VIVTC

VIVTC is a set of filters that can be used for inverse telecine. It is a rewrite of some of tritical’s TIVTC filters.

vivtc.VFM(clip clip, int order[, int field=2, int mode=1, bint mchroma=1, int cthresh=9, int mi=80, bint chroma=1, int blockx=16, int blocky=16, int y0=16, int y1=16, float scthresh=12, int micmatch=1, bint micout=0, clip clip2])

VFM is a field matching filter that recovers the original progressive frames from a telecined stream. VFM’s output will contain duplicated frames, which is why it must be further processed by a decimation filter, like VDecimate.

Unlike TFM, VFM does not have any postprocessing capabilities.

VFM adds the following properties to every frame it outputs:
VFMMics

Array of five integers.

It will contain the mic values for the five possible matches (p/c/n/b/u). Some of them may be unset (-1), depending on micout and micmatch.

These numbers represent the highest concentration of combed pixels found in any block in the frame.

_Combed
1 if VFM thinks the frame is combed, 0 if not.
VFMMatch

Match used for the frame.

0 = p

1 = c

2 = n

3 = b

4 = u

VFMSceneChange
1 if VFM thinks the frame is a scene change, 0 if not.
Parameters:
clip
Input clip. YUV420P8, YUV422P8, YUV440P8, YUV444P8, and GRAY8 are supported. Must have constant format and dimensions.
order

Sets the field order of the clip. Normally the field order is obtained from the _FieldBased frame property. This parameter is only used for those frames where the _FieldBased property has an invalid value or doesn’t exist.

If the field order is wrong, VFM’s output will be visibly wrong in mode 0.

0 - bottom field first

1 - top field first

field

Sets the field to match from. This is the field that VFM will take from the current frame in case of p or n matches. It is recommended to make this the same as the field order, unless you experience matching failures with that setting. In certain circumstances changing the field that is used to match from can have a large impact on matching performance.

0 - bottom field

1 - top field

2 - same as the field order

3 - opposite of the field order

0 and 1 will disregard the _FieldBased frame property. 2 and 3 will adapt to the field order obtained from the _FieldBased property.

Default: 2.

mode

Sets the matching mode or strategy to use. Plain 2-way matching (option 0) is the safest of all the options in the sense that it won’t risk creating jerkiness due to duplicate frames when possible, but if there are bad edits or blended fields it will end up outputting combed frames when a good match might actually exist. 3-way matching + trying the 4th/5th matches if all 3 of the original matches are detected as combed (option 5) is the most risky in terms of creating jerkiness, but will almost always find a good frame if there is one. The other settings (options 1, 2, 3, and 4) are all somewhere in between options 0 and 5 in terms of risking jerkiness and creating duplicate frames vs. finding good matches in sections with bad edits, orphaned fields, blended fields, etc.

0 = 2-way match (p/c)

1 = 2-way match + 3rd match on combed (p/c + n)

2 = 2-way match + 3rd match (same order) on combed (p/c + u)

3 = 2-way match + 3rd match on combed + 4th/5th matches if still combed (p/c + n + u/b)

4 = 3-way match (p/c/n)

5 = 3-way match + 4th/5th matches on combed (p/c/n + u/b)

The parantheses at the end indicate the matches that would be used for each mode assuming order=1 and field=1.

Default: 1.

mchroma

Sets whether or not chroma is included during the match comparisons. In most cases it is recommended to leave this enabled. Only if your clip has bad chroma problems such as heavy rainbowing or other artifacts should you set this to false. Setting this to false could also be used to speed things up at the cost of some accuracy.

Default: true.

cthresh

This is the area combing threshold used for combed frame detection. This essentially controls how “strong” or “visible” combing must be to be detected. Larger values mean combing must be more visible and smaller values mean combing can be less visible or strong and still be detected. Valid settings are from -1 (every pixel will be detected as combed) to 255 (no pixel will be detected as combed). This is basically a pixel difference value. A good range is between 8 to 12.

Default: 9.

mi

The number of combed pixels inside any of the blockx by blocky size blocks on the frame for the frame to be detected as combed. While cthresh controls how “visible” the combing must be, this setting controls “how much” combing there must be in any localized area (a window defined by the blockx and blocky settings) on the frame. The minimum is 0, the maximum is blocky * blockx (at which point no frames will ever be detected as combed).

Default: 80.

chroma

Sets whether or not chroma is considered in the combed frame decision. Only disable this if your source has chroma problems (rainbowing, etc) that are causing problems for the combed frame detection with chroma enabled. Actually, using chroma=false is usually more reliable, except in case there is chroma-only combing in the source.

Default: true.

blockx

blocky

Sets the size of the window used during combed frame detection. This has to do with the size of the area in which mi number of pixels are required to be detected as combed for a frame to be declared combed. See the mi parameter description for more info. Possible values are any power of 2 between 4 and 512.

Defaults: 16, 16.

y0

y1

The rows from y0 to y1 will be excluded from the field matching decision. This can be used to ignore subtitles, a logo, or other things that may interfere with the matching. Set y0 equal to y1 to disable.

Defaults: 16, 16.

scthresh

Sets the scenechange threshold as a percentage of maximum change on the luma plane. Good values are in the 8 to 14 range.

Default: 12.

micmatch

When micmatch is greater than 0, tfm will take into account the mic values of matches when deciding what match to use as the final match. Only matches that could be used within the current matching mode are considered. micmatch has 3 possible settings:

0 - disabled. Modes 1, 2 and 3 effectively become identical to mode 0. Mode 5 becomes identical to mode 4.

1 - micmatching will be used only around scene changes. See the scthresh parameter.

2 - micmatching will be used everywhere.

Default: 1.

micout

If true, VFM will calculate the mic values for all possible matches (p/c/n/b/u). Otherwise, only the mic values for the matches allowed by mode will be calculated.

Default: false.

clip2

Clip that VFM will use to create the output frames. If clip2 is used, VFM will perform all calculations based on clip, but will copy the chosen fields from clip2. This can be used to work around VFM’s video format limitations. For example if you have a YUV444P16 input clip:

yv12 = core.resize.Bicubic(clip=original, format=vs.YUV420P8)
fieldmatched = core.vivtc.VFM(clip=yv12, order=1, chroma=False, clip2=original)

Note

In this example chroma is ignored because the used conversion to YUV420P8 will not accurately preserve it.

vivtc.VDecimate(clip clip[, int cycle=5, bint chroma=1, float dupthresh=1.1, float scthresh=15, int blockx=32, int blocky=32, clip clip2, string ovr="", bint dryrun=0])

VDecimate is a decimation filter. It drops one in every cycle frames – the one that is most likely to be a duplicate (mode 0 in TDecimate).

Parameters:
clip
Input clip. Must have constant format and dimensions, known length, integer sample type, and bit depth between 8 and 16 bits per sample.
cycle

Size of a cycle, in frames. One in every cycle frames will be decimated.

Default: 5.

chroma

Controls whether the chroma is considered when calculating frame difference metrics.

Default: true when the input clip has chroma.

dupthresh

This sets the threshold for duplicate detection. If the difference metric for a frame is less than or equal to this value then it is declared a duplicate. This value is a percentage of maximum change for a block defined by the blockx and blocky values, so 1.1 means 1.1% of maximum possible change.

Default: 1.1.

scthresh

Sets the threshold for detecting scene changes. This value is a percentage of maximum change for the luma plane. Good values are between 10 and 15.

Default: 15.

blockx

blocky

Sets the size of the blocks used for metric calculations. Larger blocks give better noise suppression, but also give worse detection of small movements. Possible values are any power of 2 between 4 and 512.

Defaults: 32, 32.

clip2
This has the same purpose as VFM’s clip2 parameter.
ovr

Text file containing overrides. This can be used to manually choose what frames get dropped. Lines starting with # are ignored.

Drop a specific frame:

314 -

Drop every fourth frame, starting at frame 1001, up to frame 5403:

1001,5403 +++-+

The frame numbers apply to the undecimated input clip, of course.

The decimation pattern must contain cycle characters.

If the overrides mark more than one frame per cycle, the first frame marked for decimation in the cycle will be dropped.

dryrun

If true, VDecimate will not drop any frames. Instead, it will attach the following properties to every frame:

VDecimateDrop
1 if VDecimate would normally drop the frame, 0 otherwise.
VDecimateMaxBlockDiff
This is the highest absolute difference between the current frame and the previous frame found in any blockx*blocky block. It is known in Yatta as “DMetric”.
VDecimateTotalDiff
This is the absolute difference between the current frame and the previous frame.

Default: false.

Large parts of this document were copied from “TFM - READ ME.txt” and “TDecimate - READ ME.txt”, written by Kevin Stone (aka tritical).