Revision 19
© 2021-2024, 2026 by Zack Smith. All rights reserved.

What is FFMPEG?

FFMPEG is the Swiss Army Knife of video conversion and alteration. It can't do everything, but it can do quite a lot.

It is very much a manually-operated utility and requires using various command line options to achieve the desired effects and the best video output quality.

FFMPEG is accompanied by ffplay which is a video player built on top of the same underlying code as ffmpeg.

To preview what ffmpeg's video filters, you can typically use ffplay with the same options.

Useful commands

Remove audio from a video

Use the -an switch:

 ffmpeg -i input.mp4 -vcodec copy -an output.mp4

Remove right audio channel from a video, making it a mono video

 ffmpeg -i input.mp4 -af 'pan=mono|c0=c0' -c:v copy output.mp4

Increase audio volume of a video

 ffmpeg -i input.mp4 -filter:a "volume=1.6" output.mp4

Extract audio from a video

 ffmpeg -i input.mp4 output.wav

Or convert directly to MP3, setting the bit-rate:

 ffmpeg -i input.mp4 -b:a 160k output.mp3

Or you can also convert WAV to MP3 with:

 lame -V0 output.wav

This generates output.mp3.

Add audio onto existing in a video, mixing with original audio

 ffmpeg -i input_video.mp4 -i new_audio.mp3 -filter_complex \
   "[0:a][1:a]amix=inputs=2" -c:v copy output.mp4

Replace audio track of a video file with another one

Don't specify an audio codec.

 ffmpeg -i video.mp4 -i audio.wav -vcodec copy -map 0:v -map 1:a output.mp4

Extract a segment of a video

The following extracts a segment starting at the 5 minute mark with a length of 1 minute:

 ffmpeg -i video.mp4 -ss 5:00 -t 1:00 -c copy output.mp4

Drop/skip every other frame (speed up video)

 ffmpeg -i video.mp4 -vf "select='not(mod(n,2))',setpts=N/FRAME_RATE/TB" output.mp4

Speed up a video by 2X

This works by changing timestamps:

 ffmpeg -i video.mp4 -vf 'setpts=0.5*PTS' output.mp4

Crop a video

Specify the rectangle to crop to.

 ffmpeg -i input.mp4 -filter:v "crop=width:height:x:y" output.mp4

Strip out metadata

 ffmpeg -i input.mp4 -map_metadata -1 -c copy output.mp4

Stabilize a shaky video

This is an alternative to using the Windows program Virtualdub's deshaker function.

 ffmpeg -i input.mp4 -vf deshake output.mp4

Sharpen a video

 ffmpeg -i input.mp4 -vf unsharp=3:3:1.5 output.mp4

Increase video brightness

 ffmpeg -i input.mp4 -vf eq=brightness=0.1 output.mp4
 or
 ffmpeg -i input.mp4 -vf lutyuv=y=val*2 output.mp4

To take a nighttime video and increase the brightness to where you can see people, use the video filter eq=brightness=0.5.

Note! To find the perfect brightness level, you can use this filter with ffplay thus:

 ffplay -vf eq=brightness=0.5 input.mp4

Rotate a video by a multiple of 90 degrees

 ffmpeg -i input.mp4 -vf "transpose=1" output.mp4

Where:

1 = 90 degrees clockwise
2 = 90 degrees counter-clockwise

Rotate a video by an arbitrary angle

 ffmpeg -i input.mp4 -vf "rotate=angle*(PI/180)"  output.mp4

As you can see, ffmpeg expects the angle to be in radians. If you want to provide it in degrees, multiply by the PI/180 expression.

Prevent loss of video orientation info

Sometimes ffmpeg will automatically rotate a portrait video to landscape without warning, because it removes the video orientation data. To prevent that, use the -noautorotate flag but put it before the input file.

 ffmepg -noautorotate -i input ... output.mp4

Horizontally flip a video

 ffmpeg -i input.mp4 -vf "hflip" output.mp4

Vertically flip a video

 ffmpeg -i input.mp4 -vf "vflip" output.mp4

Concatenate videos with reencode

 ffmpeg -i 1.mp4 -i 2.mp4 \
  -filter_complex "[0:v] [0:a] [1:v] [1:a] concat=n=2:v=1:a=1 [v] [a]" \
  -map "[v]" -map "[a]" -b 9M output.mp4

Concatenate videos without reencode

 echo 'file 1.mp4' > files.txt
 echo 'file 2.mp4' >> files.txt
 ffmpeg -f concat -safe 0 -i files.txt -c copy output.mp4

Extact all frames from a video

 ffmpeg -i input.mp4 '%05d.bmp'

Concatenate images (frames) to make a video

Let's say your images are IMG_1000.jpg with increasing numbers. This is useful for creating a time lapse or stop motion movie.

  ffmpeg -i IMG_%04d.png -qscale:v 1 output.mov

In order to set the frame rate in this case, you need to specify it before the -i:

  ffmpeg -framerate 60 -i img_%03d.png -qscale:v 1 output.mov

Play a video

FFMPEG includes the movie player ffplay. It's roughly similar in quality to MPlayer.

 ffplay myfile.mp4

Play a video with decreased brightness

 ffplay -vf eq=brightness=-0.5:saturation=2 myfile.mp4
 or
 ffplay -vf lutyuv=y=val*0.5 myfile.mp4

Multiple commands

FFMPEG lets you combine multiple commands in series e.g.

 -vf crop=100:100:0:0,rotate=45*PI/180,...

About h264 Video quality

Many computers and mobile devices now have built-in h264 decoding hardware, so it's a good idea to encode in that format.

The encoding quality is represented mainly as the h264 profile.

The default video encoding quality for h264 that ffmpeg uses however is the Low profile, which allows for rapid encoding but will often result in sub-par videos. Even if you set the bitrate to a high value, if the profile is Low, the quality will still be poor.

This is due to the fact that the profile tells ffmpeg how much algorithmic effort should go into producing a quality encoding, or essentially how much thinking the encoder should do.

To achieve a smaller, higher quality output the h264 profile must be set to High which results in more careful processing.

There is also a level setting that corresponds roughly to the resolution of your video, with 6 being appropriate up to 4K video.

Finally you can specify the amount of time to let ffmpeg think over how to best encode your video. This is the preset, with veryslow being the second-to-last choice, the last being very time consuming.

Thus I recommend these settings:

 -vcodec h264 -profile:v high -level:v 6.0 -preset veryslow

An example usage might be:

 ffmpeg input.mp4 -vcodec h264 -profile:v high -level:v 6.0 \
   -preset veryslow -acodec mp2 -b:a 160k output.mp4

zs3.me			FFMPEG Quick Reference
Open source Bandwidth memory benchmark Eratosthenes prime generator Division-based prime generator zSpreadsheet zInspect zOutline SwiftQt Randomizing drive verifier zBenchmark Documentation Linux command-line quick ref Computer security tips FFMPEG quick ref ImageMagick quick ref Object-oriented C ADB shell tips x86 Instruction Set GPG quick ref MacOS command-line tips How to force dark mode Useful bashrc Closed source iOS apps			Revision 19 © 2021-2024, 2026 by Zack Smith. All rights reserved. What is FFMPEG? FFMPEG is the Swiss Army Knife of video conversion and alteration. It can't do everything, but it can do quite a lot. It is very much a manually-operated utility and requires using various command line options to achieve the desired effects and the best video output quality. FFMPEG is accompanied by `ffplay` which is a video player built on top of the same underlying code as `ffmpeg`. To preview what `ffmpeg`'s video filters, you can typically use `ffplay` with the same options. Useful commands Remove audio from a video Use the `-an` switch: ffmpeg -i input.mp4 -vcodec copy -an output.mp4 Remove right audio channel from a video, making it a mono video ffmpeg -i input.mp4 -af 'pan=mono\|c0=c0' -c:v copy output.mp4 Increase audio volume of a video ffmpeg -i input.mp4 -filter:a "volume=1.6" output.mp4 Extract audio from a video ffmpeg -i input.mp4 output.wav Or convert directly to MP3, setting the bit-rate: ffmpeg -i input.mp4 -b:a 160k output.mp3 Or you can also convert WAV to MP3 with: lame -V0 output.wav This generates output.mp3. Add audio onto existing in a video, mixing with original audio ffmpeg -i input_video.mp4 -i new_audio.mp3 -filter_complex \ "[0:a][1:a]amix=inputs=2" -c:v copy output.mp4 Replace audio track of a video file with another one Don't specify an audio codec. ffmpeg -i video.mp4 -i audio.wav -vcodec copy -map 0:v -map 1:a output.mp4 Extract a segment of a video The following extracts a segment starting at the 5 minute mark with a length of 1 minute: ffmpeg -i video.mp4 -ss 5:00 -t 1:00 -c copy output.mp4 Drop/skip every other frame (speed up video) ffmpeg -i video.mp4 -vf "select='not(mod(n,2))',setpts=N/FRAME_RATE/TB" output.mp4 Speed up a video by 2X This works by changing timestamps: ffmpeg -i video.mp4 -vf 'setpts=0.5PTS' output.mp4 Crop a video Specify the rectangle to crop to. ffmpeg -i input.mp4 -filter:v "crop=width:height:x:y" output.mp4 Strip out metadata ffmpeg -i input.mp4 -map_metadata -1 -c copy output.mp4 Stabilize a shaky video This is an alternative to using the Windows program Virtualdub's deshaker function. ffmpeg -i input.mp4 -vf deshake output.mp4 Sharpen a video ffmpeg -i input.mp4 -vf unsharp=3:3:1.5 output.mp4 Increase video brightness ffmpeg -i input.mp4 -vf eq=brightness=0.1 output.mp4 or ffmpeg -i input.mp4 -vf lutyuv=y=val2 output.mp4 To take a nighttime video and increase the brightness to where you can see people, use the video filter eq=brightness=0.5. Note! To find the perfect brightness level, you can use this filter with ffplay thus: ffplay -vf eq=brightness=0.5 input.mp4 Rotate a video by a multiple of 90 degrees ffmpeg -i input.mp4 -vf "transpose=1" output.mp4 Where: 1 = 90 degrees clockwise 2 = 90 degrees counter-clockwise Rotate a video by an arbitrary angle ffmpeg -i input.mp4 -vf "rotate=angle(PI/180)" output.mp4 As you can see, `ffmpeg` expects the angle to be in radians. If you want to provide it in degrees, multiply by the PI/180 expression. Prevent loss of video orientation info Sometimes ffmpeg will automatically rotate a portrait video to landscape without warning, because it removes the video orientation data. To prevent that, use the `-noautorotate` flag but put it before the input file. ffmepg -noautorotate -i input ... output.mp4 Horizontally flip a video ffmpeg -i input.mp4 -vf "hflip" output.mp4 Vertically flip a video ffmpeg -i input.mp4 -vf "vflip" output.mp4 Concatenate videos with reencode ffmpeg -i 1.mp4 -i 2.mp4 \ -filter_complex "[0:v] [0:a] [1:v] [1:a] concat=n=2:v=1:a=1 [v] [a]" \ -map "[v]" -map "[a]" -b 9M output.mp4 Concatenate videos without reencode echo 'file 1.mp4' > files.txt echo 'file 2.mp4' >> files.txt ffmpeg -f concat -safe 0 -i files.txt -c copy output.mp4 Extact all frames from a video ffmpeg -i input.mp4 '%05d.bmp' Concatenate images (frames) to make a video Let's say your images are IMG_1000.jpg with increasing numbers. This is useful for creating a time lapse or stop motion movie. ffmpeg -i IMG_%04d.png -qscale:v 1 output.mov In order to set the frame rate in this case, you need to specify it before the -i: ffmpeg -framerate 60 -i img_%03d.png -qscale:v 1 output.mov Play a video FFMPEG includes the movie player `ffplay`. It's roughly similar in quality to MPlayer. ffplay myfile.mp4 Play a video with decreased brightness ffplay -vf eq=brightness=-0.5:saturation=2 myfile.mp4 or ffplay -vf lutyuv=y=val0.5 myfile.mp4 Multiple commands FFMPEG lets you combine multiple commands in series e.g. -vf crop=100:100:0:0,rotate=45PI/180,... About h264 Video quality Many computers and mobile devices now have built-in h264 decoding hardware, so it's a good idea to encode in that format. The encoding quality is represented mainly as the h264 profile. The default video encoding quality for h264 that `ffmpeg` uses however is the Low* profile, which allows for rapid encoding but will often result in sub-par videos. Even if you set the bitrate to a high value, if the profile is Low, the quality will still be poor. This is due to the fact that the profile tells `ffmpeg` how much algorithmic effort should go into producing a quality encoding, or essentially how much thinking the encoder should do. To achieve a smaller, higher quality output the h264 profile must be set to High which results in more careful processing. There is also a level setting that corresponds roughly to the resolution of your video, with 6 being appropriate up to 4K video. Finally you can specify the amount of time to let `ffmpeg` think over how to best encode your video. This is the preset, with veryslow being the second-to-last choice, the last being very time consuming. Thus I recommend these settings: -vcodec h264 -profile:v high -level:v 6.0 -preset veryslow An example usage might be: ffmpeg input.mp4 -vcodec h264 -profile:v high -level:v 6.0 \ -preset veryslow -acodec mp2 -b:a 160k output.mp4 Links Using FFMPEG as a benchmark FFMPEG Website MPlayer MainConcept makers of codecs commonly used to create online videos.

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