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/*
* Copyright 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef API_DTMF_SENDER_INTERFACE_H_
#define API_DTMF_SENDER_INTERFACE_H_
#include <string>
#include "api/media_stream_interface.h"
#include "rtc_base/ref_count.h"
namespace webrtc {
// DtmfSender callback interface, used to implement RTCDtmfSender events.
// Applications should implement this interface to get notifications from the
// DtmfSender.
class DtmfSenderObserverInterface {
public:
// Triggered when DTMF `tone` is sent.
// If `tone` is empty that means the DtmfSender has sent out all the given
// tones.
// The callback includes the state of the tone buffer at the time when
// the tone finished playing.
virtual void OnToneChange(const std::string& tone,
const std::string& tone_buffer) {}
// DEPRECATED: Older API without tone buffer.
// TODO(bugs.webrtc.org/9725): Remove old API and default implementation
// when old callers are gone.
virtual void OnToneChange(const std::string& tone) {}
protected:
virtual ~DtmfSenderObserverInterface() = default;
};
// The interface of native implementation of the RTCDTMFSender defined by the
// WebRTC W3C Editor's Draft.
// See: https://www.w3.org/TR/webrtc/#peer-to-peer-dtmf
class DtmfSenderInterface : public rtc::RefCountInterface {
public:
// Provides the spec compliant default 2 second delay for the ',' character.
static const int kDtmfDefaultCommaDelayMs = 2000;
// Used to receive events from the DTMF sender. Only one observer can be
// registered at a time. UnregisterObserver should be called before the
// observer object is destroyed.
virtual void RegisterObserver(DtmfSenderObserverInterface* observer) = 0;
virtual void UnregisterObserver() = 0;
// Returns true if this DtmfSender is capable of sending DTMF. Otherwise
// returns false. To be able to send DTMF, the associated RtpSender must be
// able to send packets, and a "telephone-event" codec must be negotiated.
virtual bool CanInsertDtmf() = 0;
// Queues a task that sends the DTMF `tones`. The `tones` parameter is treated
// as a series of characters. The characters 0 through 9, A through D, #, and
// * generate the associated DTMF tones. The characters a to d are equivalent
// to A to D. The character ',' indicates a delay of 2 seconds before
// processing the next character in the tones parameter.
//
// Unrecognized characters are ignored.
//
// The `duration` parameter indicates the duration in ms to use for each
// character passed in the `tones` parameter. The duration cannot be more
// than 6000 or less than 70.
//
// The `inter_tone_gap` parameter indicates the gap between tones in ms. The
// `inter_tone_gap` must be at least 50 ms but should be as short as
// possible.
//
// The `comma_delay` parameter indicates the delay after the ','
// character. InsertDtmf specifies `comma_delay` as an argument
// with a default value of 2 seconds as per the WebRTC spec. This parameter
// allows users to comply with legacy WebRTC clients. The `comma_delay`
// must be at least 50 ms.
//
// If InsertDtmf is called on the same object while an existing task for this
// object to generate DTMF is still running, the previous task is canceled.
// Returns true on success and false on failure.
virtual bool InsertDtmf(const std::string& tones,
int duration,
int inter_tone_gap) {
return InsertDtmf(tones, duration, inter_tone_gap,
kDtmfDefaultCommaDelayMs);
}
virtual bool InsertDtmf(const std::string& tones,
int duration,
int inter_tone_gap,
int comma_delay) {
// TODO(bugs.webrtc.org/165700): Remove once downstream implementations
// override this signature rather than the 3-parameter one.
return InsertDtmf(tones, duration, inter_tone_gap);
}
// Returns the tones remaining to be played out.
virtual std::string tones() const = 0;
// Returns the current tone duration value in ms.
// This value will be the value last set via the InsertDtmf() method, or the
// default value of 100 ms if InsertDtmf() was never called.
virtual int duration() const = 0;
// Returns the current value of the between-tone gap in ms.
// This value will be the value last set via the InsertDtmf() method, or the
// default value of 50 ms if InsertDtmf() was never called.
virtual int inter_tone_gap() const = 0;
// Returns the current value of the "," character delay in ms.
// This value will be the value last set via the InsertDtmf() method, or the
// default value of 2000 ms if InsertDtmf() was never called.
virtual int comma_delay() const { return kDtmfDefaultCommaDelayMs; }
protected:
~DtmfSenderInterface() override = default;
};
} // namespace webrtc
#endif // API_DTMF_SENDER_INTERFACE_H_
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