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Simplification of histogram normalization in delay estimator.

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- Replaces a for loop with a single element update to save complexity. No regression in performance seen on set of recordings.
- Removes UpdatesMadeUponChange() and put code straight into ProcessBinarySpectrum().

BUG=None
TESTED=module_unittest, trybots, verified manually on set of recordings.
R=aluebs@webrtc.org, andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/5929004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5298 4adac7df-926f-26a2-2b94-8c16560cd09d
This commit is contained in:
bjornv@webrtc.org 2013-12-16 13:37:28 +00:00
parent 5ab756703e
commit 1e7d61270c
1 changed files with 9 additions and 31 deletions
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40
webrtc/modules/audio_processing/utility/delay_estimator.c
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@ -258,36 +258,6 @@ static int RobustValidation(const BinaryDelayEstimator* self,
return is_robust;
}
// UpdatesMadeUponChange() makes two parameter updates only done when we have a
// change/jump in delay. For further description, see commented code.
//
// Inputs:
// - candidate_delay : The delay to validate.
static void UpdatesMadeUponChange(BinaryDelayEstimator* self,
int candidate_delay) {
int i = 0;
self->last_delay_histogram =
(self->histogram[candidate_delay] > kLastHistogramMax ?
kLastHistogramMax : self->histogram[candidate_delay]);
// TODO(bjornv): Investigate if we can simplify to only change
// self->histogram[self->last_delay] instead of looping through all histogram
// bins. Looping through all bins is to ensure
// self->histogram[candidate_delay] is currently the most likely bin.
// Otherwise we might jump back too easy to a neighbor even for spurious
// changes.
// Since we may jump to a new delay even if it is not the most likely
// according to the histogram, we here adjust the histogram to make sure the
// |candidate_delay| now is the most likely one.
if (self->histogram[candidate_delay] < self->histogram[self->compare_delay]) {
for (i = 0; i < self->farend->history_size; ++i) {
if (self->histogram[i] > self->histogram[candidate_delay]) {
self->histogram[i] = self->histogram[candidate_delay];
}
}
}
}
void WebRtc_FreeBinaryDelayEstimatorFarend(BinaryDelayEstimatorFarend* self) {
if (self == NULL) {
@ -552,7 +522,15 @@ int WebRtc_ProcessBinarySpectrum(BinaryDelayEstimator* self,
}
if (valid_candidate) {
if (candidate_delay != self->last_delay) {
UpdatesMadeUponChange(self, candidate_delay);
self->last_delay_histogram =
(self->histogram[candidate_delay] > kLastHistogramMax ?
kLastHistogramMax : self->histogram[candidate_delay]);
// Adjust the histogram if we made a change to |last_delay|, though it was
// not the most likely one according to the histogram.
if (self->histogram[candidate_delay] <
self->histogram[self->compare_delay]) {
self->histogram[self->compare_delay] = self->histogram[candidate_delay];
}
}
self->last_delay = candidate_delay;
if (value_best_candidate < self->last_delay_probability) {