Basic Commandline Video Processing In Linux

Prerequisite: Install packages for MP4Box and ffpmpeg commands:
sudo apt install gpac ffmpeg

 

Three Methods to Trim Video:

1. MP4Box -splitx ss:ss input.mp4 -out output.mp4 , where ss:ss are numerical values for start-seconds and stop-seconds. (Fastest, does not transcode)
2. ffmpeg -i input.mp4 -ss hh:mm:ss -t hh:mm:ss -async 1 output.mp4, where hh:mm:ss are numerical values for hours, minutes, seconds.
3. ffmpeg -i input.mp4 -vf trim=ss:ss output.mp4, where ss is a numerical value for seconds.

Annoyed with converting hours, minutes, seconds into total seconds? Use this bash function:

function to_sec() { echo "$1" | awk -F':' '{if (NF == 2) {print $1 * 60 + $2} else {print $1 * 60 * 60 + $2 * 60 + $3}}'; }

Usage examples: to_sec 2:47 or to_sec 1:2:47 or $(to_sec 2:47) or MP4Box -splitx $(to_sec 2:47):$(to_sec 7:33) input.mp4 -out output.mp4

 

Overlay a Logo onto Video:

    1. Static graphic logo:

ffmpeg -i input.mp4 \
-i logo.png \
-filter_complex "X:Y" \  # set logo position
-codec:a copy \  # just copy audio
output.mp4

where X:Y is the horizontal and vertical pixel positioning.

    2. Animated graphic logo:

ffmpeg -i input.mp4 \
-ignore_loop 0 -i animated-logo.gif \  # do not ignore looping
-filter_complex "X:Y:shortest=1" \  # limit to input video length
-codec:a copy \
output.mp4

where :shortest=1 is required, and where X:Y is the horizontal and vertical pixel positioning. Without shortest, the video transcoding will not end.
X and Y may be static numerical values, or ffmpeg built-in variables and equations. Examples:

• Top right with 10 pixel margin : main_w-overlay_w-10:10
• Top left with 10 pixel margin : 10:10
• Bottom left with 10 pixel margin : 10:main_h-overlay_h-10
• Bottom right with 10 pixel margin : main_w-overlay_w-10:main_h-overlay_h-10

 

 

Trim First x Seconds off Audio File:

ffmpeg -ss x -i input.mp3 -codec:a copy output.mp3 , where x is a numerical value for seconds.

 

Add Audio to Video and Trim to Shortest Source:

ffmpeg -i input.mp4 -i audio.mp3 -codec copy -shortest output.mp4

 

Overlay Logo and Add Audio with One Command:

ffmpeg -i input.mov \
 -i logo.png \
 -filter_complex "overlay=main_w-overlay_w-10:10" \
 -i music.mp3 -codec:a copy \
 -shortest output.mov

As always, good luck!
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