Useful commands for converting videos using ffmpeg

videoconversionsamples.sh

#!/bin/bash

# Examples taken from https://opensource.com/article/17/6/ffmpeg-convert-media-file-formats

# Convert a webm file to a matroska format with a vp9 encoding and keeping the same audio encoding.
# Also changes the bitrate to 1Mb/s
ffmpeg -i input.webm -c:a copy -c:v vp9 -b:v 1M output.mkv
# Same but change the frame rate to 30 FPS and dropping the bitrate conversion
ffmpeg -i input.webm -c:a copy -c:v vp9 -r 30 output.mkv
# Same but only setting the video size to a predetermined format HD 720 in this case
ffmpeg -i input.mkv -c:a copy -s hd720 output.mkv
# Same but sets the size explicitely
ffmpeg -i input.mkv -c:a copy -s 1280x720 output.mkv
# This cuts 10 seconds away from the original movie starting at 00:01:00, i.e., after one minute.
ffmpeg -i input.mkv -c:av copy -ss 00:01:00 -t 10 output.mkv

# The "-vn / -an / -sn / -dn" options can be used to skip inclusion of
# video, audio, subtitle and data streams respectively

# Remove the video stream from a mkv file and save the remaining streams as an ogg
ffmpeg -i input.mkv -vn audio_only.ogg
# Remove the audio from a mkv file and save it as an mkv
ffmpeg -i input.mkv -an video_only.mkv
# Remove the subtitles from a mkv file and save it as an mkv
ffmpeg -i input.mkv -sn audio_only.mkv