1 /* 2 * libjingle 3 * Copyright 2011 Google Inc. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 // CurrentSpeakerMonitor monitors the audio levels for a session and determines 29 // which participant is currently speaking. 30 31 #ifndef TALK_SESSION_MEDIA_CURRENTSPEAKERMONITOR_H_ 32 #define TALK_SESSION_MEDIA_CURRENTSPEAKERMONITOR_H_ 33 34 #include <map> 35 36 #include "webrtc/base/basictypes.h" 37 #include "webrtc/base/sigslot.h" 38 39 namespace cricket { 40 41 struct AudioInfo; 42 struct MediaStreams; 43 44 class AudioSourceContext { 45 public: 46 sigslot::signal2<AudioSourceContext*, const cricket::AudioInfo&> 47 SignalAudioMonitor; 48 sigslot::signal1<AudioSourceContext*> SignalMediaStreamsReset; 49 sigslot::signal3<AudioSourceContext*, 50 const cricket::MediaStreams&, 51 const cricket::MediaStreams&> SignalMediaStreamsUpdate; 52 }; 53 54 // CurrentSpeakerMonitor can be used to monitor the audio-levels from 55 // many audio-sources and report on changes in the loudest audio-source. 56 // Its a generic type and relies on an AudioSourceContext which is aware of 57 // the audio-sources. AudioSourceContext needs to provide two signals namely 58 // SignalAudioInfoMonitor - provides audio info of the all current speakers. 59 // SignalMediaSourcesUpdated - provides updates when a speaker leaves or joins. 60 // Note that the AudioSourceContext's audio monitor must be started 61 // before this is started. 62 // It's recommended that the audio monitor be started with a 100 ms period. 63 class CurrentSpeakerMonitor : public sigslot::has_slots<> { 64 public: 65 CurrentSpeakerMonitor(AudioSourceContext* audio_source_context); 66 ~CurrentSpeakerMonitor(); 67 68 void Start(); 69 void Stop(); 70 71 // Used by tests. Note that the actual minimum time between switches 72 // enforced by the monitor will be the given value plus or minus the 73 // resolution of the system clock. 74 void set_min_time_between_switches(uint32_t min_time_between_switches); 75 76 // This is fired when the current speaker changes, and provides his audio 77 // SSRC. This only fires after the audio monitor on the underlying 78 // AudioSourceContext has been started. 79 sigslot::signal2<CurrentSpeakerMonitor*, uint32_t> SignalUpdate; 80 81 private: 82 void OnAudioMonitor(AudioSourceContext* audio_source_context, 83 const AudioInfo& info); 84 void OnMediaStreamsUpdate(AudioSourceContext* audio_source_context, 85 const MediaStreams& added, 86 const MediaStreams& removed); 87 void OnMediaStreamsReset(AudioSourceContext* audio_source_context); 88 89 // These are states that a participant will pass through so that we gradually 90 // recognize that they have started and stopped speaking. This avoids 91 // "twitchiness". 92 enum SpeakingState { 93 SS_NOT_SPEAKING, 94 SS_MIGHT_BE_SPEAKING, 95 SS_SPEAKING, 96 SS_WAS_SPEAKING_RECENTLY1, 97 SS_WAS_SPEAKING_RECENTLY2 98 }; 99 100 bool started_; 101 AudioSourceContext* audio_source_context_; 102 std::map<uint32_t, SpeakingState> ssrc_to_speaking_state_map_; 103 uint32_t current_speaker_ssrc_; 104 // To prevent overswitching, switching is disabled for some time after a 105 // switch is made. This gives us the earliest time a switch is permitted. 106 uint32_t earliest_permitted_switch_time_; 107 uint32_t min_time_between_switches_; 108 }; 109 110 } 111 112 #endif // TALK_SESSION_MEDIA_CURRENTSPEAKERMONITOR_H_ 113