yuvfps(1) MJPEG tools manual yuvfps(1) 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 al- low the generation of video streams with the frame rates required for each standard video format. yuvfps reads a YUV4MPEG stream from the standard in- put and outputs a YUV4MPEG stream to the standard output in which frames from the original ones are skipped (downsampling) or duplicated (upsam- pling). 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. More- over, 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 orig- inal 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 in- terlacing 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 inter- lacing mode can be changed only when using the weighted average re- sampling 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 as- sumes this interlacing mode for the input stream. The possible val- ues 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 interlac- ing mode for the output stream header. -n By default yuvfps tries to find a normalized framerate. Some pro- grams create framerates like: 29969909:1000000 which is actually th typical NTSC framerate of 30000:1001. yuvfps prints out the normal- izes values and the original when it starts. If you think the nor- malized 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 re- duces visible stepping compared to the default drop/duplicate algo- rithm 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 in- formation. 2 = add chatty debugging message, too. AUTHOR This man page was written by Alfonso Garcia-Patino 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) MJPEG Tools Team 8 Jan 2006 yuvfps(1)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | AUTHOR | SEE ALSO
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