/*
  * Copyright (c) 2014 Tim Walker <tdskywalker@gmail.com>
  *

  * This file is part of FFmpeg.

  *

  * FFmpeg is free software; you can redistribute it and/or

  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *

  * FFmpeg 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
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public

  * License along with FFmpeg; if not, write to the Free Software

  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 #ifndef AVUTIL_DOWNMIX_INFO_H
 #define AVUTIL_DOWNMIX_INFO_H
 
 #include "frame.h"
 
 /**
  * @file
  * audio downmix medatata
  */
 
 /**
  * @addtogroup lavu_audio
  * @{
  */
 
 /**
  * @defgroup downmix_info Audio downmix metadata
  * @{
  */
 
 /**
  * Possible downmix types.
  */
 enum AVDownmixType {
     AV_DOWNMIX_TYPE_UNKNOWN, /**< Not indicated. */
     AV_DOWNMIX_TYPE_LORO,    /**< Lo/Ro 2-channel downmix (Stereo). */
     AV_DOWNMIX_TYPE_LTRT,    /**< Lt/Rt 2-channel downmix, Dolby Surround compatible. */
     AV_DOWNMIX_TYPE_DPLII,   /**< Lt/Rt 2-channel downmix, Dolby Pro Logic II compatible. */
     AV_DOWNMIX_TYPE_NB       /**< Number of downmix types. Not part of ABI. */
 };
 
 /**
  * This structure describes optional metadata relevant to a downmix procedure.
  *
  * All fields are set by the decoder to the value indicated in the audio
  * bitstream (if present), or to a "sane" default otherwise.
  */
 typedef struct AVDownmixInfo {
     /**
      * Type of downmix preferred by the mastering engineer.
      */
     enum AVDownmixType preferred_downmix_type;
 
     /**
      * Absolute scale factor representing the nominal level of the center
      * channel during a regular downmix.
      */
     double center_mix_level;
 
     /**
      * Absolute scale factor representing the nominal level of the center
      * channel during an Lt/Rt compatible downmix.
      */
     double center_mix_level_ltrt;
 
     /**
      * Absolute scale factor representing the nominal level of the surround
      * channels during a regular downmix.
      */
     double surround_mix_level;
 
     /**
      * Absolute scale factor representing the nominal level of the surround
      * channels during an Lt/Rt compatible downmix.
      */
     double surround_mix_level_ltrt;
 
     /**
      * Absolute scale factor representing the level at which the LFE data is
      * mixed into L/R channels during downmixing.
      */
     double lfe_mix_level;
 } AVDownmixInfo;
 
 /**
  * Get a frame's AV_FRAME_DATA_DOWNMIX_INFO side data for editing.
  *

  * If the side data is absent, it is created and added to the frame.

  *

  * @param frame the frame for which the side data is to be obtained or created

  *

  * @return the AVDownmixInfo structure to be edited by the caller, or NULL if

  *         the structure cannot be allocated.

  */
 AVDownmixInfo *av_downmix_info_update_side_data(AVFrame *frame);
 
 /**
  * @}
  */
 
 /**
  * @}
  */
 
 #endif /* AVUTIL_DOWNMIX_INFO_H */