audiooutputnull.h

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#ifndef AUDIOOUTPUTNULL
#define AUDIOOUTPUTNULL

#include <qmutex.h>
#include <pthread.h>

#include "audiooutputbase.h"

#define NULLAUDIO_OUTPUT_BUFFER_SIZE 32768

/*

    In its default invocation, this AudioOutput object does almost nothing. 
    It takes all bytes written to its "device" and just ignores them. Since
    there is no device in the way consuming the audio bytes, nothing
    throttles the speed of decoding.
    
    If it is told to buffer the output data (bufferOutputData(true)), then
    it will maintain a small buffer and will not let anymore audio data be
    decoded until something pulls the data off (via readOutputData()). 

*/

class AudioOutputNULL : public AudioOutputBase
{
public:
    AudioOutputNULL(QString laudio_main_device,
                    QString laudio_passthru_device,
                    int laudio_bits,
                    int laudio_channels, int laudio_samplerate,
                    AudioOutputSource lsource,
                    bool lset_initial_vol, bool laudio_passthru);
    virtual ~AudioOutputNULL();

    virtual void Reset(void);


    // Volume control
    virtual int GetVolumeChannel(int /* channel */){ return 100; }
    virtual void SetVolumeChannel(int /* channel */, int /* volume */){ return; }

    virtual int readOutputData(unsigned char *read_buffer, int max_length);

protected:
    // You need to implement the following functions
    virtual bool OpenDevice(void);
    virtual void CloseDevice(void);
    virtual void WriteAudio(unsigned char *aubuf, int size);
    virtual inline int getSpaceOnSoundcard(void);
    virtual inline int getBufferedOnSoundcard(void);

private:

    QMutex        pcm_output_buffer_mutex;
    unsigned char pcm_output_buffer[NULLAUDIO_OUTPUT_BUFFER_SIZE];
    int           current_buffer_size;

    int           locked_audio_channels;
    int           locked_audio_bits;
    int           locked_audio_samplerate;
};

#endif

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