• There is some wonkiness in the small next/previous links at the top of each page.

Design

• Lists could use some work
• The metatext in the grey bar at the bottom of the page should be vertically centered (only happens when there are no prev/next links).
• Increase margin-top on bodytext h3’s

The interface is similar to After Effects time-mapping functions, the vertical keyframe axis represents the frame to display while the horizontal axis is the current moment in time. Normal speed playback is a straight diagonal line from 0 at the in point to 100 at the out point.

Example Images

Start fast and slow down at the end

FCP Keyframe Graph

Start Slow and speed up towards the end

FCP Keyframe Graph

Start fast and end fast, slowing down in the middle

FCP Keyframe Graph

Start normal, slow in middle, reverse fast back to start

FCP Keyframe Graph

Start fast, slow and reverse in middle, finish fast

FCP Keyframe Graph

Keyframing

To make keyframing easier, I recommend expanding the Viewer keyframe area. Dragging the bottom line of the Frame slider’s keyframe space towards the bottom of the window will stretch it vertically.

To set up the filter for re-mapping time, do the following:

1. Press Shift-I to go to the In Point
2. Click the Keyframe button to add a keyframe here with a value of 0
3. Press Shift-O to go to the Out Point.
4. Drag the Frame slider to 100.

Now the effect is set up for normal speed playback. This line is important because whatever pitch (steepness) it is will be 100% playback speed. Making the line flatter (less steep) will slow playback, increasing it’s pitch (steeper) will cause the clip to playback faster.

Control clicking on the keyframe points allows them to be changed to Smooth points, which adds control handles for bending the curve between points. Below are some examples of what is possible with a few simple curves.

Field Separation

Time Bender can also be used to separate fields, essentially playing back each field as a frame while reducing the apparent speed to 50%. To playback fields as frames, turn off Frame Blending and set the inpoint to 0% and the outpoint to 50% (or any combination which results in 50% between keyframes)

Controls

Frame (1 - 100)

Sets the position of the current frame as a percentage of the complete clip. Zero is the first frame and 100 is the last frame. Keyframing this value results in the specified frame showing at position of the keyframe.

Frame Blending

Blends frames for smoother output motion. Frame Blending is weighted so inbetween frames will lean towards or away from whichever frame it’s closer to.

Reverse Fields

Reverses the default field order when frame blending. The default is lower field first.

Show Timecode

Shows the actual timecode of the currently visible frame.

Timecode Format (Clip Default, 24 fps, 25 fps, 30 fps-drop frame, 30 fps, 60 fps-drop frame, 60 fps, 16mm, 35mm)

Setting to override the default timecode format and report the virtual frame position in a user specified format.

Additionally this plugin includes two motion differencing options to reduce artifacts from changing areas in a clip. The motion differencing options can be used to isolate and mark moving areas.

Example Images

Original Image

Past Frames: 5 Future Frames: 0 Mask Highlights: No

Past Frames: 5 Future Frames: 0 Mask Highlights: No Motion Difference: All Frames Threshold: 154 View: Colorize Motion

Original Image

Past Frames: 5 Future Frames: 5 Motion Difference: 3 Frame Threshold: 234

Multi-Frame Blending to lighten images

Combining multiple frames of video can also be used to bring out detail from extremely dark clips. Because images are combined from different points in time, this process works best on clips shot with a static camera.

Original Image

Blend Method: Add Past Frames: 4 Future Frames: 4

Blend Method: Screen Past Frames: 8 Future Frames: 8

Multi-Frame Blending and Levels

Another method is to combine Multi-Frame Blending and Levels to lighten the image. Combining multiple frames using the Matte blending method will smooth out the image without changing the lightness values. Using Levels on this smoothed image produces much better results than trying to use Levels on a single frame.

Multi-Frame Blender and Levels Past Frames: 8 Future Frames: 8 Blend Method: Matte Levels: 6, 0.4, 165

Levels only Levels: 6, 0.4, 165

Controls

Frame Blending

Blend Method (Matte, Screen, Add)

The blending method to use for combining multiple frames.

Past & Future Frames (0 - 10)

Sets how many additional frames will be combined into the final image.

PreMultiply (Straight, Black, White)

Straight is a passthrough setting. When combined with Mask Highlights, white or black PreMultiplication will flatten the transparent image onto white or black. This can cause tremendous differences in the blending results.

Mask Highlights

Uses a clip’s averaged lightness as an alpha mask to reduce excessive glowing of bright areas.

Motion Differencing

Motion Difference (None (off), 3 Frame, All Frames)

Chooses whether to generate a motion difference mask for moving areas of the image. Three Frames uses only the current, previous and next frames to generate the mask, All Frames combines all the blended frames together for a more comprehensive motion mask. Note that these settings will significantly increase rendering time, especially the All Frames setting.

Difference Using (RGB, YUV)

Selects which color space to use for motion differencing.

Threshold (128 - 254)

Determines the sensitivity of motion differencing. Higher numbers select more pixels as moving, lower numbers select fewer pixels as moving. Setting the threshold to 254 is very similar to disabling motion differencing. Note that selecting RGB differencing may result in a slightly different colors due to the colorspace conversion.

Soften (0 - 10)

Softens the motion mask to reduce motion artifacting.

Motion Check

View (Merged Output, Motion Mask, Colorize Motion)

These settings are used to preview the motion differencing mask. Selecting Motion Mask will show the current motion mask as a grayscale image, white pixels represent moving areas. Colorize Motion will mark the clip’s moving areas with the mask color. Both of these options require Motion Differencing to be turned on to show any results.

Mask Color, Color Opacity

Used to specify how motion is represented when Colorize Motion is selected in the Motion Check View setting.

Fade With Original

Opacity (0 - 100)

Blends the final image back onto the original. This can be used to fade effects on and off using keyframes.

This effect works by translating a clip’s default playback framerate to a virtual framerate and then resampling fields and frames for playback. Duration is calculated to the field playback rate for smoother motion. De-Interlacing is automatic when the framerate causes fields to stretch across multiple frames.

Example Images

Click to open movies in new windows:

Original NTSC Clip

Frame Rate 24fps

Frame Rate 50fps

Frame Rate 12fps

Note that these preview movies are encoded at 60fps to attempt to preserve their original motion. Because this plugin is made to work with interlaced video, the best way to preview the effect is to download the demo and see them on an external video monitor.

Standards Conversion: NTSC < -> PAL

Some users have reported success using Joe’s Frame Rate Adjuster for translating between PAL and NTSC video in Final Cut Pro. To change from NTSC to PAL, try setting the fps to 50 or 25. Because the filter is field-based, 50fps should result in smoother motion. To change PAL to NTSC, set fps to 29.97.

Interlacing and Still Frames

To create the virtual playback framerate, Joe’s Frame Rate Adjuster makes optimum use of the timeline’s field playback rate. Because of this some virutal frames may exist across more than one field. This results in what is referred to as a ‘judder frame’. These frames are normal and will not be seen during playback.

Mixing Actual Frame Rates

Final Cut Pro’s default behavior regarding unmatched actual framerates may cause unexpected results with Frame Rate Adjuster. When clips with non-matched framerates are inserted into a timeline, FCP automatically interpolates the clips to match the timeline’s framerate. This means that a true 12fps clip placed into a 29.97fps timeline will be processed as if it’s framerate were 29.97. Unfortunately FCP doesn’t do a particularly good job of interpolating these new frame rates. At first I thought this might be a bug, but it’s consistant with other FXScript effects behavior. I’m continuing to look for workarounds and options for standards conversion, feedback is welcomed.

Controls

Frame Rate (1 - 60)

Sets the virual playback framerate for the filtered clip. This value is field-based so interlaced clips can be played back at any value up to their actual field rate. NTSC can playback at anything up to 60fps and PAL playback at anything up to 50fps.

Motion Trail (0 - 100)

Blends the current virtual frame with the next actual frame to help ease strobing and smooth out motion information lost between virtual frames. Setting Motion Trail to zero shows only the current virtual frame.

Without Joe’s Field Fixer many field-order problems had to be fixed in After Effects or corrected with a de-interlace filter. For mis-matched and out of order fields, re-ordering is a better solution than de-interlacing because the video data is fine, it’s just slightly out of order by being offset in time.

Example Images

Reversed Field Order

Upper Field: Lower Field Lower Field: Upper Field

Analog dubs

Occasionally when analog sources are dubbed with non-pro equipment the normal field sequence can spill across frames. Instead of reversed field order, the frames break across fields resulting in mis-matched fields. The following example frame was dubbed from VHS to DV and shows a cut between two cameras existing in a single frame.

Analog Dub Original

Upper Field: Upper Field Lower Field: Lower Field (Next Frame)

When correcting slipped fields, notice the effect of diagonals and curves. Make sure you’re not outputting the same field twice (once for the top and once for the bottom). If there is motion in the frame, the amount of interlace ‘tearing’ may also be a helpful indicator of which fields belong together. While there is a definite set of matching frames, whether you push the fields forward or backwards in time is up to you.

Other Uses

Joe’s Field Fixer can also quickly correct field-order problems resulting from processes which up-res DV to a Kona SDI card, which occasionally result in flopped fields.

Controls

Upper Field, Lower Field (upper/lower field, previous/current/next frame)

Determines the sources for each of the two fields making up the resulting frame.

Important Note about field-based effect previews

All of Final Cut Pro’s field-based effects need to be rendered for an accurate preview. At zoom values below 100%, the FCP desktop preview only shows the lower field of an interlaced video frame and pre-rendered effects use this scaled down, single-field image to preview before rendering.

The controls for Joe’s Field Blender are deliberately simple. The single slider moves from the lower field on the left to the upper field on the right. In DV the lower field comes first, so the slider acts a selector of time, moving between two instants with a fraction of a second between them. On a fast computer, moving the slider back and forth will make moving objects in a frame appear to shift forward and backward in time.

This filter provides results similar to Joel Peregrine’s adaptation of Shawn Bockoven’s Film Look technique. Because this effect uses a significantly faster de-interlace routine than Final Cut Pro’s De-Interlace filter, the same effect can be created in less than half the time. (In preliminary testing, Joe’s Field Blender was consistently 230% faster than the twin de-interlacing technique.)

Example Images

Original Interlaced Image

Blend: 0 Lower Field

Blend: 100 Upper Field

Blend: 30

Blend: 50

Blend: 70

The two interlaced fields of video are either 1/60 (NTSC) or 1/50 (PAL) of a second apart in time. Setting the blend value towards the second field (above 50) creates a motion trail following the direction of motion, blending towards the preceding frame (below 50) results in a motion trail before the image, backwards from how we tend to see and understand motion.

DV vs. non-DV Field Order

DV’s field order is the opposite of most other video standards. The orientation of the Field Blender slider definitions is basically arbitrary so if you are working with non-DV source just reverse the slider’s behavior for the same results.

Controls

Blend (0 - 100)

Determines balance of the two fields in the resulting image. Setting Blend to 0 (right side) it results in 100% of the lower/first field, 100 (left) results in 100% of the upper/second field. Moving the slider adds opacity of one field while subtracting the opacity of the other. A setting of 70 means 70% upper field and 30% lower field. 50% is an even mix of both fields.

Method

Sets the de-interlacing method for the pre-blended fields.

Important Note about field-based effect previews

All of Final Cut Pro’s field-based effects need to be rendered for an accurate preview. At zoom values below 100%, the FCP desktop preview only shows the lower field of an interlaced video frame and pre-rendered effects use this scaled down, single-field image to preview before rendering.

Joe’s De-Interlacer is written in Final Cut Pro’s native FXScript effects language so filtered clips stay in their native YUV color space.

Advantages of Motion Differencing

Original Image

Motion Difference De-Interlace

Standard Fullframe De-Interlace

The differences between motion differenced and standard de-interlaced clips becomes especially apparent on diagonals and areas of fine detail. (1) The diagonal lines on the roof and (3) the painted lines in the street become jagged without Motion Differencing. Also notice how the fine detail of (2) the brick wall in the background becomes soft and muddy. Because none of these elements changed between frames, motion differencing preserves the vertical information from both fields of the video frame for a better quality image.

Motion Differencing works by calculating which pixels have changed between the previous frame and the following frame. This information is used to generate a mask so only the changed pixels are de-interlaced. Motion Differencing works best with a static camera.

De-Interlace Methods

The following examples show the different methods of de-interlacing clips. Motion Differencing has been turned off to show the differences.

Field Double

Interpolate

Fast Interpolate

Fast Interpolate is the default option because it is the fastest to render (thus the name) and almost indistinguishable from the slightly better looking Interpolate method, especially when combined with Motion Differencing.

Motion Difference Artifacts

The default Motion Differencing settings do a good job for most clips but there are occasions where the settings need tweaking. Below is an extreme example where a bicyclist is moving quickly through the frame. The default settings leave lots of motion artifacts due to the distance between fields. Increasing the Threshold and Soften settings corrects the problem, which can also be seen by viewing the Motion Mask.

Original Image

Default Settings

Motion Mask

Threshold 245 Soften 8

Corrected Motion Mask

Colorize Motion

Field Order and Final Cut Pro’s De-Interlace Filter

Final Cut Pro’s De-Interlace filter has it’s fields reversed. This can be easily checked by applying the de-interlace effect to a frame with fast motion. Since DV NTSC has a known field order of bottom field first, the top field should be offset in time forward 1/60 of a second.

The following images of a swimmer caught mid-dive provide an excellent indication of field order. Within the duration of this frame the diver’s hands break the surface of the water. In the first field his hand are above the water, in the second they’ve broken the surface. This clip was shot on DV NTSC clip so the lower field should come first in time.

Interlaced Original

Joe’s De-Interlacer: Lower Field

Joe’s De-Interlacer: Upper Field

FCP’s De-Interlacer: Lower Field

FCP’s De-Interlacer: Upper Field

FCP’s Lower Field appears later in time than the Upper Field, showing that it is isolating the opposite field from what was selected.

Render Time

Adding Motion Differencing increases rendering time due to the added complexity and additional calculations. Below is a small, non-scientific chart showing rendering times on a 10 second NTSC DV clip:

• Default Settings: 3:45
• Fast Interpolate, no motion differencing: 1:15
• Interpolate, no motion differencing: 1:26
• Field Double, no motion differencing: 1:23
• Final Cut Pro De-Interlace filter: 1:43

Tests were run on an 800mhz G4 PowerBook with 1Gb RAM, OSX 10.2.2 and FCP 3.0.4. During the tests I had over a dozen other applications running in the background (thank you OS X!). Your results may vary.

Controls

De-Interlace

Field (Upper Field (odd), Lower Field (even))

Chooses which field to use as the basis of the resulting image.

Method (Field Double, Interpolate, Fast Interpolate)

Determines the method of de-interlacing the video frame.

Motion Differencing

Motion Difference

Turns Motion Differencing on and off.

Difference Using (Luma, RGB)

Sets which color space to use for motion difference calculations.

Threshold (128 - 254)

Determines the sensitivity of motion differencing. Higher numbers select more pixels as moving, lower numbers select fewer pixels as moving. Setting the threshold to 254 is very similar to disabling motion differencing. Note that selecting RGB differencing may result in a slightly different colors due to the colorspace conversion.

Soften (0 - 10)

Softens the motion mask to reduce motion artifacting.

Mask Check

View (Merged Output, Motion Mask, Colorize Motion)

These settings are used to preview the motion differencing mask. Selecting Motion Mask will show the current motion mask as a grayscale image, black pixels represent moving areas. Colorize Motion will mark the clip’s moving areas with the mask color. Both of these options require Motion Differencing to be turned on to show any results.

Mask Color, Color Opacity

Used to specify how motion is represented when Colorize Motion is selected in the Motion Check View setting.

Fade With Original

Opacity (0 - 100)

Blends the final image back onto the original. This can be used as a flicker-filter or to fade the effect on and off using keyframes.

Important Note about field-based effect previews

All of Final Cut Pro’s field-based effects need to be rendered for an accurate preview. At zoom values below 100%, the FCP desktop preview only shows the lower field of an interlaced video frame and pre-rendered effects use this scaled down, single-field image to preview before rendering.

All corrections are based on the on the maximum reported value range of 0-116 IRE. Output values have been calibrated against Final Cut Pro’s Video Scopes. Please check your output levels on external equipment whenever possible.

Joe’s Broadcast Legalizer also works with Final Cut Express and all versions of Final Cut Pro since 1.2.5. Even though these do not have video scopes, the calculations should be consistant with those in Final Cut Pro 3.

Luma Adjustment

Original Image

Waveform and Histogram for Original Image

Joe’s Broadcast Legalizer

Corrected Waveform and Histogram with Joe’s Broadcast Legalizer Luma Ceiling: 100 IRE Luma Floor: 7.5 IRE

Final Cut Pro’s Broadcast Safe

Corrected Waveform and Histogram with Final Cut Pro’s Broadcast Safe Mode: Conservative [115]

Some things to note about these examples:

• Joe’s Broadcast Legalizer scales image values so changes are distributed evenly across the entire range.
• FCP’s Broadcast Safe affects only out of range values compressing them at the top of the range but leaving other values unchanged. Out of range values are rolled in by Broadcast Safe.
• Joe’s Broadcast Legalizer is also elevating the Luma floor to 7.5 IRE. FCP’s Broadcast Safe filter only corrects Luma ceilings with it’s default settings.

Chroma Adjustment

The Chroma Amplitude, Phase and Offset controls can be used to correct Chroma problems in video clips. Amplitude is a simple Chroma Limiter, which reduces the saturation of a clip’s color information without affecting it’s overall hue.

Original Image

Original Vectorscope

Joe’s Broadcast Safe

Amplitude: -25

Joe’s Broadcast Safe

Amplitude: -75

Phase and offset work by shifting the chroma relative to the view in the Vectorscope. This can be used to quickly affect the overall color balance of a clip towards a specific hue.

Joe’s Broadcast Safe

Original Image

Joe’s Broadcast Safe

Phase: 135° Offset: 15

Joe’s Broadcast Safe

Phase: 270° Offset: 15

Combining Amplitude limiting with large offsets creates unique color effects.

Joe’s Broadcast Safe

Amplitude: -50 Phase: 105° Offset: 40

Y/C Correction

The Y/C Correction controls shift the Chroma or Luma components of a video image relative to one another. A common use of Y/C correction is to compensate for poor image alignment in analog dubs but it’s also quite useful for shifting DV chroma sampling against right-side color drift.

Original Image (200% enlargement)

This detail shows a slip in color of the pepper against the blue background resulting from NTSC DV’s 4:1:1 chroma sampling. All the color in the image is drifting to the right, resulting in a blue cast on the left edge of the pepper and a trailing reddish cast on the right edge. Additionally, the green stem has a yellowish left edge and a green shadow.

Horizontal offset: 2 px

Using the Y/C Correction controls, the color information can be shifted to the left, helping to better align the sampled color point against the Luma information. This still isn’t perfect, partly because of DV’s oversized and blocky Chroma sampling, but centering the color on the pepper helps to improve the quality of the image.

When viewed on a video monitor, this image showed a significant reduction in dot-crawl along the pepper’s horizontal edges .

Horizontal offset: 2 px Joe’s Channel Blur: Chroma only, 2px, aspect: 4

When combined with Joe’s Channel Blur to smoother out the Chroma, the resulting image appears smoother and less blocky. This process can be used to help improve the appearance and success of color keys pulled from DV material.

Adam Wilt’s DV Sampling page has much more information and examples about different methods of video color sampling.

Controls

Luma Adjustment

Ceiling (70…110 IRE)

Sets the absolute maximum value to output.

Floor (0…25 IRE)

Sets the absolute minimum value to output.

Chroma Adjustment

Amplitude (-100…0)

Sets the intensity of the Chroma (color) signal. -100 removes all color information.

Phase (-360…360°)

Determines the direction to use with the Offset value.

Offset (0…112)

Shifts all color information towards the direction set in Phase.

Y/C Correction

Target (Both, Luma, Chroma)

Chooses which channels to offset. When ‘Both’ is selected, both channels are offset half the total distance relative to each other.

Horizontal, Vertical (-10…10)

Sets how far to offset the selected channels.

Acknowledgements

Thank you to Michael at Pixelmover for suggesting the Y/C correction tools.