Re: [Linphone-developers] Intercapt microphone path

[Simon Morlat]

Le mercredi 29 septembre 2010 à 12:02 -0400, Andre Courchesne a écrit :
> Hi Simon,
> 
>   Thanks for the pointer.
> 
>   So If I want to create my own filter (let's name it filter_andre), I guess 
> I just have to add my C file and add filter_andre.c in Makefile.am 

> (in libmediastreamer_la_SOURCES) and it will be compiled-in?

And need to add your filter id in the big enum in
include/mediastreamer2/allfilters.h
OR use MS_FILTER_PLUGIN_ID which is a kind of wildcard id.
In this case you will need first to register your MSFilterDesc manually
using ms_filter_register() , then you will need to use MSFilter
*ms_filter_new_from_name(const char *name); to instanciate your filter
instead of ms_filter_new().

> 
>   Also looking at chanadapt.c. In the function adapter_process. I guess that 
> in the for loop used for the conversion *(int16_t*)im->b_rptr represent a 
> single byte of raw data ?
Yes, bytes of data are comprised between im->b_rptr and im->b_wptr. When
cast as int16_t* it represents 16 bit sound samples.
mblk_t are the structures that hold the media data in mediastreamer2.

Simon

> 
> ---
> 
> Andre Courchesne - Consultant
> 
> http://www.net-forces.com
> 
> MSN: address@hidden
> 
> Skype: VoipForces
> 
> 
> 
> L'information contenue dans le présent document est la propriété de Andre 
> Courchesne. Et est divulguée en toute confidentialité. Cette information ne 
> doit pas être utilisée, divulguée à d'autres personnes ou reproduite sans le 
> consentement écrit explicite de Andre Courchesne.
> 
> The information contained in this document is confidential and property of 
> Andre Courchesne. It shall not be used, disclosed to others or reproduced 
> without the express written consent of Andre Courchesne.
> 
> 
> 
> 
> 
> On 2010-09-28, at 11:11 AM, Simon Morlat wrote:
> 
> > Hi Andre,
> > 
> > I think you need to implement a new mediastreamer2 filter to work on the
> > stream.
> > And then you could insert your filter just after the sound reader
> > filter.
> > See in mediastreamer2/src/audiostream.c, near line 359:
> > 
> >     ms_connection_helper_start(&h);
> >     ms_connection_helper_link(&h,stream->soundread,-1,0);
> >     if (stream->read_resampler)
> >     ms_connection_helper_link(&h,stream->read_resampler,0,0);
> >     if (stream->ec)
> >             ms_connection_helper_link(&h,stream->ec,1,1);
> >     if (stream->volsend)
> >             ms_connection_helper_link(&h,stream->volsend,0,0);
> >     if (stream->dtmfgen_rtp)
> >             ms_connection_helper_link(&h,stream->dtmfgen_rtp,0,0);
> >     ms_connection_helper_link(&h,stream->encoder,0,0);
> >     ms_connection_helper_link(&h,stream->rtpsend,0,-1);
> > 
> > This code builds the following processing graph (when software echo
> > canceller and resampler are not needed, which is the case on the
> > iPhone):
> > MSAuRead-->MSVolume-->MSDtmfGen-->MSMulawEnc-->MSRtpSend
> > 
> > The 'soundread' filter just output raw 16 bit samples, so you can work
> > on them before they are transmitted to next filter.
> > 
> > If you need an example on how to build a mediastreamer2 filter, you can
> > have a look at mediastreamer2/src/chanadapt.c . This is probably the
> > simplest filter in mediastreamer2. Its purpose is to convert an
> > interleaved stereo audio stream to a mono audio stream and vice-versa.
> > 
> > Best regards,
> > 
> > Simon
> > 
> > 
> > Le dimanche 26 septembre 2010 à 20:22 -0400, Andre Courchesne a écrit :
> >> Hi,
> >> 
> >>   I need to modify the iPhone version of Linphone in such a way that  
> >> I can do a process on the microphone input data prior to that data  
> >> going through the rest of the Linphone path.
> >> 
> >>   The process I need to do on the data is fairly simple but I need to  
> >> do it on uncompressed data and dta that had not gone through the coded  
> >> process.
> >> 
> >>   Any hints on where in the code I could insert my code or a hook?
> >> 
> >>   Thanks,
> >> 
> >> Andre
> >> 
> >> _______________________________________________
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> >> http://lists.nongnu.org/mailman/listinfo/linphone-developers
> > 
> > 
> > 
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