A quick note on how to boost the audio stream in a video using the volume filter in ffmpeg
#;For newer versions of ffmpeg ffmpeg -i input.mkv -filter:a "volume=4.0" output.mkv; #For older versions of ffmpeg (we use multiples of 256) ffmpeg -i input.mkv -vol 1024 -vcodec copy output.mkv;
Using the above command we were able to make the audio LOUDER!
Using the youtube-dl command line application you can download videos and directly extract the audio of the video in various formats.
youtube-dl supports a large variety of online video hosts, including:
Note: Please be sure that you are allowed to download a video before you do that, many of these hosts do not expect that you will be downloading their videos as they do not allow that.
The following command, will download a video, convert it to an mp3 and delete the original video:
youtube-dl --extract-audio --audio-format mp3 https://www.youtube.com/watch?v=cwI-n3sI8ec
If you want to keep the original video, you just add the parameter -k or --keep-video.
The --audio-format parameter accepts other types of audio format outputs, specifically it supports
youtube-dl is a very powerful tool, advice the documentation for some of the great features it supports.
The following command will find all mkv files that are in the current directory and in all sub-folders and extract the audio to mp3 format.
find . -type f -name "*.mkv" -exec bash -c 'FILE="$1"; ffmpeg -i "${FILE}" -vn -c:a libmp3lame -y "${FILE%.mkv}.mp3";' _ '{}' \;
The filename of the audio file will be the same as the mkv video with the correct extension. The mkv extension will be removed and replaced by the mp3 extension e.g hi.mkv will create a new file named hi.mp3
The following command will find all mp4 files that are in the current directory and in all sub-folders and extract the audio to mp3 format.
find . -type f -iname "*.mp4" -exec bash -c 'FILE="$1"; ffmpeg -i "${FILE}" -vn -y "${FILE%.mp4}.mp3";' _ '{}' \;
The filename of the audio file will be the same as the mp4 video with the correct extension. The mp4 extension will be removed and replaced by the mp3 extension e.g hi.mp4 will become hi.mp3
If you need to extract the audio from an .WEBM movie file to an .OGG audio file you can execute the following:
FILE="the-file-you-want-to-process.webm";
ffmpeg -i "${FILE}" -vn -y "${FILE%.webm}.ogg"
The first command will assign the file name to a variable, we do this to avoid typing errors in the second command where we might want to use the same name for the audio file.
The second command, will use ffmpeg to extract the audio. The -i flag, indicates the file name of the input. We used the flag -vn that will instruct ffmpeg to disable video recording. The -acodec flag will set the output audio codec to vorbis. The -y flag will overwrite output file without asking, so be careful when you use it.
In case we want to automatically process (batch process) all .WEBM video files in a folder we can use the following:
for FILE in *.webm;
do
echo -e "Processing video '\e[32m$FILE\e[0m'";
ffmpeg -i "${FILE}" -vn -y "${FILE%.webm}.ogg"
done
The above script will find all .WEBM files in the folder and process them one after the other.
UPDATE:
The following command will find all webm files that are in the current directory and in all sub-folders and extract the audio to ogg format.
find . -type f -iname "*.webm" -exec bash -c 'FILE="$1"; ffmpeg -i "${FILE}" -vn -y "${FILE%.webm}.ogg";' _ '{}' \;
The filename of the audio file will be the same as the webm video with the correct extension. The webm extension will be removed and replaced by the ogg extension e.g hi.webm will become hi.ogg
