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mpegtslivesrc: Rename variables to make it clear which time domain they refer to

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We have the internal time domain (monotonic clock) and the external time
domain (scaled monotonic clock in the rate of the PCR).

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/-/merge_requests/1933>
This commit is contained in:
Sebastian Dröge 2024-11-21 13:29:25 +02:00 committed by GStreamer Marge Bot
parent 25bb2a12f1
commit d32d499856
1 changed files with 43 additions and 38 deletions
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81
net/mpegtslive/src/mpegtslive/imp.rs
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@ -167,9 +167,9 @@ struct State {
// Last observed PCR (for handling wraparound) // Last observed PCR (for handling wraparound)
last_seen_pcr: Option<MpegTsPcr>, last_seen_pcr: Option<MpegTsPcr>,
// First observed PCR and associated timestamp // First observed PCR since discont and associated external clock time
base_pcr: Option<MpegTsPcr>, base_pcr: Option<MpegTsPcr>,
base_monotonic: Option<gst::ClockTime>, base_external: Option<gst::ClockTime>,
// If the next outgoing packet should have the discont flag set // If the next outgoing packet should have the discont flag set
discont_pending: bool, discont_pending: bool,
@ -377,50 +377,55 @@ impl FromBitStream for ProgramMappingTable {
} }
impl State { impl State {
/// Store PCR / monotonic time observation /// Store PCR / internal (monotonic) clock time observation
fn store_observation( fn store_observation(
&mut self, &mut self,
imp: &MpegTsLiveSource, imp: &MpegTsLiveSource,
pcr: u64, pcr: u64,
monotonic_time: gst::ClockTime, observation_internal: gst::ClockTime,
) { ) {
// If this is the first PCR we observe: // If this is the first PCR we observe:
// * Remember the PCR *and* the associated monotonic clock value when capture // * Remember the PCR *and* the associated internal (monotonic) == external (scaled
// * `base_pcr` `base_monotonic` // monotonic) clock value when capture
// * Store base_pcr = pcr, base_external = observation_internal
// If we have a PCR we need to store an observation // If we have a PCR we need to store an observation
// * Subtract the base PCR from that value and add the base monotonic value // * Subtract the base PCR from that value and add the base external clock value
// * observation_monotonic = pcr - base_pcr + base_monotonic // * observation_external = pcr - base_pcr + base_external
// * Store (observation_monotonic, buffer_pts) // * Store (observation_internal, observation_external)
let new_pcr: MpegTsPcr; let new_pcr: MpegTsPcr;
if let (Some(base_pcr), Some(base_monotonic), Some(last_seen_pcr)) = if let (Some(base_pcr), Some(base_external), Some(last_seen_pcr)) =
(self.base_pcr, self.base_monotonic, self.last_seen_pcr) (self.base_pcr, self.base_external, self.last_seen_pcr)
{ {
gst::trace!(CAT, imp = imp, "pcr:{pcr}, monotonic_time:{monotonic_time}"); gst::trace!(
CAT,
imp = imp,
"pcr:{pcr}, observation_internal:{observation_internal}"
);
let mut handled_pcr = MpegTsPcr::new_with_reference(imp, pcr, &last_seen_pcr); let mut handled_pcr = MpegTsPcr::new_with_reference(imp, pcr, &last_seen_pcr);
if let Some(new_pcr) = handled_pcr { if let Some(new_pcr) = handled_pcr {
// First check if this is more than 1s off from the current clock calibration and // First check if this is more than 1s off from the current clock calibration and
// if so consider it a discontinuity too. // if so consider it a discontinuity too.
let (internal, external, num, denom) = imp.external_clock.calibration(); let (cinternal, cexternal, cnum, cdenom) = imp.external_clock.calibration();
let expected_external = gst::Clock::adjust_with_calibration( let expected_external = gst::Clock::adjust_with_calibration(
monotonic_time, observation_internal,
internal, cinternal,
external, cexternal,
num, cnum,
denom, cdenom,
); );
let new_external = let observation_external =
gst::ClockTime::from(new_pcr.saturating_sub(base_pcr)) + base_monotonic; gst::ClockTime::from(new_pcr.saturating_sub(base_pcr)) + base_external;
if expected_external.absdiff(new_external) >= gst::ClockTime::SECOND { if expected_external.absdiff(observation_external) >= gst::ClockTime::SECOND {
gst::warning!( gst::warning!(
CAT, CAT,
imp = imp, imp = imp,
"New PCR clock estimation {new_external} too far from old estimation {expected_external}: {}", "New PCR clock estimation {observation_external} too far from old estimation {expected_external}: {}",
new_external.into_positive() - expected_external, observation_external.into_positive() - expected_external,
); );
handled_pcr = None; handled_pcr = None;
} }
@ -432,41 +437,41 @@ impl State {
CAT, CAT,
imp = imp, imp = imp,
"Adding new observation internal: {} -> external: {}", "Adding new observation internal: {} -> external: {}",
gst::ClockTime::from(new_pcr.saturating_sub(base_pcr)) + base_monotonic, observation_internal,
monotonic_time, gst::ClockTime::from(new_pcr.saturating_sub(base_pcr)) + base_external,
); );
imp.external_clock.add_observation( imp.external_clock.add_observation(
monotonic_time, observation_internal,
gst::ClockTime::from(new_pcr.saturating_sub(base_pcr)) + base_monotonic, gst::ClockTime::from(new_pcr.saturating_sub(base_pcr)) + base_external,
); );
} else { } else {
let (internal, external, num, denom) = imp.external_clock.calibration(); let (cinternal, cexternal, cnum, cdenom) = imp.external_clock.calibration();
let scaled_monotonic = gst::Clock::adjust_with_calibration( let base_external = gst::Clock::adjust_with_calibration(
monotonic_time, observation_internal,
internal, cinternal,
external, cexternal,
num, cnum,
denom, cdenom,
); );
gst::warning!( gst::warning!(
CAT, CAT,
imp = imp, imp = imp,
"DISCONT detected, Picking new reference times (pcr:{pcr:#?}, monotonic:{monotonic_time}, scaled monotonic:{scaled_monotonic}", "DISCONT detected, Picking new reference times (pcr:{pcr:#?}, observation_internal:{observation_internal}, base_external:{base_external}",
); );
new_pcr = MpegTsPcr::new(pcr); new_pcr = MpegTsPcr::new(pcr);
self.base_pcr = Some(new_pcr); self.base_pcr = Some(new_pcr);
self.base_monotonic = Some(monotonic_time); self.base_external = Some(observation_internal);
self.discont_pending = true; self.discont_pending = true;
} }
} else { } else {
gst::debug!( gst::debug!(
CAT, CAT,
imp = imp, imp = imp,
"Picking initial reference times (pcr:{pcr:#?}, monotonic:{monotonic_time}" "Picking initial reference times (pcr:{pcr:#?}, observation_internal:{observation_internal}"
); );
new_pcr = MpegTsPcr::new(pcr); new_pcr = MpegTsPcr::new(pcr);
self.base_pcr = Some(new_pcr); self.base_pcr = Some(new_pcr);
self.base_monotonic = Some(monotonic_time); self.base_external = Some(observation_internal);
self.discont_pending = true; self.discont_pending = true;
} }
self.last_seen_pcr = Some(new_pcr); self.last_seen_pcr = Some(new_pcr);