src/modules/audio_conference_mixer/interface/audio_conference_mixer.h

/*
 *  Copyright (c) 2011 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 WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_H_
#define WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_H_

#include "audio_conference_mixer_defines.h"
#include "module.h"
#include "module_common_types.h"

namespace webrtc {
class AudioMixerOutputReceiver;
class AudioMixerStatusReceiver;
class MixerParticipant;
class Trace;

class AudioConferenceMixer : public Module
{
public:
    enum {kMaximumAmountOfMixedParticipants = 3};
    enum Frequency
    {
        kNbInHz           = 8000,
        kWbInHz           = 16000,
        kSwbInHz          = 32000,
        kLowestPossible   = -1,
        kDefaultFrequency = kWbInHz
    };

    // Factory method. Constructor disabled.
    static AudioConferenceMixer* Create(int id);
    virtual ~AudioConferenceMixer() {}

    // Module functions
    virtual WebRtc_Word32 ChangeUniqueId(const WebRtc_Word32 id) = 0;
    virtual WebRtc_Word32 TimeUntilNextProcess() = 0 ;
    virtual WebRtc_Word32 Process() = 0;

    // Register/unregister a callback class for receiving the mixed audio.
    virtual WebRtc_Word32 RegisterMixedStreamCallback(
        AudioMixerOutputReceiver& receiver) = 0;
    virtual WebRtc_Word32 UnRegisterMixedStreamCallback() = 0;

    // Register/unregister a callback class for receiving status information.
    virtual WebRtc_Word32 RegisterMixerStatusCallback(
        AudioMixerStatusReceiver& mixerStatusCallback,
        const WebRtc_UWord32 amountOf10MsBetweenCallbacks) = 0;
    virtual WebRtc_Word32 UnRegisterMixerStatusCallback() = 0;

    // Add/remove participants as candidates for mixing.
    virtual WebRtc_Word32 SetMixabilityStatus(
        MixerParticipant& participant,
        const bool mixable) = 0;
    // mixable is set to true if a participant is a candidate for mixing.
    virtual WebRtc_Word32 MixabilityStatus(
        MixerParticipant& participant,
        bool& mixable) = 0;
    // amountOfMixableParticipants is set to the number of participants that are
    // eligible for mixing.
    virtual WebRtc_Word32 AmountOfMixables(
        WebRtc_UWord32& amountOfMixableParticipants) = 0;

    // Inform the mixer that the participant should always be mixed and not
    // count toward the number of mixed participants. Note that a participant
    // must have been added to the mixer (by calling SetMixabilityStatus())
    // before this function can be successfully called.
    virtual WebRtc_Word32 SetAnonymousMixabilityStatus(
        MixerParticipant& participant, const bool mixable) = 0;
    // mixable is set to true if the participant is mixed anonymously.
    virtual WebRtc_Word32 AnonymousMixabilityStatus(
        MixerParticipant& participant, bool& mixable) = 0;

    // Set the minimum sampling frequency at which to mix. The mixing algorithm
    // may still choose to mix at a higher samling frequency to avoid
    // downsampling of audio contributing to the mixed audio.
    virtual WebRtc_Word32 SetMinimumMixingFrequency(Frequency freq) = 0;

protected:
    AudioConferenceMixer() {}
};
} // namespace webrtc

#endif // WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_H_