Introduction

The available (internal) filters are listed here and divided into categories. A short description is added, including the supported color formats (and sample types for the audio filters). There are some functions which combine two or more clips in different ways. How the video content is calculated is described for each function, but here is a summary which explains which properties that the resulting clip will have.

Media file filters

These filters can be used to read or write media files. Usually they produce source clips for processing. See debug filters for non-file source filters.

AVISource / OpenDMLSource / AVIFileSourceOpens an AVI file.
DirectShowSourceDirectShowSource reads filename using DirectShow
ImageReader / ImageSourceThis filter produces a video clip by reading in still images. 
ImagewriterWrites frames as images to your hard disk.
ImportImport an AviSynth script into the current script
SegmentedAVISource / SegmentedDirectShowSourceThe SegmentedAVISource filter automatically loads up to 100 avi files per argument
WAVSourceOpens a WAV file or the audio of an AVI file.

Color conversion and adjustment filters

These filters can be used to change the color format or adjust the colors of a clip.

ColorYUVAdjusts colors and luma independently.
ConvertToRGB / ConvertToYUY2 / ConvertToYV12 / ConvertBackToYUY2 ConvertToRGB32 / ConvertToRGB24AviSynth can deal internally with four color formats, RGB24, RGB32, YUY2 and YV12. These filters convert between them.
FixLuminanceCorrect shifting vertical luma offset
GreyscaleConverts a video to greyscale.
InvertInverts selected color channels of a video.
LevelsThe Levels filter scales and clamps the blacklevel and whitelevel and adjusts the gamma.
LimiterA filter for clipping levels to within CCIR-601 range.
MergeARGB / MergeRGBThis filter makes it possible to select and combine a color channel from each of the input videoclips.
Merge / MergeChroma / MergeLumaThis filter makes it possible to merge luma, chroma or both from a videoclip into another. There is an optional weighting, so a percentage between the two clips can be specified.
RGBAdjustAdjust each color channel seperately.
ShowAlpha / ShowRed / ShowGreen / ShowBlueShows the selected channel of an (A)RGB clip.
SwapUV / UToY / VToY / YToUVSwaps/copies chroma channels of a clip.
TweakAdjust the hue, saturation, brightness, and contrast.

Overlay and Mask filters

These filters can be used to layer clips with or without using masks and to create masks.

ColorKeyMaskSets the alpha-channel (similar as Mask does) but generates it by comparing the color.
LayerLayering two videos.
MaskApplies an alpha-mask to a clip.
OverlayOverlay puts two clips on top of each other with an optional displacement of the overlaying image, and using different overlay methods. Furthermore opacity can be adjusted for the overlay clip.
ResetMaskApplies an "all-opaque" alpha-mask to clip.
SubtractSubtract produces an output clip in which every pixel is set according to the difference between the corresponding pixels

Geometric deformation filters

These filters can be used to change image size, process borders or make other deformations of a clip.

AddBordersAddBorders adds black borders around the image.
Crop / CropBottomCrop crops excess pixels off of each frame.
FlipHorizontal / FlipVerticalFlips the video upside-down or left-to-right
LetterboxLetterbox simply blackens out the top and the bottom and optionally left and right side of each frame.
ReduceBy2 / HorizontalReduceBy2 / VerticalReduceBy2ReduceBy2 reduces the size of each frame by half.
BilinearResize / BicubicResize / BlackmanResize / GaussResize / LanczosResize / Lanczos4Resize / PointResize / Spline16Resize / Spline36Resize / Spline64ResizeThe Resize filters rescale the input video frames to an arbitrary new resolution, using different sampling algorithms.
TurnLeft / TurnRight / Turn180Rotates the clip 90 degrees counterclock wise / 90 degrees clock wise / 180 degrees.

Pixel restoration filters

These filters can be used for image detail (pixel) restoration (like denoising, sharpening) of a clip.

Blur / SharpenThese are simple 3x3-kernel blurring and sharpening filters.
GeneralConvolutionGeneral 3x3 or 5x5 convolution matrix.
SpatialSoften / TemporalSoftenThe SpatialSoften and TemporalSoften filters remove noise from a video clip by selectively blending pixels.
FixBrokenChromaUpsamplingI noticed that the MS DV codec upsamples the chroma channels incorrectly, and I added a FixBrokenChromaUpsampling filter to compensate for it.

Timeline editing filters

These filters can be used to arrange frames in time (clip cutting, splicing and other editing).

AlignedSplice / UnalignedSpliceAlignedSplice and UnalignedSplice join two or more video clips end to end.
AssumeFPS / AssumeScaledFPS / ChangeFPS / ConvertFPSChanges framerates in different ways.
DeleteFrameDeleteFrame deletes a set of single frames, given as a number of arguments.
DissolveDissolve is like AlignedSplice, except that the clips are combined with some overlap.
DuplicateFrameDuplicateFrame duplicates a set of single frames, given as a number of arguments.
FadeIn0 / FadeOut0 / FadeIn / FadeOut / FadeIn2 / FadeOut2 / FadeIO0 / FadeIO / FadeIO2FadeIn and FadeOut cause the video stream to fade linearly to black at the start or end.
FreezeFrameThe FreezeFrame filter replaces all the frames between first-frame and last-frame with a selected frame.
InterleaveInterleave interleaves frames from several clips on a frame-by-frame basis.
LoopLoops the segment from start frame to end frame a given number of times.
ReverseThis filter makes a clip play in reverse.
SelectEven / SelectOddSelectEven makes an output video stream using only the even-numbered frames
SelectEverySelectEvery is a generalization of filters like SelectEven and Pulldown.
SelectRangeEveryThis filters selects a range of frames with a certain period.
TrimTrim trims a video clip so that it includes only the frames first-frame through last-frame.

Interlace filters

These filters can be used for creating and processing field-based material (which is frame-based material separated into fields). AviSynth is capable of dealing with both progressive and interlaced material. The main problem is, that it often doesn't know what it receives from source filters. This is the reason that the field-based flag exists and can be used when dealing with interlaced material. More information about field-based video can be found here.

AssumeFrameBased / AssumeFieldBasedForces frame-based or field-based material.
AssumeTFF / AssumeBFFForces field order.
BobBob takes a clip and bob-deinterlaces it
ComplementParityChanges top fields to bottom fields and vice-versa.
DoubleWeaveThe DoubleWeave filter operates like Weave, except that it produces double the number of frames by combining both the odd and even pairs of fields.
PeculiarBlendThis filter blends each frame with the following frame in a peculiar way.
PulldownThe Pulldown filter simply selects two out of every five frames of the source video.
SeparateFieldsSeparateFields takes a frame-based clip and splits each frame into its component top and bottom fields.
SwapFieldsThe SwapFields filter swaps the two fields in an interlaced frame
WeaveWeave takes even pairs of fields from a Fields Separated input video clip and combines them together to produce interlaced frames.

Audio processing filters

These filters can be used to process audio. Audio samples from a clip will be automatically converted if any filters requires a special type of sample. This means that if a filter doesn't support the type of sample it is given, it will automatically convert the samples to something it supports. The internal formats supported in each filter is listed in the sample type column. A specific sample type can be forced by using the ConvertAudio functions.

If the sample type is float, when AviSynth has to output the data, it will be converted to 16 bit, since float cannot be passed as valid AVI data. 

Amplify / AmplifydBAmplify multiply audio samples by amount.
AssumeSampleRateAdjusts the playback speed of the audio.
AudioDub / AudioDubExAudioDub takes the video stream from the first argument and the audio stream from the second argument and combines them. AudioDubEx is similar, but it doesn't throw an exception if both clips don't have a video or audio stream.
ConvertToMonoMerges all audio channels.
ConvertAudioTo8bit / ConvertAudioTo16bit / ConvertAudioTo24bit / ConvertAudioTo32bit / ConvertAudioToFloatConverts audio samples to 8, 16, 24, 32 bits or float.
DelayAudioDelayAudio delays the audio track by seconds seconds.
EnsureVBRMP3SyncCorrects out-of-sync mp3-AVI's, when seeking ot trimming.
GetChannelReturns a channel from an audio signal.
KillAudioRemoves the audio from a clip completely.
KillVideoRemoves the video from a clip completely.
MergeChannelsMerges channels of two or more audio clips.
MixAudioMixes audio from two clips.
NormalizeAmplifies the entire waveform as much as possible, without clipping.
ResampleAudioPerforms a change of the audio sample rate.
SSRCPerforms a high-quality change of the audio sample rate. It uses SSRC by Naoki Shibata, which offers the best resample quality available.
SuperEQHigh quality 16 band sound equalizer.
TimeStretchThis filter can change speed of the sound without changing the pitch, and change the pitch of a sound without changing the length of a sound.

Conditional and other Meta filters

These special filters can be used to control other filters execution.

The basic characteristic of conditional filters is that 'their scripts' are evaluated (executed) at every frame instead of the whole clip. This allows for complex video processing that would be difficult or impossible to be performed by a normal AviSynth script.

Animate / ApplyRangeAnimate (ApplyRange) is a meta-filter which evaluates its parameter filter with continuously varying (the same) arguments.
ConditionalFilter / FrameEvaluate / ScriptClipConditionalFilter returns source1 if some condition is met, otherwise it returns source2. ScriptClip/FrameEvaluate returns the clip which is returned by the function evaluated on every frame.
ConditionalReaderConditionalReader allows you to import information from a text file, with different values for each frame - or a range of frames.
TCPDeliverThis filter will enable you to send clips over your network. You can connect several clients to the same machine.
WriteFile / WriteFileIf / WriteFileStart / WriteFileEndThese filters evaluate expressions and output the results to a text-file.

Debug filters

BlankClip / BlacknessThe BlankClip filter produces a solid color, silent video clip of the specified length (in frames).
ColorBarsThe ColorBars filter produces a video clip containing SMPTE color bars scaled to any image size.
CompareCompares two clips and prints out information about the differences.
HistogramAdds a Histogram.
InfoPrints out image and sound information.
MessageClipMessageClip produces a clip containing a text message
ShowFiveVersionsShowFiveVersions takes five video streams and combines them in a staggered arrangement from left to right.
ShowFrameNumber / ShowSMPTE / ShowTimeShowFrameNumber draws text on every frame indicating what number Avisynth thinks it is.
ShowSMPTE displays the SMPTE timecode. hh:mm:ss:ff
ShowTime displays the duration with millisecond resolution. hh:mm:ss.sss
StackHorizontal / StackVerticalStackHorizontal takes two or more video clips and displays them together in left-to-right order.
SubtitleThe Subtitle filter adds a single line of anti-aliased text to a range of frames.
ToneThis will generate sound.
VersionThe Version filter generates a video clip with a short version and copyright statement

$Date: 2008/07/20 03:36:57 $