AVX Plug-Ins
(Show frame with Topics and Control Panel)
User Guide"Tips" appear
in green. Tips will save you time but are not essential information.
"Cautions" appear in
red. Be sure to read and understand this information.
3Prong's WaveScope AVX Plug-In lets you measure video levels in your timeline. Instrument displays include:
|
Special features of WaveScope inlcude color coded displays, with the Y Waveform display able to show True Color from the image. The image being measured can be shown as a Background to the display, and a Quad view permits four displays simultaneously.
This guide assumes you are familiar with these types of displays and their use. If not, please read the WaveScope Primer first.
After installing, you will find WaveScope in the 3Prong category of your Avid system's Effect Palette. You may apply the WaveScope effect to any video segment in the timeline. Make sure "Render On-the-Fly" is turned on, and you can spot-check individual fields which are representative of your clip. If you need to see the instrument display continuously as the footage plays, you must render a precompute.
For more flexibility, apply WaveScope to the filler of a new video track above your program. With this technique, applying and setting just once lets you quickly check anywhere in the entire sequence by monitoring the topmost track. There is no need to nest another effect such as 3Prong's ColorFiX in order to measure it. (On some Avid systems, you cannot apply an effect to a completely empty video track. In this case, simply add a match-frame edit at the end of the filler.)
After applying WaveScope, simply choose the desired instrument display from the menus in the Effect Editor. Experienced video users will find the displays familiar.
Use the Background button or select Image in the Quad view to see your image and an instrument display at the same time.
In Trial mode, WaveScope measures only the top half of your image. After an Unlocking Code is entered, the entire image is measured and the 3Prong outlet logo no longer appears.
Before making a digital cut of your program, remove the WaveScope effects, or just deselect that track.
The Waveform and Parade displays indicates levels with these specific
colors:
Limits are set with Safe Color Warning controls. Note that there are no universal standards for safe levels, so check the delivery specifications for your particular project. |
 |
If you wish to use a single large instrument display, choose it the Main
menu above the Quad group. To see four smaller displays at once, choose them from the four
menus in the Quad group. Toggle between the Quad and Main views by using
the enable button at the top right of the Quad group.
Intensity sets the brightness of the trace only.
Particularly when test patterns are being measured, compression artifacts and blanking edges may produce spurious pixel values in the image which will tend to clutter the trace. As you would expect of any accurate measuring instrument, WaveScope reveals these image defects when the Intensity is increased. However, if you wish to minimize this and get a more general sense of the trace, reduce the Intensity.
Scale sets the brightness of the scale only. At times, you may want to turn it down or even off to see some trace details more clearly.
Setup 7.5 IRE sets the black reference level in the YC Waveform scale. Generally (outside of Japan), this setting will be left on, placing NTSC composite video black at 7.5 IRE. This setting does not affect the output video, just the scale by which it is measured.
True Color switches the trace colors of the Y Waveform from green to the actual colors used in the image. This can be very useful to identify which parts of the image are producing which traces.
Background switches the display background from black to the actual
image being measured. Use this while color correcting to see the image and its
measurements simultaneously.
Use the Y Waveform to check the luma levels of your image. The digital video standard allows for headroom and footroom, so that a mistake in level can be corrected later in the post-production process. The absolute minimum is digital 0 or -8%, and the absolute maximum is digital 255 or 108%. However, beware that excessive levels may be clipped by processes further down the line, and many broadcasters require the Luma range to be restricted to 0-100%.
Chroma peaks are easiest to see on the Vectorscope. To be cautious, you might like to keep vectors no further from the center than the 75% color bar squares.
Composite (YC) video will frequently fall outside the 0% to 100% range, but should be kept within certain limits. Even if neither luma nor chroma alone is excessive, the combination of the two in a composite signal can be illegal. Watch the YC Waveform for saturated bright or dark colors with very low or high luma values, together with a lot of chroma. For example, vivid yellow and cyan might be too high, and vivid blue may be unacceptably low. In North America, you may wish to avoid composite chroma levels above 110 IRE and below -20 IRE.
Generally, EBU specs require RGB values to remain inside the range of 16-235. This will keep Y values in the range of 16-235.
While WaveScope can be used to spot-check video levels, you can ensure that your entire program meets the required standards if you use a legalizer such as 3Prong's ColorFiX AVX plug-in or the Safe Color Limiting feature of Avid Symphony.
Using the Bounds controls, you may isolate and measure a portion of the image in a smaller rectangular area. Watching the Image in one corner of the Quad view, set the Left and Top first, then set the Width and Height.
(If the bottom half of the Image quadrant is black
when the Bounds settings are at maximum, and the 3Prong outlet logo is visible in the
display, WaveScope is operating in Trial mode and is not licensed.)
Due to AVX limitations, WaveScope uses a field-based video display which has limited vertical resolution. You may notice aliasing, particularly on the Scale details.
WaveScope does not directly measure analog levels, only the digital levels within the Avid system. For example, the YC Waveform does not measure the actual composite video output of your Avid system, if it has one. Rather, it acccurately models parts of an encoder in software. If and when your video is encoded into composite form, you should see similar results. If you are using adjustable analog outputs of your Avid system, you should verify those levels with an external waveform monitor.
WaveScope is not compatible with Avid|DS.
Also see AVX Limitations in the Common Topics section.