vf / -af syntax $ ffmpeg -i input.mp4 -vf reverse -af areverse output.mp4 Using -filter_complex will allow you omit the movie multimedia source filter and have a shorter command.īelow is an example of reversing the video and audio of the input with both syntax types:

vf / -af (video filter / audio filter) is used for simple filtergraphs (one input, one output), and -filter_complex is used for complex filtergraphs (one or more inputs, one or more outputs). Filters follow a sequential order as given by the command. Filters are used to manipulate audio and video with the libavfilter library.Ī filter might result in a single change to an input file with a new output file or multiple changes to multiple output files or anything in between. To check levels before (and after) any adjustment you do, you can generate a RGB parade for a frame like so ffmpeg -i input.mp4 -vf 'format=rgb24,waveform=c=7:d=parade,scale=1200x512' -vframes 1 frame1parade.pngįor a specific frame, use ffmpeg -ss 12.4 -i input.mp4 -vf 'format=rgb24,waveform=c=7:d=parade,scale=1200x512' -vframes 1 frameNparade.Converting between one file format to another is extremely useful and might be all that’s needed for your use of FFMPEG but where the real fun begins is in the filters. What this does is stretch luminance to full range. The interpolation between the points is natural cubic spline.įor auto leveling, a crude method would be use the autolevels subfilter of the pp filter. Where you have multiple pairs in quotes, separated by commas, the sequence is 'R','G','B' mapping. Whereas 0/1 would mean set input black pixels to white in output.

input black = output black and input white = output white. If not set, the filter automatically sets 0/0 and 1/1 i.e. Here's the details on what the presets do: = ,įor each preset, each x/y pair maps input x to output y, where the range is 0-1.

Ffmpeg filter stretching