audiodevice.h

Linux下比较早的基于命令行的DVD播放器

// Copyright (c) 2004 by Istv醤 V醨adi

// This file is part of dxr3Player, a DVD player written specifically 
// for the DXR3 (aka Hollywood+) decoder card.

// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

#ifndef DXR3PLAYER_OUTPUT_AUDIODEVICE_H
#define DXR3PLAYER_OUTPUT_AUDIODEVICE_H
//------------------------------------------------------------------------------

#include "util/Util.h"

#include "enums.h"

#include <cstdlib>

//------------------------------------------------------------------------------

namespace output {

//------------------------------------------------------------------------------

/**
 * Interface for audio devices. 
 */
class AudioDevice
{
private:
    /**
     * The size of samples on a single channel.
     */
    static const size_t singleSampleSize = 2;

protected:
    /**
     * Indicate if the audio device has real-time capabilities. Some
     * methods may be called only if it has.
     */
    bool realTime;
    
    /**
     * Indicate if the audio device is triggeralbe. Some
     * methods may be called only if it has.
     */
    bool triggerable;
    
    /**
     * Our current audio mode.
     */
    audioMode_t audioMode;

    /**
     * The sample rate.
     */
    unsigned sampleRate;

    /**
     * Indicate if stereo playback is enabled.
     */
    bool stereo;

public:
    /**
     * Default constructor.
     */
    AudioDevice();

    /**
     * Virtual destructor.
     */
    virtual ~AudioDevice();

    /**
     * Get if the audio device has real-time capabilities.
     */
    bool isRealTime() const;

    /**
     * Get if the audio device is triggerable.
     */
    bool isTriggerable() const;

    /**
     * Setup the audio device.
     *
     * @param s the audio mode
     * @param rate the sampling rate in Hz
     * @param s indicate if stereo or mono mode
     */
    void setup(audioMode_t mode, unsigned rate, bool s);

    /**
     * Get the audio mode.
     */
    audioMode_t getAudioMode() const;
    
    /**
     * Get the sample rate of the sound card.
     */
    unsigned getSampleRate() const;

    /**
     * Get the size of a sample.
     */
    size_t getSampleSize() const;

    /**
     * Determine if stereo playback is enabled.
     */
    bool isStereo() const;

    /**
     * Start playback on the card.
     *
     * Can be called only for triggerable sound cards.
     */
    virtual void startPlayback() = 0;

    /**
     * Write the given data to the card. It returns when all data has
     * been written or when the playback has been stopped by a call
     * to stopPlayback().
     */
    virtual size_t play(const void* d, size_t length, bool interruptible = true) = 0;

    /**
     * Get the number of samples played since starting the playback.
     *
     * Can be called only for sound cards with real-time capability
     */
    virtual unsigned long long getNumberOfSamplesPlayed() = 0;

    /**
     * Get the amount of sound played since starting the playback in PTS.
     *
     * Can be called only for sound cards with real-time capability
     */
    ptsdiff_t getPTSPlayed();

    /**
     * Get the number of samples currently buffered.
     *
     * Can be called only for sound cards with real-time capability
     */
    virtual unsigned long long getNumberOfSamplesBuffered() = 0;

    /**
     * Get the amount of sound buffered in PTS.
     *
     * Can be called only for sound cards with real-time capability
     */
    ptsdiff_t getPTSBuffered();

    /**
     * Stop the playback.
     */
    virtual void stopPlayback() = 0;

    /**
     * Stop the audio device.
     */
    virtual void stop() = 0;

private:
    /**
     * Perform the real setting up of the device.
     */
    virtual void doSetup(audioMode_t& mode, unsigned& rate, bool& s) = 0;

    /**
     * Convert the given number of samples to a PTS difference value.
     */
    ptsdiff_t samples2PTS(unsigned long long samples) const;
};

//------------------------------------------------------------------------------
// Inline definitions
//------------------------------------------------------------------------------

inline AudioDevice::AudioDevice() :
    realTime(false),
    triggerable(false),
    audioMode(AM_ANALOGUE),
    sampleRate(48000),
    stereo(true)
{
}

//------------------------------------------------------------------------------

inline AudioDevice::~AudioDevice()
{
}

//------------------------------------------------------------------------------

inline bool AudioDevice::isRealTime() const
{
    return realTime;
}

//------------------------------------------------------------------------------

inline bool AudioDevice::isTriggerable() const
{
    return triggerable;
}

//------------------------------------------------------------------------------

inline audioMode_t AudioDevice::getAudioMode() const
{
    return audioMode;
}

//------------------------------------------------------------------------------

inline unsigned AudioDevice::getSampleRate() const
{
    return sampleRate;
}

//------------------------------------------------------------------------------

inline size_t AudioDevice::getSampleSize() const
{
    return singleSampleSize * (stereo ? 2 : 1);
}

//------------------------------------------------------------------------------

inline bool AudioDevice::isStereo() const
{
    return stereo;
}

//------------------------------------------------------------------------------

inline ptsdiff_t AudioDevice::samples2PTS(unsigned long long samples) const
{
    ptsdiff_t ptsDiff = samples;
    
    ptsDiff *= Util::ptsFrequency;
    ptsDiff /= sampleRate;

    return ptsDiff;
}

//------------------------------------------------------------------------------

inline ptsdiff_t AudioDevice::getPTSPlayed()
{
    return samples2PTS(getNumberOfSamplesPlayed());
}

//------------------------------------------------------------------------------

inline ptsdiff_t AudioDevice::getPTSBuffered()
{
    return samples2PTS(getNumberOfSamplesBuffered());
}

//------------------------------------------------------------------------------


} /* namespace output */

//------------------------------------------------------------------------------
#endif // DXR3PLAYER_OUTPUT_AUDIODEVICE_H

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