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PJMEDIA之录音器的使用（capture sound to avi file）

發布時間：2023/12/2 编程问答 45 豆豆

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為了熟悉pjmedia的相關函數以及使用方法，這里練習了官網上的一個錄音器的例子。

核心函數：

pj_status_t pjmedia_wav_writer_port_create	(	pj_pool_t *?	pool,
?	?	const char *?	filename,
?	?	unsigned?	clock_rate,
?	?	unsigned?	channel_count,
?	?	unsigned?	samples_per_frame,
?	?	unsigned?	bits_per_sample,
?	?	unsigned?	flags,
?	?	pj_ssize_t?	buff_size,
?	?	pjmedia_port **?	p_port?
?	)	?	?

Create a media port to record streams to a WAV file. Note that the port must be closed properly (with pjmedia_port_destroy()) so that the WAV header can be filled with correct values (such as the file length). WAV writer port supports for writing audio in uncompressed 16 bit PCM format or compressed G.711 U-law/A-law format, this needs to be specified in flags param.

Parameters

pool	Pool to create memory buffers for this port.
filename	File name.
clock_rate	The sampling rate.
channel_count	Number of channels.
samples_per_frame	Number of samples per frame.
bits_per_sample	Number of bits per sample (eg 16).
flags	Port creation flags, see pjmedia_file_writer_option.
buff_size	Buffer size to be allocated. If the value is zero or negative, the port will use default buffer size (which is about 4KB).
p_port	Pointer to receive the file port instance.

Returns

PJ_SUCCESS on success.

pj_status_t pjmedia_snd_port_create_rec	(	pj_pool_t *?	pool,
?	?	int?	index,
?	?	unsigned?	clock_rate,
?	?	unsigned?	channel_count,
?	?	unsigned?	samples_per_frame,
?	?	unsigned?	bits_per_sample,
?	?	unsigned?	options,
?	?	pjmedia_snd_port **?	p_port?
?	)	?	?

Create unidirectional sound device port for capturing audio streams from the sound device with the specified parameters.

Parameters

pool	Pool to allocate sound port structure.
index	Device index, or -1 to let the library choose the first available device.
clock_rate	Sound device's clock rate to set.
channel_count	Set number of channels, 1 for mono, or 2 for stereo. The channel count determines the format of the frame.
samples_per_frame	Number of samples per frame.
bits_per_sample	Set the number of bits per sample. The normal value for this parameter is 16 bits per sample.
options	Options flag.
p_port	Pointer to receive the sound device port instance.

Returns

PJ_SUCCESS on success, or the appropriate error code.

pj_status_t pjmedia_endpt_create	(	pj_pool_factory *?	pf,
?	?	pj_ioqueue_t *?	ioqueue,
?	?	unsigned?	worker_cnt,
?	?	pjmedia_endpt **?	p_endpt?
?	)	?	?

Create an instance of media endpoint.

Parameters

pf	Pool factory, which will be used by the media endpoint throughout its lifetime.
ioqueue	Optional ioqueue instance to be registered to the endpoint. The ioqueue instance is used to poll all RTP and RTCP sockets. If this argument is NULL, the endpoint will create an internal ioqueue instance.
worker_cnt	Specify the number of worker threads to be created to poll the ioqueue.
p_endpt	Pointer to receive the endpoint instance.

Returns

PJ_SUCCESS on success.

pj_status_t pjmedia_snd_port_connect	(	pjmedia_snd_port *?	snd_port,
?	?	pjmedia_port *?	port?
?	)	?	?

Connect a port to the sound device port. If the sound device port has a sound recorder device, then this will start periodic function call to the port's put_frame() function. If the sound device has a sound player device, then this will start periodic function call to the port's get_frame() function.

For this version of PJMEDIA, the media port MUST have the same audio settings as the sound device port, or otherwise the connection will fail. This means the port MUST have the same clock_rate, channel count, samples per frame, and bits per sample as the sound device port.

Parameters

snd_port	The sound device port.
port	The media port to be connected.

Returns

PJ_SUCCESS on success, or the appropriate error code.

//capture sound to wav file //heat nan -test #include<pjmedia.h> #include<pjlib.h> #include<stdio.h> #include<stdlib.h>#define CLOCK_RATE 44100 //采樣率 #define NCHANNELS 2 //通道數 #define SAMPLES_PER_FRAME (NCHANNELS *(CLOCK_RATE*10/1000)) //每幀包含的采樣數 #define BITS_PER_SAMPLE 16 //每個抽樣的字節數int main() {pj_caching_pool cp;pjmedia_endpt *med_endpt;pj_pool_t *pool;pjmedia_port *file_port; pjmedia_snd_port *snd_port;pj_status_t status;char tmp[10];char filename[20];status=pj_init();if(status!=PJ_SUCCESS){PJ_LOG(3,("failed","pj_init"));}pj_caching_pool_init(&cp,&pj_pool_factory_default_policy,0); //創建endpointstatus=pjmedia_endpt_create(&cp.factory,NULL,1,&med_endpt);if(status!=PJ_SUCCESS){PJ_LOG(3,("failed","pjmedia_endpt_create"));}pool=pj_pool_create(&cp.factory,"wav_recoder",4000,4000,NULL); //輸入要保存錄音的文件名 PJ_LOG(3,("wav_recorder","please input the file name!"));gets(filename); //創建錄音端口把音頻流寫成wav文件status=pjmedia_wav_writer_port_create(pool,filename,CLOCK_RATE,NCHANNELS,SAMPLES_PER_FRAME,BITS_PER_SAMPLE,0,0,&file_port //指向接收該實例的pjmedia_port);if(status!=PJ_SUCCESS){PJ_LOG(3,("failed","pjmedia_wav_write_port_create"));} //創建單向的音頻設備端口用來捕獲音頻status=pjmedia_snd_port_create_rec(pool,-1,PJMEDIA_PIA_SRATE(&file_port->info),PJMEDIA_PIA_CCNT(&file_port->info),PJMEDIA_PIA_SPF(&file_port->info),PJMEDIA_PIA_BITS(&file_port->info),0,&snd_port);if(status!=PJ_SUCCESS){PJ_LOG(3,("failed","pjmedia_snd_port_create_rec"));} //連接兩個端口開始錄音status=pjmedia_snd_port_connect(snd_port,file_port);if(status!=PJ_SUCCESS){PJ_LOG(3,("failed","pjmedia_snd_port_connect"));}pj_thread_sleep(10);//顯示終止信息 puts("PRESS <ENTER> to stop recording and quit");if(fgets(tmp,sizeof(tmp),stdin)==NULL){puts("EOF while reading stdin,will quit now..");}//養成良好習慣，吃完飯總要刷刷碗吧！ pjmedia_snd_port_destroy(snd_port);pjmedia_port_destroy(file_port);pj_pool_release(pool);pjmedia_endpt_destroy(med_endpt);pj_caching_pool_destroy(&cp);pj_shutdown();return 0; // pj_thread_sleep(10);}

轉載于:https://www.cnblogs.com/heat-man/p/3664558.html

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