aac5773f
 hucm
功能基本完成，接口待打磨
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/*
* 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 */
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