Trim

Revision as of 01:36, 8 January 2016

Trim

Trim(clip, int first_frame, int last_frame [, bool "pad"])
Trim(clip, int first_frame, int -num_frames [, bool "pad"])
Trim(clip, int first_frame, [int "end" , bool "pad"])
Trim(clip, int first_frame, [int "length" , bool "pad"])

Trim trims a clip so that it includes only the frames first_frame up to and including last_frame. 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 -num_frames, you will get a clip starting at first_frame and running for num_frames frames. If you set last_frame to zero, you will get a clip starting at first_frame 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_frame 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 start_time, float end_time)
AudioTrim(clip, float start_time, float -duration)
AudioTrim(clip, float start_time [, float "end"])
AudioTrim(clip, float start_time [, 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 start_time up to and including time end_time. All time arguments are in seconds.

If you set a negative value for the second argument, that is -duration, you will get a clip starting at start_time seconds and running for duration seconds. If you set end_time to zero, you will get a clip starting at start_time 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