Legal Matters

If you started in video after the mid-90’s there’s a good chance you never used a tape-to-tape, linear, A/B Roll system or a flatbed (I’ve used the former but not the latter, which gives my wife bragging rights in that department). Today, for most people, the definition of “post production hardware” is a computer and maybe some bits and pieces plugged into it, but in the old days you needed a roomful of expensive and complicated gear to get anything done.

Software like Adobe’s DV Rack simulates a lot of the gear you’d find in an old-school edit suite like a broadcast monitor and waveform/vectorscopes.

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The first thing you learned in old-school editing school was how to read those scopes –they’re key to making sure your video is broadcast legal. You’ll also find them in Premiere Pro by opening your Reference Monitor (from the Program Monitor’s flyout menu) and selecting the scope you want from its flyout menu (the flyout menu is the little round button with the triangle inside it that’s in the upper-right corner of every panel in Adobe’s video & audio tools).

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The YC Waveform Monitor and the Vectorscope in Premiere Pro.

The basic idea is that TV screens, unlike computer screens, display an image comprised of Luma (brighness) and Chroma (color). The three channels that make up a video signal are Y (Luma) Cr (Chroma Red) and Cb (Chroma Blue), also referred to as YUV. Broadcast legal for NTSC video is within the range 7.5 IRE and 100 IRE on the waveform monitor (IRE stands for “Institute of Radio Engineers” for those of you keeping score).

7.5 IRE is black, and 100 IRE is white, and everything else needs to fall in between in order for video to be “broadcast legal” (exception is in Japan where they use NTSC with 0 IRE black). You can see the IRE scale on the right hand side of the YC Waveform Monitor in the image above.

If your video isn’t broadcast legal it will not be aired, and even if it will never be broadcast it will cause many TV sets to produce an annoying “buzz” in the audio.

Now you may be thinking “my videos aren’t for broadcast, they’re not even for a TV set, and I don’t need to worry about this.” Well, one reason you should care is that video looks completely different on a computer screen than it does on a TV screen and if your video is going to be viewed on a computer monitor (e.g. on the web) or a handheld device (e.g. iPod) you should color correct it. Computers display images in terms of RGB or Red (R) Green (G) and Blue (B) so if you want your video to look its best you’ll need to compensate.

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In computer land, 0 RGB is black and 255 RGB is white. The problem is that when you convert video black (7.5 IRE) to computer black it actually translates as 16 RGB, not 0 RGB where it should be. Likewise, video white (100 IRE) translates to 235 RGB, not 255. So what you wind up with is less contrast, and blacks & whites that aren’t true. Color correcting your video can fix this and here’s a quick and easy way to do it:

If you’re editing in Premiere Pro, once you’re finished and done apply the Levels effect to your entire sequence. Start by nesting your sequence in a new sequence by clicking the New Item button and selecting Sequence

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Accept the default settings in the New Sequence dialog, then drag your existing sequence from the Project Panel into the Video 1 track in your new sequence (this basically flattens all the layers in your original sequence so you can apply the Levels effect to the whole thing at once).

In the Effects panel, type “Levels” in the Contains field, and drag the Levels effect onto your nested sequence in Video 1. Open the Effect Controls panel and twirl down the controls for Levels

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Since your video has levels of 16 black and 235 white, change the settings for (RGB) Black Input Level to 16 and (RGB) White Input Level to 235. See the difference?

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Your blacks & whites are now where they should be, and you’ve regained the full contrast range in your video.

In After Effects, the same thing can be done by creating an Adjustment Layer, dragging it to the top of the layer stack in the Timeline, and applying the Levels effect to it (using the same settings above).

Remember, if you have graphics, photos, or other elements in your Premiere Pro edit or After Effects comp, you’ll have to take that into account when applying the Levels effect – but for many cases this is a great way to make video look its best on a non-TV viewing medium.