sound.h

mgcp协议源代码。支持多种编码：g711

    /** Create a sound channel.
        Create a reference to the sound drivers for the platform.
      */
    PSoundChannel(
      const PString & device,       /// Name of sound driver/device
      Directions dir,               /// Sound I/O direction
      unsigned numChannels = 1,     /// Number of channels eg mono/stereo
      unsigned sampleRate = 8000,   /// Samples per second
      unsigned bitsPerSample = 16   /// Number of bits per sample
    );
    // 

    ~PSoundChannel();
    // Destroy and close the sound driver
  //@}

  /**@name Open functions */
  //@{
    /**Get all of the names for sound devices/drivers that are available on
       this platform. Note that a named device may not necessarily do both
       playing and recording so the arrays returned with the #dir#
       parameter in each value is not necessarily the same.

       @return
       An array of platform dependent strings for each sound player/recorder.
     */
    static PStringArray GetDeviceNames(
      Directions dir    // Sound I/O direction
    );

    /**Get the name for the default sound devices/driver that is on this
       platform. Note that a named device may not necessarily do both
       playing and recording so the arrays returned with the #dir#
       parameter in each value is not necessarily the same.

       @return
       A platform dependent string for the sound player/recorder.
     */
    static PString GetDefaultDevice(
      Directions dir    // Sound I/O direction
    );


    /**Open the specified device for playing or recording. The device name is
       platform specific and is as returned in the GetDevices() function.

       @return
       TRUE if the sound device is valid for playing/recording.
     */
    BOOL Open(
      const PString & device,       /// Name of sound driver/device
      Directions dir,               /// Sound I/O direction
      unsigned numChannels = 1,     /// Number of channels eg mono/stereo
      unsigned sampleRate = 8000,   /// Samples per second
      unsigned bitsPerSample = 16   /// Number of bits per sample
    );

    /**Abort the background playing/recording of the sound channel.

       @return
       TRUE if the sound has successfully been aborted.
     */
    BOOL Abort();
  //@}

  /**@name Channel set up functions */
  //@{
    /**Set the format for play/record. Note that linear PCM data is the only
       one supported at this time.

       Note that if the PlayFile() function is used, this may be overridden
       by information in the file being played.

       @return
       TRUE if the format is valid.
     */
    BOOL SetFormat(
      unsigned numChannels = 1,     /// Number of channels eg mono/stereo
      unsigned sampleRate = 8000,   /// Samples per second
      unsigned bitsPerSample = 16   /// Number of bits per sample
    );


    /**Set the internal buffers for the sound channel I/O.

       Note that with Linux OSS, the size is always rounded up to the nearest
       power of two, so 20000 => 32768.

       @return
       TRUE if the sound device is valid for playing/recording.
     */
    BOOL SetBuffers(
      PINDEX size,      /// Size of each buffer
      PINDEX count = 2  /// Number of buffers
    );

    /**Get the internal buffers for the sound channel I/O.

       @return
       TRUE if the buffer size were obtained.
     */
    BOOL GetBuffers(
      PINDEX & size,    // Size of each buffer
      PINDEX & count    // Number of buffers
    );
  //@}

  /**@name Play functions */
  //@{
    /**Play a sound to the open device. If the #wait# parameter is
       TRUE then the function does not return until the file has been played.
       If FALSE then the sound play is begun asynchronously and the function
       returns immediately.

       Note if the driver is closed of the object destroyed then the sound
       play is aborted.

       Also note that not all possible sounds and sound files are playable by
       this library. No format conversions between sound object and driver are
       performed.

       @return
       TRUE if the sound is playing or has played.
     */

    BOOL PlaySound(
      const PSound & sound,   /// Sound to play.
      BOOL wait = TRUE        /// Flag to play sound synchronously.
    );
    /**Play a sound file to the open device. If the #wait#
       parameter is TRUE then the function does not return until the file has
       been played. If FALSE then the sound play is begun asynchronously and
       the function returns immediately.

       Note if the driver is closed of the object destroyed then the sound
       play is aborted.

       Also note that not all possible sounds and sound files are playable by
       this library. No format conversions between sound object and driver are
       performed.

       @return
       TRUE if the sound is playing or has played.
     */
    BOOL PlayFile(
      const PFilePath & file, /// Sound file to play.
      BOOL wait = TRUE        /// Flag to play sound synchronously.
    );

    /**Indicate if the sound play begun with PlayBuffer() or PlayFile() has
       completed.

       @return
       TRUE if the sound has completed playing.
     */
    BOOL HasPlayCompleted();

    /**Block the thread until the sound play begun with PlayBuffer() or
       PlayFile() has completed.

       @return
       TRUE if the sound has successfully completed playing.
     */
    BOOL WaitForPlayCompletion();

  //@}

  /**@name Record functions */
  //@{
    /**Record into the sound object all of the buffer's of sound data. Use the
       SetBuffers() function to determine how long the recording will be made.

       For the Win32 platform, the most efficient way to record a PSound is to
       use the SetBuffers() function to set a single buffer of the desired
       size and then do the recording. For Linux OSS this can cause problems
       as the buffers are rounded up to a power of two, so to gain more
       accuracy you need a number of smaller buffers.

       Note that this function will block until all of the data is buffered.
       If you wish to do this asynchronously, use StartRecording() and
       AreAllrecordBuffersFull() to determine when you can call RecordSound()
       without blocking.

       @return
       TRUE if the sound has been recorded.
     */
    BOOL RecordSound(
      PSound & sound /// Sound recorded
    );

    /**Record into the platform dependent sound file all of the buffer's of
       sound data. Use the SetBuffers() function to determine how long the
       recording will be made.

       Note that this function will block until all of the data is buffered.
       If you wish to do this asynchronously, use StartRecording() and
       AreAllrecordBuffersFull() to determine when you can call RecordSound()
       without blocking.

       @return
       TRUE if the sound has been recorded.
     */
    BOOL RecordFile(
      const PFilePath & file /// Sound file recorded
    );

    /**Start filling record buffers. The first call to Read() will also
       initiate the recording.

       @return
       TRUE if the sound driver has successfully started recording.
     */
    BOOL StartRecording();

    /**Determine if a record buffer has been filled, so that the next Read()
       call will not block. Provided that the amount of data read is less than
       the buffer size.

       @return
       TRUE if the sound driver has filled a buffer.
     */
    BOOL IsRecordBufferFull();

    /**Determine if all of the record buffer allocated has been filled. There
       is an implicit Abort() of the recording if this occurs and recording is
       stopped. The channel may need to be closed and opened again to start
       a new recording.

       @return
       TRUE if the sound driver has filled a buffer.
     */
    BOOL AreAllRecordBuffersFull();

    /**Block the thread until a record buffer has been filled, so that the
       next Read() call will not block. Provided that the amount of data read
       is less than the buffer size.

       @return
       TRUE if the sound driver has filled a buffer.
     */
    BOOL WaitForRecordBufferFull();

    /**Block the thread until all of the record buffer allocated has been
       filled. There is an implicit Abort() of the recording if this occurs
       and recording is stopped. The channel may need to be closed and opened
       again to start a new recording.

       @return
       TRUE if the sound driver has filled a buffer.
     */
    BOOL WaitForAllRecordBuffersFull();
  //@}


  private:
    void Construct();

#ifdef DOC_PLUS_PLUS
};
#endif

// Class declaration continued in platform specific header file ///////////////