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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #ifndef MEDIA_BASE_SINC_RESAMPLER_H_ | 5 #ifndef MEDIA_BASE_SINC_RESAMPLER_H_ |
6 #define MEDIA_BASE_SINC_RESAMPLER_H_ | 6 #define MEDIA_BASE_SINC_RESAMPLER_H_ |
7 | 7 |
8 #include "base/callback.h" | 8 #include "base/callback.h" |
9 #include "base/gtest_prod_util.h" | 9 #include "base/gtest_prod_util.h" |
10 #include "base/memory/aligned_memory.h" | 10 #include "base/memory/aligned_memory.h" |
11 #include "base/memory/scoped_ptr.h" | 11 #include "base/memory/scoped_ptr.h" |
| 12 #include "build/build_config.h" |
12 #include "media/base/media_export.h" | 13 #include "media/base/media_export.h" |
13 | 14 |
14 namespace media { | 15 namespace media { |
15 | 16 |
16 // SincResampler is a high-quality single-channel sample-rate converter. | 17 // SincResampler is a high-quality single-channel sample-rate converter. |
17 class MEDIA_EXPORT SincResampler { | 18 class MEDIA_EXPORT SincResampler { |
18 public: | 19 public: |
19 // The maximum number of samples that may be requested from the callback ahead | 20 enum { |
20 // of the current position in the stream. | 21 // The kernel size can be adjusted for quality (higher is better) at the |
21 static const int kMaximumLookAheadSize; | 22 // expense of performance. Must be a multiple of 32. |
| 23 // TODO(dalecurtis): Test performance to see if we can jack this up to 64+. |
| 24 kKernelSize = 32, |
| 25 |
| 26 // The number of destination frames generated per processing pass. Affects |
| 27 // how often and for how much SincResampler calls back for input. Must be |
| 28 // greater than kKernelSize. |
| 29 kBlockSize = 512, |
| 30 |
| 31 // The kernel offset count is used for interpolation and is the number of |
| 32 // sub-sample kernel shifts. Can be adjusted for quality (higher is better) |
| 33 // at the expense of allocating more memory. |
| 34 kKernelOffsetCount = 32, |
| 35 kKernelStorageSize = kKernelSize * (kKernelOffsetCount + 1), |
| 36 |
| 37 // The size (in samples) of the internal buffer used by the resampler. |
| 38 kBufferSize = kBlockSize + kKernelSize, |
| 39 |
| 40 // The maximum number of samples that may be requested from the callback |
| 41 // ahead of the current position in the stream. |
| 42 kMaximumLookAheadSize = kBufferSize |
| 43 }; |
22 | 44 |
23 // Callback type for providing more data into the resampler. Expects |frames| | 45 // Callback type for providing more data into the resampler. Expects |frames| |
24 // of data to be rendered into |destination|; zero padded if not enough frames | 46 // of data to be rendered into |destination|; zero padded if not enough frames |
25 // are available to satisfy the request. | 47 // are available to satisfy the request. |
26 typedef base::Callback<void(float* destination, int frames)> ReadCB; | 48 typedef base::Callback<void(float* destination, int frames)> ReadCB; |
27 | 49 |
28 // Constructs a SincResampler with the specified |read_cb|, which is used to | 50 // Constructs a SincResampler with the specified |read_cb|, which is used to |
29 // acquire audio data for resampling. |io_sample_rate_ratio| is the ratio of | 51 // acquire audio data for resampling. |io_sample_rate_ratio| is the ratio of |
30 // input / output sample rates. | 52 // input / output sample rates. |
31 SincResampler(double io_sample_rate_ratio, const ReadCB& read_cb); | 53 SincResampler(double io_sample_rate_ratio, const ReadCB& read_cb); |
32 virtual ~SincResampler(); | 54 virtual ~SincResampler(); |
33 | 55 |
34 // Resample |frames| of data from |read_cb_| into |destination|. | 56 // Resample |frames| of data from |read_cb_| into |destination|. |
35 void Resample(float* destination, int frames); | 57 void Resample(float* destination, int frames); |
36 | 58 |
37 // The maximum size in frames that guarantees Resample() will only make a | 59 // The maximum size in frames that guarantees Resample() will only make a |
38 // single call to |read_cb_| for more data. | 60 // single call to |read_cb_| for more data. |
39 int ChunkSize(); | 61 int ChunkSize() const; |
40 | 62 |
41 // Flush all buffered data and reset internal indices. | 63 // Flush all buffered data and reset internal indices. |
42 void Flush(); | 64 void Flush(); |
43 | 65 |
44 private: | 66 private: |
45 FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve); | 67 FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve); |
46 FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark); | 68 FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark); |
47 | 69 |
48 void InitializeKernel(); | 70 void InitializeKernel(); |
49 | 71 |
50 // Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are | 72 // Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are |
51 // linearly interpolated using |kernel_interpolation_factor|. On x86, the | 73 // linearly interpolated using |kernel_interpolation_factor|. On x86, the |
52 // underlying implementation is chosen at run time based on SSE support. On | 74 // underlying implementation is chosen at run time based on SSE support. On |
53 // ARM, NEON support is chosen at compile time based on compilation flags. | 75 // ARM, NEON support is chosen at compile time based on compilation flags. |
54 static float Convolve(const float* input_ptr, const float* k1, | 76 static float Convolve(const float* input_ptr, const float* k1, |
55 const float* k2, double kernel_interpolation_factor); | 77 const float* k2, double kernel_interpolation_factor); |
56 static float Convolve_C(const float* input_ptr, const float* k1, | 78 static float Convolve_C(const float* input_ptr, const float* k1, |
57 const float* k2, double kernel_interpolation_factor); | 79 const float* k2, double kernel_interpolation_factor); |
| 80 #if defined(ARCH_CPU_X86_FAMILY) |
58 static float Convolve_SSE(const float* input_ptr, const float* k1, | 81 static float Convolve_SSE(const float* input_ptr, const float* k1, |
59 const float* k2, | 82 const float* k2, |
60 double kernel_interpolation_factor); | 83 double kernel_interpolation_factor); |
| 84 #elif defined(ARCH_CPU_ARM_FAMILY) && defined(USE_NEON) |
61 static float Convolve_NEON(const float* input_ptr, const float* k1, | 85 static float Convolve_NEON(const float* input_ptr, const float* k1, |
62 const float* k2, | 86 const float* k2, |
63 double kernel_interpolation_factor); | 87 double kernel_interpolation_factor); |
| 88 #endif |
64 | 89 |
65 // The ratio of input / output sample rates. | 90 // The ratio of input / output sample rates. |
66 double io_sample_rate_ratio_; | 91 const double io_sample_rate_ratio_; |
67 | 92 |
68 // An index on the source input buffer with sub-sample precision. It must be | 93 // An index on the source input buffer with sub-sample precision. It must be |
69 // double precision to avoid drift. | 94 // double precision to avoid drift. |
70 double virtual_source_idx_; | 95 double virtual_source_idx_; |
71 | 96 |
72 // The buffer is primed once at the very beginning of processing. | 97 // The buffer is primed once at the very beginning of processing. |
73 bool buffer_primed_; | 98 bool buffer_primed_; |
74 | 99 |
75 // Source of data for resampling. | 100 // Source of data for resampling. |
76 ReadCB read_cb_; | 101 ReadCB read_cb_; |
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91 float* const r3_; | 116 float* const r3_; |
92 float* const r4_; | 117 float* const r4_; |
93 float* const r5_; | 118 float* const r5_; |
94 | 119 |
95 DISALLOW_COPY_AND_ASSIGN(SincResampler); | 120 DISALLOW_COPY_AND_ASSIGN(SincResampler); |
96 }; | 121 }; |
97 | 122 |
98 } // namespace media | 123 } // namespace media |
99 | 124 |
100 #endif // MEDIA_BASE_SINC_RESAMPLER_H_ | 125 #endif // MEDIA_BASE_SINC_RESAMPLER_H_ |
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