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			117 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C++
		
	
			
		
		
	
	
			117 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C++
		
	
/*
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 *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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 *
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 *  Use of this source code is governed by a BSD-style license
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 *  that can be found in the LICENSE file in the root of the source
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 *  tree. An additional intellectual property rights grant can be found
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 *  in the file PATENTS.  All contributing project authors may
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 *  be found in the AUTHORS file in the root of the source tree.
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 */
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#ifndef WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_BUFFER_H_
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#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_BUFFER_H_
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#include <list>
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#include <string>  // size_t
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#include "webrtc/base/constructormagic.h"
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#include "webrtc/typedefs.h"
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namespace webrtc {
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struct DtmfEvent {
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  uint32_t timestamp;
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  int event_no;
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  int volume;
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  int duration;
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  bool end_bit;
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  // Constructors
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  DtmfEvent()
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      : timestamp(0),
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        event_no(0),
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        volume(0),
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        duration(0),
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        end_bit(false) {
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  }
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  DtmfEvent(uint32_t ts, int ev, int vol, int dur, bool end)
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      : timestamp(ts),
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        event_no(ev),
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        volume(vol),
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        duration(dur),
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        end_bit(end) {
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  }
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};
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// This is the buffer holding DTMF events while waiting for them to be played.
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class DtmfBuffer {
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 public:
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  enum BufferReturnCodes {
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    kOK = 0,
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    kInvalidPointer,
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    kPayloadTooShort,
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    kInvalidEventParameters,
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    kInvalidSampleRate
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  };
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  // Set up the buffer for use at sample rate |fs_hz|.
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  explicit DtmfBuffer(int fs_hz) {
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    SetSampleRate(fs_hz);
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  }
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  virtual ~DtmfBuffer() {}
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  // Flushes the buffer.
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  virtual void Flush() { buffer_.clear(); }
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  // Static method to parse 4 bytes from |payload| as a DTMF event (RFC 4733)
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  // and write the parsed information into the struct |event|. Input variable
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  // |rtp_timestamp| is simply copied into the struct.
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  static int ParseEvent(uint32_t rtp_timestamp,
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                        const uint8_t* payload,
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                        int payload_length_bytes,
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                        DtmfEvent* event);
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  // Inserts |event| into the buffer. The method looks for a matching event and
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  // merges the two if a match is found.
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  virtual int InsertEvent(const DtmfEvent& event);
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  // Checks if a DTMF event should be played at time |current_timestamp|. If so,
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  // the method returns true; otherwise false. The parameters of the event to
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  // play will be written to |event|.
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  virtual bool GetEvent(uint32_t current_timestamp, DtmfEvent* event);
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  // Number of events in the buffer.
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  virtual size_t Length() const { return buffer_.size(); }
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  virtual bool Empty() const { return buffer_.empty(); }
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  // Set a new sample rate.
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  virtual int SetSampleRate(int fs_hz);
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 private:
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  typedef std::list<DtmfEvent> DtmfList;
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  int max_extrapolation_samples_;
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  int frame_len_samples_;  // TODO(hlundin): Remove this later.
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  // Compares two events and returns true if they are the same.
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  static bool SameEvent(const DtmfEvent& a, const DtmfEvent& b);
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  // Merges |event| to the event pointed out by |it|. The method checks that
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  // the two events are the same (using the SameEvent method), and merges them
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  // if that was the case, returning true. If the events are not the same, false
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  // is returned.
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  bool MergeEvents(DtmfList::iterator it, const DtmfEvent& event);
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  // Method used by the sort algorithm to rank events in the buffer.
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  static bool CompareEvents(const DtmfEvent& a, const DtmfEvent& b);
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  DtmfList buffer_;
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  DISALLOW_COPY_AND_ASSIGN(DtmfBuffer);
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};
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}  // namespace webrtc
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#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_DTMF_BUFFER_H_
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