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Revert 4837 "Add an extended filter mode to AEC."

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> Add an extended filter mode to AEC.
> 
> This mode extends the filter length from the current 48 ms to 128 ms.
> It is runtime selectable which allows it to be enabled through
> experiment. We reuse the DelayCorrection infrastructure to avoid having
> to replumb everything up to libjingle.
> 
> Increases AEC complexity by ~50% on modern x86 CPUs.
> Measurements (in percent of usage on one core):
> 
> Machine/CPU                                     Normal Extended
> MacBook Retina (Early 2013),
> Core i7 Ivy Bridge (2.7 GHz, hyperthreaded)     0.6%   0.9%
> 
> MacBook Air (Late 2010), Core 2 Duo (2.13 GHz)  1.4%   2.7%
> 
> Chromebook Pixel, Core i5 Ivy Bridge (1.8 GHz)  0.6%   1.0%
> 
> Samsung ARM Chromebook,
> Samsung Exynos 5 Dual (1.7 GHz)                 3.2%   5.6%
> 
> The relative value is large of course but the absolute should be
> acceptable in order to have a working AEC on some platforms.
> 
> Detailed changes to the algorithm:
> - The filter length is changed from 48 to 128 ms. This comes with tuning
> of several parameters: i) filter adaptation stepsize and error
> threshold; ii) non-linear processing smoothing and overdrive.
> - Option to ignore the reported delays on platforms which we deem
> sufficiently unreliable. Currently this will be enabled in Chromium for
> Mac.
> - Faster startup times by removing the excessive "startup phase"
> processing of reported delays.
> - Much more conservative adjustments to the far-end read pointer. We
> smooth the delay difference more heavily, and back off from the
> difference more. Adjustments force a readaptation of the filter, so they
> should be avoided except when really necessary.
> 
> Corresponds to these changes:
> https://chromereviews.googleplex.com/9412014
> https://chromereviews.googleplex.com/9514013
> https://chromereviews.googleplex.com/9960013
> 
> BUG=454,827,1261
> R=bjornv@webrtc.org
> 
> Review URL: https://webrtc-codereview.appspot.com/2151007

TBR=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2296005

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4839 4adac7df-926f-26a2-2b94-8c16560cd09d
This commit is contained in:
asapersson@webrtc.org
2013-09-25 12:27:27 +00:00
parent 2f240b43f5
commit ce014d97cd
11 changed files with 270 additions and 595 deletions
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26
webrtc/modules/audio_processing/echo_cancellation_impl.h
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@ -15,30 +15,6 @@
namespace webrtc {
// Use to enable the delay correction feature. This now engages an extended
// filter mode in the AEC, along with robustness measures around the reported
// system delays. It comes with a significant increase in AEC complexity, but is
// much more robust to unreliable reported delays.
//
// Detailed changes to the algorithm:
// - The filter length is changed from 48 to 128 ms. This comes with tuning of
// several parameters: i) filter adaptation stepsize and error threshold;
// ii) non-linear processing smoothing and overdrive.
// - Option to ignore the reported delays on platforms which we deem
// sufficiently unreliable. See WEBRTC_UNTRUSTED_DELAY in echo_cancellation.c.
// - Faster startup times by removing the excessive "startup phase" processing
// of reported delays.
// - Much more conservative adjustments to the far-end read pointer. We smooth
// the delay difference more heavily, and back off from the difference more.
// Adjustments force a readaptation of the filter, so they should be avoided
// except when really necessary.
struct DelayCorrection {
DelayCorrection() : enabled(false) {}
DelayCorrection(bool enabled) : enabled(enabled) {}
bool enabled;
};
class AudioProcessingImpl;
class AudioBuffer;
@ -58,7 +34,6 @@ class EchoCancellationImpl : public EchoCancellationImplWrapper {
// ProcessingComponent implementation.
virtual int Initialize() OVERRIDE;
virtual void SetExtraOptions(const Config& config) OVERRIDE;
private:
// EchoCancellation implementation.
@ -95,7 +70,6 @@ class EchoCancellationImpl : public EchoCancellationImplWrapper {
bool was_stream_drift_set_;
bool stream_has_echo_;
bool delay_logging_enabled_;
bool delay_correction_enabled_;
};
} // namespace webrtc