Hi,

I would like to experiment with some audio-codecs (one of them sitting on an external device --> AMBE-chip). So I wrote a simple pjsua2-based frontend (works) and after that I now try to implement my own variant of a passthrough-codec which should use a callback-function whenever audio-frames need to be encoded into codec-frames and another callback-function for the reverse way.

Obviously this will require me to set these callback-functions (very much preferably on a by call basis) and this is the point where I somewhat got stuck. It seems to me, that there is no way of doing so without patching pjsua2?

If so, could someone please give me a hint for a good starting-point for doing this starting from pj::Call? Can I -- for instance in onCallMediaState (or another callback from within pj::Call) -- just call pjsua_codec_set_param? And if so, how would this be directed/mapped to the codec-instance used for the current call?

Many thanks in advance,
Stefan

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You have to implement your own media transport adapter.
I have used it to mangle rtp packet in one of my projects. You can use it to completely rewrote rtp packet.

https://trac.pjsip.org/repos/wiki/Media_Transport_Adapter

Inviato dal mio dispositivo Huawei

-------- Messaggio originale --------
Oggetto: [pjsip] individual codec parameters for every call
Da: Stefan Fendt
A: pjsip@lists.pjsip.org
CC:

Hi,

I would like to experiment with some audio-codecs (one of them sitting on an external device --> AMBE-chip). So I wrote a simple pjsua2-based frontend (works) and after that I now try to implement my own variant of a passthrough-codec which should use a callback-function whenever audio-frames need to be encoded into codec-frames and another callback-function for the reverse way.

Obviously this will require me to set these callback-functions (very much preferably on a by call basis) and this is the point where I somewhat got stuck. It seems to me, that there is no way of doing so without patching pjsua2?

If so, could someone please give me a hint for a good starting-point for doing this starting from pj::Call? Can I -- for instance in onCallMediaState (or another callback from within pj::Call) -- just call pjsua_codec_set_param? And if so, how would this be directed/mapped to the codec-instance used for the current call?

Many thanks in advance,
Stefan

Diese Nachricht wurde von meinem Android-Gerät mit K-9 Mail gesendet.

Have you see here: http://www.pjsip.org/pjmedia/docs/html/group__PJMEDIA__CODEC.htm
There is a section named "register new codec"...

Inviato dal mio dispositivo Huawei

-------- Messaggio originale --------
Oggetto: Re: [pjsip] Ris: individual codec parameters for every call
Da: Stefan Fendt
A: pjsip list
CC:

>You have to implement your own media transport adapter.
I have used it to mangle rtp packet in one of my projects. You can use it to completely rewrote rtp packet.

Which is not what I want to do. Actually I do not want to mess with the network-stream but with the audio and/or audio-quality of different audio-codecs.

>https://trac.pjsip.org/repos/wiki/Media_Transport_Adapter

As far as I understand this wiki-article the MediaTransportAdapter sits right in between Media and MediaTransport. So it could see codec-frames but not audio-frames. For what I want to do it is essential that I can see both. This was the main reason, why I thought it would be a good idea to just implement a passthrough-codec.

Maybe I didn't explain too well, what I want to do, so I'll try to detail it a little bit more:

I have some external audio-codecs. That is not inside pjsip/pjsua. Some are software-based and I could integrate them into pjsip, some are hardware-based -- yes, some neat multi-legged black silicone-bug sitting on a PCB outside of the PC. All these codecs require callbacks for setting parameters and for doing the actual samplescodecframes translation, "somewhere(tm)" inside of pjsua/pjsip.

I am looking for the most effective, least obscure way of integrating an external audio-codec into pjsip/pjsua while keeping it external (I need to for the PCB-codecs for obvious reasons) and being able to tweak it's parameters during an active call.

all the best,
Stefan

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Hi Alexey,

This already works. As mentioned before I already have a working passthrough-codec. The only remaining problem is to set parameters for it on a by-call basis. Currently all parameters are hard-coded which is not to ideal for experimentation.

All the best,
Stefan

Diese Nachricht wurde von meinem Android-Gerät mit K-9 Mail gesendet.