audlinux_alsa.cpp

linux下的一款播放器

/* ***** BEGIN LICENSE BLOCK *****
 * Source last modified: $Id: audlinux_alsa.cpp,v 1.1.2.1 2004/07/09 02:01:42 hubbe Exp $
 * 
 * Portions Copyright (c) 1995-2004 RealNetworks, Inc. All Rights Reserved.
 * 
 * The contents of this file, and the files included with this file,
 * are subject to the current version of the RealNetworks Public
 * Source License (the "RPSL") available at
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 * the file under the current version of the RealNetworks Community
 * Source License (the "RCSL") available at
 * http://www.helixcommunity.org/content/rcsl, in which case the RCSL
 * will apply. You may also obtain the license terms directly from
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 * to this file, the RCSL.  Please see the applicable RPSL or RCSL for
 * the rights, obligations and limitations governing use of the
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 * 
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 * developer of the Original Code and owns the copyrights in the
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 * 
 * This file, and the files included with this file, is distributed
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 * ***** END LICENSE BLOCK ***** */

#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/ioctl.h>

#define ALSA_PCM_NEW_HW_PARAMS_API
#define ALSA_PCM_NEW_SW_PARAMS_API

#include <alsa/asoundlib.h>

#include <stdio.h> 
#include <math.h>

#include "ihxpckts.h"
#include "hxtick.h"
#include "hxprefs.h"
#include "timeval.h"
#include "hxthread.h"
#include "audlinux_alsa.h"
#include "hxstrutl.h"

#include "dllacces.h"
#include "dllpath.h"

//------------------------------------------
// Ctors and Dtors.
//------------------------------------------
CAudioOutLinuxAlsa::CAudioOutLinuxAlsa() :
  CAudioOutUNIX(),
  m_ulTickCount(0),
  m_ulLastBytesPlayed(0),
  m_ulLastTimeStamp(0),
  m_ulPausePosition(0),
  m_bHasHardwarePause(FALSE),
  m_bHasHardwareResume(FALSE),
  pcm_handle(0),
  mixer_handle(0)
{
};

CAudioOutLinuxAlsa::~CAudioOutLinuxAlsa()
{
#ifdef _DEBUG
  printf("d\'tor\n");
#endif
  //The mixer is opened independently of the audio device. Make sure
  //it is closed.
  _CloseMixer();

  snd_pcm_hw_params_free(hwparams);
  //    snd_pcm_status_free(status);
};


// These Device Specific methods must be implemented
// by the platform specific sub-classes.
INT16 CAudioOutLinuxAlsa::_Imp_GetAudioFd(void)
{
  return (INT16) pcm_handle;
}


//Device specific methods to open/close the mixer and audio devices.
HX_RESULT CAudioOutLinuxAlsa::_OpenAudio()
{
  HX_RESULT retCode = RA_AOE_NOERR;
  int err=0;
    
  //Set the tick count to zero
  m_ulTickCount       = 0;
  m_ulLastTimeStamp   = 0;
  m_ulLastBytesPlayed = 0;
  m_ulPausePosition   = 0;

  //Check the environmental variable to let user overide default device.
  char *pszOverrideName = getenv( "AUDIO" );
  char szDevName[MAX_DEV_NAME];

  // Use defaults if no environment variable is set.
  if ( pszOverrideName && strlen(pszOverrideName)>0 )
    {
      SafeStrCpy( szDevName, pszOverrideName, MAX_DEV_NAME );
    }
  else
    {
      SafeStrCpy( szDevName, "default", MAX_DEV_NAME );
      //        SafeStrCpy( szDevName, "hw:0,0", MAX_DEV_NAME );
      //        SafeStrCpy( szDevName, "plughw:0,0", MAX_DEV_NAME );
    }

  // Open the audio device if it isn't already open
  if ( pcm_handle <= 0 )
    {
      if ( snd_pcm_open( &pcm_handle, szDevName, SND_PCM_STREAM_PLAYBACK /*stream*/, 0) < 0) {
#ifdef _DEBUG
        fprintf( stderr, "Failed to open audio device %s : %d  errno: %d\n",
                 szDevName, pcm_handle, errno );
#endif
        retCode = RA_AOE_BADOPEN;
      }
    }

  if((err=snd_pcm_nonblock( pcm_handle, 1)) < 0)
    {
#ifdef _DEBUG
      fprintf (stderr, "Cannot set nonblock (%s)\n",
               snd_strerror (err));
#endif
    }

  //     if((err = snd_pcm_status_malloc( &status)) <0)
  //       {
  //           fprintf (stderr, "cannot allocate status parameter structure (%s)\n",
  //                    snd_strerror (err));
  //       }

  if((err = snd_pcm_hw_params_malloc( &hwparams)) < 0)
    {
#ifdef _DEBUG
      fprintf (stderr, "HW parameters malloc failed %s\n",
               snd_strerror (err));
#endif
    }
 
  if ((err = snd_pcm_hw_params_any( pcm_handle, hwparams)) < 0) {
#ifdef _DEBUG
    fprintf (stderr, "HW parameters init failed %s\n",
             snd_strerror (err));
#endif
  }

  m_wLastError = retCode;
  return m_wLastError;
}


HX_RESULT CAudioOutLinuxAlsa::_CloseAudio()
{
  HX_RESULT retCode = RA_AOE_NOERR;
  if( pcm_handle > 0 )
    //        if (snd_pcm_state( pcm_handle) == SND_PCM_STATE_OPEN)
    {
      snd_pcm_close( pcm_handle);
      pcm_handle = 0;//NO_FILE_DESCRIPTOR;
#ifdef _DEBUG
      printf("pcm_handle is now %d\n", pcm_handle);
#endif
    }
  else
    {
      retCode = RA_AOE_DEVNOTOPEN;
    }

  m_wLastError = retCode;
  return m_wLastError;
}


HX_RESULT CAudioOutLinuxAlsa::_OpenMixer()
{
  HX_RESULT retCode = RA_AOE_NOERR;
  int result;
    
  if(!m_bMixerPresent)
    {
      //Let user override default device with environ variable.
      char *pszOverrideName = getenv( "MIXER" );
      char szDevCtlName[MAX_DEV_NAME];

      // could be "hw:0,0", or "plughw:0,0" or similiar
      if (pszOverrideName && strlen(pszOverrideName) > 0 )
        {
          SafeStrCpy( szDevCtlName , pszOverrideName, MAX_DEV_NAME );
        }
      else
        {
          SafeStrCpy( szDevCtlName , "default", MAX_DEV_NAME ); 
          // default for volume
        }

      if (( result = snd_mixer_open( &mixer_handle, 0)) < 0)
        {
#ifdef _DEBUG
          printf( "Open audio device failed %d", result);
#endif
          retCode = RA_AOE_BADOPEN;
        }
  
      if (( result = snd_mixer_attach( mixer_handle, szDevCtlName )) < 0) {
#ifdef _DEBUG
        printf("Mixer attach %s failed: %s", szDevCtlName, snd_strerror( result));
#endif
        snd_mixer_close( mixer_handle);
        retCode = RA_AOE_NOTENABLED;
      }
  
      if (( result = snd_mixer_selem_register( mixer_handle, NULL, NULL)) < 0) {
#ifdef _DEBUG
        printf("Register mixer error: %s", snd_strerror( result));
#endif
        snd_mixer_close( mixer_handle);
        retCode = RA_AOE_NOTENABLED;
      }

      if((result = snd_mixer_load( mixer_handle)) < 0 )
        {
          retCode = RA_AOE_NOTENABLED;
        }

      if (mixer_handle > 0)
        {
          m_bMixerPresent = 1;
          _Imp_GetVolume();
        }
      else
        {
          mixer_handle = 0;// NO_FILE_DESCRIPTOR;
          m_bMixerPresent = 0;
        }
    }

  m_wLastError = retCode;
  return m_wLastError;
}

HX_RESULT CAudioOutLinuxAlsa::_CloseMixer()
{
  if( mixer_handle > 0 )
    {
      //Let user override default device with environ variable.
      char *pszOverrideName = getenv( "MIXER" );
      char szDevCtlName[MAX_DEV_NAME];

      // could be "hw:0,0", or "plughw:0,0" or similiar
      if (pszOverrideName && strlen(pszOverrideName) > 0 )
        {
          SafeStrCpy( szDevCtlName , pszOverrideName, MAX_DEV_NAME );
        }
      else
        {
          SafeStrCpy( szDevCtlName , "default", MAX_DEV_NAME ); 
          // default for volume
        }

      if( snd_mixer_detach( mixer_handle, szDevCtlName) < 0)
        {
#ifdef _DEBUG
          printf("Detach mixer failed\n");
#endif
        }
  
      if(snd_mixer_close ( mixer_handle) < 0)
        {
#ifdef _DEBUG
          printf("Close mixer failed\n");
#endif
          mixer_handle = 0;//NO_FILE_DESCRIPTOR;
        }
    }

  return m_wLastError;
}


//Devic specific method to set the audio device characteristics. Sample rate,
//bits-per-sample, etc.
//Method *must* set member vars. m_unSampleRate and m_unNumChannels.
HX_RESULT CAudioOutLinuxAlsa::_SetDeviceConfig( const HXAudioFormat* pFormat )
{
  HX_RESULT retCode = RA_AOE_NOERR;
  int err=0;

  if (snd_pcm_state( pcm_handle) != SND_PCM_STATE_OPEN)
    return RA_AOE_DEVNOTOPEN;

  if (snd_pcm_hw_params_any( pcm_handle, hwparams) < 0) {
#ifdef _DEBUG
    fprintf(stderr, "Configure device failed\n");
#endif
    return  retCode = RA_AOE_NOTENABLED;
  }

  // SND_PCM_ACCESS_RW_INTERLEAVED or       
  // SND_PCM_ACCESS_RW_NONINTERLEAVED.      
  // There are also access types for MMAPed 
  if (snd_pcm_hw_params_set_access( pcm_handle, hwparams,
                                    SND_PCM_ACCESS_RW_INTERLEAVED) < 0) {
#ifdef _DEBUG
    fprintf(stderr, "Set access failed\n");
#endif
    return  retCode = RA_AOE_NOTENABLED;
  }

  //  Now set the format. Either 8-bit or 16-bit audio is supported.
  // alsa supports up to 64 bit
  int      nSampleWidth  = pFormat->uBitsPerSample;
  ULONG32  nSampleRate   = pFormat->ulSamplesPerSec;
  int      numChannels   = pFormat->uChannels;
  int      nFormat1      = 0;
  int      nFormat2      = 0;

  snd_pcm_format_t m_format;
  snd_pcm_uframes_t bufferSz;
  unsigned long buffer_size, period_size;

  if( nSampleWidth == 16)
    {
      m_format = SND_PCM_FORMAT_S16;
    }
  else
    {
      m_format =  SND_PCM_FORMAT_U8;
    }

  m_frameBytes = snd_pcm_format_physical_width( m_format);

  if ((err = snd_pcm_hw_params_set_format( pcm_handle, hwparams,
                                           m_format) < 0)) {
#ifdef _DEBUG
    fprintf (stderr, "Set sample format failed %s %d\n",
             snd_strerror (err), m_format );
#endif        
    return (  m_wLastError = RA_AOE_NOTENABLED );
  }

  //If we went to 8-bit then
  if( m_format ==  SND_PCM_FORMAT_U8 )
    {
      nSampleWidth = 8;
    }

  m_uSampFrameSize = samplesize =nSampleWidth/8;

  if ( nSampleWidth != pFormat->uBitsPerSample )
    {
      ((HXAudioFormat*)pFormat)->uBitsPerSample = nSampleWidth;
    }

  // Set sample rate. If the exact rate is not supported
  // by the hardware, use nearest possible rate.         
  unsigned int rrate = (unsigned int) nSampleRate;
  if(( err = snd_pcm_hw_params_set_rate_near( pcm_handle, hwparams, &rrate, 0) ) < 0 )
    {
#ifdef _DEBUG
      fprintf(stderr,
              "The rate %d Hz is not supported by your hardware.\n==> Using %d Hz instead.\n",
              nSampleRate, rrate);
#endif
      return ( m_wLastError = RA_AOE_NOTENABLED );
    }

  m_unSampleRate = rrate;

  if ( rrate != pFormat->ulSamplesPerSec )
    {
      ((HXAudioFormat*)pFormat)->ulSamplesPerSec = rrate;
    }


  if (snd_pcm_hw_params_set_channels( pcm_handle, hwparams, numChannels) < 0) {
#ifdef _DEBUG
    fprintf(stderr, "Error setting channels.\n");
#endif
    return ( m_wLastError = RA_AOE_NOTENABLED );
  }