Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 391 insertions, 0 deletions

diff --git a/third_party/libwebrtc/modules/audio_coding/neteq/merge.cc b/third_party/libwebrtc/modules/audio_coding/neteq/merge.cc
new file mode 100644
index 0000000000..0aec6d2597
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_coding/neteq/merge.cc
@@ -0,0 +1,391 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/audio_coding/neteq/merge.h"
+
+#include <string.h>  // memmove, memcpy, memset, size_t
+
+#include <algorithm>  // min, max
+#include <memory>
+
+#include "common_audio/signal_processing/include/signal_processing_library.h"
+#include "modules/audio_coding/neteq/audio_multi_vector.h"
+#include "modules/audio_coding/neteq/cross_correlation.h"
+#include "modules/audio_coding/neteq/dsp_helper.h"
+#include "modules/audio_coding/neteq/expand.h"
+#include "modules/audio_coding/neteq/sync_buffer.h"
+#include "rtc_base/numerics/safe_conversions.h"
+#include "rtc_base/numerics/safe_minmax.h"
+
+namespace webrtc {
+
+Merge::Merge(int fs_hz,
+             size_t num_channels,
+             Expand* expand,
+             SyncBuffer* sync_buffer)
+    : fs_hz_(fs_hz),
+      num_channels_(num_channels),
+      fs_mult_(fs_hz_ / 8000),
+      timestamps_per_call_(static_cast<size_t>(fs_hz_ / 100)),
+      expand_(expand),
+      sync_buffer_(sync_buffer),
+      expanded_(num_channels_) {
+  RTC_DCHECK_GT(num_channels_, 0);
+}
+
+Merge::~Merge() = default;
+
+size_t Merge::Process(int16_t* input,
+                      size_t input_length,
+                      AudioMultiVector* output) {
+  // TODO(hlundin): Change to an enumerator and skip assert.
+  RTC_DCHECK(fs_hz_ == 8000 || fs_hz_ == 16000 || fs_hz_ == 32000 ||
+             fs_hz_ == 48000);
+  RTC_DCHECK_LE(fs_hz_, kMaxSampleRate);  // Should not be possible.
+  if (input_length == 0) {
+    return 0;
+  }
+
+  size_t old_length;
+  size_t expand_period;
+  // Get expansion data to overlap and mix with.
+  size_t expanded_length = GetExpandedSignal(&old_length, &expand_period);
+
+  // Transfer input signal to an AudioMultiVector.
+  AudioMultiVector input_vector(num_channels_);
+  input_vector.PushBackInterleaved(
+      rtc::ArrayView<const int16_t>(input, input_length));
+  size_t input_length_per_channel = input_vector.Size();
+  RTC_DCHECK_EQ(input_length_per_channel, input_length / num_channels_);
+
+  size_t best_correlation_index = 0;
+  size_t output_length = 0;
+
+  std::unique_ptr<int16_t[]> input_channel(
+      new int16_t[input_length_per_channel]);
+  std::unique_ptr<int16_t[]> expanded_channel(new int16_t[expanded_length]);
+  for (size_t channel = 0; channel < num_channels_; ++channel) {
+    input_vector[channel].CopyTo(input_length_per_channel, 0,
+                                 input_channel.get());
+    expanded_[channel].CopyTo(expanded_length, 0, expanded_channel.get());
+
+    const int16_t new_mute_factor = std::min<int16_t>(
+        16384, SignalScaling(input_channel.get(), input_length_per_channel,
+                             expanded_channel.get()));
+
+    if (channel == 0) {
+      // Downsample, correlate, and find strongest correlation period for the
+      // reference (i.e., first) channel only.
+      // Downsample to 4kHz sample rate.
+      Downsample(input_channel.get(), input_length_per_channel,
+                 expanded_channel.get(), expanded_length);
+
+      // Calculate the lag of the strongest correlation period.
+      best_correlation_index = CorrelateAndPeakSearch(
+          old_length, input_length_per_channel, expand_period);
+    }
+
+    temp_data_.resize(input_length_per_channel + best_correlation_index);
+    int16_t* decoded_output = temp_data_.data() + best_correlation_index;
+
+    // Mute the new decoded data if needed (and unmute it linearly).
+    // This is the overlapping part of expanded_signal.
+    size_t interpolation_length =
+        std::min(kMaxCorrelationLength * fs_mult_,
+                 expanded_length - best_correlation_index);
+    interpolation_length =
+        std::min(interpolation_length, input_length_per_channel);
+
+    RTC_DCHECK_LE(new_mute_factor, 16384);
+    int16_t mute_factor =
+        std::max(expand_->MuteFactor(channel), new_mute_factor);
+    RTC_DCHECK_GE(mute_factor, 0);
+
+    if (mute_factor < 16384) {
+      // Set a suitable muting slope (Q20). 0.004 for NB, 0.002 for WB,
+      // and so on, or as fast as it takes to come back to full gain within the
+      // frame length.
+      const int back_to_fullscale_inc = static_cast<int>(
+          ((16384 - mute_factor) << 6) / input_length_per_channel);
+      const int increment = std::max(4194 / fs_mult_, back_to_fullscale_inc);
+      mute_factor = static_cast<int16_t>(DspHelper::RampSignal(
+          input_channel.get(), interpolation_length, mute_factor, increment));
+      DspHelper::UnmuteSignal(&input_channel[interpolation_length],
+                              input_length_per_channel - interpolation_length,
+                              &mute_factor, increment,
+                              &decoded_output[interpolation_length]);
+    } else {
+      // No muting needed.
+      memmove(
+          &decoded_output[interpolation_length],
+          &input_channel[interpolation_length],
+          sizeof(int16_t) * (input_length_per_channel - interpolation_length));
+    }
+
+    // Do overlap and mix linearly.
+    int16_t increment =
+        static_cast<int16_t>(16384 / (interpolation_length + 1));  // In Q14.
+    int16_t local_mute_factor = 16384 - increment;
+    memmove(temp_data_.data(), expanded_channel.get(),
+            sizeof(int16_t) * best_correlation_index);
+    DspHelper::CrossFade(&expanded_channel[best_correlation_index],
+                         input_channel.get(), interpolation_length,
+                         &local_mute_factor, increment, decoded_output);
+
+    output_length = best_correlation_index + input_length_per_channel;
+    if (channel == 0) {
+      RTC_DCHECK(output->Empty());  // Output should be empty at this point.
+      output->AssertSize(output_length);
+    } else {
+      RTC_DCHECK_EQ(output->Size(), output_length);
+    }
+    (*output)[channel].OverwriteAt(temp_data_.data(), output_length, 0);
+  }
+
+  // Copy back the first part of the data to `sync_buffer_` and remove it from
+  // `output`.
+  sync_buffer_->ReplaceAtIndex(*output, old_length, sync_buffer_->next_index());
+  output->PopFront(old_length);
+
+  // Return new added length. `old_length` samples were borrowed from
+  // `sync_buffer_`.
+  RTC_DCHECK_GE(output_length, old_length);
+  return output_length - old_length;
+}
+
+size_t Merge::GetExpandedSignal(size_t* old_length, size_t* expand_period) {
+  // Check how much data that is left since earlier.
+  *old_length = sync_buffer_->FutureLength();
+  // Should never be less than overlap_length.
+  RTC_DCHECK_GE(*old_length, expand_->overlap_length());
+  // Generate data to merge the overlap with using expand.
+  expand_->SetParametersForMergeAfterExpand();
+
+  if (*old_length >= 210 * kMaxSampleRate / 8000) {
+    // TODO(hlundin): Write test case for this.
+    // The number of samples available in the sync buffer is more than what fits
+    // in expanded_signal. Keep the first 210 * kMaxSampleRate / 8000 samples,
+    // but shift them towards the end of the buffer. This is ok, since all of
+    // the buffer will be expand data anyway, so as long as the beginning is
+    // left untouched, we're fine.
+    size_t length_diff = *old_length - 210 * kMaxSampleRate / 8000;
+    sync_buffer_->InsertZerosAtIndex(length_diff, sync_buffer_->next_index());
+    *old_length = 210 * kMaxSampleRate / 8000;
+    // This is the truncated length.
+  }
+  // This assert should always be true thanks to the if statement above.
+  RTC_DCHECK_GE(210 * kMaxSampleRate / 8000, *old_length);
+
+  AudioMultiVector expanded_temp(num_channels_);
+  expand_->Process(&expanded_temp);
+  *expand_period = expanded_temp.Size();  // Samples per channel.
+
+  expanded_.Clear();
+  // Copy what is left since earlier into the expanded vector.
+  expanded_.PushBackFromIndex(*sync_buffer_, sync_buffer_->next_index());
+  RTC_DCHECK_EQ(expanded_.Size(), *old_length);
+  RTC_DCHECK_GT(expanded_temp.Size(), 0);
+  // Do "ugly" copy and paste from the expanded in order to generate more data
+  // to correlate (but not interpolate) with.
+  const size_t required_length = static_cast<size_t>((120 + 80 + 2) * fs_mult_);
+  if (expanded_.Size() < required_length) {
+    while (expanded_.Size() < required_length) {
+      // Append one more pitch period each time.
+      expanded_.PushBack(expanded_temp);
+    }
+    // Trim the length to exactly `required_length`.
+    expanded_.PopBack(expanded_.Size() - required_length);
+  }
+  RTC_DCHECK_GE(expanded_.Size(), required_length);
+  return required_length;
+}
+
+int16_t Merge::SignalScaling(const int16_t* input,
+                             size_t input_length,
+                             const int16_t* expanded_signal) const {
+  // Adjust muting factor if new vector is more or less of the BGN energy.
+  const auto mod_input_length = rtc::SafeMin<size_t>(
+      64 * rtc::dchecked_cast<size_t>(fs_mult_), input_length);
+
+  // Missing input, do no muting
+  if (mod_input_length == 0) {
+    return 16384;
+  }
+
+  const int16_t expanded_max =
+      WebRtcSpl_MaxAbsValueW16(expanded_signal, mod_input_length);
+  int32_t factor =
+      (expanded_max * expanded_max) / (std::numeric_limits<int32_t>::max() /
+                                       static_cast<int32_t>(mod_input_length));
+  const int expanded_shift = factor == 0 ? 0 : 31 - WebRtcSpl_NormW32(factor);
+  int32_t energy_expanded = WebRtcSpl_DotProductWithScale(
+      expanded_signal, expanded_signal, mod_input_length, expanded_shift);
+
+  // Calculate energy of input signal.
+  const int16_t input_max = WebRtcSpl_MaxAbsValueW16(input, mod_input_length);
+  factor = (input_max * input_max) / (std::numeric_limits<int32_t>::max() /
+                                      static_cast<int32_t>(mod_input_length));
+  const int input_shift = factor == 0 ? 0 : 31 - WebRtcSpl_NormW32(factor);
+  int32_t energy_input = WebRtcSpl_DotProductWithScale(
+      input, input, mod_input_length, input_shift);
+
+  // Align to the same Q-domain.
+  if (input_shift > expanded_shift) {
+    energy_expanded = energy_expanded >> (input_shift - expanded_shift);
+  } else {
+    energy_input = energy_input >> (expanded_shift - input_shift);
+  }
+
+  // Calculate muting factor to use for new frame.
+  int16_t mute_factor;
+  if (energy_input > energy_expanded) {
+    // Normalize `energy_input` to 14 bits.
+    int16_t temp_shift = WebRtcSpl_NormW32(energy_input) - 17;
+    energy_input = WEBRTC_SPL_SHIFT_W32(energy_input, temp_shift);
+    // Put `energy_expanded` in a domain 14 higher, so that
+    // energy_expanded / energy_input is in Q14.
+    energy_expanded = WEBRTC_SPL_SHIFT_W32(energy_expanded, temp_shift + 14);
+    // Calculate sqrt(energy_expanded / energy_input) in Q14.
+    mute_factor = static_cast<int16_t>(
+        WebRtcSpl_SqrtFloor((energy_expanded / energy_input) << 14));
+  } else {
+    // Set to 1 (in Q14) when `expanded` has higher energy than `input`.
+    mute_factor = 16384;
+  }
+
+  return mute_factor;
+}
+
+// TODO(hlundin): There are some parameter values in this method that seem
+// strange. Compare with Expand::Correlation.
+void Merge::Downsample(const int16_t* input,
+                       size_t input_length,
+                       const int16_t* expanded_signal,
+                       size_t expanded_length) {
+  const int16_t* filter_coefficients;
+  size_t num_coefficients;
+  int decimation_factor = fs_hz_ / 4000;
+  static const size_t kCompensateDelay = 0;
+  size_t length_limit = static_cast<size_t>(fs_hz_ / 100);  // 10 ms in samples.
+  if (fs_hz_ == 8000) {
+    filter_coefficients = DspHelper::kDownsample8kHzTbl;
+    num_coefficients = 3;
+  } else if (fs_hz_ == 16000) {
+    filter_coefficients = DspHelper::kDownsample16kHzTbl;
+    num_coefficients = 5;
+  } else if (fs_hz_ == 32000) {
+    filter_coefficients = DspHelper::kDownsample32kHzTbl;
+    num_coefficients = 7;
+  } else {  // fs_hz_ == 48000
+    filter_coefficients = DspHelper::kDownsample48kHzTbl;
+    num_coefficients = 7;
+  }
+  size_t signal_offset = num_coefficients - 1;
+  WebRtcSpl_DownsampleFast(
+      &expanded_signal[signal_offset], expanded_length - signal_offset,
+      expanded_downsampled_, kExpandDownsampLength, filter_coefficients,
+      num_coefficients, decimation_factor, kCompensateDelay);
+  if (input_length <= length_limit) {
+    // Not quite long enough, so we have to cheat a bit.
+    // If the input is shorter than the offset, we consider the input to be 0
+    // length. This will cause us to skip the downsampling since it makes no
+    // sense anyway, and input_downsampled_ will be filled with zeros. This is
+    // clearly a pathological case, and the signal quality will suffer, but
+    // there is not much we can do.
+    const size_t temp_len =
+        input_length > signal_offset ? input_length - signal_offset : 0;
+    // TODO(hlundin): Should `downsamp_temp_len` be corrected for round-off
+    // errors? I.e., (temp_len + decimation_factor - 1) / decimation_factor?
+    size_t downsamp_temp_len = temp_len / decimation_factor;
+    if (downsamp_temp_len > 0) {
+      WebRtcSpl_DownsampleFast(&input[signal_offset], temp_len,
+                               input_downsampled_, downsamp_temp_len,
+                               filter_coefficients, num_coefficients,
+                               decimation_factor, kCompensateDelay);
+    }
+    memset(&input_downsampled_[downsamp_temp_len], 0,
+           sizeof(int16_t) * (kInputDownsampLength - downsamp_temp_len));
+  } else {
+    WebRtcSpl_DownsampleFast(
+        &input[signal_offset], input_length - signal_offset, input_downsampled_,
+        kInputDownsampLength, filter_coefficients, num_coefficients,
+        decimation_factor, kCompensateDelay);
+  }
+}
+
+size_t Merge::CorrelateAndPeakSearch(size_t start_position,
+                                     size_t input_length,
+                                     size_t expand_period) const {
+  // Calculate correlation without any normalization.
+  const size_t max_corr_length = kMaxCorrelationLength;
+  size_t stop_position_downsamp =
+      std::min(max_corr_length, expand_->max_lag() / (fs_mult_ * 2) + 1);
+
+  int32_t correlation[kMaxCorrelationLength];
+  CrossCorrelationWithAutoShift(input_downsampled_, expanded_downsampled_,
+                                kInputDownsampLength, stop_position_downsamp, 1,
+                                correlation);
+
+  // Normalize correlation to 14 bits and copy to a 16-bit array.
+  const size_t pad_length = expand_->overlap_length() - 1;
+  const size_t correlation_buffer_size = 2 * pad_length + kMaxCorrelationLength;
+  std::unique_ptr<int16_t[]> correlation16(
+      new int16_t[correlation_buffer_size]);
+  memset(correlation16.get(), 0, correlation_buffer_size * sizeof(int16_t));
+  int16_t* correlation_ptr = &correlation16[pad_length];
+  int32_t max_correlation =
+      WebRtcSpl_MaxAbsValueW32(correlation, stop_position_downsamp);
+  int norm_shift = std::max(0, 17 - WebRtcSpl_NormW32(max_correlation));
+  WebRtcSpl_VectorBitShiftW32ToW16(correlation_ptr, stop_position_downsamp,
+                                   correlation, norm_shift);
+
+  // Calculate allowed starting point for peak finding.
+  // The peak location bestIndex must fulfill two criteria:
+  // (1) w16_bestIndex + input_length <
+  //     timestamps_per_call_ + expand_->overlap_length();
+  // (2) w16_bestIndex + input_length < start_position.
+  size_t start_index = timestamps_per_call_ + expand_->overlap_length();
+  start_index = std::max(start_position, start_index);
+  start_index = (input_length > start_index) ? 0 : (start_index - input_length);
+  // Downscale starting index to 4kHz domain. (fs_mult_ * 2 = fs_hz_ / 4000.)
+  size_t start_index_downsamp = start_index / (fs_mult_ * 2);
+
+  // Calculate a modified `stop_position_downsamp` to account for the increased
+  // start index `start_index_downsamp` and the effective array length.
+  size_t modified_stop_pos =
+      std::min(stop_position_downsamp,
+               kMaxCorrelationLength + pad_length - start_index_downsamp);
+  size_t best_correlation_index;
+  int16_t best_correlation;
+  static const size_t kNumCorrelationCandidates = 1;
+  DspHelper::PeakDetection(&correlation_ptr[start_index_downsamp],
+                           modified_stop_pos, kNumCorrelationCandidates,
+                           fs_mult_, &best_correlation_index,
+                           &best_correlation);
+  // Compensate for modified start index.
+  best_correlation_index += start_index;
+
+  // Ensure that underrun does not occur for 10ms case => we have to get at
+  // least 10ms + overlap . (This should never happen thanks to the above
+  // modification of peak-finding starting point.)
+  while (((best_correlation_index + input_length) <
+          (timestamps_per_call_ + expand_->overlap_length())) ||
+         ((best_correlation_index + input_length) < start_position)) {
+    RTC_DCHECK_NOTREACHED();                  // Should never happen.
+    best_correlation_index += expand_period;  // Jump one lag ahead.
+  }
+  return best_correlation_index;
+}
+
+size_t Merge::RequiredFutureSamples() {
+  return fs_hz_ / 100 * num_channels_;  // 10 ms.
+}
+
+}  // namespace webrtc