Trim

Revision as of 15:23, 7 January 2016

Trim

Trim(clip, int first, int [-]last [, bool "pad"])
Trim(clip, int first, [int "end" , bool "pad"])
Trim(clip, int first, [int "length" , bool "pad"])

Trim trims a clip so that it includes only the frames first up to and including last. The audio is similarly trimmed so that it stays synchronized (see pad below). Remember AviSynth starts counting at frame 0.

If you set a negative value for the second argument, that is -last, you will get a clip starting at first and running for last frames. If you set last to zero, you will get a clip starting at first and running to the end of the clip.

int  end = 0
int  length = 0

In Avisynth v2.60, you may use the alternate syntax with named arguments; for example,

• Trim(3, 7)  →  Trim(3, end=7)
• Trim(3, -5) →  Trim(3, length=5)

Unlike the first syntax, the alternate syntax has no discontinuous boundary values: end=0 means end at frame 0; length=0 means return a zero length clip. These are most useful in avoiding unexpected boundary conditions in your user functions.

bool  pad = true

Causes the audio stream to be padded to align with the video stream. Otherwise the tail of a short audio stream is left so. You should use pad=false when the soundtracks being joined were originally contiguous (see Splice)

Trim with audio-only clips

In AviSynth v2.60, to trim an audio-only clip, you simply set a fake frame rate with AssumeFPS. In earlier versions you cannot do this: you must make a BlankClip, use AudioDub, trim that, and then KillVideo. Otherwise, AviSynth returns the error message "cannot trim if there is no video".

AudioTrim

AudioTrim(clip, float first, float [-]last)
AudioTrim(clip, float first [, float "end"])
AudioTrim(clip, float first [, float "length"])

AudioTrim (in Avisynth v2.60) trims a clip based on time, not on frames. This is most useful for audio-only clips, where "frames" have no meaning anyway, and you may want to edit with finer precision than whole frames (at 30fps, 1 frame=33.3ms). The returned clip includes only the audio (or video+audio) from time first up to and including time last. All time arguments are in seconds.

If you set a negative value for the second argument, that is -last, you will get a clip starting at first seconds and running for last seconds. If you set last to zero, you will get a clip starting at first seconds and running to the end of the clip.

float  end = 0.0
float  length = 0.0

You may prefer the alternate syntax with named arguments; for example,

• AudioTrim(3.0, 7.0)  →  AudioTrim(3.0, end=7.0)
• AudioTrim(3.0, -4.0) →  AudioTrim(3.0, length=4.0)

Examples

Trim(100,0)             # delete the first 100 frames, audio padded
                        # or trimmed to match the video length.

Trim(100,0,false)       # delete the first 100 frames of audio and video,
                        # the resulting stream lengths remain independent.

Trim(100,-100)          # is the same as trim(100,199) ie, start=100, duration=100

Trim(100,199,false)     # audio will be trimmed if longer but not
                        # padded if shorter to frame 199

Trim(0,-1)              # returns only the first frame
Trim(0,end=0)           #
Trim(0,length=1)        #

AudioTrim(1,5.5)        # keeps the audio samples between 1 and 5.5 seconds
AudioTrim(1,end=5.5)    #

AudioTrim(1,-5.5)       # cuts the first second and keeps the following 5.5 seconds
AudioTrim(1,length=5.5) #

Changes