.. _multiple_extraction_models:

Use Multiple Extraction Models within a Single ``extraction-api`` Instance 
===================================================================================

Starting from version 12.240830, FindFace Server allows using multiple attribute extraction models on the installations with a single ``extraction-api`` instance. This functionality can be employed in user liveness verification scenarios, e.g., when users register on a certain platform from various devices. Considering a user device type (e.g., a mobile phone, a laptop camera), you can now configure a neural network model that will be used for liveness recognition. Along with the default model, you can now configure a variant.

In this section, we will cover configuration of models for the ``face_liveness`` attribute. Use this instruction as an example to configure models for other attributes if needed.

.. important::
   The ``sf-api`` service will not work with any variants of ``*_emben`` models other than default. Even if you set up a variant for an ``*_emben`` extractor, the ``sf-api`` service will only send feature vectors extracted by the default model in to the Tarantool gallery.


To start using multiple ``face_liveness`` extraction models on a single ``extraction-api`` instance installation, configure the ``extraction-api.yaml`` file.
    
.. rubric:: In this section:

.. contents::
   :local:


Configure ``face_liveness`` Extraction Models in the ``extraction-api.yaml`` 
----------------------------------------------------------------------------------------

In the ``extraction-api.yaml`` file, specify a variant for each model of the ``face_liveness`` attribute. Do the following:

#. Open the ``extraction-api.yaml`` configuration file.

   .. code::

      sudo vi /path/to/ffserver-12.240830.2/configs/extraction-api.yaml


#. Locate ``extractors`` → ``face_liveness``. The default configuration will look like this:

   .. rubric:: GPU

   .. code::

      extractors:
        max_batch_size: 1
        models:
          face_liveness:
            default:
              model: faceattr/faceattr.liveness_web.v1.gpu.fnk
            ...

   .. rubric:: CPU

   .. code::

      extractors:
        max_batch_size: 1
        models:
          face_liveness:
            default:
              model: faceattr/faceattr.liveness_web.v1.cpu.fnk
            ...

#. Specify a variant for each model of the ``face_liveness`` attribute, e.g., ``mobile`` and ``pvn``. A variant name is limited to lowercase letters, digits and an underscore. Specify a corresponding neural network model for each variant:

   .. rubric:: GPU

   .. code::

      extractors:
        models:
          face_liveness:
            default:
              model: faceattr/faceattr.liveness_web.v1.gpu.fnk
            mobile:
              model: faceattr/faceattr.liveness_mobile.hart.gpu.fnk
            pvn:
              model: faceattr/liveness.pvn.v2.gpu.fnk
            ...

   .. rubric:: CPU

   .. code::

      extractors:
        models:
          face_liveness:
            default:
              model: faceattr/faceattr.liveness_web.v1.cpu.fnk
            mobile:
              model: faceattr/faceattr.liveness_mobile.hart.cpu.fnk
            pvn:
              model: faceattr/liveness.pvn.v2.cpu.fnk
            ...


Once configuration is complete, :ref:`specify <liveness_api_requests>` the ``liveness_variant`` parameter in the HTTP API requests to ``liveness-api``.