By
now you'd better be pretty impressed with Flash. If you aren't, perhaps you haven't
read my previous articles about easy
animation and shape
tweens. If you have read these articles and you're just not buying into this
Flash hoo ha, then sit back and open your ears.
That's right. Flash can deliver a veritable symphony of music and
sounds to delight, amaze, and possibly annoy your viewers. So once again, prepare
to be amazed and dazzled, but save room for good judgement lest you send your
viewers screaming with Queen's Flash! Ah-haaaaaa.......
Flash
can import WAV or AIFF audio files. If you have sound files in a different format,
you can most likely convert them to a format Flash can read. The last section
of this article tells you where to find free sound effects and how to convert
them.
Before importing sounds and music into your movie, you should consider file
size and the length of your clip. Though Flash has some ability to edit sounds,
you are better off importing a sound that is ready to play.
The size of your sound file is determined by length, sample rate, channels
(stereo or mono), and bit depth (seconds of audio x sample rate in hertz x number
of channels x (bit depth / 8) = file size).
- Sample rate-- the number of times an audio signal is analyzed when
recorded digitally. This rate is measured in hertz (Hz) or kilohertz (kHz).
So a sound sampled at 44.1 kHz analyzes the sound 44,1000 times per second,
recording the differences between each analysis. Higher sample rates provide
a better audio range.
- Bit resolution-- also known as bit depth, the number of bits used
to describe each audio sample. An 8-bit sound sample has a range of 28,
or 256 levels, 16-bit sound samples have a range of 216, or 65,536,
levels and so on. Higher bit depth has exponentially more information and
will provide clearer sound.
- Channels-- Sound files can be stereo (a channel for each left and
right) or mono (one channel).
As all of these factors affect the sound's file size and quality, so you will
need to find a happy balance. As Flash will compress the audio files when it
exports your movie, you are better off using the highest quality file possible--
16 bit, 44.1 kHz is ideal.
Sound
can enhance your Flash movies in a number of ways. Add background music for ambiance,
assign sounds to events such as the push of a button, or give your characters
voices. My project began a bit backwards, as I chose my sounds before I had an
idea for a movie. I happened to like a car screech, a laser gun, bubbles, and
a cow's moo. Together these sounds might not groove so well. So I decided to have
each sound come out of the aforementioned screeching car's trunk. Now that makes
sense.
I like to jump head first into a project creating images, sounds, and order
as I go. Though the results might display a bit of spontaneity, such disorganization
can make your Flash project a nightmare. So in a proper "do as I say"
tone, I am telling you to plan your movie first. Create your art, sound, and
storyboard, tuck them all in their cute little folders and then start your project.
Click on the Play button to the right and then hold the mouse button
down over each object to hear the sounds.
I used sound in two different ways for this movie. The first sound synchs with
an object that makes the sound-- the screeching car, the floating objects. The
second type of sound only happens when an event occurs-- an object is clicked.
Decide how you want to use your sound, then read on to find out how to do it.
These steps will teach you how to assign a sound to an animation. You can then
tweak the steps to make your own noisy movie.
- Start a new Flash movie.
- Go to File, Import, and select a sound you want to use. The sound file will
automatically appear in your library (Control + L).
- Either import an image, or create a new one that will make the sound. I
chose Import, New Symbol, drew a car, then placed it in the tenth frame of
layer one (this allows room in the beginning of the movie for the Play button).
Don't forget to label your layers as multiple layers can be confusing.
I tweened the car so that it moved across the screen. Read
the tween article if you don't yet know how to do this. Now add a layer
above the car layer and enter a keyframe in frame ten. Select the sound from
the library and drag it to the work area. As it is just sound, you won't see
anything on the work area, but you will notice a small line in the frame of
the timeline.
Select the first frame and choose Modify, Frame. Click on the Sounds tab. You
will see two boxes with wavy lines. These are the images of your sound. You
can edit a few things about your sound such as in and out points, fades, and
volume. There are two sliders in between the two pictures that determine the
in and out points. They are sort of hard to see, but try clicking and dragging
them to edit your sound. You can then press the little play button on the bottom
to hear the results.
On the right, choose a type of synchronization. You have four options: event,
start, stop, and stream.
- Event sounds play independently of the timeline and will play to their end
even if the animation has finished.
- Start is the same as event, though if the sound is already playing, a new
instance of the sound will begin.
- Stop silences the sound. Remember that you can modify each frame the sound
occupies so you can start or stop the sound per frame.
- Stream makes Flash force the animation to keep up with the sound. I chose
stream as it allowed me to drop individual frames of sound to synch better
with my car.
You can also play with the effects to make your sound fade in or out, or create
a custom effect.
When
you click on one of the objects in my movie, it makes a sound. This sound is assigned
to the object (which is really a button) and requires no extra work in the timeline
itself. Here is how it is done:
- Choose Insert, New Symbol. Choose Button as its behavior. You will be taken
to edit mode.
- Draw a button.
- In layer one, you will see a keyframe in the Up frame of your button. Add
a keyframe to the Down and Over frames.
- You can modify your button in each frame for fancy sake. For example, you
might make the button smaller in the Down state so when you click on it, it
looks like the button is being pushed. Likewise you can change the button's
color in the Up frame to create a mouse over effect.
- Add a layer above the button layer and add a keyframe to the Down frame.
- Select your sound from the library and drag it to the work area.
- Press Control + e to return to the scene.
- Make a keyframe in the first layer and drag your button to the work area.
Choose Control, Enable Buttons and try out your new, noisy button.
Any
sound files brought into Flash will greatly increase the file size. My original
movie was only around 10K, but when I added four short, simple sounds, the size
crept up to 46K. When exporting your Flash movie, you will need to find a happy
middle ground between file size and audio quality. Decide which is more important
for your audience: download time or quality.
Choose File, Publish Settings, and click on the Flash tab. Three publish settings
are available: Audio Stream, Audio Event, and Override Sound Settings.
You can further customize your settings by pressing the Set button next to
Audio Stream and Audio Event. Disable causes the sound to not be exported with
the movie. ADPCM allows you to choose: Convert Stereo to Mono (combines sound
into one channel), Sample Rate, or ADPCM Bits (the higher the bit number, the
better the quality).
If you choose MP3, you may also convert stereo to mono, change the bit rate,
and choose the quality settings. Increasing the bit rate in the MP3 audio compression
scheme will not greatly increase file size. For quality, choose fast for the
Interent, and best for CD-ROMs. The Flash 4 Bible recommends you choose
MP3 at 64Kbps for moderate-to-good sound quality.
For more control over your sound's compression, try customizing the sound's
settings in the Flash Library. This is particularly useful if you have sounds
that can have different qualities. Double-click on the sound you want to edit
in the Library. In the Sound Properties box, you will see a section called Export
Settings. Here you can tweak individual sound files. The Sound Properties box
also allows you to update changed sounds, import new files, preview the export
quality of your sound, and also offers a Help button.
In
my search for free sound effects, I stumbled across Partners
in Rhyme. Not only did I pause to chuckle at the name, but I found a ton of
weird sound effects (thus the bubble, car, cow combo). Many of the files I found
had an .au extension that won't work in Flash. So I downloaded a program called
GoldWave. You can open all sorts of sound files in GoldWave, tweak them, then
save them as WAVs. Voilą-- instant sound effects.
I did have a small problem importing the cow moo into Flash. In GoldWave, the
cow sounded perky as can be. But when I brought the sound into Flash, the poor
cow sounded ready to keel over. This is because Flash can import sample rates
of 11 kHz, 22 kHz, or 44 kHz, but the cow was sampled at only 5 kHz. So I resampled
the sound in GoldWave and re-imported it into Flash, creating a much happier
cow.