ffmpeg (and avconv)

Contents

2020 Generating a crossfaded slideshow video from images with ffmpeg and melt → see also https://github.com/mifi/editly

GUI frontend

https://mystiqapp.com/

ffmpeg help

Online resources

Man pages

man ffmpeg
man ffmpeg-all
ffmpeg -h encoder=libx264 -hide_banner
ffmpeg -h full

ffmpeg -codecs

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

File infos

Avec ffprobe
- ffprobe -i file_name -hide_banner
- ffprobe -i file_name -v quiet -print_format json -show_format -show_streams

Sinon : ffmpeg -i file_name -hide_banner

1 image → 1 video

If you want to create a video out of just one image, this will do (output video duration is set to 30 seconds with -t 30)
ffmpeg -loop 1 -i img.png -c:v libx264 -t 30 -pix_fmt yuv420p out.mp4

x images → 1 video (Stop motion)

In order to speedup image processing, you can first do the following
mogrify -auto-orient -resize 1024x768! *.JPG

Video generation
ffmpeg -f image2 -pattern_type glob -r 4 -i '*.JPG' -vcodec mpeg4 -b 15000k video.mp4

-f image2 not required, but maybe a good idea to write it (!?)
-pattern_type glob use blob pattern for input files
-r 4 number of images per second (rate)
-i '*.JPG' input file names with glob pattern
-vcodec mpeg4 video codec
-b 15000k bitrate. 30000k can be a nice value as well.

Tip

-start_number 1 default for file names interpolation

Sources

1 image + 1 audio file → 1 video

ffmpeg -f image2 -loop 1 -i image.jpg -i audio.wav -c:v libx264 -tune stillimage -c:a aac -strict experimental -b:a 192k -shortest out.mp4

This would use the libx264 encoder and provide you with better compression than the MJPEG codec. The audio is AAC, with the built-in ffmpeg AAC encoder.

1 video + 1 audio file → 1 video

ffmpeg -i audio.wav -i video.avi final.mpg

Concat

You can also use ffmpeg to concatenate multiple videos into one long video. Start by transcoding all the individual videos into MPEG format, all with exactly the same bit rates, codecs, image resolutions, frame rates etc. Mistakes can be avoided by using one of ffmpeg's predefined targets such as ntsc-dvd or pal-dvd. Once that's done, simply string the resulting .mpg files together using "cat" and redirect the output to another .mpg file. Now, the timestamps inside the resulting, big .mpg file are all going to be messed up, so you'll have to process the big .mpg file with ffmpeg again. This will have the effect of putting the timestamps right.

Découper une vidéo

ffmpeg -i source.mp4 -codec:v libx264 -codec:a copy -codec:d copy -ss 00:10:21 -to 00:12:44.250 destination.mp4

-i source.mp4 source file
-codec:v libx264 video codec. Important : copy does not reencodes the video... which may cause some issues during the first seconds of the video.
-codec:a copy audio codec
-codec:d copy data codec
-ss start timestamp
-to end timestamp. Can be replaced by -t <duration>

Retourner à 180° une vidéo

avconv -i original.mp4 -vf "hflip,vflip" -codec:v libx264 -preset slow -crf 20 -codec:a copy flipped.mp4

Notice the -crf option. That sets the output quality. It goes from 0 (lossless) upwards logarithmically. You'll probably want a value between 19 and 25 in most cases. -preset sets the speed of the encoding, either "slow", "medium", or "fast". Slow should get you smaller file sizes with an obvious tradeoff. You should adjust -codec:v to match the original. If you don't set these options you'll get the defaults, which don't work well when flipping iphone video.

Conversion de formats

ogv to avi

ffmpeg -i input.ogv -qscale:v 1 output.avi

-qscale:v 1 Note : qscale is codec-dependent. Ici entre 1 (haute qualité) et 31 (basse qualité)

mov to mp4

ffmpeg -i input.mov -codec:v libx264 -b:v 1500k -g 30 output.mp4

to be tested...
ffmpeg -i input.mov -codec:v h264 -codec:a aac -strict -2 output.mp4
ffmpeg -i input.mov -b 1500k -codec:v libx264 -vpre slow -vpre baseline -g 30 output.mp4

mov to WebM

ffmpeg -i input.mov -codec:v vp8 -c:a libvorbis output.webm
to be tested
ffmpeg -i input.mov -codec:v libvpx -crf 10 -b:v 1M -codec:a libvorbis output.webm
ffmpeg -i input.mov -b 1500k -codec:v libvpx -codec:a libvorbis -ab 160000 -f webm -g 30 output.webm

mov to ogg

to be tested...
ffmpeg -i input.mov -codec:v libtheora -qscale:v 7 -codec:a libvorbis -qscale:a 5 output.ogv
ffmpeg -i input.mov -b 1500k -vcodec libtheora -acodec libvorbis -ab 160000 -g 30 output.ogv