ff_decode/shared/
seek.rs

1//! Seek mode configuration for decoder positioning.
2
3/// Seek mode for positioning the decoder.
4///
5/// This enum determines how seeking is performed when navigating
6/// through a media file.
7///
8/// # Performance Considerations
9///
10/// - [`Keyframe`](Self::Keyframe) is fastest but may land slightly before or after the target
11/// - [`Exact`](Self::Exact) is slower but guarantees landing on the exact frame
12/// - [`Backward`](Self::Backward) is useful for editing workflows where the previous keyframe is needed
13///
14/// # Examples
15///
16/// ```
17/// use ff_decode::SeekMode;
18///
19/// // Default is Keyframe mode
20/// let mode = SeekMode::default();
21/// assert_eq!(mode, SeekMode::Keyframe);
22///
23/// // Use exact mode for frame-accurate positioning
24/// let exact = SeekMode::Exact;
25/// assert_eq!(format!("{:?}", exact), "Exact");
26/// ```
27#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
28#[repr(u8)]
29pub enum SeekMode {
30    /// Seek to nearest keyframe (fast, may have small offset).
31    ///
32    /// This mode seeks to the closest keyframe to the target position.
33    /// It's the fastest option but the actual position may differ from
34    /// the requested position by up to the GOP (Group of Pictures) size.
35    #[default]
36    Keyframe = 0,
37
38    /// Seek to exact frame (slower but precise).
39    ///
40    /// This mode first seeks to the previous keyframe, then decodes
41    /// frames until reaching the exact target position. This guarantees
42    /// frame-accurate positioning but is slower, especially for long GOPs.
43    Exact = 1,
44
45    /// Seek to keyframe at or before the target position.
46    ///
47    /// Similar to [`Keyframe`](Self::Keyframe), but guarantees the resulting
48    /// position is at or before the target. Useful for editing workflows
49    /// where you need to start decoding before a specific point.
50    Backward = 2,
51}
52
53#[cfg(test)]
54mod tests {
55    use super::*;
56
57    #[test]
58    fn seek_mode_default_should_be_keyframe() {
59        let mode = SeekMode::default();
60        assert_eq!(mode, SeekMode::Keyframe);
61    }
62
63    #[test]
64    fn seek_mode_variants_should_be_accessible() {
65        let modes = [SeekMode::Keyframe, SeekMode::Exact, SeekMode::Backward];
66        for mode in modes {
67            let _ = format!("{mode:?}");
68        }
69    }
70}
ff_decode/shared/seek.rs

ff_decode/shared/
seek.rs
