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Webcamming

Add your face to your screencasts with the command below. Beware, video0 works for me but it might be a different source on your machine (video1, video2, etc.)

ffmpeg -y -i /dev/video0 out.mkv

Determining Available Resolutions

Before you run the entire ffmpeg command to record your screen, it is important to determine which resolutions are available.

xrandr

Find Size And Offset Of Particular Window To Capture

xwininfo

Find Out Which Pulseaudio Sound Sources Exist

pactl list sources # To record, find the input source (not output)

The entire ffmpeg command.

ffmpeg -video_size 1366x768 -framerate 25 -f x11grab -i :0.0 -f pulse -ac 2 -i 1 output.mkv -async 1 -vsync 1
# video_size 1920×1080: Sets the size of the video capture. This is the value we used xrandr to find.
# framerate 25: Sets the frames per second value.
# f x11grab: Force the video format to a specific type. Here we’re setting the input format to the output of your X server.
# i :0.0: This specifies the video input will come from the main screen.
# f pulse: Sets the expected format to be PulseAudio.
# ac 2: Set two audio channels
# i 1: Take audio input from PulseAudio source #1. This is the value we used pactl to discover.
# output.mkv: The name of the file we wish to create.
# async 1: Set the audio sync method. This is a deprecated parameter, but we’re using it here to avoid error messages that can be ignored.
# vsync 1: set the video sync method. This is a deprecated parameter, but we’re using it here to avoid error messages that can be ignored.

NB: If you don’t specify a directory to save the video, it will be saved in the directory ffmpeg was launched from.

Extract Audio From Video

If you are like me and enjoy listening to the movies you have seen over and over again, the following command may come in handy.

ffmpeg -i sample.avi -q:a 0 -map a sample.mp3

Capture Only Video No Audio

This is particularly useful when you wish to first record your screen and then record your voice.

ffmpeg -video_size 1366x768 -framerate 25 -f x11grab -i :0.0 output.mkv -vsync 1

Converting Files

ffmpeg -i output.mkv output.mp4
# General formula : ffmpeg -i output.oldformat output.wantedformat

Add Background Music To Video

ffmpeg -i arch-install.mp4  -i archinstall-soundtrack.mp4 -c copy -map 0:v:0 -map 1:a:0 output2.mp4

Add New Audio Track To Existing File

Concatenating Files

  1. Create a list of files in a FILE example: filename file “file1_path” file2 “file1_path” file3 “file1_path”
  2. Run: 
    ffmpeg -f concat -safe 0 -i /home/soimuen/Downloads/FILENAME -c copy output.webm

Trimming Videos

ffmpeg -ss 00:01:00 -i input.mp4 -to 00:02:00 -c copy output.mp4

Burning Subs To Video

NOTE: This solution “burns the subtitles” into the video, so that every viewer of the video will be forced to see them.

Use the libass library (make sure your ffmpeg install has the library in the configuration –enable-libass).

First convert the subtitles to .ass format:

ffmpeg -i subtitles.srt subtitles.ass

Then add them using a video filter:

ffmpeg -i mymovie.mp4 -vf ass=subtitles.ass mysubtitledmovie.mp4