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August 2008 Archives

STP-Spectrum-View.pngAs a quick aside from my audio sermons, I'd like to take a quick look at something a bit more practical.  In Soundtrack Pro, we're all used to seeing waveforms when we open up clips.  But there's another perspective on the sound that, while it's a little more scary at first, can be almost as useful once you figure it out.  You can separate some sounds from others, spot areas with funny spikes that don't show up in the waveform, and even copy and paste specific sounds from within a flat clip.  With practice, you can even begin to recognize the "fingerprints" of individual words.  They call this view ... Spectrum View.
During Editing
B2B-Audio-FCP-Mark-Peaks.png
You've laid down your sequence, you've got your clips sounding consistent relative to each other - now you should check for peaks.  In Final Cut, this is as simple as picking Mark Menu -> Audio Peaks -> Mark.  Markers will appear above the sequence anywhere there's a peak.  Now, you could just pot down the gain on those clips, but if you do that you'll lose the consistency between your clips' audio levels.  So instead, you can hack out the individual peaks themselves.

You can do it by hand, or you can do it with a single step in Soundtrack Pro.  Read on ...




B2B-Audio-PeakMeter.png During Shooting

The first step comes while you're producing your footage in the first place: if you happen to be a one-man show and you're doing your own taping, be absolutely sure to check your audio levels on your camera as you're shooting.  Most cameras can be set up to show some kind of audio meters on their display; as a last resort, though, almost all will let your plug in headphones and listen for gross distortion.



Ever seen your audio meters go into the red?  Marked those unsightly peaks in your audio?  Heard the raging distortion that happens when somebody shouts into a mic?

B2B-Audio-Clipping.png

Oftentimes, despite your best efforts in production, you'll find yourself editing together clips shot with audio that sounds different.  Most importantly for our purposes today, some clips' audio might be louder or quieter than other clips'.  One way to bring every clip into the same volume range is called normalization - and, while audiophiles have good reason to turn up their noses, it's probably the best way we have to fix this kind of editing problem.

What does normalization do?  Read on now.  How do you actually do it?  Tune in again tomorrow for the cheat sheet ...


B2B-Normalize-Teaser.png

Just as a computer thinks of video as a set of images, it thinks as audio as a whole lot of "snapshots" of this sound wave - tens of thousands of snapshots every second.  Each of those tiny little snapshots reflects the energy of the sound wave at that point.  Now, the human ear is capable of hearing frequencies that repeat up to about 20,000 times per second (20,000 Hertz).  Because of some fancy math, we have a rule of thumb: if the computer taps in to the sound wave twice as many times as the highest frequency we want to represent, it will describe the sound fully for us.  That's where the most common full-quality sample rates - 44,100Hz and 48,000Hz - come from.

Creating a photo montage to the beat of music in Final Cut Pro can be much easier with a couple simple steps. The first step is to establish the beat of the music. Before doing this you will want to make sure your audio is ready for Final Cut. Once in your sequence you will want to set markers in the audio track to the beat of the music. By playing the music, and hitting the "M" key to the desired interval, you will create a template for your montage. If you have limited ability in this regard, another option is to load the audio into the Viewer, and apply the Markers visually, by looking at the wave form in the Audio Tab.

audio_markers.gif

I'm going to shift gears into discussing ways we can enhance the audio on our videos.  In order to do this, we should take a whirlwind tour of how computers think about audio.

B2B-Audio-Wave.png
Application: Fonts and Vector Images
Antialiasing also has something to do with why fonts and vector images always look good, even if they're really big or really small.  Actually, fonts are vector images, so that's a bit of a strange thing to say - but at any rate, vector images are simply a set of mathematical equations that describe the curves that make up a shape.  So, like the real world, the computer can "look at" these images with infinite precision.  Therefore, it knows enough about the shapes to behave like our eyes do, and approximate the way we would see the fonts and such if they didn't have to be on a quilt of pixels.

Application: Photoshop
One place where this knowledge might help you think is in Photoshop, especially if you're designing for compositing software or DVD production.  Say you're doing a glass bug for your video: did you notice the anti-alias checkbox when you used the Magic Wand tool?  That checkbox means that the computer will actually select fractions of pixels on the edge of the selection it shows - "blurring" the selection boundary in the same way that it did to the red channel in the example reproduced below.
B2B-AA-CirclesBoth.png

We know antialiasing best as "smoothing" the jagged edges that any digital editor will eventually happen across.  Why do we need to antialias, and where do aliasing artifacts come from in the first place?  The answer is a little mathy, but we'll bring it down to size.

B2B-AA-Teaser.png

Sony EX-1 Peaking.gif
One of the best ways to tell if you are in focus or not with the Sony EX-1 is by using the Peaking function. Peaking allows you to make precise adjustments to your focus and helps you ensure your picture is in perfect focus. To put into simple terms, peaking, applies a color around everything that is in focus. This is only in the viewfinder or monitor and not recorded onto your footage. The default color is red but you have your choice of yellow, blue, white or red. I do not recommend using white because it can easily be confused with your zebra lines. You can also choose the level of peaking from low, mid and high which changes the thickness of the peaking color. I prefer mid and the color blue but you need to play with it and choose your preference. Once you start using Peaking you will never turn it off. It is a must have feature that helps you ensure you are capturing the picture you need.

Masks vs. Alphas

Alpha channels are our most sophisticated way to handle transparency, but they're by no means the only way.  We commonly use the term "Mask" to refer to something similar to the alpha channel above - that is to say, a full range of "see-through-ness" for each point.  Photoshop, for example, uses the term "Mask" to mean just that.  But more primitive incarnations of "image masks" in applications like DVDs and some still image files like GIFs use a different approach.


Alpha Channels

As we first start thinking about transparency in a computer sense, let's go back to the beginning of how computers think about our NTSC broadcast images.  You might remember that, for our purposes, a computer thinks about videos as a sequence of many individual images (frames).  It thinks about each frame as a big rectangular "quilt" of pixels, or individual dots of color - for our purposes, 720 dots wide and 480 dots tall.  And it thinks of each of those dots of color as the amount of red, green, and blue in the color.


B2B-Alpha3.png
The Sony EX-1 has many great features that can sometimes feel very overwhelming but if you follow a few set-up suggestions you will be on your way to mastering this great camera. There are several settings I want to cover and a few in detail so I will cover them over the next few blogs so yo can practice them in small increments. Sony EX-1 Full Auto.gifThe Full Auto feature is actually not a feature. This setting should never be used and will be a dead give away that an amateur was operating the camera. With this turned on yo will have no control over critical settings like white balance, exposure, audio levels and focus. If you record in this mode your EX-1 will do its best to make settings accordingly. For example: as you pan a scene with different tones and light levels the Sony EX-1 will constantly be refocusing, setting different white balance settings and adjusting the exposure which will not only look awful but will also take away from the story you are trying to tell. So if there is anything you take away from these set-up tips I am going to offer you; never ever use Full Auto. Manual Focus Ring.gifManual Focus.gifNext is the manual versus auto focus. First you need to understand that it is very important that you maintain perfect focus on our intended subject or for that matter out of focus for the intended subject. This is impossible with the auto focus turned on. Maybe you are trying to achieve a nice rack-focus, not possible unless you enter full manual mode. To do this you need to pull the focus ring back to MF and flip the switch on the side to Manual focus. This will give you, the operator, full control of the focus on your EX-1. You might be tempted to push the PUSH AF button to see if you have focus. This is not a good on the EX-1. On most other cameras this will seek and find focus as long as you hold the button down, but not so on the EX-1. The EX-1 will search for a up to 15 seconds trying to find the proper focus. This is very annoying and you will more than likely never use this feature. The best way to check your focus is with Peaking. I will cover Peaking along with Zebra in the next tutorial. Stay tuned and make sure you sign up for one of our Sony EX-1 production classes bundled with your favorite editing program.
Whether you're using titles, creating supers, or doing any other sort of compositing, you're trying to tell the computer to show some parts of an image but to hide other parts.  

I've been surprised by the number of folks who were never really taught how that process works from the computer's point of view.  After the jump, an easy little primer that may help you understand --

B2B-Alpha1.png

To avoid any issues with your audio, you will want to convert your audio files to AIFF. An easy way is to export using the Quicktime Conversion.  I had always done this in iTunes, but just discovered an easier way.

I locate the audio file I need in the finder, and drag it into the Viewer. If you don't know where it is, use the Spotlight to locate it. Once your audio file is in the Viewer, you will Export Using Quicktime Conversion. This is a good function to map to a key, because we are often exporting thru the Quicktime Conversion. When the Quicktime Conversion window pops up you will want to choose the location you want the converted to go to, and change the Format from Quicktime to AIFF.

When iTunes did the conversion it would put the converted file into the same folder the source was from. Using this method we can skip the step of moving the file from where it was saved to our Project Folder.

audion_conversion.gif



When using a still image in Final Cut Pro, consider down sizing the image based on the application. For example if you are using a 3456 x 2304 (8 Megapixel) photo in a DV sequence (720 x 480) then Final Cut needs to do the scaling. If you were doing a photo montage with 200 pictures, this would cause a serious slow down in performance, and you would have plenty of opportunities to stare into the spinning beach ball.

Depending on how much you are planning to zoom in on an image, you will choose the size to reduce to. If you are working in a DV sequence and not zooming in on the photo at all, or applying a subtitle Ken Burns effect setting the height to 700 will provide a 1050 x 700 image. which will work great. When working in an HD sequence size your pictures to a height of 1500, which will give you a 2250 x 1500 image. You can do the down sizing using iPhoto, Aperture, Photoshop, or many other applications. You can export 1 image, or an entire folder of images.

Not working with images larger than they need to be is certainly a easy way to increase your productivity with Final Cut Pro.
Keyframes can be added in the Motion Tab of the viewer, but do you realize what the Keyframe button in the Canvas does? The Keyframe button in the Canvas will apply multiple Keyframes. It is defaulted to apply a Keyframe to all of the attributes in the Basic Motion, Crop, & Distort categories within the Motion tab.

If you right (control) click on the Keyframe button in the Canvas, you can edit the types of Keyframes that are being applied when the button is used.

keyframe_FCP.gif


As you know, fonts normally come in a single color. Essentially, each letter is a shape - and the computer needs to describe your logo as a shape as well. Therefore, you need to reduce your logo into one or more black-and-white images that correspond to the regions you want the computer to fill when you're using your font.

Incidentally, the very basic techniques we'll use in Photoshop might help you with other matte and compositing work as well.

Installing the free software you need to create your fonts can be a little bit tricky.  Read on to find out how to set up the font software and the auto-tracing plugin on Mac or Windows.

resolution.jpg

Most modern titling software allows you to import logos or graphics to incorporate with your text.  Avid's Marquee Title Tool does not, at least in any sophisticated way - which is a shame.  Wouldn't it be nice to be able to do the easy 3D manipulations to logos just like you can to letters?

That's what motivated this little tutorial series, but, depending on your workflow, the implications may be even broader.  If you have a set of many logos or shapes that you use often, for example, you can put all of them just a keystroke away.  You can use them as an easy way to make mattes, as some of our other tutorials describe.  For that matter, you could create characters (glyphs) for things like your signature.

Also, the kinds of fonts that we'll be using are vector-based - meaning that they're a set of equations that completely describe each character.  In English, that means that you can zoom the characters up to the size of a skyscraper without worrying about the ugly, fuzzy, pixelated edges that a normal image would show.

resolution.jpg

* - If you're just doing one-off work with logos (or anything else for that matter), the process we're about to go into is probably overkill.  Interested in a tutorial on vectorizing these more "expendable" images?  Drop us a line, and we'll get one in the pipeline ...

This time, we'll write a script to detect whether the DVD player is showing in widescreen (16:9 anamorphic) mode or standard (4:3) mode - and automatically play the video in the appropriate format.

I hope that this tutorial will be a practical one for those of you who are putting both regular NTSC-DV content and anamorphic on the same disc, but more importantly I hope that the introduction to bit math might be useful if you need to extract other characteristics from the bitwise SPRMs, like SPRM14 (Video Config), SPRM15 (Audio Config), and SPRM11 (Karaoke).

You'll have to excuse me for getting all technical up in here; "bitwise" just means that the single SPRM stores a lot of pieces of information in one number. Read on for what I promise will be a painless introduction ...

Let's say your title is a bit ... racy. And maybe, because you're a good citizen, you don't want it to play on sets where parents have enabled parental control.

Using DVD Script, the solution is surprisingly simple. First, create a script - call it, say, "Verify Parental Controls" ...

Finally, a practical example! And we won't even need all the SPRMs or most of the GPRMs from last time as we create a video that plays its tracks in random order.

In fact, we'll only use a single GPRM - those are the variables that are ours-all-ours, remember? - plus a jump or two, a little math, and the conveniently-named Set GPRM Random command. Let's say you have four tracks of video, and you want them to cycle randomly ad infinitum - maybe you're at an exhibition or something, who knows.

Ever think that those old algebra classes would come in handy producing video? Well, I'll ignore the fact that algebra is a major part of almost all of the editing process, and pretend that I'm BLOWING YOUR MIND.
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This page is an archive of entries from August 2008 listed from newest to oldest.

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