Changes between Version 2 and Version 3 of Null


Ignore:
Timestamp:
Dec 30, 2015, 12:19:50 AM (4 years ago)
Author:
rogerdpack
Comment:

cleanup page

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  • Null

    v2 v3  
    1 There are several ways to "output to null" in FFmpeg.
     1There are several ways to "output to null" in FFmpeg.  This can be helpful for benchmarking purposes, for instance testing encoding speeds (without having to worry about the cost of disk writes) etc.
    22
    3 there is the null muxer, like
     3There is the null muxer, use it like this:
     4{{{
     5         ffmpeg -i INPUT -f null out.null # file out.null will not be created, no encoding will occur
     6}}}
    47
    5      ffmpeg -i INPUT -f null out.null # file out.null will not be created
     8or just output to /dev/null (or the reserved filename NUL in windows) for your file to just disappear, if you want to perform encoding but not create a file
    69
    7 There is the null video sink:
     10{{{
     11     ffmpeg -i INPUT -f mpeg4 -f nut -y /dev/null # no file is created, encoding occurs and packaging occurs
     12}}}
    813
    9 https://ffmpeg.org/ffmpeg-filters.html#nullsink (not clear if you can actually use this from the command line) (NB the "null" filter actually does nothing and is just a video pass through, but nullsink exists.
    10 
    11 or just output to /dev/null (or the reserved filename NUL in windows) for your file to just disappear.
    12 
    13      ffmpeg -i INPUT -f rawvideo /dev/null # avoids doing any conversion before writing time (may still demuxes and decodes the input though)
    14 
    15 
    16 All useful in testing/analyzing when you don't want the "writing out" part to get in your way.  See also the "-benchmark" parameter.
    17 
    18 There may be a way to use the "-map" parameter as well, unclear.
     14See also the "-benchmark" parameter.