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ffmpeg

  • Convert one format to another (basic)
    • ffmpeg -i [file.[input-extension]] [file.[output-extension]]
  • Join audio and video together
    • ffmpeg -i [video] -i [audio] -c:v copy aac [output]
  • Remove audio stream from the video
    • ffmpeg -i video.mkd -c copy -an video_without_audo.mkv

  • Join audio video, no encoding and decoding

    • ffmpeg -i video.mkv -i audio.mp3 -c output.mkv

  • get certain part of the video file

    • ffmpeg [input] -ss 00:00:00 -to 00:00:60 -c:v copy -c:a copy [output]

  • loop for conversion

for f in *.avi; do 
    ffmpeg \
        -i "$f" \
        -c:v libx264 \
        -crf 23 \
        -preset medium \
        -c:a aac \
        -b:a 128k \
        -movflags +faststart \
        -vf scale=-2:720,format=yuv420p \
        "${f%.avi}.mp4"; 
done

Codecs

  • -c means codecs
  • convert and use the same codecs
    • ffmpeg -i [input-file] -c copy [output-file]
  • convert and change video codec and audio codec
    • ffmpeg -i [input-file] -c:v [video-codec] -c:a [audio-codec] [output-file]
    • use copy as codec if you want to keep the current codec
    • video
      • H.268 - libx268
      • h.264 - lossless - libx264 -crf 0
    • audio
      • AAC - aac

Fastest way to convert videos

https://askubuntu.com/questions/352920/fastest-way-to-convert-videos-batch-or-single/353282#353282

MP4

ffmpeg \
    -i input \
    -c:v libx264 \
    -crf 23 \
    -preset medium \
    -c:a aac \
    -b:a 128k \
    -movflags \
    +faststart \
    -vf scale=-2:720,format=yuv420p \
    output.mp4
  • -crf
    • Quality. Range is logarithmic 0 (lossless) to 51 (worst quality). Default is 23. Subjective sane range is ~18-28 or so. Use the highest value that still gives you an acceptable quality. If you are re-encoding impractically large inputs to upload to YouTube or similar then try a value of 17 or 18 since these video services will re-encode anyway.
  • -preset
    • Encoding speed. A slower preset provides better compression (quality per file size) but is slower. Use the slowest that you have patience for: ultrafast, superfast, veryfast, faster, fast, medium (the default), slow, slower, veryslow.

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