How to use pjsip on android device in order to have G.729 codec functionality

android, codec, pjsip, sip, voip

Solution

First step is build `pjsip` source code for Android (steps for Ubuntu Linux):

- Set `ANDROID_NDK_ROOT` environment variable to your NDK's root folder.

- Go to pjsip 2.x folder and create `pjlib/include/pj/config_site.h` including `config_site_sample.h` (`#include <pj/config_site_sample.h>`)

- Run `./configure-android`

- Run `make clean && make depend && make`

After these steps, you will have several static libraries in several folders. I suggest to group them in a same folder (better in your project) by:

mkdir <your_project_path>/pjsip_libs
find . -name *.a | xargs -I % cp % <your_project_path>/pjsip_libs/

Once you've all libraries, you need to add those libraries into your project's Android.mk file, this is done by including a new module section per library. This module section should be something like:

include $(CLEAR_VARS)
LOCAL_MODULE := pjsua-arm-unknown-linux-androideabi
LOCAL_SRC_FILES := $(MY_PJLIB_PATH)/libpjsua-arm-unknown-linux-androideabi.a
include $(PREBUILT_STATIC_LIBRARY)

And, in the section you're actually building your JNI project's source code, add all modules to your static library references:

 LOCAL_STATIC_LIBRARIES := pjsua-arm-unknown-linux-androideabi ...

This will include `pjsip` references into your JNI library. Now, you need to configure a `pjsip` UA instance.

You've a explanation about init and start `pjsip`'s UA (pjsua) in `pjsip/include/pjsua-lib/pjsua.h` but main steps to follow are:

- Create a UA instance with `pjsua_create`

- Create a worker thread with `pj_thread_create`

Set default configuration for UA instance:

pjsua_config cfg; pjsua_logging_config log_cfg; pjsua_media_config media_cfg;

pj_cli_cfg_default(&app_config.cli_cfg.cfg); pjsua_logging_config_default(&log_cfg); pjsua_media_config_default(&media_cfg);

Init the stack with `pjsua_init`

- Start the stack with `pjsua_start`

From here, you've plenty of configuration options (log, media, transport, etc.)

You can find a basic PJSIP tutorial here and, inside pjsip's source root path, you've a basic (but complete enough for a basic SIP usage) at: `pjsip-apps/src/samples/simple_pjsua.c`

Edit: When building android project in pjsip-apps, you can face a problem because pjsua-app is not generated by default on the general build (more specifically, pjsua: target is not included on all: target at pjsip-apps/build/Makefile). To fix this just go to pjsip-apps/build and run:

make pjsua

This would create proper object files at: pjsip-apps/build/output/pjsua-arm-unknown-linux-androideabi/ (needed when building android sample).

Once you've all corresponding object files, you can run ndk-build again at pjsip-apps/src/pjsua/android

Problem

Original source