1 /* 2 * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef COMMON_AUDIO_RESAMPLER_INCLUDE_PUSH_RESAMPLER_H_ 12 #define COMMON_AUDIO_RESAMPLER_INCLUDE_PUSH_RESAMPLER_H_ 13 14 #include <memory> 15 #include <vector> 16 17 namespace webrtc { 18 19 class PushSincResampler; 20 21 // Wraps PushSincResampler to provide stereo support. 22 // TODO(ajm): add support for an arbitrary number of channels. 23 template <typename T> 24 class PushResampler { 25 public: 26 PushResampler(); 27 virtual ~PushResampler(); 28 29 // Must be called whenever the parameters change. Free to be called at any 30 // time as it is a no-op if parameters have not changed since the last call. 31 int InitializeIfNeeded(int src_sample_rate_hz, 32 int dst_sample_rate_hz, 33 size_t num_channels); 34 35 // Returns the total number of samples provided in destination (e.g. 32 kHz, 36 // 2 channel audio gives 640 samples). 37 int Resample(const T* src, size_t src_length, T* dst, size_t dst_capacity); 38 39 private: 40 int src_sample_rate_hz_; 41 int dst_sample_rate_hz_; 42 size_t num_channels_; 43 // Vector that is needed to provide the proper inputs and outputs to the 44 // interleave/de-interleave methods used in Resample. This needs to be 45 // heap-allocated on the state to support an arbitrary number of channels 46 // without doing run-time heap-allocations in the Resample method. 47 std::vector<T*> channel_data_array_; 48 49 struct ChannelResampler { 50 std::unique_ptr<PushSincResampler> resampler; 51 std::vector<T> source; 52 std::vector<T> destination; 53 }; 54 55 std::vector<ChannelResampler> channel_resamplers_; 56 }; 57 } // namespace webrtc 58 59 #endif // COMMON_AUDIO_RESAMPLER_INCLUDE_PUSH_RESAMPLER_H_ 60