FFmpeg tiny cheat sheet


In the following commands, we assume that the user has set the video filename to the variable named $video.

FFmpeg export audio from any video to mp3

ffmpeg -i "$video" -vn -c:a libmp3lame -y "$audio";

FFmpeg export frames from video to images

ffmpeg -i "$video" "$frames_folder/%08d.ppm";

Retrieve the frame rate from the input video

#To view it on screen
ffprobe -v 0 -of csv=p=0 -select_streams v:0 -show_entries stream=r_frame_rate "$video";
#To assign it to a variable use the following
frame_rate=`ffprobe -v 0 -of csv=p=0 -select_streams v:0 -show_entries stream=r_frame_rate "$video"`;

To create a video out of a folder with frames/images and an audio file.

ffmpeg -framerate "$frame_rate" -i "$frames_folder/%08d.ppm" -i "$audio" -pix_fmt yuv420p -acodec copy -y "$output_video";
#To set a custom starting index for the frames you can use the -start_number argument
ffmpeg -start_number 62 -framerate "$frame_rate" -i "$frames_folder/%08d.ppm" -i "$audio" -pix_fmt yuv420p -acodec copy -y "$output_video";
#To use the MP4 coded use -vcodec libx264
ffmpeg -framerate "$frame_rate" -i "$frames_folder/%08d.ppm" -i "$audio" -vcodec libx264 -pix_fmt yuv420p -acodec copy -y "$output_video";

To merge an audio less video with an audio file

ffmpeg -i "$no_audio_video" -i "$audio" -shortest -vcodec copy -acodec copy "$output_video";

To change the frame rate of a video

ffmpeg -i "$video" -filter:v fps=20 "$output_video";

To merge two videos side by side

ffmpeg -i "$left_video" -i "$right_video" -filter_complex hstack "$output_video";

Concatenate multiple videos into one

The easiest way without writing huge commands is the following: First, create a file named parts.txt and add content similar to what we list below:

#Lines starting with # will be ignored
file 'part00-03.mp4'
file 'part04.mp4'
file 'part05-07.mp4'
file 'part08-09.mp4'
file 'part10.mp4'
file 'part11-13.mp4'

Then execute the following command to concatenate all those videos into one:

ffmpeg -f concat -safe 0 -i parts.txt -c copy "$output_video";

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