Trim

Trim

Trims a clip – removes frames from one or both ends.

Trim cannot trim a clip if there is no video. Use AudioTrim (from AviSynth v2.60) for that case; for versions prior to v2.60, you must AudioDub your audio-only clip to a video clip and Trim that.

The resulting clip starts with frame number 0, and this must be taken into account when making additional edits using that clip. To view a clip's frame number at any point in your script, temporarily insert an Info or ShowFrameNumber statement.

For convenience, Trim can be called in four slightly different ways:

Trim(clip, int first_frame, int last_frame [, bool pad] )

Returns a clip starting at first_frame and running up to and including last_frame.

• For example, Trim(3, 5) returns source clip frames 3, 4 and 5.
• Remember, AviSynth starts counting at frame 0.
• If you set last_frame to 0, you will get a clip starting at first_frame and running to the end of the clip.

 pad

 bool  pad = true

True by default, pad 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 – compare to UnalignedSplice.

Trim(clip, int first_frame, int -num_frames [, bool pad] )

With a negative value for the second argument, you get a clip starting at first_frame and running for num_frames frames.

• For example, Trim(0, -4) returns source clip frames 0, 1, 2 and 3.

Trim(clip, int first_frame, [int end , bool pad] )

Returns a clip starting at first_frame and running up to and including frame end. From Avisynth v2.60.

• For example, Trim(3, end=7) is equivalent to Trim(3, 7); both return frames 3, 4, 5, 6 and 7.
• end default = 0; must be >= first_frame.
• Unlike the last_frame syntax, the end syntax has no discontinuous boundary values: end=0 means end at frame 0. This feature is useful in avoiding unexpected boundary conditions in your user functions.

Trim(clip, int first_frame, [int length , bool pad] )

Returns a clip starting at first_frame and running for length frames. From Avisynth v2.60.

• For example, Trim(3, length=5) is equivalent to Trim(3, -5); both return frames 3, 4, 5, 6 and 7.
• length default = 0; must be >= 0.
• Unlike the num_frames syntax, the length syntax has no discontinuous boundary values: length=0 means return a zero length clip. This feature is useful in avoiding unexpected boundary conditions in your user functions.

AudioTrim

AudioTrim (from 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).

All time arguments are in seconds, floating-point.

• Trims on audio-only clips are accurate to the nearest audio sample.
• Trims on clips with video are accurate to the nearest whole video frame.

AudioTrim cannot trim a clip if there is no audio. Use Trim for that case.

The resulting clip starts with time = 0.0, and this must be taken into account when making additional edits to that clip. To view a clip's time at any point in your script, temporarily insert an Info or ShowTime statement.

For convenience, AudioTrim can be called in four slightly different ways:

AudioTrim(clip, float start_time, float end_time)

Returns a clip starting at start_time and running up to and including time end_time.

• For example, AudioTrim(3.0, 5.0) returns source clip from time 00:00:03.000 to 00:00:05.000.
• If you set end_time to 0.0, you will get a clip starting at start_time seconds and running to the end of the clip.

AudioTrim(clip, float start_time, float -duration)

With a negative value for the second argument, you will get a clip starting at start_time and running for duration seconds.

• For example, AudioTrim(0.0, -4.0) returns the source clip from time 00:00:00.000 to 00:00:04.000.

AudioTrim(clip, float start_time [, float end] )

Returns a clip starting at start_time and running up to and including time end.

• For example, AudioTrim(3.0, end=7.0) is equivalent to AudioTrim(3.0, 7.0)
• end default = 0.0; must be >= start_time.
• Unlike the end_time syntax, the end syntax has no discontinuous boundary values: end=0.0 means return a zero length clip. This feature is useful in avoiding unexpected boundary conditions in your user functions.

AudioTrim(clip, float start_time [, float length] )

Returns a clip starting at start_time and running for length seconds.

• For example, AudioTrim(3.0, length=4.0) is equivalent to AudioTrim(3.0, -4.0)
• length default = 0.0; must be >= 0.
• Unlike the duration syntax, the length syntax has no discontinuous boundary values: length=0.0 means return a zero length clip. This feature is useful in avoiding unexpected boundary conditions in your user functions.

Examples

• Return only the first frame (frame 0)

Trim(0, -1)
Trim(0, end=0)
Trim(0, length=1)

• Return only the last frame

Trim(FrameCount, -1)
Trim(FrameCount, end=Framecount)
Trim(FrameCount, length=1)

• Return frames 100-199 (duration=100)

Trim(100, 199)
Trim(100, -100)

• Delete the first 100 frames; audio padded or trimmed to match the video length.

Trim(100, 0) # (pad=true by default)

• Delete the first 100 frames of audio and video; the resulting stream lengths remain independent.^{[dubious – discuss]}

Trim(100, 0, pad=false)

• Trim audio if longer than video (pad does affect this action)

Trim(0, FrameCount-1) 

• Audio will be trimmed if longer, but not padded if shorter to frame 199

Trim(100, 199, pad=false)

• AudioTrim: trim video if longer than audio

AudioTrim(0, AudioDuration)

• AudioTrim: keep the audio between 1.0 and 6.5 seconds

(ie, delete the first second, keep the following 5.5 seconds)

AudioTrim(1, 6.5)       
AudioTrim(1, -5.5)       
AudioTrim(1, length=5.5)

Changes

v2.60	Added AudioTrim. Added length and end parameters.
v2.56	Added pad audio.