FFmpeg Basics

Contents

  • Introduction
  • Rewrap
  • Transcoding
  • Change Image Format
  • Split A/V
  • Video Excerpts
  • Video to Image (and back)

FFmpeg? Whatisthat?

FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams.

At its core is the command-line ffmpeg tool itself, designed for processing of video and audio files.

 

Source: Wikipedia: FFmpeg

Where to get it from?

...from an Organic Farmer's Market.

Digital Video Trinity

Basic Syntax

ffmpeg [-y] -i INPUT_FILE [PARAMETER] [-f FORMAT] OUTPUT_FILE

FFmpeg, what can you do?

  • List Containers: -formats 
    File formats:
  D. = Demuxing supported
  .E = Muxing supported
  • List Codecs: -codecs / -encoder / -decoder 
    Codecs:
  D..... = Decoding supported
  .E.... = Encoding supported
  ..V... = Video codec
  ..A... = Audio codec
  ..S... = Subtitle codec
  ...I.. = Intra frame-only codec
  ....L. = Lossy compression
  .....S = Lossless compression

Rewrap

ffmpeg -i INPUT_FILE -c copy -map 0 OUTPUT_FILE

Check Result

ffprobe -i INPUT_FILE

ffprobe -i INPUT_FILE [-show_format] [-show_streams] [-of ...] [-pretty]

 

FFprobe Dokumentation

A/V separately

  • Video 'None': -vn
  • Audio 'None': -an

Set Encoding Codec

  • Videocodec: -c:v CODEC
  • Audiocodec: -c:a CODEC
  • Copy all streams 'as-is': -c copy

Transcode

ffmpeg -i INPUT_FILE -c:v ffv1 -c:a pcm_s24le OUTPUT_FILE

ffmpeg -i INPUT_FILE -c:v ffv1 -c:a pcm_s16le OUTPUT_FILE

Video 1

  • Resolution: -s WIDTHxHEIGHT
  • Aspect Ratio (DAR): -aspect X:Y
  • Framerate: -r FPS

Change the "image"

ffmpeg -i INPUT_FILE -an -c:v ffv1 -vf scale=720:-1 OUTPUT_FILE

ffmpeg -i INPUT_FILE -an -c:v ffv1 -aspect 4:3 OUTPUT_FILE

ffmpeg -i INPUT_FILE -an -c:v ffv1 -r 30000/1001 OUTPUT_FILE

Video 2

  • Color model / bit-depth: -pix_fmt FORMAT

pix_fmt?

  • yuv422p = YUV 4:2:2 planar
  • yuv420p

  • yuv422p10le
  • yuv420p10le

  • yuva422p

  • "Keep-or-die": -pix_fmt +

 

Show list: -pix_fmts

Change Subsampling

By simply setting the output pix_fmt 'as desired':

ffmpeg -i INPUT_FILE -c:v ffv1 -pix_fmt yuv422p OUTPUT_FILE

(Watch out: requires re-encoding!)

Audio

  • Audiocodec: -c:a CODEC
  • Samplerate: -ar SAMPLERATE
  • Channels: -ac CHANNELS
  • Bitrate: -b:a BITRATE{k,M}

A/V separately

  • Only Image (keep encoding):
    ffmpeg -i INPUT_FILE -an -c:v copy OUTPUT_FILE
  • Only Audio (keep encoding):
    ffmpeg -i INPUT_FILE -vn -c:v copy OUTPUT_FILE
  • Only Audio (to MP3):
    ffmpeg -i INPUT_FILE -vn -c:a mp3 -b:a 128k out.mp3
  • Only Audio (to FLAC):
    ffmpeg -i INPUT_FILE -vn -c:a flac out.flac

Video 3

  • Bitrate: -b:v BITRATE{k,M}
  • Bitrate (min): -minrate BITRATE
  • Bitrate (max): -maxrate BITRATE
  • GOP size: -g FRAMES

Video Excerpts

  • Start position: -ss TIME_BEGIN
  • Backwards: -sseof TIME
  • Length: -t TIME_DURATION
  • End position: -to TIME_END

 

FFmpeg's "TIME" SYNTAX:
Timecode: [-][HH:]MM:SS[.m]
or
Seconds: [-]S[.m]

Video Excerpts

  • Start Offset:
    ffmpeg -ss TIME_BEGIN -i INPUT_FILE -c copy OUTPUT_FILE
  • Only Beginning:
    ffmpeg -t TIME_DURATION -i INPUT_FILE -c copy OUTPUT_FILE
  • Offset + Length:
    ffmpeg -ss TIME_BEGIN -t TIME_DURATION -i INPUT_FILE -c copy OUTPUT_FILE
  • Absolute In/Out:
    ffmpeg -ss TIME_BEGIN -to TIME_END -i INPUT_FILE -c copy OUTPUT_FILE

Transcoding II

FFV1

FFV1, which stands for "FF video codec 1", is a lossless intra-frame video codec.

 

  • Codec: -c:v ffv1
  • Version: -level {1,3}
  • Coder: -coder {0=golomb,1=range}
  • Context: -context {0=small,1=large}
  • Slices: -slices {4,6,9,12,16,24,..}
  • CRC: -slicecrc {0,1}

 

Quellen: Wikipedia: FFV1, ffv1.info

FFV1

ffmpeg -i INPUT_FILE -an -c:v ffv1 -level 3 -slices 24 -slicecrc 1

ProRes

"Apple ProRes is a lossy video compression format developed by Apple Inc. for use in post-production"

 

  • Codec: -c:v {prores,prores_aw,prores_ks}
  • Profiles: -profile:v {proxy,lt,standard,hq,4444,4444xq}

 

Quellen/Links: Wikipedia: Apple ProRes, FFmpeg docs, Kieran Kunya's Blog, FinalCut docs

ProRes

ffmpeg -i INPUT_FILE -an -c:v prores_ks -profile:v hq

H.264

"x264 H.264/MPEG-4 AVC encoder wrapper. [...]
libx264 supports an impressive number of features, [...]"

 

  • Codec: -c:v libx264
  • Bitrate: -b:v BITRATE{k,M}
  • CRF: -crf 0 (lossless) - 51 (worst)
  • Presets: -preset:v {ultrafast,superfast,veryfast,faster,fast,medium(*),slow,slower,veryslow}
  • Feintuning: -tune {film,animation,grain,...}

 

Quellen/Links: FFmpeg Wiki, FFmpeg docs

H.264

ffmpeg -i INPUT_FILE -an -c:v libx264 -preset:v superfast -crf 22

From Video to Image

ffmpeg -i input.mp4 -an out/delme_%04d.png -vn -c:a pcm_s16le out/delme.wav

From Image to Video

ffmpeg -r $FPS -start_number $FRAMENO -i out/xxx_%04d.png -i out/xxx.wav -c:v libx264 -crf 22 -c:a aac -b:a 128k output.mkv

Links

License and Credits

Der Text dieser Präsentation steht unter einer freien Lizenz zur Verfügung:

Creative Commons "Attribution-ShareAlike"
(CC-BY-SA)

Peter Bubestinger-Steindl
(Peter@ArkThis.com)