alsa播放音频类

点击打开链接      http://airmanisvip.blog.163.com/blog/static/18058158201292694231575/

//CAudioplayer.h

#include <alsa/asoundlib.h>
class CAudioPlayer
{
public:
CAudioPlayer();
~CAudioPlayer();

bool InitPlayer(int iHwnd,int iSampleRate,char nBits,
char nChannels,int iFrameSize);
bool OpenPlayer();
void ClosePlayer();
void PlaySound(char*pszBuffer,int iSize,int iMillSec);

bool PausePlay();
bool ResumePlay();
private:
bool m_bFirstPlay;//第一次播放
int m_iHwnd;//播放窗口句柄
int m_iFrameSize;//帧数据大小

int m_iSampleRate;//采样率
char m_nSampleBits;//位宽
char m_nChannels;//通道数

snd_pcm_sw_params_t*m_sw_params;
snd_pcm_hw_params_t*m_params;
snd_pcm_t *m_hDevice;
int m_iBytesPerSample;
int m_iBufferSize;
int m_iBytesPerPeriod;
};

//CAudioplayer.cpp
#include "audioplayer.h"
#define THIS_FILE "audioplayer.cpp"

CAudioPlayer::CAudioPlayer()
{
m_bFirstPlay =true;//第一次播放
m_iHwnd = NULL;//播放窗口句柄
m_iFrameSize =0;//帧数据大小

m_iSampleRate =8000;//采样率
m_nSampleBits =16;//位宽
m_nChannels =1;//通道数

m_sw_params = NULL;
m_params = NULL;
m_hDevice = NULL;
m_iBytesPerSample =0;
m_iBufferSize =0;
m_iBytesPerPeriod =0;

}

CAudioPlayer::~CAudioPlayer()
{
ClosePlayer();

}

bool CAudioPlayer::InitPlayer(int iHwnd,int iSampleRate,char nBits,
char nChannels,int iFrameSize)
{
m_bFirstPlay =true;
m_iHwnd = iHwnd;
m_iFrameSize = iFrameSize;

m_iSampleRate = iSampleRate;
m_nSampleBits = nBits;
m_nChannels = nChannels;

return true;
}

bool CAudioPlayer::OpenPlayer()
{

m_iBytesPerSample = m_nChannels*m_nSampleBits/8;

int rc = snd_pcm_open(&m_hDevice,"default", SND_PCM_STREAM_PLAYBACK,0);
if( rc<0)
{
return false;
}

if( snd_pcm_nonblock( m_hDevice,1)<0)
{
WriteLog("snd_pcm_nonblock error");
return false;
}

snd_pcm_hw_params_alloca(&m_params);
snd_pcm_sw_params_alloca(&m_sw_params);

if((rc= snd_pcm_hw_params_any( m_hDevice, m_params))<0)
{
return false;
}

rc = snd_pcm_hw_params_set_access(m_hDevice, m_params, SND_PCM_ACCESS_RW_INTERLEAVED);
if ( rc<0)
{
WriteLog("audioplayer set hw access failed!");
return false;
}

if(( rc= snd_pcm_hw_params_set_format(m_hDevice, m_params, SND_PCM_FORMAT_S16_LE))<0)
{
WriteLog("audioplayer set hw format failed!");
return false;
}

WriteLog("%s set channels:%d!", THIS_FILE, m_nChannels);
if(( rc= snd_pcm_hw_params_set_channels(m_hDevice, m_params, m_nChannels))<0)
{
WriteLog("audioplayer set hw channels failed!");
return false;
}

//samplerate
int val = m_iSampleRate;
WriteLog("%s set rate:%d!", THIS_FILE, val);
if(( rc= snd_pcm_hw_params_set_rate_near( m_hDevice, m_params,(unsignedint*)&val, NULL))<0)
{
WriteLog("audioplayer set hw rate failed!");
return false;
}
WriteLog("%s rate set to:%d!", THIS_FILE, val);

//hardware buffer times
unsigned int ibuffertime =500000;
if (( rc= snd_pcm_hw_params_set_buffer_time_near( m_hDevice, m_params,&ibuffertime, NULL))<0)
{
WriteLog("audioplayer set hw buffer time failed!");
return false;
}

//cache count
unsigned int fragcount =16;
if (( rc= snd_pcm_hw_params_set_periods_near( m_hDevice, m_params,&fragcount, NULL))<0)
{
WriteLog("audioplayer set hw periods failed!");
return false;
}

/* finally install hardware parameters */
if (( rc= snd_pcm_hw_params(m_hDevice, m_params))<0)
{
WriteLog("audioplayer set hw params failed!");
return false;
}
// end setting hw-params

// gets buffersize for control
snd_pcm_uframes_t bufsize=0;
if (( rc= snd_pcm_hw_params_get_buffer_size( m_params,&bufsize))<0)
{
return false;
}
else
{
m_iBufferSize = bufsize* m_iBytesPerSample;
WriteLog("audioplayer get buffersize = %d", m_iBufferSize);
}

//get sample count per period
snd_pcm_uframes_t chunksize=0;
if (( rc= snd_pcm_hw_params_get_period_size( m_params,&chunksize, NULL))<0)
{
WriteLog("audioplayer get period failed!");
return false;
}
else
{
WriteLog("audioplayer get period = %d", chunksize);
}
m_iBytesPerPeriod = chunksize* m_iBytesPerSample;

/* setting software parameters */
if (( rc= snd_pcm_sw_params_current( m_hDevice, m_sw_params))<0)
{
WriteLog("audioplayer sw params current failed, errorcode = %s", snd_strerror(rc));
return false;
}

/* start playing when one period has been written */
if (( rc= snd_pcm_sw_params_set_start_threshold( m_hDevice, m_sw_params, chunksize) )<0)
{
WriteLog("audioplayer sw params start threshold failed, errorcode = %s", snd_strerror(rc));
return false;
}

snd_pcm_uframes_t boundary;
if (( rc= snd_pcm_sw_params_get_boundary( m_sw_params,&boundary))<0)
{
WriteLog("audioplayer sw params get boundary failed, errorcode = %s", snd_strerror(rc));
return false;
}

/* disable underrun reporting */
if (( rc= snd_pcm_sw_params_set_stop_threshold(m_hDevice, m_sw_params, boundary ))<0)
{
WriteLog("audioplayer sw params stop threshold failed, errorcode = %s", snd_strerror(rc));
return false;
}

/* play silence when there is an underrun */
if (( rc= snd_pcm_sw_params_set_silence_size( m_hDevice, m_sw_params, boundary) )<0)
{
WriteLog("audioplayer sw params set silence size failed, errorcode = %s", snd_strerror(rc));
return false;
}

if (( rc= snd_pcm_sw_params( m_hDevice, m_sw_params))<0)
{
WriteLog("audioplayer sw params failed, errorcode = %s", snd_strerror(rc));
return false;
}
/* end setting sw-params */

return true;
}

void CAudioPlayer::ClosePlayer()
{
m_bFirstPlay =true;

if( NULL!= m_hDevice)
{
snd_pcm_drain(m_hDevice);
snd_pcm_close(m_hDevice);
m_hDevice = NULL;
}
}

void CAudioPlayer::PlaySound(char*pszBuffer,int iSize,int iMillSec)
{
if(NULL== pszBuffer)
{
return;
}

int iNumFrames=0;
snd_pcm_sframes_t res=0;

iNumFrames = iSize/m_iBytesPerSample;

do
{
res = snd_pcm_writei( m_hDevice, pszBuffer, iNumFrames );
if ( res==-EINTR)
{
res = 0;
}
else if( res==-ESTRPIPE)
{
WriteLog("audio player play return -ESTRPIPE1");
while ( (res= snd_pcm_resume(m_hDevice))==-EAGAIN)
{
WriteLog("audio player play return -ESTRPIPE2");
Tos_thread_sleep(1);
}
}

if ( res<0)
{
if (( res= snd_pcm_prepare(m_hDevice))<0)
{
return ;
}
}
} while(res==0);

}

bool CAudioPlayer::PausePlay()
{
int err = 0;
if ((err= snd_pcm_drop(m_hDevice))<0)
{
return false;
}

return true;
}

bool CAudioPlayer::ResumePlay()
{
int err = 0;
if((err= snd_pcm_prepare(m_hDevice))<0)
{
return false;
}

return true;
}