Provided by: mjpegtools_2.1.0+debian-5_amd64 
NAME
yuvfps - Converts to a different frame rate
SYNOPSIS
yuvfps [-r Num:Den] [-s Num:Den] [-i Interlacing] [-I Interlacing] [-c] [-n] [-w] [-v 0-2] [-h]
DESCRIPTION
yuvfps is a general (UP or DOWN) resampling utility that is provided to allow the generation of video
streams with the frame rates required for each standard video format. yuvfps reads a YUV4MPEG stream from
the standard input and outputs a YUV4MPEG stream to the standard output in which frames from the original
ones are skipped (downsampling) or duplicated (upsampling). This allows for other mjpegtools that
require a specific frame rate to process the stream.
yuvfps uses by default Bresenham's algorithm to do the resampling so that the new video stream is similar
to the original one. Note, however, that downscaling is a non-reversible operation because frames are
dropped. Moreover, the resulting video stream may not have the exact same duration as the original one if
the new frame rate is not a whole multiple of the original rate.
As an alternative to simply dropping or duplicating frames each output frame/field can be produced as a
weighted average of the two temporally closest input frames/fields. In this mode, yuvfps can also change
the interlacing mode of the stream.
yuvfps also can "fix" the framerate specified in the YUV4MPEG header. This allows for the generation of
effects (fast-forwarding, slow motion) and also when the source stream has some framerate that is very
close, but not exactly, the rate required for some standard video (for example, 24.9 vs 25).
OPTIONS
-r Num:Den
Specifies the resulting stream frame rate.
-s Num:Den
Ignores the frame rate in the input stream and assumes this frame rate for the input stream.
-i Interlacing
Specifies the interlacing mode of the resulting stream. The interlacing mode can be changed only
when using the weighted average resampling mode (the -w option).
p - progressive (non-interlaced)
t - top-field first
b - bottom-field first
-I Interlacing
Ignores the interlacing mode information in the input stream and assumes this interlacing mode for
the input stream. The possible values are the same as for the -i option.
-c
Changes the stream header frame rate and interlacing mode in the output stream but copies frames
from the original stream without changes. The -r and -i options specify the frame rate and
interlacing mode for the output stream header.
-n
By default yuvfps tries to find a normalized framerate. Some programs create framerates like:
29969909:1000000 which is actually th typical NTSC framerate of 30000:1001. yuvfps prints out the
normalizes values and the original when it starts. If you think the normalized value is not
correct and want yuvfps to use the original given number you have to add that option. So yuvfps
does not try to normalize the values.
-w
Produce each output frame/field as a weighted average of the two temporally closest input
frames/fields instead of simply dropping or duplicating frames. The blending of two adjacent
frames/fields reduces visible stepping compared to the default drop/duplicate algorithm but as a
drawback it makes fast moving objects appear blurred and is much slower.
-v [0,1,2]
Set verbosity level.
0 = warnings and error messages only.
1 = add informative messages, like the framerate conversation information.
2 = add chatty debugging message, too.
AUTHOR
This man page was written by Alfonso García-Patiño Barbolani.
Johannes Lehtinen added information about the weighted average resampling mode and the related options.
If you have questions, remarks, problems or you just want to contact the developers, the main mailing
list for the MJPEG-tools is:
mjpeg-users@lists.sourceforge.net
For more info, see our website at
http://mjpeg.sourceforge.net/
SEE ALSO
yuvscaler(1), mjpegtools(1), lavpipe(1), lav2yuv(1) mpeg2enc(1)