osssoundcard.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_SOUNDCARD_H
#define DXR3PLAYER_OUTPUT_SOUNDCARD_H
//------------------------------------------------------------------------------

#include "AudioDevice.h"

#include "sched/Thread.h"

#include "util/Device.h"
#include "util/FDWriter.h"

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

namespace output {

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

/**
 * Wrapper class for an OSS soundcard device
 */
class OSSSoundcard : public AudioDevice, 
                     public FDWriter< Device<> >,
                     public sched::Thread
{
private:
    /**
     * The size of the sound card driver's buffer.
     */
    size_t bufferSize;

    /**
     * The number of bytes written so far.
     */
    unsigned long long bytesWritten;

    /**
     * The data to write.
     */
    const void* volatile data;

    /**
     * The length of the data to write.
     */
    volatile size_t dataLength;

public:
    /**
     * Construct the sound card with the given DSP device.
     */
    OSSSoundcard(const char* dsp);

    /**
     * Destroy the sound card.
     */
    ~OSSSoundcard();

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

    /**
     * Write the given buffer to the sound card. It also keeps track
     * of the number of bytes written.
     */
    virtual size_t play(const void* buf, size_t count, bool interruptible = true);

    /**
     * Get the number of samples played since opening the device.
     *
     * Can be called only for sound cards with real-time capability
     */
    virtual unsigned long long getNumberOfSamplesPlayed();
    
    /**
     * Get the number of samples buffered (i.e. in the buffer, ready
     * to be played, but not yet played!). 
     *
     * Can be called only for sound cards with real-time capability
     */
    virtual unsigned long long getNumberOfSamplesBuffered();

    /**
     * Stop the playback. For triggerable sound cards, the output will
     * be disabled as well, and has to be started with a call to start().
     */
    virtual void stopPlayback();

    /**
     * Stop the sound card.
     */
    virtual void stop();

private:
    /**
     * Convert the given number of samples to a PTS difference value.
     */
    ptsdiff_t samples2PTS(unsigned long long samples) 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
     */
    virtual void doSetup(audioMode_t& mode, unsigned& rate, bool& s);

    /**
     * Perform the actual writing of the data.
     */
    virtual void perform();
};

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

} /* namespace output */

//------------------------------------------------------------------------------
#endif // DXR3PLAYER_OUTPUT_SOUNDCARD_H

// Local variables:
// mode: c++
// End: