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Jim Krause | Classes | P354 Program Graphics & Animation

Week 7

Agenda:

  • Review Midterm Project Ideas. Pre-production work is due Thursday.
  • After Effects (working with audio, video, + time stretching & other tidbits)

Notes

After Effects (continued)

NOTE: If you need some audio/video clips for today's exercise you can download the one's from Week 6 (AV folder) and these (AV2 folder).

Audio ------------------------------------

After Effects is not ideally suited for editing or manipulating sound, but it offers some useful tools. Given that sound is an important component in animation, it's important to understand the basics.

Be sure to copy your audio into your local media folder *before* you import it and try to work with it.

Hardware: AE can output through any hardware you might have hooked up to your computer. Use AE's preferences to choose the output device.

Note: After Effects sometimes does not work well with compressed audio files (eg. MP3s). If you run into weird audio playback errors, try using uncompressed PCM (digital audio) formats (WAV or AIF). If you use multpile clips, make sure they are similar in bit rate and sample size.

Layer Markers - A useful way to "see" your audio

When working with audio, coordinating and aligning visual elements with the soundtrack is a must. Whether you're timing movement with music or aligning "boing" sounds to a bouncing ball, some sort of a visual reference in the audio track in useful.

Revealing the waveform is one way to look at what's going on in your audio track, but takes up room and doesn't always clearly show audio events. Layer markers to the rescue!

After Effects won't necessarily play your audio when you hit the spacebar or do a RAM preview. However, you can force an audio preview by pressing the period key on the extended, numeric keypad. This sacrifices video in order to perform an audio preview.

For a real-time audio preview, press the period/decimal point key on the numeric keypad. You can then set markers by tapping on the asterisk key (on the extended, numeric keypad). You can slide them around to fine-tune them. They can be deleted by right-clicking or control clicking them.

If your audio doesn't play long enough, check your audio preview settings in preferences.

Simple Exercise:

Import some audio into your project and into your timeline. Then you can twirl down the audio layer's arrow button to expand the view until you can see levels. Note you can set keyframes and adjust the volume. If you view the audio monitor you can also set levels and keyframes there as well.

  • Try previewing the audio. (period key on the numeric keypad)
  • Tap the asterisk key while it's playing to set layer markers.

Audio Spectrum and Audio Waveform are two cool effects you can use with sound. Note: Audio Spectrum and Audio Waveform effects must be applied to a layer other than the audio. Solid layers work well for this.

If you want to use Audio Spectrum or Audio Waveform:

First make sure you have an audio layer in your comp. Then create a new solid layer. Apply the audio effect to the solid layer. (Effects -> Render -> Audio Spectrum / Audio Waveform.) Make sure the "Audio Layer" pull-down selector is pointing to the audio layer. Try experimenting with the controls.

Working with and outputting video

While After Effects is not video editing software, you can still do basic trimming and a number of interesting video effects. (Yes, if you really wanted to, you could edit video, but it's not well suited for this.) However, manipulating video and compositing video with animations and other elements is one of the things that After Effects is best known for. It's also a good tool for making looping motion menus for DVDs.

Importing video

AE can access and work with a multitude of video codecs. Be sure to maintain the same relationship between project and media! Don't import video from temporary places like "Downloads" or "Desktop" .Assuming you have access to the same storage your video is on, simply navigate to the appropriate media folder and import your video. (You can import directly from Final Cut Pro's "Capture Scratch" folder or from Avid's "Avid MediaFiles" folder). Otherwise, you'll have to copy the individual clips you need into your AE media folder before importing.

Trimming

Clips can be trimmed in the Timeline or in the Layer Window. Import a video clip into the Timeline. Slide the layer to the right a little so it doesn't start at 0. Double click the clip in the Timeline to open the layer window. The display shows 3 sets of counter numbers: in point, out point and duration.

Position the Layer window so you can see the Timeline. Note the in and out points in the Timeline. Move the time indicator somewhere near the beginning of the clip and press the in-point button. The duration value in the Layer window updates accordingly and the clip slides forward in the Timeline.

Now try dragging the triangular handle in the Timeline. This is another way you can move in and out points.

As you may know, pressing the left bracket [ button re-positions the layer to begin at wherever the time indicator is. With video clips, it will reposition the layer's in point to the current time indicator.

Slip Edits

Once you have a video clip (or any other layer that changes over time) in your Timeline, you may want to slide the video around without messing up your in and out points relative to the Timeline. In other words you want to do a slip edit.

Position the video clip so you can see the in and out points. Select the Pan Behind tool from the Tools palette and position the pointer over the video clips. It changes into a left-right arrow. You're now in Slip mode. Try dragging the pointer to the left and right with your video clip layer selected. It slides the clip around while retaining the in and out points relative to the Timeline.

In-class Audio Spectrum and Audio Waveform Exercise

  • Start with a 1920x1080 comp, 15 seconds long, called "audio"
  • Import some audio
  • Create 2 solids (one for each effect)
  • Adjust the parameters (height, fill, color, etc.) to create a pleasing and dynamic effect
  • Add some text to Identify/label the effect (or use text of your own choice.) Please treat/format your text with some care/thought.
  • Turn in an H.264, ProRes422, or MP4 movie (with audio) to the appropriate Canvas assignment.

Thursday ----------------------

Miscellaneous AE Tips

Making animated glints

  • The layer to be glinted should not be 100% bright, or you won't be able to see the "light" reflecting off of it.
  • To make a glint, start off by making a tall, bright, light solid in your comp.Make it the color of the "light" you want to "reflect".
  • Use a mask to feather the edges
  • Turn it diagonally a little
  • Place the glint layer directly over the layer to be glinted
  • Turn on the preserve transparency (T) checkbox of the glint layer
  • Use position keyframes to move the glint solid across the layer you'd like to glint
  • You will likely need to precompose the glint with the layer you are glinting.

Blend Modes

These are the same modes available in Photoshop. They provide many interesting ways to blend layers.

Frame blending

Each frame of a 15 FPS animation or movie will be duplicated in a 30 FPS comp. Some movements might not appear as smooth since frames will be repeated. Frame blending interpolates between the different frames. While it is a good thing to use- it takes longer to render. Click the box under the movie frame icon to turn it on.

Time stretching and time-remapping

Time Stretching is easy in After Effects. As with most effects, there are a number of ways you can access it.

  • With the layer highlighted in the Timeline, select: Layer -> Time Stretch to open the Time Stretch window.
  • Control click or right-click on the headings in the TImeline and turn on Stretch (If it's not already on). Stretch values will appear in the Timeline. Click on one to open the Time Stretch window.

In the Time Stretch window you can either enter a value other than 100% or make a new duration.

Note that you can also select a different item to hold in place other than the Layer in point, (which is the default as it's what we usually expect when we enable slow motion or fast motion).

Note: Time stretching is NOT a good way to change the duration of still images.

Time re-mapping

Time remapping is a bit more interesting than simple time stretching. You can use it to vary time and the rate in which motion changes occur.

To use it first import a comp or a video clip. (something with movement)

The, highlight the layer and select Layer -> Enable Time Remapping.

Expand the layer's arrows to show the time remapping controls. You'll see two keyframes. One at the start of the clip, the other at the end.

What the numbers mean:

The number next to Time remap shows what frame is being displayed.

Value Time: The max is the length of the movie file. The value line is a visual cue as to what parts are playing and if they are playing forward or backward

Velocity time: The middle number is the important one. It shows how fast the movie is playing and if it’s going forward or backward (uses a minus sign for backward) The numbers at the top & bottom simply show the maximum time change used.

Try adding a couple keyframes in the middle. Then you can slide the time values up and down, or the keyframes left and right.

Gradient Wipes

You can duplicate many popular wipe transitions with the transition tools. To use these you'll need to set two keyframes, one at the beginning of the transition and one at the end.

Interpret Footage

When importing interlaced video, After Effects usually guesses the field order correctly, but occasionally gets it wrong. If your video is stuttering or showing interlacing lines, try checking the field order, which is specified in the interpret footage window. To get to the interpret footage window, right click on the footage in the project window and choose Interpret footage > Main. 

In this area you can set parameters such as if the type of alpha channel, the frame rate, the field order, and the number of loops. If the video is stuttering or not playing smoothly, try changing the field order (upper or lower). Whether you should use upper or lower field first is determined by the particular hardware of the video editing system. One thing to remember is that most HD video is upper field first. DV and most legacy firewire-captured video is lower field first.

Adobe's guide to field rendering for interlaced formats.

Once useful parameter in this area is the loop __ times function. If you want a movie to loop, simply bump the number from 1 up to something higher.

In-class "Time" Exercise:

  • Find two short video clips to work with.
  • Make a comp that matches their pixel dimensions and frame rate, about 20 seconds long. (You can name it "time.")
  • Make sure both video clips are in your comp
  • Apply an obvious time-remap to one clip and time stretch to another.
  • Insert a wipe of some type between the 2 layers
  • Using on-screen text, identify/label the time effects and wipe you used.
  • Brownie points if you add an animated glint to your text.
  • Render out a an MP4, H.264, or ProRes422 movie and upload it to the Week 7 In-class assignment called "time".

Homework/Next week:

  • Read chapter 12 of the Meyer book
  • Review for Tuesday's AE quiz. (Assume it covers all of the After Effects lectures and chapters 1-12 & chptr 21 of the Meyer book.)
  • Turn in and review Midterm Projects & turn in critiques (Thursday)

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