Split stereo sound into two channels

Problem

Split a stereo sound file into its front left (FL) and front right (FR) channels.

Solution

ffmpeg                   \
    -i input_sound_file  \
    -map_channel 0.a.0   \
    output_FL_file       \
    -map_channel 0.a.1   \
    output_FR_file

Command syntax

ffmpeg

starts the command

-i input_sound_file

path, name and extension of the input sound file

-map_channel 0.a.0

grabs the left channel of a stereo sound

output_FL_file

path, name and extension of the output file for the left sound channel

-map_channel 0.a.1

grabs the right channel of a stereo sound

output_FR_file

path, name and extension of the output file for the right sound channel

Discussion

As usual in IT, the numbering of the sound channels starts at 0, not at 1 (“zero-based numbering”).

Check with ffprobe the streams’ mapping to ensure the code is accurate, and invert the sound channels if needed.

2024-11-27