Index: media/base/sinc_resampler.cc |
diff --git a/media/base/sinc_resampler.cc b/media/base/sinc_resampler.cc |
index 1df8d4d08f894201a823c15c2066ca3ad43904ec..a2918c3f0d2e590c2eedc48ed29aa92a3e015343 100644 |
--- a/media/base/sinc_resampler.cc |
+++ b/media/base/sinc_resampler.cc |
@@ -138,7 +138,7 @@ void SincResampler::InitializeCPUSpecificFeatures() {} |
#endif |
SincResampler::SincResampler(double io_sample_rate_ratio, |
- size_t request_frames, |
+ int request_frames, |
const ReadCB& read_cb) |
: io_sample_rate_ratio_(io_sample_rate_ratio), |
read_cb_(read_cb), |
@@ -155,8 +155,9 @@ SincResampler::SincResampler(double io_sample_rate_ratio, |
base::AlignedAlloc(sizeof(float) * input_buffer_size_, 16))), |
r1_(input_buffer_.get()), |
r2_(input_buffer_.get() + kKernelSize / 2) { |
+ CHECK_GT(request_frames_, 0); |
Flush(); |
- CHECK_GT(block_size_, static_cast<size_t>(kKernelSize)) |
+ CHECK_GT(block_size_, kKernelSize) |
<< "block_size must be greater than kKernelSize!"; |
memset(kernel_storage_.get(), 0, |
@@ -255,14 +256,25 @@ void SincResampler::Resample(int frames, float* destination) { |
int remaining_frames = frames; |
// Step (1) -- Prime the input buffer at the start of the input stream. |
- if (!buffer_primed_) { |
+ if (!buffer_primed_ && remaining_frames) { |
read_cb_.Run(request_frames_, r0_); |
buffer_primed_ = true; |
} |
- // Step (2) -- Resample! |
+ // 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) { |
- while (virtual_source_idx_ < block_size_) { |
+ // |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 = ceil((block_size_ - virtual_source_idx_) / current_io_ratio); |
+ i > 0; --i) { |
+ 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 = virtual_source_idx_; |
@@ -274,8 +286,8 @@ void SincResampler::Resample(int frames, float* destination) { |
// We'll compute "convolutions" for the two kernels which straddle |
// |virtual_source_idx_|. |
- const float* k1 = kernel_storage_.get() + offset_idx * kKernelSize; |
- const float* k2 = k1 + kKernelSize; |
+ const float* const k1 = kernel_ptr + offset_idx * kKernelSize; |
+ const float* const k2 = k1 + kKernelSize; |
// Ensure |k1|, |k2| are 16-byte aligned for SIMD usage. Should always be |
// true so long as kKernelSize is a multiple of 16. |
@@ -283,7 +295,7 @@ void SincResampler::Resample(int frames, float* destination) { |
DCHECK_EQ(0u, reinterpret_cast<uintptr_t>(k2) & 0x0F); |
// Initialize input pointer based on quantized |virtual_source_idx_|. |
- const float* input_ptr = r1_ + 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 = |
@@ -292,7 +304,7 @@ void SincResampler::Resample(int frames, float* destination) { |
input_ptr, k1, k2, kernel_interpolation_factor); |
// Advance the virtual index. |
- virtual_source_idx_ += io_sample_rate_ratio_; |
+ virtual_source_idx_ += current_io_ratio; |
if (!--remaining_frames) |
return; |