Varispeed support for SincResampler.

media/base/sinc_resampler.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_SINC_RESAMPLER_H_
 #define MEDIA_BASE_SINC_RESAMPLER_H_
 
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/aligned_memory.h"
@@ skipping 35 matching lines @@
   // of data to be rendered into |destination|; zero padded if not enough frames
   // are available to satisfy the request.
   typedef base::Callback<void(float* destination, int frames)> ReadCB;
 
   // Constructs a SincResampler with the specified |read_cb|, which is used to
   // acquire audio data for resampling.  |io_sample_rate_ratio| is the ratio of
   // input / output sample rates.
   SincResampler(double io_sample_rate_ratio, const ReadCB& read_cb);
   virtual ~SincResampler();
 
   // Resample |frames| of data from |read_cb_| into |destination|.

[henrika (OOO until Aug 14), 2013/04/11 18:27:20]

nit, remove trailing _

[DaleCurtis, 2013/04/15 20:27:31]

read_cb_ is correct here since it's referring to the class variable.

   void Resample(float* destination, int frames);
 
   // The maximum size in frames that guarantees Resample() will only make a
   // single call to |read_cb_| for more data.

[henrika (OOO until Aug 14), 2013/04/11 18:27:20]

same here

[DaleCurtis, 2013/04/15 20:27:31]

Ditto.

   int ChunkSize() const;
 
   // Flush all buffered data and reset internal indices.
   void Flush();
 
+  void UpdateSampleRateRatio(double io_sample_rate_ratio_);

[Chris Rogers, 2013/04/08 19:38:11]

nit: method param should not have "_" at end

Also, not a big deal but a name such as SetRatio() seems simpler

[henrika (OOO until Aug 14), 2013/04/11 18:27:20]

Would it make any sense to add sanity checks here and return bool. Or is any
value fine here?

[DaleCurtis, 2013/04/15 20:27:31]

Removed _. Changed to SetRatio().

[DaleCurtis, 2013/04/15 20:27:31]

Any value is okay.

+
  private:
   FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve);
   FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark);
 
-  void InitializeKernel();
+  void InitializeKernel(bool first_run);

[Chris Rogers, 2013/04/08 19:38:11]

Can't we avoid having to pass this in as a param and simply keep track of this
in a member variable?

[DaleCurtis, 2013/04/15 20:27:31]

Done.

 
   // Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are
   // linearly interpolated using |kernel_interpolation_factor|.  On x86, the
   // underlying implementation is chosen at run time based on SSE support.  On
   // ARM, NEON support is chosen at compile time based on compilation flags.
   static float Convolve_C(const float* input_ptr, const float* k1,
                           const float* k2, double kernel_interpolation_factor);
 #if defined(ARCH_CPU_X86_FAMILY)
   static float Convolve_SSE(const float* input_ptr, const float* k1,
                             const float* k2,
                             double kernel_interpolation_factor);
 #elif defined(ARCH_CPU_ARM_FAMILY) && defined(USE_NEON)
   static float Convolve_NEON(const float* input_ptr, const float* k1,
                              const float* k2,
                              double kernel_interpolation_factor);
 #endif
 
   // The ratio of input / output sample rates.
-  const double io_sample_rate_ratio_;
+  double io_sample_rate_ratio_;
 
   // An index on the source input buffer with sub-sample precision.  It must be
   // double precision to avoid drift.
   double virtual_source_idx_;
 
   // The buffer is primed once at the very beginning of processing.
   bool buffer_primed_;
 
   // Source of data for resampling.
   ReadCB read_cb_;
 
   // Contains kKernelOffsetCount kernels back-to-back, each of size kKernelSize.
   // The kernel offsets are sub-sample shifts of a windowed sinc shifted from
   // 0.0 to 1.0 sample.
-  scoped_ptr_malloc<float, base::ScopedPtrAlignedFree> kernel_storage_;
+  scoped_ptr<float[], base::ScopedPtrAlignedFree> kernel_storage_;
+  scoped_ptr<float[], base::ScopedPtrAlignedFree> kernel_pre_sinc_storage_;
+  scoped_ptr<float[], base::ScopedPtrAlignedFree> kernel_window_storage_;
 
   // Data from the source is copied into this buffer for each processing pass.
-  scoped_ptr_malloc<float, base::ScopedPtrAlignedFree> input_buffer_;
+  scoped_ptr<float[], base::ScopedPtrAlignedFree> input_buffer_;
 
   // Stores the runtime selection of which Convolve function to use.
 #if defined(ARCH_CPU_X86_FAMILY) && !defined(__SSE__)
   typedef float (*ConvolveProc)(const float*, const float*, const float*,
                                 double);
   const ConvolveProc convolve_proc_;
 #endif
 
   // Pointers to the various regions inside |input_buffer_|.  See the diagram at
   // the top of the .cc file for more information.
   float* const r0_;
   float* const r1_;
   float* const r2_;
   float* const r3_;
   float* const r4_;
   float* const r5_;
 
   DISALLOW_COPY_AND_ASSIGN(SincResampler);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_SINC_RESAMPLER_H_