Welcome to the second tutorial in DoReMedia's Dynamic Audio Trilogy. In the first tutorial, Creating Dynamic Soundtracks Using Layering, we showed you how to make your sound tracks more interesting and smaller in size by using layering techniques and controlling individual instrument parts. Sound Family Layers provide the "unmixed" instrument tracks necessary to accomplish this. But layers are just one of three dimensions of the Sound Family. The second dimension is Chunks.
What are Chunks?
Chunks are pre-mixed phrases taken out of a musical arrangement. Chunks open a whole new world of possibilities for audio interactivity in Flash. And in some ways, they are more powerful and easier to work with than layers. Rather than individual instrument parts, Chunks provided with DoReMedia Sound Families are the most common song sections, such as the verse, chorus, breakdown, intro, and outro. By shuffling the order and repetitions of each chunk, you can easily tailor your own musical arrangement to the timing and visuals of your Flash project.
Why Use Chunks?
Chunks can be implemented in a few different ways. They can be implemented almost exactly the same way as layers, triggering 2 or more chunks on the same keyframe, and then using volume envelopes to mute and unmute each piece of audio to create musical dynamics. Or, Chunks can be used in a linear fashion and inserted at various points across the timeline, using Flash to "shuffle" the playing order to build a unique musical arrangement. Using chunks frees you from the 8 part limitation of Layers, and allows for more musical variation. Layers give you more permutations, but less dynamic range. Think of it this way: Layers put together make up a groove. Chunks put together make up a song.
As described in Tutorial 1, by using layers and volume envelopes, we can avoid the need to force frame rates (see below). But Layers can be limiting. You can only have up to 8 layers at a time (muted or unmuted). You can only have up to 8 envelopes per layer, which can become an limiting issue with longer or more complex soundtracks. And layers can be difficult to modify - if your movie structure changes, or you want to change the arrangement of your layered soundtrack, you have to progressively edit every layer's envelope many times. In these situations, Chunks can be more scalable and simpler to modify.
Chunks are like sound Legos. You simply "attach" one clip to the next to construct your own musical arrangement. Similarly to layers, after you use a chunk for the first time, it's "free". The file is stored in cache and can be re-used later in your movie without adding to file size. And you can associate specific pages, scenes, buttons and user actions with specific chunks, making your soundtrack truly interactive.
Forcing Flash's Frame Rate
Flash allows you to select a frame rate for your movie between 1 frame per second and 30 frames per second. The two most common rates are 12fps and 15fps, but any rate is acceptable to a tenth of a frame per second resolution. The tricky part is that no matter what frame rate you pick, actual playback is dependent on the user's processor and the complexity of the movie. So even though you may choose 12fps, your audience may only experience 10fps, or 6fps. This poses a problem when trying to synchronize audio and graphic elements in your Flash movie.
It's fairly easy to synchronize the beginning of a sound clip with an event by simply triggering the audio at the same keyframe as your event. But what if you want to synchronize something with the end of a sound clip, like another sound clip, as in our Lego example? How do you know on which keyframe to trigger your second clip? We need to know what frame the timeline is on when one chunk finishes, so we can then trigger the next chunk to build our arrangement.
In order for all of this to work, we have to force Flash to keep a precise, consistent frame rate. We could set the sound SYNC METHOD to STREAMING for all of our sounds, but this would increase our file size by a factor of 10 or more.
The answer is what DoReMedia calls a Sync Track. Every Sound Family comes with a corresponding, tempo-matched Sync track. The purpose of the Sync Track is two-fold. It forces Flash's frame rate to be constant, and it provides a very useful visual reference which can be used to avoid trial and error in placing and synchronizing sound clips.
What is a Sync Track?
A Sync Track is a one measure sound clip that is recorded at the same tempo as the Sound Family. It is a multiple in length of every component (layers and chunks) in a Sound Family. It also has an audio spike at the beginning of the clip, which acts as a visual reference to help synchronize audio components. By inserting this low-resolution clip throughout the length of your movie soundtrack with a SYNC SETTING of STREAMING, we can force Flash's frame rate to be constant and determine when to trigger the next chunk.
Using Chunks and the Sync Track to Build a Custom SoundTrack
*The Companion FLA file for this tutorial is available free from DoReMedia's Resources page.
In the following exercise, we will create a background track using DoReMedia Sound Family chunks that will save over 50% download time versus streaming the same amount of audio. Begin by setting your frame rate from the MODIFY>MOVIE dialog box. We will use 13 fps for this exercise because it is an optimized frame rate for the musical tempo of our soundrack (see "Dealing With Seams and Timing Inconsistencies" below). IMPORT your audio components and sync track into your Flash movie. In this example we will use Spankin_intro.aif, Spankin_A.aif, Spankin_B.aif, and Spankin_break.aif. ADD 6 new LAYERS and rename them to match your audio components - including your sync track: "Sync", "Intro", "A", "B", "Break", and "Outro" {figure 1}. |  |
 | Next, drop your sync track onto your timeline by selecting SYNC_130.aif in the Sound pulldown menu of the SOUND PROPERTIES dialogue box. Set the SYNC METHOD to STREAMING and enter 50 in the LOOPS box {figure 2}. |
Click the EDIT button. Drag the volume envelop handles down to the bottom to turn the volume for this track off {figure 3}.
Scroll right, select frame 600 on the sync track and INSERT FRAME. This will extend a visual representation of the sync track on the timeline . You should be able to see the spikes in the waveform display on the timeline, indicating the beginning of each measure. Now you're ready to start building a custom musical arrangement.
Here's where the fun begins! Select frame one of the second track of your movie and add the sound Spankin_intro.aif using the sound properties dialogue box. Make sure that the SYNC METHOD is set to EVENT {figure 4}.
Once again, to see where on the timeline the sound clip ends, you may have to INSERT FRAMES after each sound keyframe. Add enough frames so you can see the end of the waveform display. Notice how the waveform of the intro track ends perfectly at the end of frame 48, with no extra space. And notice that the spike on the sync track displays perfectly at the start of frame 49 {figure 5}. This is due to the precise timing of Sound Family components and selection of an optimized frame rate (see "Dealing With Seams" below). On Frame 49 of track A, INSERT KEYFRAME and add the sound Spankin_A.aif {figure 5}. Again, make sure you are setting the SYNC METHOD to EVENT. Set the LOOP parameter to FOUR (4). {Follow this same procedure as we add more audio tracks} |  |
This will take us to frame 239. On frame 240 of track B, add the sound Spankin_B.aif. Set the LOOP parameter to TWO (2) for this clip {figure 6}. You should now be at frame 337. At frame 338, add the sound Spankin_break.aif on the track labeled Break, and set it's LOOP parameter to TWO (2) {figure 7}. | |
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 Now go back to track A, frame 433 and add another instance of Spankin_A.aif Set it's loop parameter to 2 {figure 8}.  |
| Finally, we are ready to wrap up our arrangement with an ending. On the one remaining unused track labeled Outro, insert Spankin_outro.aif at frame 529 {figure 9}. We now have all of our component pieces on the timeline. You can play your movie to hear the arrangement you just created. Using the Sync Track's Waveform Display to Help Create Dynamics Lets IMPORT two more components from our Sound Family called Spankin_fill_01.aif and Spankin_crash.aif. Sound Family chunks have been engineered without drum fills and cross-phrase melodies for looping purposes. Because of the uniqueness of every multimedia project, having fills and melodies as part of the chunk would be a disadvantage. But fills and melodies add impact and dynamics, right? Isn't that why traditional loops get so mundane? The answer is, yes. Loops alone are almost the opposite of dynamic and compelling. However, using the sync track and layerable audio components like drum fills, give you the ability to add these impact building elements back into our mix... when YOU want them. Fills provided with Sound Families are always edited to be one or two full measures in length. This means that they will always align with a waveform spike on our sync track.
Using the Sync Track's Waveform Display to Help Create Dynamics Lets IMPORT two more components from our Sound Family called Spankin_fill_01.aif and Spankin_crash.aif. Sound Family chunks have been engineered without drum fills and cross-phrase melodies for looping purposes. Because of the uniqueness of every multimedia project, having fills and melodies as part of the chunk would be a disadvantage. But fills and melodies add impact and dynamics, right? Isn't that why traditional loops get so mundane? The answer is, yes. Loops alone are almost the opposite of dynamic and compelling. However, using the sync track and layerable audio components like drum fills, give you the ability to add these impact building elements back into our mix... when YOU want them. Fills provided with Sound Families are always edited to be one or two full measures in length. This means that they will always align with a waveform spike on our sync track.
Dealing with Seams and timing inconsistencies Seams are small gaps or pauses between chunks or loops that are placed back to back. Depending on processor speed, playback quality may vary within Flash, causing small seams between chunks. However, if all chunks have been inserted in the correct frames, this should not be a problem upon export to SWF format. If seams still exist in your exported movie, there are a couple of possible causes and resolutions. The first reason you may experience seams is due to mis-matched frame rates and beats per minute. Flash's timing method is frames per second, while music is measured in beats per minute. The average ear can hear a 1/100 of a second gap in a solid music stream. So, if your frame rate is set at 10 frames per second, and your first chunk ends in the middle of a frame, you will have a 5/100 of a second space before the next chunks starts, causing a seam. This problem is solved by choosing frame rates and beat-per-minute rates that divide evenly. Basically the number of frames per beat must be a whole number. To illustrate this better, go to MODIFY> MOVIE and change your frame rate to 12 FPS. Notice in the timeline that the audio waveforms no longer end precisely at the end of a frame. All DoReMedia Sound Families are recorded at optimal BPM rates and engineered to have timing accurate to 1 millisecond. DoReMedia provides a BPM to Frame Rate calculator which is available free for all registered users.
More Tips and Tricks
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ADD a new LAYER and label it "FILLS". Lets look on our timeline to find frame number 240. This is where we switch from Spankin_A to Spankin_B.Go back one spike to frame 217 and insert a new keyframe {figure 10}.
Repeat the same process throughout your soundtrack to suit your taste. I have put the fill and crash on some transitions, while using only the crash on others.
If you are using frame-optimized sound files such as a Sound Family, and still experience timing inconsistencies upon export, there are a couple of work arounds. | » Level Advanced |
Added: : 2001-02-13 Rating: 6.49 Votes: 16 Hits: 2143 |
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