ffmpeg

Bash/FFMPEG: Batch resize .mp4 videos to fixed resolution 2

 in Bash / GNU/Linux  tagged bash / ffmpeg / mp4 / resize by

We needed to shrink a bunch of mp4 videos so that they would have the same size as the screen of an android device.
We did that both to save space on the internal memory of the device and to make the device perform as efficient as possible as it would not have to shrink the video on the fly.

The command we used was the following:

find . -type f -name "*.mp4" -exec bash -c 'FILE="$1"; ffmpeg -i "${FILE}" -s 1280x720 -acodec copy -y "${FILE%.mp4}.shrink.mp4";' _ '{}' \;

What this command does is the following:

  • Find all files in current folder (and sub-folders) that have the extension .mp4
  • For each file, create a new bash instance in which it will call ffmpeg taking as first parameter the filename that matched
  • -i "${FILE}" – ffmpeg will take as input the filename we matched
  • -s 1280x720 – Then change the video size to 1280x720
  • -acodec copy – It will keep the audio as is
  • -y "${FILE%.mp4}.shrink.mp4 – Finally, create a new file (or overwrite existing) that has the extension .shrink.mp4 in the same folder

Windows with ffmpeg — recursively convert all *.mov movies to .mp4. with fixed resolution for android 1

 in HowTos  tagged cmd / dos / ffmpeg / windows by

We needed to convert a bunch of mov files to mp4 and while doing that we wanted to shrink them down so that they would fit the screen of an older android device.
We did that both to save space on the internal memory and to make the device perform as efficient as possible as it would not have to shrink the video on the fly.

We downloaded the windows binary for ffmpeg from https://ffmpeg.org/ and copied it to the folder we wanted to execute the command from using Windows Explorer.
After that, while holding the Shift key we right clicked in the Windows Explorer empty area to popup the menu. From the menu we selected Open command window here, that opened a Command Prompt that was already navigated in the folder we placed the binary.
To convert the movies we executed the following:

for /R %f in ("*.mov") do (ffmpeg.exe -i "%~f" -s 864x486 -acodec copy "%~pf%~nf.mp4")

What the above command did was, direct command prompt to find recursively all the files that their name ends in .mov (this is the part that looks like this for /R %f in ("*.mov")) and then execute for each a command, in our case was to convert the file to mp4, resize the video while preserving the audio as is and produce a new file that has the same name but different file extension so that new files will have the mp4 extension instead of mov.

ffmpeg: Extract audio from .MP4 to .MP3

 in Bash  tagged audio / extract / ffmpeg / mp3 / mp4 / video by

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

ffmpeg: Extract audio from .WEBM to .OGG 3

 in Bash  tagged audio / extract / ffmpeg / ogg / video / webm by

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