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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_ | |
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