---

/*
 * Recorder (or passive port) callback.
 */
static pj_status_t put_frame(pjmedia_port *this_port, 
                             pjmedia_frame *frame)
{
    pjmedia_conf *conf = (pjmedia_conf*) this_port->port_data.pdata;
    struct conf_port *port = conf->ports[this_port->port_data.ldata];
    pj_status_t status;

    /* Check for correct size. */
    PJ_ASSERT_RETURN( frame->size == conf->samples_per_frame *
                                     conf->bits_per_sample / 8,
                      PJMEDIA_ENCSAMPLESPFRAME);

    /* Check existance of delay_buf instance */
    PJ_ASSERT_RETURN( port->delay_buf, PJ_EBUG );

    /* Skip if this port is muted/disabled. */
    if (port->rx_setting != PJMEDIA_PORT_ENABLE) {
        return PJ_SUCCESS;
    }

    /* Skip if no port is listening to the microphone */
    if (port->listener_cnt == 0) {
        return PJ_SUCCESS;
    }

    status = pjmedia_delay_buf_put(port->delay_buf, (pj_int16_t*)frame->buf);

    return status;
}

static pj_status_t get_frame(pjmedia_port *this_port, 
                             pjmedia_frame *frame)
{
    pjmedia_conf *conf = (pjmedia_conf*) this_port->port_data.pdata;
    pjmedia_frame_type speaker_frame_type = PJMEDIA_FRAME_TYPE_NONE;
    unsigned ci, cj, i, j;
    pj_int16_t *p_in;
    
    TRACE_((THIS_FILE, "- clock -"));

    /* Check that correct size is specified. */
    pj_assert(frame->size == conf->samples_per_frame *
                             conf->bits_per_sample / 8);
...........................................

Assert failed: frame->size == conf->samples_per_frame * conf->bits_per_sample / 8
надо задать новый frame->size. Могу распечать полностью дополнительно для теста значение frame->size.