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AEC3: Improved anti-aliasing filter for DSF 4

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This change contains a new anti-aliasing filter for the delay estimator
for down-sampling factor 4. The new (elliptic) filter has a much wider
main lobe allowing for faster convergence.

Bug: webrtc:9288,chromium:846615
Change-Id: Id109974a59fe6f48c5e0ccc4f4e06c0d94c8bd03
Reviewed-on: https://webrtc-review.googlesource.com/81680
Reviewed-by: Per Åhgren <peah@webrtc.org>
Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23534}
This commit is contained in:
Gustaf Ullberg 2018-06-07 11:25:21 +02:00 committed by Commit Bot
parent 7210af206c
commit f469b63d44
2 changed files with 12 additions and 10 deletions
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8
modules/audio_processing/aec3/decimator.cc
View File

@ -20,11 +20,11 @@ const std::vector<CascadedBiQuadFilter::BiQuadParam> kLowPassFilterDS2 = {
{{-1.f, 0.f}, {0.13833231f, 0.40743176f}, 0.22711796393486466f},
{{-1.f, 0.f}, {0.13833231f, 0.40743176f}, 0.22711796393486466f}};
// signal.butter(2, 750/8000.0, 'lowpass', analog=False)
// signal.ellip(6, 1, 40, 1800/8000, btype='lowpass', analog=False)
const std::vector<CascadedBiQuadFilter::BiQuadParam> kLowPassFilterDS4 = {
{{-1.f, 0.f}, {0.79396855f, 0.17030506f}, 0.017863192751682862f},
{{-1.f, 0.f}, {0.79396855f, 0.17030506f}, 0.017863192751682862f},
{{-1.f, 0.f}, {0.79396855f, 0.17030506f}, 0.017863192751682862f}};
{{-0.08873842f, 0.99605496f}, {0.75916227f, 0.23841065f}, 0.26250696827f},
{{0.62273832f, 0.78243018f}, {0.74892112f, 0.5410152f}, 0.26250696827f},
{{0.71107693f, 0.70311421f}, {0.74895534f, 0.63924616f}, 0.26250696827f}};
// signal.cheby1(1, 6, [1000/8000, 2000/8000], btype='bandpass', analog=False)
const std::vector<CascadedBiQuadFilter::BiQuadParam> kBandPassFilterDS8 = {

14
modules/audio_processing/aec3/echo_path_delay_estimator_unittest.cc
View File

@ -93,12 +93,14 @@ TEST(EchoPathDelayEstimator, DelayEstimation) {
}
if (estimated_delay_samples) {
// Due to the internal down-sampling done inside the delay estimator
// the estimated delay cannot be expected to be exact to the true delay.
EXPECT_NEAR(delay_samples,
estimated_delay_samples->delay -
(config.delay.api_call_jitter_blocks + 1) * 64,
config.delay.down_sampling_factor);
// Allow estimated delay to be off by one sample in the down-sampled
// domain.
size_t delay_ds = delay_samples / down_sampling_factor;
size_t estimated_delay_ds =
(estimated_delay_samples->delay -
(config.delay.api_call_jitter_blocks + 1) * 64) /
down_sampling_factor;
EXPECT_NEAR(delay_ds, estimated_delay_ds, 1);
} else {
ADD_FAILURE();
}