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28 #ifndef TALK_SOUND_SOUNDINPUTSTREAMINTERFACE_H_
29 #define TALK_SOUND_SOUNDINPUTSTREAMINTERFACE_H_
31 #include "webrtc/base/constructormagic.h"
32 #include "webrtc/base/sigslot.h"
36 // Interface for consuming an input stream from a recording device.
37 // Semantics and thread-safety of StartReading()/StopReading() are the same as
39 class SoundInputStreamInterface {
41 virtual ~SoundInputStreamInterface() {}
43 // Starts the reading of samples on the current thread.
44 virtual bool StartReading() = 0;
45 // Stops the reading of samples.
46 virtual bool StopReading() = 0;
48 // Retrieves the current input volume for this stream. Nominal range is
49 // defined by SoundSystemInterface::k(Max|Min)Volume, but values exceeding the
50 // max may be possible in some implementations. This call retrieves the actual
51 // volume currently in use by the OS, not a cached value from a previous
52 // (Get|Set)Volume() call.
53 virtual bool GetVolume(int *volume) = 0;
55 // Changes the input volume for this stream. Nominal range is defined by
56 // SoundSystemInterface::k(Max|Min)Volume. The effect of exceeding kMaxVolume
57 // is implementation-defined.
58 virtual bool SetVolume(int volume) = 0;
60 // Closes this stream object. If currently reading then this may only be
61 // called from the reading thread.
62 virtual bool Close() = 0;
64 // Get the latency of the stream.
65 virtual int LatencyUsecs() = 0;
67 // Notifies the consumer of new data read from the device.
68 // The first parameter is a pointer to the data read, and is only valid for
69 // the duration of the call.
70 // The second parameter is the amount of data read in bytes (i.e., the valid
71 // length of the memory pointed to).
72 // The 3rd parameter is the stream that is issuing the callback.
73 sigslot::signal3<const void *, size_t,
74 SoundInputStreamInterface *> SignalSamplesRead;
77 SoundInputStreamInterface() {}
80 DISALLOW_COPY_AND_ASSIGN(SoundInputStreamInterface);
83 } // namespace cricket
85 #endif // TALK_SOUND_SOUNDOUTPUTSTREAMINTERFACE_H_