linux下ALSA播放声音的源程序.docxVIP

linux下ALSA播放声音的源程序 #include stdio.h/* Use the newer ALSA API */#define ALSA_PCM_NEW_HW_PARAMS_API#include alsa/asoundlib.hint main() {?? ?long loops;?? ?int rc;?? ?int size;?? ?snd_pcm_t *handle;?? ?snd_pcm_hw_params_t *params;?? ?unsigned int val;?? ?int dir;?? ?snd_pcm_uframes_t frames;?? ?snd_pcm_uframes_t periodsize;?? ?char *buffer;?? ?FILE *fp = fopen(play.wav, rb);?? ?if(fp == NULL)?? ?return 0;?? ?fseek(fp, 100, SEEK_SET);?? ?/* Open PCM device for playback. */?? ?rc = snd_pcm_open(handle, default,?? ??? ???????????? SND_PCM_STREAM_PLAYBACK, 0);//SND_PCM_NONBLOCK);?? ?if (rc 0) {?? ?fprintf(stderr,?? ??? ???? unable to open pcm device: %s\n,?? ??? ???? snd_strerror(rc));?? ?exit(1);?? ?}?? ?/* Allocate a hardware parameters object. */?? ?snd_pcm_hw_params_alloca(params);?? ?/* Fill it in with default values. */?? ?snd_pcm_hw_params_any(handle, params);?? ?/* Set the desired hardware parameters. */?? ?/* Interleaved mode */?? ?snd_pcm_hw_params_set_access(handle, params,?? ??? ?????????????? SND_PCM_ACCESS_RW_INTERLEAVED);?? ?/* Signed 16-bit little-endian format */?? ?snd_pcm_hw_params_set_format(handle, params,?? ??? ?????????????????????? SND_PCM_FORMAT_S16_LE);?? ?/* Two channels (stereo) */?? ?snd_pcm_hw_params_set_channels(handle, params, 1);?? ?/* 44100 bits/second sampling rate (CD quality) */?? ?val = 8000;?? ?snd_pcm_hw_params_set_rate_near(handle, params,?? ??? ?????????????????????????? val, dir);?? ?/* Set period size to 32 frames. */?? ?frames = 32;?? ?periodsize = frames * 2;?? ?rc = snd_pcm_hw_params_set_buffer_size_near(handle, params, periodsize);?? ?if (rc 0) ?? ?{?? ??? ? printf(Unable to set buffer size %li : %s\n, frames * 2, snd_strerror(rc));?? ??? ? ?? ?}?? ? ??? ?periodsize /= 2;?? ?rc = snd_pcm_hw_params_set_period_size_near(handle, params, periodsize, 0);?? ?if (rc 0) ?? ?{?? ??? ?printf(Unable to set period size %li : %s\n, periodsize,? snd_strerror(rc));??