1 /* 2 * Copyright 2004 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_SOUND_SOUNDINPUTSTREAMINTERFACE_H_ 12 #define WEBRTC_SOUND_SOUNDINPUTSTREAMINTERFACE_H_ 13 14 #include "webrtc/base/constructormagic.h" 15 #include "webrtc/base/sigslot.h" 16 17 namespace rtc { 18 19 // Interface for consuming an input stream from a recording device. 20 // Semantics and thread-safety of StartReading()/StopReading() are the same as 21 // for rtc::Worker. 22 class SoundInputStreamInterface { 23 public: 24 virtual ~SoundInputStreamInterface(); 25 26 // Starts the reading of samples on the current thread. 27 virtual bool StartReading() = 0; 28 // Stops the reading of samples. 29 virtual bool StopReading() = 0; 30 31 // Retrieves the current input volume for this stream. Nominal range is 32 // defined by SoundSystemInterface::k(Max|Min)Volume, but values exceeding the 33 // max may be possible in some implementations. This call retrieves the actual 34 // volume currently in use by the OS, not a cached value from a previous 35 // (Get|Set)Volume() call. 36 virtual bool GetVolume(int *volume) = 0; 37 38 // Changes the input volume for this stream. Nominal range is defined by 39 // SoundSystemInterface::k(Max|Min)Volume. The effect of exceeding kMaxVolume 40 // is implementation-defined. 41 virtual bool SetVolume(int volume) = 0; 42 43 // Closes this stream object. If currently reading then this may only be 44 // called from the reading thread. 45 virtual bool Close() = 0; 46 47 // Get the latency of the stream. 48 virtual int LatencyUsecs() = 0; 49 50 // Notifies the consumer of new data read from the device. 51 // The first parameter is a pointer to the data read, and is only valid for 52 // the duration of the call. 53 // The second parameter is the amount of data read in bytes (i.e., the valid 54 // length of the memory pointed to). 55 // The 3rd parameter is the stream that is issuing the callback. 56 sigslot::signal3<const void *, size_t, 57 SoundInputStreamInterface *> SignalSamplesRead; 58 59 protected: 60 SoundInputStreamInterface(); 61 62 private: 63 RTC_DISALLOW_COPY_AND_ASSIGN(SoundInputStreamInterface); 64 }; 65 66 } // namespace rtc 67 68 #endif // WEBRTC_SOUND_SOUNDINPUTSTREAMINTERFACE_H_ 69