ffmpeg支持几个声道

aac支持的声道：

支持多声道：可提供最多48个全音域声道；

更高的解析度：最高支持96KHz的采样频率；

ffmpeg支持的声道：支持单声道到8声道

#define AV_CH_LAYOUT_MONO (AV_CH_FRONT_CENTER)

#define AV_CH_LAYOUT_STEREO (AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT)

#define AV_CH_LAYOUT_2POINT1 (AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY)

#define AV_CH_LAYOUT_2_1 (AV_CH_LAYOUT_STEREO|AV_CH_BACK_CENTER)

#define AV_CH_LAYOUT_SURROUND (AV_CH_LAYOUT_STEREO|AV_CH_FRONT_CENTER)

#define AV_CH_LAYOUT_3POINT1 (AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY)

#define AV_CH_LAYOUT_4POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_CENTER)

#define AV_CH_LAYOUT_4POINT1 (AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY)

#define AV_CH_LAYOUT_2_2 (AV_CH_LAYOUT_STEREO|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)

#define AV_CH_LAYOUT_QUAD (AV_CH_LAYOUT_STEREO|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)

#define AV_CH_LAYOUT_5POINT0 (AV_CH_LAYOUT_SURROUND|AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT)

#define AV_CH_LAYOUT_5POINT1 (AV_CH_LAYOUT_5POINT0|AV_CH_LOW_FREQUENCY)

#define AV_CH_LAYOUT_5POINT0_BACK (AV_CH_LAYOUT_SURROUND|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)

//5.1声道，杜比音效

#define AV_CH_LAYOUT_5POINT1_BACK (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_LOW_FREQUENCY)

#define AV_CH_LAYOUT_6POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_CENTER)

#define AV_CH_LAYOUT_6POINT0_FRONT (AV_CH_LAYOUT_2_2|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)

#define AV_CH_LAYOUT_HEXAGONAL (AV_CH_LAYOUT_5POINT0_BACK|AV_CH_BACK_CENTER)

#define AV_CH_LAYOUT_6POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_CENTER)

#define AV_CH_LAYOUT_6POINT1_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_BACK_CENTER)

#define AV_CH_LAYOUT_6POINT1_FRONT (AV_CH_LAYOUT_6POINT0_FRONT|AV_CH_LOW_FREQUENCY)

#define AV_CH_LAYOUT_7POINT0 (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)

#define AV_CH_LAYOUT_7POINT0_FRONT (AV_CH_LAYOUT_5POINT0|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)

#define AV_CH_LAYOUT_7POINT1 (AV_CH_LAYOUT_5POINT1|AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT)

#define AV_CH_LAYOUT_7POINT1_WIDE (AV_CH_LAYOUT_5POINT1|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)

#define AV_CH_LAYOUT_7POINT1_WIDE_BACK (AV_CH_LAYOUT_5POINT1_BACK|AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER)

#define AV_CH_LAYOUT_OCTAGONAL (AV_CH_LAYOUT_5POINT0|AV_CH_BACK_LEFT|AV_CH_BACK_CENTER|AV_CH_BACK_RIGHT)

#define AV_CH_LAYOUT_HEXADECAGONAL (AV_CH_LAYOUT_OCTAGONAL|AV_CH_WIDE_LEFT|AV_CH_WIDE_RIGHT|AV_CH_TOP_BACK_LEFT|AV_CH_TOP_BACK_RIGHT|AV_CH_TOP_BACK_CENTER|AV_CH_TOP_FRONT_CENTER|AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT)

#define AV_CH_LAYOUT_STEREO_DOWNMIX (AV_CH_STEREO_LEFT|AV_CH_STEREO_RIGHT)

这些声道宏命名和声道数对应关系

channel_layout_map[]

{ “mono”, 1, AV_CH_LAYOUT_MONO },

{ “stereo”, 2, AV_CH_LAYOUT_STEREO },

{ “2.1”, 3, AV_CH_LAYOUT_2POINT1 },

{ “3.0”, 3, AV_CH_LAYOUT_SURROUND },

{ “3.0(back)”, 3, AV_CH_LAYOUT_2_1 },

{ “4.0”, 4, AV_CH_LAYOUT_4POINT0 },

{ “quad”, 4, AV_CH_LAYOUT_QUAD },

{ “quad(side)”, 4, AV_CH_LAYOUT_2_2 },

{ “3.1”, 4, AV_CH_LAYOUT_3POINT1 },

{ “5.0”, 5, AV_CH_LAYOUT_5POINT0_BACK },

{ “5.0(side)”, 5, AV_CH_LAYOUT_5POINT0 },

{ “4.1”, 5, AV_CH_LAYOUT_4POINT1 },

{ “5.1”, 6, AV_CH_LAYOUT_5POINT1_BACK },

{ “5.1(side)”, 6, AV_CH_LAYOUT_5POINT1 },

{ “6.0”, 6, AV_CH_LAYOUT_6POINT0 },

{ “6.0(front)”, 6, AV_CH_LAYOUT_6POINT0_FRONT },

{ “hexagonal”, 6, AV_CH_LAYOUT_HEXAGONAL },

{ “6.1”, 7, AV_CH_LAYOUT_6POINT1 },

{ “6.1”, 7, AV_CH_LAYOUT_6POINT1_BACK },

{ “6.1(front)”, 7, AV_CH_LAYOUT_6POINT1_FRONT },

{ “7.0”, 7, AV_CH_LAYOUT_7POINT0 },

{ “7.0(front)”, 7, AV_CH_LAYOUT_7POINT0_FRONT },

{ “7.1”, 8, AV_CH_LAYOUT_7POINT1 },

{ “7.1(wide)”, 8, AV_CH_LAYOUT_7POINT1_WIDE },

{ “octagonal”, 8, AV_CH_LAYOUT_OCTAGONAL },

{ “downmix”, 2, AV_CH_LAYOUT_STEREO_DOWNMIX, }

在ffmpeg4.4.1中包含这个宏，它支持22个声道：

AV_CH_LAYOUT_22POINT2