57 lines
1.7 KiB
Rust
57 lines
1.7 KiB
Rust
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#![forbid(unsafe_code)]
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use std::sync::OnceLock;
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use std::time::{Duration, Instant};
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static CAPTURE_ORIGIN: OnceLock<Instant> = OnceLock::new();
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fn origin() -> Instant {
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*CAPTURE_ORIGIN.get_or_init(Instant::now)
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}
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/// Return the shared live-capture timestamp for upstream camera/mic packets.
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///
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/// Inputs: none.
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/// Outputs: microseconds elapsed since the relay child first stamped live media.
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/// Why: camera and microphone capture pipelines run independently, so they need
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/// one explicit common origin before the server can keep them on the same live
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/// call timeline.
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#[must_use]
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pub fn capture_pts_us() -> u64 {
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origin().elapsed().as_micros().min(u64::MAX as u128) as u64
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}
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/// Measure how old one shared capture timestamp is right now.
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///
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/// Inputs: a packet timestamp previously produced by `capture_pts_us`.
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/// Outputs: the elapsed age as a `Duration`.
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/// Why: upstream freshness telemetry should use the same shared live clock as
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/// packet timestamps so queue-age calculations stay honest.
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#[must_use]
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pub fn packet_age(pts_us: u64) -> Duration {
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Duration::from_micros(capture_pts_us().saturating_sub(pts_us))
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}
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#[cfg(test)]
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mod tests {
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use super::{capture_pts_us, packet_age};
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use std::time::Duration;
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#[test]
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fn capture_pts_us_monotonically_advances() {
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let first = capture_pts_us();
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std::thread::sleep(Duration::from_millis(2));
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let second = capture_pts_us();
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assert!(second >= first);
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}
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#[test]
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fn packet_age_is_small_for_recent_packets() {
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let pts = capture_pts_us();
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std::thread::sleep(Duration::from_millis(2));
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let age = packet_age(pts);
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assert!(age >= Duration::from_millis(1));
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assert!(age < Duration::from_secs(1));
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}
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}
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