parade.g must have one vec per column");
    assert_eq!(parade.b.len(), 8, "parade.b must have one vec per column");

    for col in 0..8 {
        let avg_r: f32 = parade.r[col].iter().sum::<f32>() / parade.r[col].len() as f32;
        let avg_g: f32 = parade.g[col].iter().sum::<f32>() / parade.g[col].len() as f32;
        let avg_b: f32 = parade.b[col].iter().sum::<f32>() / parade.b[col].len() as f32;
        let diff_rg = (avg_r - avg_g).abs();
        let diff_gb = (avg_g - avg_b).abs();
        assert!(
            diff_rg < 0.05,
            "neutral chroma column {col}: R and G must be close; diff={diff_rg:.4}"
        );
        assert!(
            diff_gb < 0.05,
            "neutral chroma column {col}: G and B must be close; diff={diff_gb:.4}"
        );
    }
}

/// A very bright YUV frame (Y near 255) should produce high values in all
/// channels because neutral chroma means R≈G≈B≈Y.
#[test]
fn rgb_parade_bright_yuv_frame_should_have_high_luma_across_channels() {
    let frame = yuv420p_frame(4, 4, 235, 128, 128); // BT.601 white
    let parade = ScopeAnalyzer::rgb_parade(&frame);

    assert!(
        !parade.r.is_empty(),
        "bright frame must produce non-empty R parade"
    );
    let avg_r: f32 = parade.r[0].iter().sum::<f32>() / parade.r[0].len() as f32;
    assert!(
        avg_r > 0.8,
        "Y=235, neutral chroma must produce R≈1.0; got {avg_r:.4}"
    );
}

/// Unsupported formats (e.g. RGBA) must return empty parade.
#[test]
fn rgb_parade_unsupported_format_should_return_empty() {
    let frame = VideoFrame::empty(4, 4, PixelFormat::Rgba).expect("rgba frame");
    let parade = ScopeAnalyzer::rgb_parade(&frame);
    assert!(
        parade.r.is_empty() && parade.g.is_empty() && parade.b.is_empty(),
        "rgb_parade must return empty vecs for unsupported RGBA input"
    );
}

#[test]
fn rgb_parade_yuv420p_frame_should_return_nonempty_vectors() {
    let frame = yuv420p_frame(8, 8, 128, 128, 128);
    let parade = ScopeAnalyzer::rgb_parade(&frame);
    assert_eq!(parade.r.len(), 8, "YUV parade must have one vec per column");
    for col in 0..8 {
        assert!(
            !parade.r[col].is_empty(),
            "column {col}: R must have at least one sample"
        );
    }
}

#[test]
fn rgb_parade_column_values_should_be_in_normalised_range() {
    let frame = yuv420p_frame(4, 4, 200, 100, 150);
    let parade = ScopeAnalyzer::rgb_parade(&frame);
    for col in 0..4 {
        for &v in &parade.r[col] {
            assert!(v >= 0.0 && v <= 1.0, "R value must be in [0,1]; got {v:.4}");
        }
        for &v in &parade.g[col] {
            assert!(v >= 0.0 && v <= 1.0, "G value must be in [0,1]; got {v:.4}");
        }
        for &v in &parade.b[col] {
            assert!(v >= 0.0 && v <= 1.0, "B value must be in [0,1]; got {v:.4}");
        }
    }
}