alsa_udp_r.c:
#include "alsa/asoundlib.h"
struct snd_pcm
{
snd_pcm_t *handle;
snd_pcm_uframes_t frame;
};
int init_pcm_capture(snd_pcm_t **handle,snd_pcm_uframes_t *frame)
{
//1.定义pcm句柄
snd_pcm_hw_params_t *params = NULL;
//2.打开pcm设备---采集方式打开
//(SND_PCM_STREAM_CAPTURE:打开模式)
snd_pcm_open(handle, "default", SND_PCM_STREAM_CAPTURE, 0);
//3 分配参数空间， 设置默认参数
snd_pcm_hw_params_alloca(¶ms);
//分配空间
snd_pcm_hw_params_any(*handle, params); //默认值
//4.设置交错模式
snd_pcm_hw_params_set_access(*handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
//5设置量化
snd_pcm_hw_params_set_format(*handle, params, SND_PCM_FORMAT_S16_LE);
//6设置通道数据
snd_pcm_hw_params_set_channels(*handle, params, 2);
//7设置采样率
int val = 44100;
snd_pcm_hw_params_set_rate_near(*handle, params, &val,0);
//8把设置好的参数设置到pcm设备
snd_pcm_hw_params(*handle,params);
//9.分配一个周期空间
//获取一个周期的帧数
snd_pcm_hw_params_get_period_size(params, frame, 0);
}
int init_pcm_playback(snd_pcm_t **handle,snd_pcm_uframes_t *frame)
{
//1.定义pcm句柄
//snd_pcm_t *handle = NULL;
snd_pcm_hw_params_t *params = NULL;
//2.打开pcm设备---采集方式打开
//(SND_PCM_STREAM_CAPTURE:打开模式)
snd_pcm_open(handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
//3 分配参数空间， 设置默认参数
snd_pcm_hw_params_alloca(¶ms);
//分配空间
snd_pcm_hw_params_any(*handle, params); //默认值
//4.设置交错模式
snd_pcm_hw_params_set_access(*handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
//5设置量化
snd_pcm_hw_params_set_format(*handle, params, SND_PCM_FORMAT_S16_LE);
//6设置通道数据
snd_pcm_hw_params_set_channels(*handle, params, 2);
//7设置采样率
int val = 44100;
snd_pcm_hw_params_set_rate_near(*handle, params, &val,0);
//8把设置好的参数设置到pcm设备
snd_pcm_hw_params(*handle,params);
//9.分配一个周期空间
//获取一个周期的帧数
snd_pcm_hw_params_get_period_size(params, frame, 0);
}
int init_udp_sockfd(int *sockfd,struct sockaddr_in *s_addr,int argc,char **argv)
{
if(argc < 1)
{
printf("input error\n");
exit(0);
}
if((*sockfd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
{
perror("socket");
exit(0);
}
bzero(s_addr,sizeof(struct sockaddr_in));
s_addr->sin_family = AF_INET;
s_addr->sin_port = htons(12345);
s_addr->sin_addr.s_addr = inet_addr(argv[1]);
int sin_size = 1;
if((setsockopt(*sockfd,SOL_SOCKET,SO_REUSEADDR,&sin_size,sizeof(int))) < 0)
{
perror("setsockopt");
exit(0);
}
return 0;
}
int main(int argc,char **argv)
{
//初始化udp
int sockfd;
struct sockaddr_in s_addr;
init_udp_sockfd(&sockfd,&s_addr,argc,argv);
//初始化pcm
struct snd_pcm sp_cp;
struct snd_pcm sp_pb;
sp_cp.handle = NULL;
sp_cp.frame = 0;
sp_pb.handle = NULL;
sp_pb.frame = 0;
init_pcm_capture(&sp_cp.handle,&sp_cp.frame);
//init_pcm_playback(&pb.handle,&sp_pb.frame);
int size = sp_cp.frame * 4;//计算一个周期所需要的存储空间
unsigned char *buffer = malloc(size);//分配一个周期的空间
while(1)
{
snd_pcm_readi(sp_cp.handle, buffer, sp_cp.frame);//采集一个周期数据
if(sendto(sockfd,buffer,size,0,(struct sockaddr *)&s_addr,sizeof(s_addr)) < 0)
{
perror("sendto");
exit(0);
}
}
//销毁pcm句柄
snd_pcm_drain(sp_cp.handle);
//关闭pcm设备
snd_pcm_close(sp_cp.handle);
//释放堆空间（存储一个周期数据）
free(buffer);
return 0;
}
上面代码属于嵌入式板上获取音频信息并且通过UDP发送到目标IP，使用./可执行文件名字 目标IP
alsa_net_s.c:
#include "alsa/asoundlib.h"
struct snd_pcm
{
snd_pcm_t *handle;
snd_pcm_uframes_t frame;
};
int init_pcm_playback(snd_pcm_t **handle,snd_pcm_uframes_t *frame)
{
//1.定义pcm句柄
snd_pcm_hw_params_t *params = NULL;
//2.打开pcm设备---采集方式打开
//(SND_PCM_STREAM_CAPTURE:打开模式)
snd_pcm_open(handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
//3 分配参数空间， 设置默认参数
snd_pcm_hw_params_alloca(¶ms);
//分配空间
snd_pcm_hw_params_any(*handle, params); //默认值
//4.设置交错模式
snd_pcm_hw_params_set_access(*handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
//5设置量化
snd_pcm_hw_params_set_format(*handle, params, SND_PCM_FORMAT_S16_LE);
//6设置通道数据
snd_pcm_hw_params_set_channels(*handle, params, 2);
//7设置采样率
int val = 44100;
snd_pcm_hw_params_set_rate_near(*handle, params, &val,0);
//8把设置好的参数设置到pcm设备
snd_pcm_hw_params(*handle,params);
//9.分配一个周期空间
//获取一个周期的帧数
snd_pcm_hw_params_get_period_size(params, frame, 0);
}
int init_udp_sockfd(int *sockfd,struct sockaddr_in *s_addr,int argc,char **argv)
{
if(argc < 1)
{
printf("input error\n");
exit(0);
}
if((*sockfd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
{
perror("socket");
exit(0);
}
memset(s_addr,0,sizeof(struct sockaddr_in));
s_addr->sin_family = AF_INET;
s_addr->sin_port = htons(12345);
s_addr->sin_addr.s_addr = inet_addr(argv[1]);
int sin_size = 1;
if((setsockopt(*sockfd,SOL_SOCKET,SO_REUSEADDR,&sin_size,sizeof(int))) < 0)
{
perror("setsockopt");
exit(0);
}
if(bind(*sockfd,(struct sockaddr *)s_addr,sizeof(struct sockaddr_in)) < 0)
{
perror("bind");
exit(0);
}
return 0;
}
int main(int argc,char **argv)
{
//初始化udp
int sockfd;
struct sockaddr_in s_addr,c_addr;
int len = sizeof(s_addr);
init_udp_sockfd(&sockfd,&s_addr,argc,argv);
//初始化pcm
struct snd_pcm sp_cp;
struct snd_pcm sp_pb;
sp_cp.handle = NULL;
sp_cp.frame = 0;
sp_pb.handle = NULL;
sp_pb.frame = 0;
//init_pcm_capture(&sp_cp.handle,&sp_cp.frame_cap);
init_pcm_playback(&sp_pb.handle,&sp_pb.frame);
int size = sp_pb.frame * 4;//计算一个周期所需要的存储空间
unsigned char *buffer = malloc(size);//分配一个周期的空间
while(1)
{
if(recvfrom(sockfd,buffer,size,0,(struct sockaddr *)&c_addr,&len) < 0)
{
perror("recvfrom");
exit(0);
}
snd_pcm_writei(sp_pb.handle, buffer, sp_pb.frame);//采集一个周期数据
}
//销毁pcm句柄
snd_pcm_drain(sp_pb.handle);
//关闭pcm设备
snd_pcm_close(sp_pb.handle);
//释放堆空间（存储一个周期数据）
free(buffer);
return 0;
}
上面代码绑定本机IP和端口接收UDP信息，把接收到的音频信息播放出来，使用./可执行文件名字 本机IP