sinc_resampler.cc | Explore in Territory

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 */

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "third_party/blink/renderer/platform/audio/sinc_resampler.h"

#include "base/memory/raw_ptr.h"
#include "build/build_config.h"
#include "third_party/blink/renderer/platform/audio/audio_bus.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
#include "third_party/fdlibm/ieee754.h"

#if defined(ARCH_CPU_X86_FAMILY)
#include <emmintrin.h>
#endif

// Input buffer layout, dividing the total buffer into regions (r0 - r5):
//
// |----------------|-----------------------------------------|----------------|
//
//                                     blockSize + kernelSize / 2
//                   <--------------------------------------------------------->
//                                                r0
//
//   kernelSize / 2   kernelSize / 2          kernelSize / 2     kernelSize / 2
// <---------------> <--------------->       <---------------> <--------------->
//         r1                r2                      r3               r4
//
//                                                     blockSize
//                                    <---------------------------------------->
//                                                         r5

// The Algorithm:
//
// 1) Consume input frames into r0 (r1 is zero-initialized).
// 2) Position kernel centered at start of r0 (r2) and generate output frames
//    until kernel is centered at start of r4, or we've finished generating
//    all the output frames.
// 3) Copy r3 to r1 and r4 to r2.
// 4) Consume input frames into r5 (zero-pad if we run out of input).
// 5) Goto (2) until all of input is consumed.
//
// note: we're glossing over how the sub-sample handling works with
// m_virtualSourceIndex, etc.

namespace blink {

SincResampler::SincResampler(double scale_factor,
                             unsigned kernel_size,
                             unsigned number_of_kernel_offsets)
    : … { … }

void SincResampler::InitializeKernel() { … }

void SincResampler::ConsumeSource(float* buffer,
                                  unsigned number_of_source_frames) { … }

namespace {

// BufferSourceProvider is an AudioSourceProvider wrapping an in-memory buffer.

class BufferSourceProvider final : public AudioSourceProvider { … };

}  // namespace

void SincResampler::Process(const float* source,
                            float* destination,
                            int number_of_source_frames) { … }

void SincResampler::Process(AudioSourceProvider* source_provider,
                            float* destination,
                            uint32_t frames_to_process) { … }

}  // namespace blink
chromium/third_party/blink/renderer/platform/audio/sinc_resampler.cc
