Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

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

1 files changed, 366 insertions, 0 deletions

diff --git a/third_party/libwebrtc/common_audio/resampler/sinc_resampler.cc b/third_party/libwebrtc/common_audio/resampler/sinc_resampler.cc
new file mode 100644
index 0000000000..fac11aa362
--- /dev/null
+++ b/third_party/libwebrtc/common_audio/resampler/sinc_resampler.cc
@@ -0,0 +1,366 @@
+/*
+ *  Copyright (c) 2013 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.
+ */
+
+// Modified from the Chromium original:
+// src/media/base/sinc_resampler.cc
+
+// Initial input buffer layout, dividing into regions r0_ to r4_ (note: r0_, r3_
+// and r4_ will move after the first load):
+//
+// |----------------|-----------------------------------------|----------------|
+//
+//                                        request_frames_
+//                   <--------------------------------------------------------->
+//                                    r0_ (during first load)
+//
+//  kKernelSize / 2   kKernelSize / 2         kKernelSize / 2   kKernelSize / 2
+// <---------------> <--------------->       <---------------> <--------------->
+//        r1_               r2_                     r3_               r4_
+//
+//                             block_size_ == r4_ - r2_
+//                   <--------------------------------------->
+//
+//                                                  request_frames_
+//                                    <------------------ ... ----------------->
+//                                               r0_ (during second load)
+//
+// On the second request r0_ slides to the right by kKernelSize / 2 and r3_, r4_
+// and block_size_ are reinitialized via step (3) in the algorithm below.
+//
+// These new regions remain constant until a Flush() occurs.  While complicated,
+// this allows us to reduce jitter by always requesting the same amount from the
+// provided callback.
+//
+// The algorithm:
+//
+// 1) Allocate input_buffer of size: request_frames_ + kKernelSize; this ensures
+//    there's enough room to read request_frames_ from the callback into region
+//    r0_ (which will move between the first and subsequent passes).
+//
+// 2) Let r1_, r2_ each represent half the kernel centered around r0_:
+//
+//        r0_ = input_buffer_ + kKernelSize / 2
+//        r1_ = input_buffer_
+//        r2_ = r0_
+//
+//    r0_ is always request_frames_ in size.  r1_, r2_ are kKernelSize / 2 in
+//    size.  r1_ must be zero initialized to avoid convolution with garbage (see
+//    step (5) for why).
+//
+// 3) Let r3_, r4_ each represent half the kernel right aligned with the end of
+//    r0_ and choose block_size_ as the distance in frames between r4_ and r2_:
+//
+//        r3_ = r0_ + request_frames_ - kKernelSize
+//        r4_ = r0_ + request_frames_ - kKernelSize / 2
+//        block_size_ = r4_ - r2_ = request_frames_ - kKernelSize / 2
+//
+// 4) Consume request_frames_ frames into r0_.
+//
+// 5) Position kernel centered at start of r2_ and generate output frames until
+//    the kernel is centered at the start of r4_ or we've finished generating
+//    all the output frames.
+//
+// 6) Wrap left over data from the r3_ to r1_ and r4_ to r2_.
+//
+// 7) If we're on the second load, in order to avoid overwriting the frames we
+//    just wrapped from r4_ we need to slide r0_ to the right by the size of
+//    r4_, which is kKernelSize / 2:
+//
+//        r0_ = r0_ + kKernelSize / 2 = input_buffer_ + kKernelSize
+//
+//    r3_, r4_, and block_size_ then need to be reinitialized, so goto (3).
+//
+// 8) Else, if we're not on the second load, goto (4).
+//
+// Note: we're glossing over how the sub-sample handling works with
+// `virtual_source_idx_`, etc.
+
+// MSVC++ requires this to be set before any other includes to get M_PI.
+#define _USE_MATH_DEFINES
+
+#include "common_audio/resampler/sinc_resampler.h"
+
+#include <math.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <limits>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/system/arch.h"
+#include "system_wrappers/include/cpu_features_wrapper.h"  // kSSE2, WebRtc_G...
+
+namespace webrtc {
+
+namespace {
+
+double SincScaleFactor(double io_ratio) {
+  // `sinc_scale_factor` is basically the normalized cutoff frequency of the
+  // low-pass filter.
+  double sinc_scale_factor = io_ratio > 1.0 ? 1.0 / io_ratio : 1.0;
+
+  // The sinc function is an idealized brick-wall filter, but since we're
+  // windowing it the transition from pass to stop does not happen right away.
+  // So we should adjust the low pass filter cutoff slightly downward to avoid
+  // some aliasing at the very high-end.
+  // TODO(crogers): this value is empirical and to be more exact should vary
+  // depending on kKernelSize.
+  sinc_scale_factor *= 0.9;
+
+  return sinc_scale_factor;
+}
+
+}  // namespace
+
+const size_t SincResampler::kKernelSize;
+
+// If we know the minimum architecture at compile time, avoid CPU detection.
+void SincResampler::InitializeCPUSpecificFeatures() {
+#if defined(WEBRTC_HAS_NEON)
+  convolve_proc_ = Convolve_NEON;
+#elif defined(WEBRTC_ARCH_X86_FAMILY)
+  // Using AVX2 instead of SSE2 when AVX2 supported.
+  if (GetCPUInfo(kAVX2))
+    convolve_proc_ = Convolve_AVX2;
+  else if (GetCPUInfo(kSSE2))
+    convolve_proc_ = Convolve_SSE;
+  else
+    convolve_proc_ = Convolve_C;
+#else
+  // Unknown architecture.
+  convolve_proc_ = Convolve_C;
+#endif
+}
+
+SincResampler::SincResampler(double io_sample_rate_ratio,
+                             size_t request_frames,
+                             SincResamplerCallback* read_cb)
+    : io_sample_rate_ratio_(io_sample_rate_ratio),
+      read_cb_(read_cb),
+      request_frames_(request_frames),
+      input_buffer_size_(request_frames_ + kKernelSize),
+      // Create input buffers with a 32-byte alignment for SIMD optimizations.
+      kernel_storage_(static_cast<float*>(
+          AlignedMalloc(sizeof(float) * kKernelStorageSize, 32))),
+      kernel_pre_sinc_storage_(static_cast<float*>(
+          AlignedMalloc(sizeof(float) * kKernelStorageSize, 32))),
+      kernel_window_storage_(static_cast<float*>(
+          AlignedMalloc(sizeof(float) * kKernelStorageSize, 32))),
+      input_buffer_(static_cast<float*>(
+          AlignedMalloc(sizeof(float) * input_buffer_size_, 32))),
+      convolve_proc_(nullptr),
+      r1_(input_buffer_.get()),
+      r2_(input_buffer_.get() + kKernelSize / 2) {
+  InitializeCPUSpecificFeatures();
+  RTC_DCHECK(convolve_proc_);
+  RTC_DCHECK_GT(request_frames_, 0);
+  Flush();
+  RTC_DCHECK_GT(block_size_, kKernelSize);
+
+  memset(kernel_storage_.get(), 0,
+         sizeof(*kernel_storage_.get()) * kKernelStorageSize);
+  memset(kernel_pre_sinc_storage_.get(), 0,
+         sizeof(*kernel_pre_sinc_storage_.get()) * kKernelStorageSize);
+  memset(kernel_window_storage_.get(), 0,
+         sizeof(*kernel_window_storage_.get()) * kKernelStorageSize);
+
+  InitializeKernel();
+}
+
+SincResampler::~SincResampler() {}
+
+void SincResampler::UpdateRegions(bool second_load) {
+  // Setup various region pointers in the buffer (see diagram above).  If we're
+  // on the second load we need to slide r0_ to the right by kKernelSize / 2.
+  r0_ = input_buffer_.get() + (second_load ? kKernelSize : kKernelSize / 2);
+  r3_ = r0_ + request_frames_ - kKernelSize;
+  r4_ = r0_ + request_frames_ - kKernelSize / 2;
+  block_size_ = r4_ - r2_;
+
+  // r1_ at the beginning of the buffer.
+  RTC_DCHECK_EQ(r1_, input_buffer_.get());
+  // r1_ left of r2_, r4_ left of r3_ and size correct.
+  RTC_DCHECK_EQ(r2_ - r1_, r4_ - r3_);
+  // r2_ left of r3.
+  RTC_DCHECK_LT(r2_, r3_);
+}
+
+void SincResampler::InitializeKernel() {
+  // Blackman window parameters.
+  static const double kAlpha = 0.16;
+  static const double kA0 = 0.5 * (1.0 - kAlpha);
+  static const double kA1 = 0.5;
+  static const double kA2 = 0.5 * kAlpha;
+
+  // Generates a set of windowed sinc() kernels.
+  // We generate a range of sub-sample offsets from 0.0 to 1.0.
+  const double sinc_scale_factor = SincScaleFactor(io_sample_rate_ratio_);
+  for (size_t offset_idx = 0; offset_idx <= kKernelOffsetCount; ++offset_idx) {
+    const float subsample_offset =
+        static_cast<float>(offset_idx) / kKernelOffsetCount;
+
+    for (size_t i = 0; i < kKernelSize; ++i) {
+      const size_t idx = i + offset_idx * kKernelSize;
+      const float pre_sinc = static_cast<float>(
+          M_PI * (static_cast<int>(i) - static_cast<int>(kKernelSize / 2) -
+                  subsample_offset));
+      kernel_pre_sinc_storage_[idx] = pre_sinc;
+
+      // Compute Blackman window, matching the offset of the sinc().
+      const float x = (i - subsample_offset) / kKernelSize;
+      const float window = static_cast<float>(kA0 - kA1 * cos(2.0 * M_PI * x) +
+                                              kA2 * cos(4.0 * M_PI * x));
+      kernel_window_storage_[idx] = window;
+
+      // Compute the sinc with offset, then window the sinc() function and store
+      // at the correct offset.
+      kernel_storage_[idx] = static_cast<float>(
+          window * ((pre_sinc == 0)
+                        ? sinc_scale_factor
+                        : (sin(sinc_scale_factor * pre_sinc) / pre_sinc)));
+    }
+  }
+}
+
+void SincResampler::SetRatio(double io_sample_rate_ratio) {
+  if (fabs(io_sample_rate_ratio_ - io_sample_rate_ratio) <
+      std::numeric_limits<double>::epsilon()) {
+    return;
+  }
+
+  io_sample_rate_ratio_ = io_sample_rate_ratio;
+
+  // Optimize reinitialization by reusing values which are independent of
+  // `sinc_scale_factor`.  Provides a 3x speedup.
+  const double sinc_scale_factor = SincScaleFactor(io_sample_rate_ratio_);
+  for (size_t offset_idx = 0; offset_idx <= kKernelOffsetCount; ++offset_idx) {
+    for (size_t i = 0; i < kKernelSize; ++i) {
+      const size_t idx = i + offset_idx * kKernelSize;
+      const float window = kernel_window_storage_[idx];
+      const float pre_sinc = kernel_pre_sinc_storage_[idx];
+
+      kernel_storage_[idx] = static_cast<float>(
+          window * ((pre_sinc == 0)
+                        ? sinc_scale_factor
+                        : (sin(sinc_scale_factor * pre_sinc) / pre_sinc)));
+    }
+  }
+}
+
+void SincResampler::Resample(size_t frames, float* destination) {
+  size_t remaining_frames = frames;
+
+  // Step (1) -- Prime the input buffer at the start of the input stream.
+  if (!buffer_primed_ && remaining_frames) {
+    read_cb_->Run(request_frames_, r0_);
+    buffer_primed_ = true;
+  }
+
+  // Step (2) -- Resample!  const what we can outside of the loop for speed.  It
+  // actually has an impact on ARM performance.  See inner loop comment below.
+  const double current_io_ratio = io_sample_rate_ratio_;
+  const float* const kernel_ptr = kernel_storage_.get();
+  while (remaining_frames) {
+    // `i` may be negative if the last Resample() call ended on an iteration
+    // that put `virtual_source_idx_` over the limit.
+    //
+    // Note: The loop construct here can severely impact performance on ARM
+    // or when built with clang.  See https://codereview.chromium.org/18566009/
+    for (int i = static_cast<int>(
+             ceil((block_size_ - virtual_source_idx_) / current_io_ratio));
+         i > 0; --i) {
+      RTC_DCHECK_LT(virtual_source_idx_, block_size_);
+
+      // `virtual_source_idx_` lies in between two kernel offsets so figure out
+      // what they are.
+      const int source_idx = static_cast<int>(virtual_source_idx_);
+      const double subsample_remainder = virtual_source_idx_ - source_idx;
+
+      const double virtual_offset_idx =
+          subsample_remainder * kKernelOffsetCount;
+      const int offset_idx = static_cast<int>(virtual_offset_idx);
+
+      // We'll compute "convolutions" for the two kernels which straddle
+      // `virtual_source_idx_`.
+      const float* const k1 = kernel_ptr + offset_idx * kKernelSize;
+      const float* const k2 = k1 + kKernelSize;
+
+      // Ensure `k1`, `k2` are 32-byte aligned for SIMD usage.  Should always be
+      // true so long as kKernelSize is a multiple of 32.
+      RTC_DCHECK_EQ(0, reinterpret_cast<uintptr_t>(k1) % 32);
+      RTC_DCHECK_EQ(0, reinterpret_cast<uintptr_t>(k2) % 32);
+
+      // Initialize input pointer based on quantized `virtual_source_idx_`.
+      const float* const input_ptr = r1_ + source_idx;
+
+      // Figure out how much to weight each kernel's "convolution".
+      const double kernel_interpolation_factor =
+          virtual_offset_idx - offset_idx;
+      *destination++ =
+          convolve_proc_(input_ptr, k1, k2, kernel_interpolation_factor);
+
+      // Advance the virtual index.
+      virtual_source_idx_ += current_io_ratio;
+
+      if (!--remaining_frames)
+        return;
+    }
+
+    // Wrap back around to the start.
+    virtual_source_idx_ -= block_size_;
+
+    // Step (3) -- Copy r3_, r4_ to r1_, r2_.
+    // This wraps the last input frames back to the start of the buffer.
+    memcpy(r1_, r3_, sizeof(*input_buffer_.get()) * kKernelSize);
+
+    // Step (4) -- Reinitialize regions if necessary.
+    if (r0_ == r2_)
+      UpdateRegions(true);
+
+    // Step (5) -- Refresh the buffer with more input.
+    read_cb_->Run(request_frames_, r0_);
+  }
+}
+
+#undef CONVOLVE_FUNC
+
+size_t SincResampler::ChunkSize() const {
+  return static_cast<size_t>(block_size_ / io_sample_rate_ratio_);
+}
+
+void SincResampler::Flush() {
+  virtual_source_idx_ = 0;
+  buffer_primed_ = false;
+  memset(input_buffer_.get(), 0,
+         sizeof(*input_buffer_.get()) * input_buffer_size_);
+  UpdateRegions(false);
+}
+
+float SincResampler::Convolve_C(const float* input_ptr,
+                                const float* k1,
+                                const float* k2,
+                                double kernel_interpolation_factor) {
+  float sum1 = 0;
+  float sum2 = 0;
+
+  // Generate a single output sample.  Unrolling this loop hurt performance in
+  // local testing.
+  size_t n = kKernelSize;
+  while (n--) {
+    sum1 += *input_ptr * *k1++;
+    sum2 += *input_ptr++ * *k2++;
+  }
+
+  // Linearly interpolate the two "convolutions".
+  return static_cast<float>((1.0 - kernel_interpolation_factor) * sum1 +
+                            kernel_interpolation_factor * sum2);
+}
+
+}  // namespace webrtc