http://www.360doc.com/content/13/1125/17/2306903_332089963.shtml
這幾天比較輕鬆,所以打算好好來看看linphone的代碼,源碼版本爲3.5.2。從linphone初始化的過程開始,首先來看linphone_core_new函數。
- LinphoneCore *linphone_core_new(const LinphoneCoreVTable *vtable,
- const char *config_path, const char *factory_config_path, void * userdata)
- {
- LinphoneCore *core=ms_new(LinphoneCore,1);
- linphone_core_init(core,vtable,config_path, factory_config_path, userdata);
- return core;
- }
主要工作基本上在函數linphone_core_init中實現
- static void linphone_core_init (LinphoneCore * lc, const LinphoneCoreVTable *vtable, const char *config_path,
- const char *factory_config_path, void * userdata)
- {
- memset (lc, 0, sizeof (LinphoneCore));
- lc->data=userdata;
- lc->ringstream_autorelease=TRUE;
- memcpy(&lc->vtable,vtable,sizeof(LinphoneCoreVTable)); //保存了回調函數表
- linphone_core_set_state(lc,LinphoneGlobalStartup,"Starting up"); //設置linphone內部狀態
- ortp_init(); //ortp模塊初始化
- lc->dyn_pt=96; //負載類型從96開始都是動態負載類型
- linphone_core_assign_payload_type(lc,&payload_type_pcmu8000,0,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_gsm,3,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_pcma8000,8,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_speex_nb,110,"vbr=on");
- linphone_core_assign_payload_type(lc,&payload_type_speex_wb,111,"vbr=on");
- linphone_core_assign_payload_type(lc,&payload_type_speex_uwb,112,"vbr=on");
- linphone_core_assign_payload_type(lc,&payload_type_telephone_event,101,"0-11");
- linphone_core_assign_payload_type(lc,&payload_type_g722,9,NULL);
- #if defined(ANDROID) || defined (__IPHONE_OS_VERSION_MIN_REQUIRED)
- /*shorten the DNS lookup time and send more retransmissions on mobiles:
- - to workaround potential packet losses
- - to avoid hanging for 30 seconds when the network doesn't work despite the phone thinks it does.
- */
- _linphone_core_configure_resolver();
- #endif
- #ifdef ENABLE_NONSTANDARD_GSM
- {
- PayloadType *pt;
- pt=payload_type_clone(&payload_type_gsm);
- pt->clock_rate=11025;
- linphone_core_assign_payload_type(lc,pt,-1,NULL);
- pt->clock_rate=22050;
- linphone_core_assign_payload_type(lc,pt,-1,NULL);
- payload_type_destroy(pt);
- }
- #endif
- #ifdef VIDEO_ENABLED
- linphone_core_assign_payload_type(lc,&payload_type_h263,34,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_theora,97,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_h263_1998,98,"CIF=1;QCIF=1");
- linphone_core_assign_payload_type(lc,&payload_type_mp4v,99,"profile-level-id=3");
- linphone_core_assign_payload_type(lc,&payload_type_h264,102,"profile-level-id=428014");
- linphone_core_assign_payload_type(lc,&payload_type_vp8,103,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_x_snow,-1,NULL);
- /* due to limited space in SDP, we have to disable this h264 line which is normally no more necessary */
- /* linphone_core_assign_payload_type(&payload_type_h264,-1,"packetization-mode=1;profile-level-id=428014");*/
- #endif
- //下面的這些負載類型,沒有指定類型號
- /*add all payload type for which we don't care about the number */
- linphone_core_assign_payload_type(lc,&payload_type_ilbc,-1,"mode=30");
- linphone_core_assign_payload_type(lc,&payload_type_amr,-1,"octet-align=1");
- linphone_core_assign_payload_type(lc,&payload_type_amrwb,-1,"octet-align=1");
- linphone_core_assign_payload_type(lc,&payload_type_lpc1015,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_g726_16,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_g726_24,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_g726_32,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_g726_40,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_aal2_g726_16,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_aal2_g726_24,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_aal2_g726_32,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_aal2_g726_40,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_silk_nb,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_silk_mb,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_silk_wb,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_silk_swb,-1,NULL);
- linphone_core_assign_payload_type(lc,&payload_type_g729,18,"annexb=no");
- ms_init(); //初始化mediastreamer模塊
- /* create a mediastreamer2 event queue and set it as global */
- /* This allows to run event's callback in linphone_core_iterate() */
- lc->msevq=ms_event_queue_new(); //事件隊列,linphone_core_iterate函數中取出事件並調用相應的回調函數
- ms_set_global_event_queue(lc->msevq); //隊列指針保存到一個全局的變量ms_global_event_queue裏
- lc->config=lp_config_new(config_path); //讀取配置文件,config保存的是一個ini文檔,類似xml文檔
- if (factory_config_path) //出廠配置文件是隻讀的,用於恢復出廠配置
- lp_config_read_file(lc->config,factory_config_path);
- lc->sal=sal_init(); //初始化exosip模塊,sal是什麼的縮寫呢?
- sal_set_user_pointer(lc->sal,lc);
- sal_set_callbacks(lc->sal,&linphone_sal_callbacks); //設置sal回調函數
- sip_setup_register_all(); //這裏將加載所有插件
- sound_config_read(lc); //讀取音頻相關配置
- net_config_read(lc); //讀取網絡相關配置
- rtp_config_read(lc); //讀取rtp相關配置
- codecs_config_read(lc); //讀取編碼器相關配置
- sip_config_read(lc); //讀取sip協議相關配置,/* this will start eXosip*/
- video_config_read(lc); //視頻相關配置
- //autoreplier_config_init(&lc->autoreplier_conf);
- lc->presence_mode=LinphoneStatusOnline; //在線、離線,還是其它
- misc_config_read(lc); //配置最大歷史記錄條數等
- ui_config_read(lc); //讀取聯繫人(朋友),讀取通話記錄
- #ifdef TUNNEL_ENABLED
- lc->tunnel=linphone_core_tunnel_new(lc);
- if (lc->tunnel) linphone_tunnel_configure(lc->tunnel);
- #endif
- if (lc->vtable.display_status)
- lc->vtable.display_status(lc,_("Ready")); //更新狀態
- lc->auto_net_state_mon=lc->sip_conf.auto_net_state_mon;
- linphone_core_set_state(lc,LinphoneGlobalOn,"Ready"); //這裏將會調用狀態改變的回調函數
- }
再來看看分配負載類型的函數linphone_core_assign_payload_type的實現
- static void linphone_core_assign_payload_type(LinphoneCore *lc, PayloadType *const_pt, int number, const char *recv_fmtp){
- PayloadType *pt;
- pt=payload_type_clone(const_pt);
- //找一個未分配的負載類型碼,分配給本負載類型
- if (number==-1){
- /*look for a free number */
- MSList *elem;
- int i;
- for(i=lc->dyn_pt;i<=127;++i){
- bool_t already_assigned=FALSE;
- for(elem=lc->payload_types;elem!=NULL;elem=elem->next){
- PayloadType *it=(PayloadType*)elem->data;
- if (payload_type_get_number(it)==i){
- already_assigned=TRUE;
- break;
- }
- }
- if (!already_assigned){
- number=i;
- lc->dyn_pt=i+1;
- break;
- }
- }
- if (number==-1){
- ms_fatal("FIXME: too many codecs, no more free numbers.");
- }
- }
- ms_message("assigning %s/%i payload type number %i",pt->mime_type,pt->clock_rate,number);
- payload_type_set_number(pt,number);
- if (recv_fmtp!=NULL) payload_type_set_recv_fmtp(pt,recv_fmtp);
- rtp_profile_set_payload(&av_profile,number,pt); //將負載類型的對應關係保存到全局的RtpProfile結構中
- lc->payload_types=ms_list_append(lc->payload_types,pt); //將支持的負載類型添加到鏈表中
- }