| /* |
| * 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 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; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "config.h" |
| |
| #if ENABLE(WEB_AUDIO) |
| |
| #include "SincResampler.h" |
| |
| #include "AudioBus.h" |
| #include <wtf/MathExtras.h> |
| |
| #if CPU(X86_SSE2) |
| #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 WebCore { |
| |
| SincResampler::SincResampler(double scaleFactor, unsigned kernelSize, unsigned numberOfKernelOffsets) |
| : m_scaleFactor(scaleFactor) |
| , m_kernelSize(kernelSize) |
| , m_numberOfKernelOffsets(numberOfKernelOffsets) |
| , m_kernelStorage(m_kernelSize * (m_numberOfKernelOffsets + 1)) |
| , m_virtualSourceIndex(0) |
| , m_blockSize(512) |
| , m_inputBuffer(m_blockSize + m_kernelSize) // See input buffer layout above. |
| , m_source(0) |
| , m_sourceFramesAvailable(0) |
| , m_sourceProvider(0) |
| , m_isBufferPrimed(false) |
| { |
| initializeKernel(); |
| } |
| |
| void SincResampler::initializeKernel() |
| { |
| // Blackman window parameters. |
| double alpha = 0.16; |
| double a0 = 0.5 * (1.0 - alpha); |
| double a1 = 0.5; |
| double a2 = 0.5 * alpha; |
| |
| // sincScaleFactor is basically the normalized cutoff frequency of the low-pass filter. |
| double sincScaleFactor = m_scaleFactor > 1.0 ? 1.0 / m_scaleFactor : 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 |
| // lowpass filter cutoff slightly downward to avoid some aliasing at the very high-end. |
| // FIXME: this value is empirical and to be more exact should vary depending on m_kernelSize. |
| sincScaleFactor *= 0.9; |
| |
| int n = m_kernelSize; |
| int halfSize = n / 2; |
| |
| // Generates a set of windowed sinc() kernels. |
| // We generate a range of sub-sample offsets from 0.0 to 1.0. |
| for (unsigned offsetIndex = 0; offsetIndex <= m_numberOfKernelOffsets; ++offsetIndex) { |
| double subsampleOffset = static_cast<double>(offsetIndex) / m_numberOfKernelOffsets; |
| |
| for (int i = 0; i < n; ++i) { |
| // Compute the sinc() with offset. |
| double s = sincScaleFactor * piDouble * (i - halfSize - subsampleOffset); |
| double sinc = !s ? 1.0 : sin(s) / s; |
| sinc *= sincScaleFactor; |
| |
| // Compute Blackman window, matching the offset of the sinc(). |
| double x = (i - subsampleOffset) / n; |
| double window = a0 - a1 * cos(2.0 * piDouble * x) + a2 * cos(4.0 * piDouble * x); |
| |
| // Window the sinc() function and store at the correct offset. |
| m_kernelStorage[i + offsetIndex * m_kernelSize] = sinc * window; |
| } |
| } |
| } |
| |
| void SincResampler::consumeSource(float* buffer, unsigned numberOfSourceFrames) |
| { |
| ASSERT(m_sourceProvider); |
| if (!m_sourceProvider) |
| return; |
| |
| // Wrap the provided buffer by an AudioBus for use by the source provider. |
| if (!m_internalBus || m_internalBus->length() != numberOfSourceFrames) |
| m_internalBus = AudioBus::create(1, numberOfSourceFrames, false); |
| |
| // FIXME: Find a way to make the following const-correct: |
| m_internalBus->setChannelMemory(0, buffer, numberOfSourceFrames); |
| |
| m_sourceProvider->provideInput(m_internalBus.get(), numberOfSourceFrames); |
| } |
| |
| namespace { |
| |
| // BufferSourceProvider is an AudioSourceProvider wrapping an in-memory buffer. |
| |
| class BufferSourceProvider : public AudioSourceProvider { |
| public: |
| explicit BufferSourceProvider(const float* source, size_t numberOfSourceFrames) |
| : m_source(source) |
| , m_sourceFramesAvailable(numberOfSourceFrames) |
| { |
| } |
| |
| // Consumes samples from the in-memory buffer. |
| void provideInput(AudioBus* bus, size_t framesToProcess) override |
| { |
| ASSERT(m_source && bus); |
| if (!m_source || !bus) |
| return; |
| |
| float* buffer = bus->channel(0)->mutableData(); |
| |
| // Clamp to number of frames available and zero-pad. |
| size_t framesToCopy = std::min(m_sourceFramesAvailable, framesToProcess); |
| memcpy(buffer, m_source, sizeof(float) * framesToCopy); |
| |
| // Zero-pad if necessary. |
| if (framesToCopy < framesToProcess) |
| memset(buffer + framesToCopy, 0, sizeof(float) * (framesToProcess - framesToCopy)); |
| |
| m_sourceFramesAvailable -= framesToCopy; |
| m_source += framesToCopy; |
| } |
| |
| private: |
| const float* m_source; |
| size_t m_sourceFramesAvailable; |
| }; |
| |
| } // namespace |
| |
| void SincResampler::process(const float* source, float* destination, unsigned numberOfSourceFrames) |
| { |
| // Resample an in-memory buffer using an AudioSourceProvider. |
| BufferSourceProvider sourceProvider(source, numberOfSourceFrames); |
| |
| unsigned numberOfDestinationFrames = static_cast<unsigned>(numberOfSourceFrames / m_scaleFactor); |
| unsigned remaining = numberOfDestinationFrames; |
| |
| while (remaining) { |
| unsigned framesThisTime = std::min(remaining, m_blockSize); |
| process(&sourceProvider, destination, framesThisTime); |
| |
| destination += framesThisTime; |
| remaining -= framesThisTime; |
| } |
| } |
| |
| void SincResampler::process(AudioSourceProvider* sourceProvider, float* destination, size_t framesToProcess) |
| { |
| bool isGood = sourceProvider && m_blockSize > m_kernelSize && m_inputBuffer.size() >= m_blockSize + m_kernelSize && !(m_kernelSize % 2); |
| ASSERT(isGood); |
| if (!isGood) |
| return; |
| |
| m_sourceProvider = sourceProvider; |
| |
| unsigned numberOfDestinationFrames = framesToProcess; |
| |
| // Setup various region pointers in the buffer (see diagram above). |
| float* r0 = m_inputBuffer.data() + m_kernelSize / 2; |
| float* r1 = m_inputBuffer.data(); |
| float* r2 = r0; |
| float* r3 = r0 + m_blockSize - m_kernelSize / 2; |
| float* r4 = r0 + m_blockSize; |
| float* r5 = r0 + m_kernelSize / 2; |
| |
| // Step (1) |
| // Prime the input buffer at the start of the input stream. |
| if (!m_isBufferPrimed) { |
| consumeSource(r0, m_blockSize + m_kernelSize / 2); |
| m_isBufferPrimed = true; |
| } |
| |
| // Step (2) |
| |
| while (numberOfDestinationFrames) { |
| while (m_virtualSourceIndex < m_blockSize) { |
| // m_virtualSourceIndex lies in between two kernel offsets so figure out what they are. |
| int sourceIndexI = static_cast<int>(m_virtualSourceIndex); |
| double subsampleRemainder = m_virtualSourceIndex - sourceIndexI; |
| |
| double virtualOffsetIndex = subsampleRemainder * m_numberOfKernelOffsets; |
| int offsetIndex = static_cast<int>(virtualOffsetIndex); |
| |
| float* k1 = m_kernelStorage.data() + offsetIndex * m_kernelSize; |
| float* k2 = k1 + m_kernelSize; |
| |
| // Initialize input pointer based on quantized m_virtualSourceIndex. |
| float* inputP = r1 + sourceIndexI; |
| |
| // We'll compute "convolutions" for the two kernels which straddle m_virtualSourceIndex |
| float sum1 = 0; |
| float sum2 = 0; |
| |
| // Figure out how much to weight each kernel's "convolution". |
| double kernelInterpolationFactor = virtualOffsetIndex - offsetIndex; |
| |
| // Generate a single output sample. |
| int n = m_kernelSize; |
| |
| #define CONVOLVE_ONE_SAMPLE \ |
| input = *inputP++; \ |
| sum1 += input * *k1; \ |
| sum2 += input * *k2; \ |
| ++k1; \ |
| ++k2; |
| |
| { |
| float input; |
| |
| #if CPU(X86_SSE2) |
| // If the sourceP address is not 16-byte aligned, the first several frames (at most three) should be processed seperately. |
| while ((reinterpret_cast<uintptr_t>(inputP) & 0x0F) && n) { |
| CONVOLVE_ONE_SAMPLE |
| n--; |
| } |
| |
| // Now the inputP is aligned and start to apply SSE. |
| float* endP = inputP + n - n % 4; |
| __m128 mInput; |
| __m128 mK1; |
| __m128 mK2; |
| __m128 mul1; |
| __m128 mul2; |
| |
| __m128 sums1 = _mm_setzero_ps(); |
| __m128 sums2 = _mm_setzero_ps(); |
| bool k1Aligned = !(reinterpret_cast<uintptr_t>(k1) & 0x0F); |
| bool k2Aligned = !(reinterpret_cast<uintptr_t>(k2) & 0x0F); |
| |
| #define LOAD_DATA(l1, l2) \ |
| mInput = _mm_load_ps(inputP); \ |
| mK1 = _mm_##l1##_ps(k1); \ |
| mK2 = _mm_##l2##_ps(k2); |
| |
| #define CONVOLVE_4_SAMPLES \ |
| mul1 = _mm_mul_ps(mInput, mK1); \ |
| mul2 = _mm_mul_ps(mInput, mK2); \ |
| sums1 = _mm_add_ps(sums1, mul1); \ |
| sums2 = _mm_add_ps(sums2, mul2); \ |
| inputP += 4; \ |
| k1 += 4; \ |
| k2 += 4; |
| |
| if (k1Aligned && k2Aligned) { // both aligned |
| while (inputP < endP) { |
| LOAD_DATA(load, load) |
| CONVOLVE_4_SAMPLES |
| } |
| } else if (!k1Aligned && k2Aligned) { // only k2 aligned |
| while (inputP < endP) { |
| LOAD_DATA(loadu, load) |
| CONVOLVE_4_SAMPLES |
| } |
| } else if (k1Aligned && !k2Aligned) { // only k1 aligned |
| while (inputP < endP) { |
| LOAD_DATA(load, loadu) |
| CONVOLVE_4_SAMPLES |
| } |
| } else { // both non-aligned |
| while (inputP < endP) { |
| LOAD_DATA(loadu, loadu) |
| CONVOLVE_4_SAMPLES |
| } |
| } |
| |
| // Summarize the SSE results to sum1 and sum2. |
| float* groupSumP = reinterpret_cast<float*>(&sums1); |
| sum1 += groupSumP[0] + groupSumP[1] + groupSumP[2] + groupSumP[3]; |
| groupSumP = reinterpret_cast<float*>(&sums2); |
| sum2 += groupSumP[0] + groupSumP[1] + groupSumP[2] + groupSumP[3]; |
| |
| n %= 4; |
| while (n) { |
| CONVOLVE_ONE_SAMPLE |
| n--; |
| } |
| #else |
| // FIXME: add ARM NEON optimizations for the following. The scalar code-path can probably also be optimized better. |
| |
| // Optimize size 32 and size 64 kernels by unrolling the while loop. |
| // A 20 - 30% speed improvement was measured in some cases by using this approach. |
| |
| if (n == 32) { |
| CONVOLVE_ONE_SAMPLE // 1 |
| CONVOLVE_ONE_SAMPLE // 2 |
| CONVOLVE_ONE_SAMPLE // 3 |
| CONVOLVE_ONE_SAMPLE // 4 |
| CONVOLVE_ONE_SAMPLE // 5 |
| CONVOLVE_ONE_SAMPLE // 6 |
| CONVOLVE_ONE_SAMPLE // 7 |
| CONVOLVE_ONE_SAMPLE // 8 |
| CONVOLVE_ONE_SAMPLE // 9 |
| CONVOLVE_ONE_SAMPLE // 10 |
| CONVOLVE_ONE_SAMPLE // 11 |
| CONVOLVE_ONE_SAMPLE // 12 |
| CONVOLVE_ONE_SAMPLE // 13 |
| CONVOLVE_ONE_SAMPLE // 14 |
| CONVOLVE_ONE_SAMPLE // 15 |
| CONVOLVE_ONE_SAMPLE // 16 |
| CONVOLVE_ONE_SAMPLE // 17 |
| CONVOLVE_ONE_SAMPLE // 18 |
| CONVOLVE_ONE_SAMPLE // 19 |
| CONVOLVE_ONE_SAMPLE // 20 |
| CONVOLVE_ONE_SAMPLE // 21 |
| CONVOLVE_ONE_SAMPLE // 22 |
| CONVOLVE_ONE_SAMPLE // 23 |
| CONVOLVE_ONE_SAMPLE // 24 |
| CONVOLVE_ONE_SAMPLE // 25 |
| CONVOLVE_ONE_SAMPLE // 26 |
| CONVOLVE_ONE_SAMPLE // 27 |
| CONVOLVE_ONE_SAMPLE // 28 |
| CONVOLVE_ONE_SAMPLE // 29 |
| CONVOLVE_ONE_SAMPLE // 30 |
| CONVOLVE_ONE_SAMPLE // 31 |
| CONVOLVE_ONE_SAMPLE // 32 |
| } else if (n == 64) { |
| CONVOLVE_ONE_SAMPLE // 1 |
| CONVOLVE_ONE_SAMPLE // 2 |
| CONVOLVE_ONE_SAMPLE // 3 |
| CONVOLVE_ONE_SAMPLE // 4 |
| CONVOLVE_ONE_SAMPLE // 5 |
| CONVOLVE_ONE_SAMPLE // 6 |
| CONVOLVE_ONE_SAMPLE // 7 |
| CONVOLVE_ONE_SAMPLE // 8 |
| CONVOLVE_ONE_SAMPLE // 9 |
| CONVOLVE_ONE_SAMPLE // 10 |
| CONVOLVE_ONE_SAMPLE // 11 |
| CONVOLVE_ONE_SAMPLE // 12 |
| CONVOLVE_ONE_SAMPLE // 13 |
| CONVOLVE_ONE_SAMPLE // 14 |
| CONVOLVE_ONE_SAMPLE // 15 |
| CONVOLVE_ONE_SAMPLE // 16 |
| CONVOLVE_ONE_SAMPLE // 17 |
| CONVOLVE_ONE_SAMPLE // 18 |
| CONVOLVE_ONE_SAMPLE // 19 |
| CONVOLVE_ONE_SAMPLE // 20 |
| CONVOLVE_ONE_SAMPLE // 21 |
| CONVOLVE_ONE_SAMPLE // 22 |
| CONVOLVE_ONE_SAMPLE // 23 |
| CONVOLVE_ONE_SAMPLE // 24 |
| CONVOLVE_ONE_SAMPLE // 25 |
| CONVOLVE_ONE_SAMPLE // 26 |
| CONVOLVE_ONE_SAMPLE // 27 |
| CONVOLVE_ONE_SAMPLE // 28 |
| CONVOLVE_ONE_SAMPLE // 29 |
| CONVOLVE_ONE_SAMPLE // 30 |
| CONVOLVE_ONE_SAMPLE // 31 |
| CONVOLVE_ONE_SAMPLE // 32 |
| CONVOLVE_ONE_SAMPLE // 33 |
| CONVOLVE_ONE_SAMPLE // 34 |
| CONVOLVE_ONE_SAMPLE // 35 |
| CONVOLVE_ONE_SAMPLE // 36 |
| CONVOLVE_ONE_SAMPLE // 37 |
| CONVOLVE_ONE_SAMPLE // 38 |
| CONVOLVE_ONE_SAMPLE // 39 |
| CONVOLVE_ONE_SAMPLE // 40 |
| CONVOLVE_ONE_SAMPLE // 41 |
| CONVOLVE_ONE_SAMPLE // 42 |
| CONVOLVE_ONE_SAMPLE // 43 |
| CONVOLVE_ONE_SAMPLE // 44 |
| CONVOLVE_ONE_SAMPLE // 45 |
| CONVOLVE_ONE_SAMPLE // 46 |
| CONVOLVE_ONE_SAMPLE // 47 |
| CONVOLVE_ONE_SAMPLE // 48 |
| CONVOLVE_ONE_SAMPLE // 49 |
| CONVOLVE_ONE_SAMPLE // 50 |
| CONVOLVE_ONE_SAMPLE // 51 |
| CONVOLVE_ONE_SAMPLE // 52 |
| CONVOLVE_ONE_SAMPLE // 53 |
| CONVOLVE_ONE_SAMPLE // 54 |
| CONVOLVE_ONE_SAMPLE // 55 |
| CONVOLVE_ONE_SAMPLE // 56 |
| CONVOLVE_ONE_SAMPLE // 57 |
| CONVOLVE_ONE_SAMPLE // 58 |
| CONVOLVE_ONE_SAMPLE // 59 |
| CONVOLVE_ONE_SAMPLE // 60 |
| CONVOLVE_ONE_SAMPLE // 61 |
| CONVOLVE_ONE_SAMPLE // 62 |
| CONVOLVE_ONE_SAMPLE // 63 |
| CONVOLVE_ONE_SAMPLE // 64 |
| } else { |
| while (n--) { |
| // Non-optimized using actual while loop. |
| CONVOLVE_ONE_SAMPLE |
| } |
| } |
| #endif |
| } |
| |
| // Linearly interpolate the two "convolutions". |
| double result = (1.0 - kernelInterpolationFactor) * sum1 + kernelInterpolationFactor * sum2; |
| |
| *destination++ = result; |
| |
| // Advance the virtual index. |
| m_virtualSourceIndex += m_scaleFactor; |
| |
| --numberOfDestinationFrames; |
| if (!numberOfDestinationFrames) |
| return; |
| } |
| |
| // Wrap back around to the start. |
| m_virtualSourceIndex -= m_blockSize; |
| |
| // Step (3) Copy r3 to r1 and r4 to r2. |
| // This wraps the last input frames back to the start of the buffer. |
| memcpy(r1, r3, sizeof(float) * (m_kernelSize / 2)); |
| memcpy(r2, r4, sizeof(float) * (m_kernelSize / 2)); |
| |
| // Step (4) |
| // Refresh the buffer with more input. |
| consumeSource(r5, m_blockSize); |
| } |
| } |
| |
| } // namespace WebCore |
| |
| #endif // ENABLE(WEB_AUDIO) |
