Samples: Reading from WAV File

This is a very simple example to use the WAV File Player, to directly read the samples from the file.

This file is pjsip-apps/src/samples/level.c

/* 
 * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
 * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 */
 
 
static const char *desc = 
 " FILE:                                                                    \n"
 "  level.c                                                                 \n"
 "                                                                          \n"
 " PURPOSE:                                                                 \n"
 "  Read PCM WAV file and display the audio level the first 100 frames.     \n"
 "  Each frame is assumed to have 160 samples.                              \n"
 "                                                                          \n"
 " USAGE:                                                                   \n"
 "  level file.wav                                                          \n"
 "                                                                          \n"
 "  The WAV file SHOULD have a 16bit mono samples.                          ";
 
#include <pjmedia.h>
#include <pjlib.h>
 
#include <stdio.h>
 
/* For logging purpose. */
#define THIS_FILE   "level.c"
 
 
/* Util to display the error message for the specified error code  */
static int app_perror( const char *sender, const char *title, 
                       pj_status_t status)
{
    char errmsg[PJ_ERR_MSG_SIZE];
 
    PJ_UNUSED_ARG(sender);
 
    pj_strerror(status, errmsg, sizeof(errmsg));
 
    printf("%s: %s [code=%d]\n", title, errmsg, status);
    return 1;
}
 
 
/*
 * main()
 */
int main(int argc, char *argv[])
{
    enum { NSAMPLES = 640, COUNT=100 };
    pj_caching_pool cp;
    pjmedia_endpt *med_endpt;
    pj_pool_t *pool;
    pjmedia_port *file_port;
    int i;
    pj_status_t status;
 
 
    /* Verify cmd line arguments. */
    if (argc != 2) {
        puts("");
        puts(desc);
        return 1;
    }
 
    /* Must init PJLIB first: */
    status = pj_init();
    PJ_ASSERT_RETURN(status == PJ_SUCCESS, 1);
 
    /* Must create a pool factory before we can allocate any memory. */
    pj_caching_pool_init(&cp, &pj_pool_factory_default_policy, 0);
 
    /* 
     * Initialize media endpoint.
     * This will implicitly initialize PJMEDIA too.
     */
    status = pjmedia_endpt_create(&cp.factory, NULL, 1, &med_endpt);
    PJ_ASSERT_RETURN(status == PJ_SUCCESS, 1);
 
    /* Create memory pool for our file player */
    pool = pj_pool_create( &cp.factory,     /* pool factory         */
                           "wav",           /* pool name.           */
                           4000,            /* init size            */
                           4000,            /* increment size       */
                           NULL             /* callback on error    */
                           );
 
    /* Create file media port from the WAV file */
    status = pjmedia_wav_player_port_create(  pool,     /* memory pool      */
                                              argv[1],  /* file to play     */
                                              0,        /* use default ptime*/
                                              0,        /* flags            */
                                              0,        /* default buffer   */
                                              &file_port/* returned port    */
                                              );
    if (status != PJ_SUCCESS) {
        app_perror(THIS_FILE, "Unable to use WAV file", status);
        return 1;
    }
 
    if (PJMEDIA_PIA_SPF(&file_port->info) > NSAMPLES) {
        app_perror(THIS_FILE, "WAV clock rate is too big", PJ_EINVAL);
        return 1;
    }
 
    puts("Time\tPCMU\tLinear");
    puts("------------------------");
 
    for (i=0; i<COUNT; ++i) {
        pj_int16_t framebuf[NSAMPLES];
        pjmedia_frame frm;
        pj_int32_t level32;
        unsigned ms;
        int level;
 
        frm.buf = framebuf;
        frm.size = sizeof(framebuf);
        
        pjmedia_port_get_frame(file_port, &frm);
 
        level32 = pjmedia_calc_avg_signal(framebuf, 
                                          PJMEDIA_PIA_SPF(&file_port->info));
        level = pjmedia_linear2ulaw(level32) ^ 0xFF;
 
        ms = i * 1000 * PJMEDIA_PIA_SPF(&file_port->info) /
                PJMEDIA_PIA_SRATE(&file_port->info);
        printf("%03d.%03d\t%7d\t%7d\n", 
                ms/1000, ms%1000, level, level32);
    }
    puts("");
    
 
    /* Destroy file port */
    status = pjmedia_port_destroy( file_port );
    PJ_ASSERT_RETURN(status == PJ_SUCCESS, 1);
 
    /* Release application pool */
    pj_pool_release( pool );
 
    /* Destroy media endpoint. */
    pjmedia_endpt_destroy( med_endpt );
 
    /* Destroy pool factory */
    pj_caching_pool_destroy( &cp );
 
    /* Shutdown PJLIB */
    pj_shutdown();
 
 
    /* Done. */
    return 0;
}