Generate two access MP3s from input. One with appended audio (such as copyright notice) and one unmodified.
-
ffmpeg -i input_file.wav -i input_file_to_append -filter_complex "[0:a:0]asplit=2[a][b];[b]afifo[bb];[1:a:0][bb]concat=n=2:v=0:a=1[concatout]" -map "[a]" -codec:a libmp3lame -dither_method modified_e_weighted -qscale:a 2 output_file.mp3 -map "[concatout]" -codec:a libmp3lame -dither_method modified_e_weighted -qscale:a 2 output_file_appended.mp3
+
ffmpeg -i input_file -i input_file_to_append -filter_complex "[0:a:0]asplit=2[a][b];[b]afifo[bb];[1:a:0][bb]concat=n=2:v=0:a=1[concatout]" -map "[a]" -codec:a libmp3lame -dither_method modified_e_weighted -qscale:a 2 output_file.mp3 -map "[concatout]" -codec:a libmp3lame -dither_method modified_e_weighted -qscale:a 2 output_file_appended.mp3
This script allows you to generate two derivative audio files from a master while appending audio from a seperate file (for example a copyright or institutional notice) to one of them.
- ffmpeg
- starts the command
- - -i input file
- path, name and extension of the input file (The master file)
- - -i input file to append
- path, name and extension of the input file (The file to be appended to access file)
+ - -i input_file
- path, name and extension of the input file (The master file)
+ - -i input_file_to_append
- path, name and extension of the input file (The file to be appended to access file)
- -filter_complex
- enables the complex filtering to manage splitting the input to two audio streams
- [0:a:0]asplit=2[a][b];
asplit allows audio streams to be split up for seperate manipulation. This command splits the audio from the first input (the master file) into two streams "a" and "b"- [b]afifo[bb];
- this buffers the stream "b" to help prevent dropped samples and renames stream to "bb"
- [1:a:0][bb]concat=n=2:v=0:a=1[concatout]
concat is used to join files. n=2 tells the filter there are two inputs. v=0:a=1 Tells the filter there are 0 video inputs and 2 audio inputs. This command appends the audio from the second input to the beginning of stream "bb" and names the output "concatout"- -map "[a]"
- this maps the unmodified audio stream to the first output
- -codec:a libmp3lame -dither_method modified_e_weighted -qscale:a 2
- sets up mp3 options (using constant quality)
- - output file
- path, name and extension of the output file (unmodified)
+ - output_file
- path, name and extension of the output file (unmodified)
- -map "[concatout]"
- this maps the modified stream to the second output
- -codec:a libmp3lame -dither_method modified_e_weighted -qscale:a 2
- sets up mp3 options (using constant quality)
- - output file appended
- path, name and extension of the output file (with appended notice)
+ - output_file_appended
- path, name and extension of the output file (with appended notice)