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      1 /*
      2  *  Copyright (c) 2011 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 WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_H_
     12 #define WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_H_
     13 
     14 #include "webrtc/modules/audio_conference_mixer/interface/audio_conference_mixer_defines.h"
     15 #include "webrtc/modules/interface/module.h"
     16 #include "webrtc/modules/interface/module_common_types.h"
     17 
     18 namespace webrtc {
     19 class AudioMixerOutputReceiver;
     20 class AudioMixerStatusReceiver;
     21 class MixerParticipant;
     22 class Trace;
     23 
     24 class AudioConferenceMixer : public Module
     25 {
     26 public:
     27     enum {kMaximumAmountOfMixedParticipants = 3};
     28     enum Frequency
     29     {
     30         kNbInHz           = 8000,
     31         kWbInHz           = 16000,
     32         kSwbInHz          = 32000,
     33         kFbInHz           = 48000,
     34         kLowestPossible   = -1,
     35         kDefaultFrequency = kWbInHz
     36     };
     37 
     38     // Factory method. Constructor disabled.
     39     static AudioConferenceMixer* Create(int id);
     40     virtual ~AudioConferenceMixer() {}
     41 
     42     // Module functions
     43     virtual int32_t ChangeUniqueId(const int32_t id) OVERRIDE = 0;
     44     virtual int32_t TimeUntilNextProcess() OVERRIDE = 0;
     45     virtual int32_t Process() OVERRIDE = 0;
     46 
     47     // Register/unregister a callback class for receiving the mixed audio.
     48     virtual int32_t RegisterMixedStreamCallback(
     49         AudioMixerOutputReceiver& receiver) = 0;
     50     virtual int32_t UnRegisterMixedStreamCallback() = 0;
     51 
     52     // Register/unregister a callback class for receiving status information.
     53     virtual int32_t RegisterMixerStatusCallback(
     54         AudioMixerStatusReceiver& mixerStatusCallback,
     55         const uint32_t amountOf10MsBetweenCallbacks) = 0;
     56     virtual int32_t UnRegisterMixerStatusCallback() = 0;
     57 
     58     // Add/remove participants as candidates for mixing.
     59     virtual int32_t SetMixabilityStatus(MixerParticipant& participant,
     60                                         bool mixable) = 0;
     61     // mixable is set to true if a participant is a candidate for mixing.
     62     virtual int32_t MixabilityStatus(MixerParticipant& participant,
     63                                      bool& mixable) = 0;
     64 
     65     // Inform the mixer that the participant should always be mixed and not
     66     // count toward the number of mixed participants. Note that a participant
     67     // must have been added to the mixer (by calling SetMixabilityStatus())
     68     // before this function can be successfully called.
     69     virtual int32_t SetAnonymousMixabilityStatus(MixerParticipant& participant,
     70                                                  const bool mixable) = 0;
     71     // mixable is set to true if the participant is mixed anonymously.
     72     virtual int32_t AnonymousMixabilityStatus(MixerParticipant& participant,
     73                                               bool& mixable) = 0;
     74 
     75     // Set the minimum sampling frequency at which to mix. The mixing algorithm
     76     // may still choose to mix at a higher samling frequency to avoid
     77     // downsampling of audio contributing to the mixed audio.
     78     virtual int32_t SetMinimumMixingFrequency(Frequency freq) = 0;
     79 
     80 protected:
     81     AudioConferenceMixer() {}
     82 };
     83 }  // namespace webrtc
     84 
     85 #endif // WEBRTC_MODULES_AUDIO_CONFERENCE_MIXER_INTERFACE_AUDIO_CONFERENCE_MIXER_H_
     86