FFmpeg Commands

Show Streams and Parameters

ffprobe -i input.mkv

Extract Streams: Subtitles, Audio, Video

Extract Subtitles

ffmpeg -i input.mkv -map 0:s:0 subs.srt

Extract Audio

ffmpeg -i input.mkv -vn -acodec copy output-audio.aac

-vn is no video.
-acodec copy says use the same audio stream that’s already in there.

More info & source: https://stackoverflow.com/questions/9913032/how-can-i-extract-audio-from-video-with-ffmpeg

Hardcoding a subtitle in a video

ffmpeg -i input.mkv -vf "subtitles=subtitle.srt" -c:v libx264 -crf 20 -c:a aac -b:a 192k output.mp4
# OR
ffmpeg -i input.mp4 -vf "subtitles=subtitle.srt" output.mp4

To change the font, directly edit the parameters in the srt/ass subtitle file.

Source: https://superuser.com/questions/869248/hardcoding-subs-with-ffmpeg

Images to Video

ffmpeg -framerate 30 -i img_%05d.png video_manual.mp4

Video to GIF

ffmpeg -ss 61.0 -t 2.5 -i input.mp4 -filter_complex "[0:v] palettegen" palette.png
ffmpeg -ss 61.0 -t 2.5 -i input.mp4 -i palette.png -filter_complex "[0:v][1:v] paletteuse" output.gif

-ss 61.0 -t 2.5: Processing only 2.5 seconds starting from time 61 seconds

ffmpeg -i Movie.mkv -map 0:s:0 subs.srt

Sources:

Video to GIF: https://engineering.giphy.com/how-to-make-gifs-with-ffmpeg/
Extract subtitles: https://superuser.com/questions/583393/how-to-extract-subtitle-from-video-using-ffmpeg
Extract audio: https://stackoverflow.com/questions/9913032/how-can-i-extract-audio-from-video-with-ffmpeg
Hardcoding subtitle: https://superuser.com/questions/869248/hardcoding-subs-with-ffmpeg