1 /* 2 * libjingle 3 * Copyright 2004--2010, 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 #ifndef TALK_SOUND_SOUNDOUTPUTSTREAMINTERFACE_H_ 29 #define TALK_SOUND_SOUNDOUTPUTSTREAMINTERFACE_H_ 30 31 #include "talk/base/constructormagic.h" 32 #include "talk/base/sigslot.h" 33 34 namespace cricket { 35 36 // Interface for outputting a stream to a playback device. 37 // Semantics and thread-safety of EnableBufferMonitoring()/ 38 // DisableBufferMonitoring() are the same as for talk_base::Worker. 39 class SoundOutputStreamInterface { 40 public: 41 virtual ~SoundOutputStreamInterface() {} 42 43 // Enables monitoring the available buffer space on the current thread. 44 virtual bool EnableBufferMonitoring() = 0; 45 // Disables the monitoring. 46 virtual bool DisableBufferMonitoring() = 0; 47 48 // Write the given samples to the devices. If currently monitoring then this 49 // may only be called from the monitoring thread. 50 virtual bool WriteSamples(const void *sample_data, 51 size_t size) = 0; 52 53 // Retrieves the current output volume for this stream. Nominal range is 54 // defined by SoundSystemInterface::k(Max|Min)Volume, but values exceeding the 55 // max may be possible in some implementations. This call retrieves the actual 56 // volume currently in use by the OS, not a cached value from a previous 57 // (Get|Set)Volume() call. 58 virtual bool GetVolume(int *volume) = 0; 59 60 // Changes the output volume for this stream. Nominal range is defined by 61 // SoundSystemInterface::k(Max|Min)Volume. The effect of exceeding kMaxVolume 62 // is implementation-defined. 63 virtual bool SetVolume(int volume) = 0; 64 65 // Closes this stream object. If currently monitoring then this may only be 66 // called from the monitoring thread. 67 virtual bool Close() = 0; 68 69 // Get the latency of the stream. 70 virtual int LatencyUsecs() = 0; 71 72 // Notifies the producer of the available buffer space for writes. 73 // It fires continuously as long as the space is greater than zero. 74 // The first parameter is the amount of buffer space available for data to 75 // be written (i.e., the maximum amount of data that can be written right now 76 // with WriteSamples() without blocking). 77 // The 2nd parameter is the stream that is issuing the callback. 78 sigslot::signal2<size_t, SoundOutputStreamInterface *> SignalBufferSpace; 79 80 protected: 81 SoundOutputStreamInterface() {} 82 83 private: 84 DISALLOW_COPY_AND_ASSIGN(SoundOutputStreamInterface); 85 }; 86 87 } // namespace cricket 88 89 #endif // TALK_SOUND_SOUNDOUTPUTSTREAMINTERFACE_H_ 90
