Transcode_Wiki: Filter Plugins/Filter Transform

Capabilities

Video	Audio	RGB	YUV	YUV422	multiple instances	processing type	frames needed
yes	no	yes	yes	yes	no	PRE	2

Introduction

If you captured a video while skiing, cycling or whatever sports then you often find strong jiggled on it. Modern cameras come along with hardware stabilization, however this does not work if you have really strong vibrations - rather the contrary sometimes this mechanisms start to oscillate. /filter stabilize and transform are your friend in this matter. It is designed to stabilize even strongly wiggled clips.

Technically transform does two things. First, it loads transformations for each frame from a file which where usually generated by the /filter stabilize filter and applies, if desired, a smoothing operations. This is what actually stabilizes the video. Second, it actually transforms the frames. See /filter stabilize for the first stage and http://public.hronopik.de/vid.stab/ for further details.

Parameters

Default values are shown in [green] in square brackets. Also available with

 tcmodinfo -i transform

input path to the file used to read the transforms [inputfile.trf]

smoothing Amount of smoothing (stabilizing) to perform (1-oo) [10]: Number of frames*2 + 1 to use for lowpass filtering. Note that it basically defines the maximal camera acceleration. With a framerate of 25fps and a smoothing of 12 camera movements on the timescale of one second remain. If you smooth too much and the camera accelerates you stabilize the clip out of the viewable area.

maxshift maximal number of pixels to translate image (-1-oo) [-1](no limit): -1 means no limitation.

maxangle maximal angle in rad to rotate image (-1-oo) [-1](no limit): -1 means no limitation.

crop what to do with the area outside of the frames (0,1) [0]: 0: keep border (pixels outside of current translated one) from previous frame(s), 1: black background

invert whether to invert the transformations (0,1) [0]: 0: nothing done, 1: invert (negate)

relative consider transforms as absolute or relative (0,1) [1]: 0: absolute (each transformation is takes as it is), 1: relative (transformation is with respect to the previous frame)

Usage Examples

Simple call with default values

  -J transform

make it very smooth and use black background for unknown areas

  -J transform=smoothing=50=crop=1