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AGC2 limiter: faster recovery

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New limiter tuning to more quickly go back to 0 dB after the limiter
kicks in and the input peak level goes back to normal.

Bug: webrtc:7494
Change-Id: I1050957ca4caf12c4562b899b16c306957dce169
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/237701
Reviewed-by: Hanna Silen <silen@webrtc.org>
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35384}
This commit is contained in:
Alessio Bazzica 2021-11-18 16:57:53 +01:00 committed by WebRTC LUCI CQ
parent 1a75d5e67b
commit a83f874d03
2 changed files with 9 additions and 8 deletions
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2
modules/audio_processing/agc2/agc2_testing_common.h
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@ -25,7 +25,7 @@ constexpr float kMaxS16 =
static_cast<float>(std::numeric_limits<int16_t>::max()); static_cast<float>(std::numeric_limits<int16_t>::max());
// Level Estimator test parameters. // Level Estimator test parameters.
constexpr float kDecayMs = 500.f; constexpr float kDecayMs = 20.0f;
// Limiter parameters. // Limiter parameters.
constexpr float kLimiterMaxInputLevelDbFs = 1.f; constexpr float kLimiterMaxInputLevelDbFs = 1.f;

15
modules/audio_processing/agc2/fixed_digital_level_estimator.cc
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@ -20,15 +20,16 @@
namespace webrtc { namespace webrtc {
namespace { namespace {
constexpr float kInitialFilterStateLevel = 0.f; constexpr float kInitialFilterStateLevel = 0.0f;
// Instant attack. // Instant attack.
constexpr float kAttackFilterConstant = 0.f; constexpr float kAttackFilterConstant = 0.0f;
// This is computed from kDecayMs by
// 10 ** (-1/20 * subframe_duration / kDecayMs). // Limiter decay constant.
// `subframe_duration` is |kFrameDurationMs / kSubFramesInFrame|. // Computed as `10 ** (-1/20 * subframe_duration / kDecayMs)` where:
// kDecayMs is defined in agc2_testing_common.h // - `subframe_duration` is `kFrameDurationMs / kSubFramesInFrame`;
constexpr float kDecayFilterConstant = 0.9998848773724686f; // - `kDecayMs` is defined in agc2_testing_common.h.
constexpr float kDecayFilterConstant = 0.9971259f;
} // namespace } // namespace