Re: [Linphone-developers] Mediastreamer2: check if a filter is a source

[Aymeric Moizard]

On Mon, 9 Mar 2009, damico wrote:

> Hi all,

Hi Michelle,

> I'm proposing a little modification to mediastreamer API:
> In order to check if a MSFilter is a source we must look at ninputs member of 
> the description: if it is 0 is a source, otherwise a filter.
> Maybe it is more useful check if a istance of a filter is used as a source or 
> not. My idea is to check if "there is a configured input" instead to check if 
> "an input could be configured". By the attached patch I could use the same 
> filter as a filter or a source simply  by liking or not to other filters.
> Moreover, ms_filter_is_source() could be used in the process callback of the 
> filter too for choosing if we must produce samples of filter incoming 
> samples.
>
> I hope it could be useful...
>
> Note: the patch preserves a backward compatibility with the old 
> implementations.

I understand this behavior is the one you expect, but it looks not
100% backward compatible.

It look to me you should use the PUMP flag instead for your filter.
You would then probably get the exact same behavior you are looking
for?

tks,
Aymeric

> Regards
>
> --Michele
>
>
> Index: include/mediastreamer2/msfilter.h
> ===================================================================
> --- include/mediastreamer2/msfilter.h    (revision 313)
> +++ include/mediastreamer2/msfilter.h    (working copy)
> @@ -333,6 +333,15 @@
> MSFilterId ms_filter_get_id(MSFilter *f);
>
> /**
> + * Check if a filter is a source: no input are linked to that filter.
> + *
> + * @param f        A MSFilter object.
> + *
> + * Returns: TRUE if f is a source, FALSE otherwise.
> + */
> +bool_t ms_filter_is_source(MSFilter *f);
> +
> +/**
> * Destroy a filter object.
> *
> * @param f        A MSFilter object.
> Index: src/msticker.c
> ===================================================================
> --- src/msticker.c    (revision 313)
> +++ src/msticker.c    (working copy)
> @@ -106,7 +106,7 @@
>    MSFilter *f;
>    for(;filters!=NULL;filters=filters->next){
>        f=(MSFilter*)filters->data;
> -        if (f->desc->ninputs==0){
> +        if (ms_filter_is_source(f)){
>            sources=ms_list_append(sources,f);
>        }
>    }
> @@ -190,7 +190,7 @@
>
> static void call_process(MSFilter *f){
>    bool_t process_done=FALSE;
> -    if (f->desc->ninputs==0 || f->desc->flags & MS_FILTER_IS_PUMP){
> +    if (ms_filter_is_source(f) || f->desc->flags & MS_FILTER_IS_PUMP){
>        ms_filter_process(f);
>    }else{
>        while (ms_filter_inputs_have_data(f)) {
> Index: src/msfilter.c
> ===================================================================
> --- src/msfilter.c    (revision 313)
> +++ src/msfilter.c    (working copy)
> @@ -233,3 +233,14 @@
>    if (f->notify!=NULL)
>        f->notify(f->notify_ud,id,NULL);
> }
> +
> +bool_t ms_filter_is_source(MSFilter *f){
> +    int i;
> +    for (i=0;i<f->desc->ninputs;++i){
> +        if (f->inputs[i]){
> +            return FALSE;
> +        }
> +    }
> +    return TRUE;
> +}
> +}
>
>
>
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