linux setup notes

Example ffmpeg commands

by T.J. Nelson

Example ffmpeg commands

F fmpeg is a powerful command-line tool for manipulating video files and movies. However, the documentation is confusing. Here are some tested commands for performing typical tasks.

Normally, you'd do this in Linux, but there's also a Windows version of ffmpeg. To use it, click the Start button and type cmd.exe, hit Enter, then type the commands in the little black command window that pops up. To change to the different directory or “folder” in a Windows command box, use the cd command. If a filename contains spaces, you have to put it in double quotes (usually; the Windows cd command doesn't seem to need them.)

Extract frames from a movie
This example extracts the first 2 seconds of a movie in video21.wmv into individual image files. The files will be called img-0001.png, img-0002.png, img-0003.png, etc. It is best to do this in a separate directory.
ffmpeg -i video21.wmv -r 30 -t 2 -f image2 img-%04d.png

For wmv files it's sometimes necessary to specify the frame rate, in this case 30 (-r 30). The parameter '-f image2' means the input movie is in "image2" format; normally it's not necessary to specify it, but if it's not automatically detected, or if the extension is wrong, it may be needed.

Combine individual frames into a movie
Create an MP4 movie from JPEG files with filenames 001.jpg, 002.jpg, etc. This example creates an mp4 with 10 frames per second and 1800 kbps.
ffmpeg -r 10 -b 1800 -i %03d.jpg test.mp4
The %3d is 'C' language notation for a 3-digit integer. Don't put a percent sign or a 'd' in the filename.

This example creates an mpeg at the default rate (25 fps, 200 kbps).
ffmpeg -i %03d.jpg test.mpeg
ffmpeg figures out what movie format to use based on the filename extension that you specify.

Sometimes you have to set the bitrate to get a good quality movie. The -b 4000 sets the bit rate to 4000 kbps. In this example, the input filenames must have names starting with 'frame' followed by a dash, then five digits, then a dot, then 'jpg'.
ffmpeg -b 4000 -i frame-%5d.jpg test.mpeg

Changing image file format
Sometimes you want to convert the files into JPEGs first. This script will do the conversion and change the extension of each file from .png to .jpg. This works in Linux. Note that scripting won't work in Windows unless you have a shell like Bash installed.
for f in *png ; do convert -quality 100 $f `basename $f png`jpg; done

Find what file formats are supported

ffmpeg -formats

Get help

ffmpeg -h

Convert movie from WMV to mp4 format
Ffmpeg determines what file format you want by the extension. If your input file doesn't have the right extension, bad things will happen.
ffmpeg -i video04.wmv -f mp4 -strict -2 -t 5 a.mp4
ffmpeg -i output2.avi -strict -2 test.mp4

Resize a movie
Resize a movie input.avi to 640 × 480 pixels. An AVI file titled output.avi is produced.
ffmpeg -i input.avi -vf scale=640:480 output.avi

Crop a movie

ffmpeg -i input.avi -vf crop=100:110:200:80 output.avi
ffmpeg -i input.avi -vf crop=in_w:in_h/2:in_w:in_h/2 output.avi

The parameters are x:y:width:height in pixels. The first command tries to create a 200×80 image, but ffmpeg will change this to the correct movie aspect ratio. The second command saves only the bottom half of your movie.

Cut a section from a movie
Cut a section out of the movie, saving only the five seconds between 70 and 75.

ffmpeg -i input.avi -ss 00:01:10 -t 00:00:05 -c:v copy -c:a copy output.avi

The -c:v copy -c:a copy option makes it faster by copying the video and audio instead of decoding and re-encoding them. You could also use -vf trim=70:75, but this doesn't re-set the time stamp, so viewers will just see a black screen for the first 70 seconds. Supposedly the setpts filter can fix this, but I couldn't get it to work.

Retrieving metadata from a movie
Reads metadata and prints it on the screen. As with all ffmpeg commands, there are many options (man ffprobe). ExifTool gives a lot more information.
ffprobe DSC_6881.MOV Metadata:
major_brand : qt
minor_version : 537331968
compatible_brands: qt niko
creation_time : 2015-06-09 01:10:21
Duration: 00:01:41.35, start: 0.000000, bitrate: 18896 kb/s
Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc, bt470bg/unknown/bt470m), 1920x1080 [SAR 1:1 DAR 16:9], 17339 kb/s, 23.98 fps, 23.98 tbr, 24k tbn, 47.95 tbc (default)
creation_time : 2015-06-09 01:10:21
Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 2 channels, s16, 1536 kb/s (default)
creation_time : 2015-06-09 01:10:21
Filtering a movie

It is possible to split a movie into frames, process each individual frame in an image analysis program, and then re-assemble it into a movie. But this gets tedious after the first few hundred thousand frames.

Brightening, changing the gamma, inverting, and many other functions are available in ffmpeg through the filter option. Filtering uses the -vf option followed by a series of commands. They can be very simple:

To resize a movie to 320 × 240 pixels:
ffmpeg -i input.avi -vf scale=320:240 output.avi

To invert the colors in a movie:
ffmpeg -i output2.avi -vf lutrgb="r=negval:g=negval:b=negval" output3.avi

To increase brightness by a factor of four:
ffmpeg -i output2.avi -vf lutyuv=y=val*4 output3.avi

To increase red by a factor of two:
ffmpeg -i output2.avi -vf lutrgb=r=val*2 output3.avi

To increase gamma by factor of 5:
ffmpeg -i output2.avi -vf 'lutyuv=y=gammaval(0.2)' output3.avi
The quotes are needed to prevent the shell from messing with the command.

To rotate a movie by 45 degrees:
ffmpeg -i output2.avi -vf rotate=45 output3.avi

The sharpen, blur, or sharpen a movie:
ffmpeg -i output2.avi -vf unsharp output3.avi
ffmpeg -i output2.avi -vf unsharp=7:7:-2:7:7:-2 output3.avi
ffmpeg -i output2.avi -vf unsharp=5:5:1.5:5:5:0.0 output3.avi

The defaults for unsharp are 5:5:1.0:5:5:0.0.
1st = kernel of luma filter x size (odd 3 to 63)
2nd = kernel of luma filter y size (odd 3 to 63)
3rd = amount of luma filtering (−1.5 to 1.5 but can be any number); negative=blur, positive=sharpen
4th = kernel of chroma filter x size (odd 3 to 63)
5th = kernel of chroma filter y size (odd 3 to 63)
6th = amount of chroma filtering (−1.5 to 1.5 but can be any number); negative=blur, positive=sharpen

To draw a box or grid on the movie:
ffmpeg -i output2.avi -vf drawbox=x=10:y=20:w=200:h=60:color=red@0.5 output3.avi

ffmpeg -i output2.avi -vf drawgrid=width=100:height=100:thickness=2:color=red@0.5 output3.avi

More complex filters

Filters can also be very complex. Many seemingly simple operations require splitting the processing stream. This example crops and flips half of the image. This information is from the man page (man ffmpeg-filters).

     input --> split ---------------------> overlay --> output
                 |                             ^
                 |[tmp]                  [flip]|
                 +-----> crop --> vflip -------+

The input is split into two streams. One stream goes through the crop filter and the vflip filter, and is then merged back with the other stream by overlaying it on top. The start and end of each path require labels enclosed in square brackets. All these commands go on a single line, not broken up as shown here.

ffmpeg -i inputmovie -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" outputmovie

Here are some examples of filtering. The first one uses the YUV look-up table filter to multiply the luminance by a factor of 5, which can be useful for making extremely dark images brighter. There are also commands for changing the gamma and contrast.

ffmpeg -i DSC_6881.MOV -vf "split [main][tmp]; [tmp] lutyuv="y=val*5" [tmp2]; [main][tmp2] overlay" output.avi

This example raises the gamma. In ffmpeg, a value less than 1.0 makes dark areas lighter and a value above 1.0 makes them darker, which is the opposite of what you'd expect:
ffmpeg -i DSC_6881.MOV -vf "split [main][tmp]; [tmp] lutyuv=y=gammaval(0.6) [tmp2]; [main][tmp2] overlay" output.avi

The RGB look-up table filter is similar, and allows you to do stuff to the red, green, and blue channels separately. In this case we invert them to make a negative image.

ffmpeg -i DSC_6887.MOV -vf "split [main][tmp]; [tmp] lutrgb="r=negval:g=negval:b=negval" [tmp2]; [main][tmp2] overlay" output.avi

This example denoises an AVI file. This helps reduce those rectangular compression artifacts.
ffmpeg -i output2.avi -vf "split [main][tmp]; [tmp] dctdnoiz=4.5 [tmp2]; [main][tmp2] overlay" output3.avi

There are numerous other options, such as deshake, delogo, drawtext, fade, lens correction, rotate, subtitles, and fft filter. Some I could get to work and some, like drawtext, I couldn't, and some take a very long time to run.

Combining filters

You can put many filters together in the same command. The following rules apply:

On the Internet, no one can tell whether you're a dolphin or a porpoise
jun 11 2015; updated aug 13 2018


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