linphone函数ms_filter_link分析

初始化filter ：
MSFilter* ms_filter_new(MSFilterId id)函数进行初始化，该函数通过MSFilterId id参数初始化一个Filter，并将新建的Filter通过函数返回给调用者。

ms_filter_link(MSFilter* f1,int pin1,MSFilter* f2,int pin2)将f1的pin1接口作为输出端口，将f2的pin2接口作为输入接口，进行链接。

int ms_filter_link(MSFilter *f1, int pin1, MSFilter *f2, int pin2){    MSQueue *q;    ms_message("ms_filter_link: %s:%p,%i-->%s:%p,%i",f1->desc->name,f1,pin1,f2->desc->name,f2,pin2);    ms_return_val_if_fail(pin1<f1->desc->noutputs, -1);    ms_return_val_if_fail(pin2<f2->desc->ninputs, -1);    ms_return_val_if_fail(f1->outputs[pin1]==NULL,-1);    ms_return_val_if_fail(f2->inputs[pin2]==NULL,-1);    q=ms_queue_new(f1,pin1,f2,pin2);    f1->outputs[pin1]=q;    f2->inputs[pin2]=q;    return 0;}

/* and then connect all */ms_filter_link(stream->source,0, stream->pixconv,0);ms_filter_link(stream->pixconv, 0, stream->output2, 0);