static snd_pcm_sframes_t (*writei_func)(snd_pcm_t *handle, const void *buffer, snd_pcm_uframes_t size);登录后复制赋值如下 writei_func = snd_pcm_writei; readi_func = snd_pcm_readi; writen_func = snd_pcm_writen; readn_func = snd_pcm_readn;登录后复制snd_pcm_writei通过调用_snd...
我正在尝试使用以下ALSAAPI记录它正在向扬声器播放的内容:snd_pcm_mmap_readi() 这两个函数在同一线程中依次调用。writei()函数返回得很快(我相信一旦回放缓冲区可用,它就会返回),而readi()函数则会返回,直到捕获到指定的样本。但捕获的样本并不是刚刚播放的那样。我猜ALSA不是在双工模式下,也就是说,它必须先...
intmain(){intfp;unsignedintpcm, tmp, dir;intbuff_size;longloops;intrc;intsize;snd_pcm_t*handle;snd_pcm_hw_params_t*params;unsignedintval;snd_pcm_uframes_tframes;char*buff;intrate, channels, seconds;/* Open PCM device for recording (capture). */rc = snd_pcm_open(&handle,"default", ...
(pcm->pcm, pcm->sw_params,1024);if(err) PERROR_GOTO(snd_strerror(err), on_error_3);#endif#if1err = snd_pcm_sw_params_set_start_threshold (pcm->pcm, pcm->sw_params,0U);if(err) PERROR_GOTO(snd_strerror(err), on_error_3);#endiferr = snd_pcm_sw_params(pcm->pcm, pcm->sw...
snd_pcm_mmap switch (i->type) { case SND_PCM_AREA_MMAP: //表示为数据区分配驱动内存,在snd_pcm_hw_channel_info中设置了type ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED, i->u.mmap.fd, i->u.mmap.offset); /* mmap ==> snd_pcm_mmap_data ==> snd_pcm_defa...
snd_pcm_mmap switch (i->type) { case SND_PCM_AREA_MMAP: // 表示为数据区分配驱动内存,在snd_pcm_hw_channel_info中设置了type ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED, i->u.mmap.fd, i->u.mmap.offset); ...
在snd_pcm_hw_channel_info中设置了type ptr = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_FILE|MAP_SHARED, i-u.mmap.fd, i-u.mmap.offset);/*mmap= snd_pcm_mmap_data= snd_pcm_default_mmap/ mmap the DMA buffer on RAMstatic int snd_pcm_default_mmap(struct snd_pcm_substream *sub...
(Advanced Linux Sound Architecture)来进行采集,ALSA是linux的默认声卡驱动...: 实际读取的音频帧个数,小于0表示错误 */ int snd_pcm_prepare( snd_pcm_t *handle ); 接口简单,参数也少,所以使用起来很方便,基本上是linux下采集和播放的第一选择...在国产化芯片平台上出现的问题在普通Linux下,这样写下来,就...
mi wmi button battery asus_acpi acpi_memhotplug ac parport_pc lp parport snd_hda_intel i2c_i801 nvidia(PU) snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss snd_pcm snd _timer snd_page_alloc snd_hwdep tpm_tis snd tpm sr_mod tpm_bios...
"mmap_emul", NULL }; _snd_pcm_empty_open和snd_pcm_open_named_slave ==>snd_pcm_open_conf(pcmp,name,root,conf,stream,mode); ==>open_func=snd_dlobj_cache_lookup(open_name);将获得lib库中_snd_pcm_empty_open函数 所以open_func将等于_snd_pcm_empty_open _snd_pcm_empty_open _snd_pcm_...