Unit 6. Working with Sounds (III)

Mp3 or Wav?

How we've already commented, the sounds, which Flash 8 can import, must have the extensions .wav or .mp3. If you do not know the differences between these types of files, you can see our basic theme .

Moreover, when we want to add a sound to our movie, we have to choose betwen one of these 2 formats. Usually the sound, which we try to insert, is already in one of them, but we haven't to forget about multitude of programs that convert a sound with extension .mp3 to one with extension .wav and vice versa, therefore, the use of original format has not to be inconvenient.

The question arises immediately: Which one is better?

This question is more important than seems, since if we want our movie to have sounds, we have to assume that load is very important in terms of movie size and, as consequence, in terms of download time. Typically the sounds sizes more than half of the total space and often it is not worth inserting them...

As we already have known, the sounds .mp3 sizes much less than the sounds .wav (10 times less or more), then, it seems to be advisable to insert .mp3 instead of .wav.

Can Flash compress sound which was already compressed? In other words, if a sound .wav has been compressed and now has the extension .mp3, can Flash compress it once more?. The answer is it cannot. Flash compresses the sounds that we insert in our movies, but if the sound is already compressed, it cannot compress it again (in fact, it tells it succeeds in compressing, but the final sound is the same as initial one).


We have a movie with an unique frame that is empty. Once we prepare this movie to be seen (.swf), it sizes 1KB.

We have 1 sound .wav that sizes 1596 KB.

We compress this sound with a compressing program of audio and obtain the same sound in format .mp3; it sizes 145 KB. (The quality of sound is practically identical).


Now we insert the sound .wav in the original movie and export it (this is discussed in the last unit).

Result: A movie with sound that sizes 37KB.


Instead we insert the sound .mp3 in the original movie.

Result: A movie with sound that sizes 145KB.


Conclusion: The movie with a sound .wav sizes nearly 5 times less than the one, which has the same sound in .mp3, hence, it seems to be recommendable to insert .wav sounds (the compression of audio obtained by Flash is great).

As counterpart, lost of quality in the sound could be appraised that is audible in the movie. This lost will be more or less important according to the type of sound. If it is one voice, for example, we have to insert .mp3 since the voice has necessarily to be well audible. If it is background music, it is probable that the final result is acceptable, although the lost of quality. It is best to probe both versions and to evaluate the result.

You can see various tests in this movies:

Background Music

Movie with sound (music) in format .wav.
Total Size: 37 KB.
Quality: Good

Movie with sound (music) in format .mp3.
Total Size: 145 KB.
Quality: Good

Sound "Voice"

Movie with sound (voice) in format .wav.
Total Size: 9 KB.
Quality: Regular

Movie with sound (voice) in format .mp3.
Total Size: 67KB.
Quality: Good

In the first case it would be advisable to remain the smaller movie, since both sounds are good. In the second case, the second movie would be more appropriate, since it is worth having the quality of sound, even though it has a larger size.


Finally, we would like to comment that Flash can’t import sounds in format MIDI (.mid). But if we want the sound in our animation to be a MIDI and do not want or cannot get a program, which converts the sound MIDI to WAV or MP3, there exists a way to do this consisting in the combined use of Flash and Javascript. Flash 8 allows to load sounds in a dynamic way (without increasing the space), this will be considered in the Unit 17 "Action Script".

  Exercises of the Unit 6

 Unit 6 Test .

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