Guidelines for exporting sound in flash documents – Adobe Flash Professional CC 2014 v.13.0 User Manual

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mp3 compression options

MP3 Compression Lets you export sounds with mp3 compression. Use mp3 when you are exporting longer stream sounds such as music sound
tracks.

If you are exporting a file that was imported in mp3 format, you can export the file using the same settings the file had when it was imported.

Use Imported mp3 Quality Default setting. Deselect to select other mp3 compression settings. Select to export an imported mp3 file with the
same settings the file had when it was imported.

Bit Rate Determines the bits per second in the exported sound file. Flash Professional supports 8 through 160 Kbps CBR (constant bit rate).
When you export music, set the bit rate to 16 Kbps or higher for best results.

Preprocessing Converts mixed stereo sounds to monaural (mono sounds are unaffected by this option).
Note: The Preprocessing option is available only if you select a bit rate of 20 Kbps or higher.

Quality Determines the compression speed and sound quality:

Fast Yields faster compression but lower sound quality.

Medium Yields somewhat slower compression but higher sound quality.

Best Yields the slowest compression and the highest sound quality.

Speech compression option

Speech compression exports sounds using a compression that is adapted to speech.
Note: Flash Lite 1.0 and Flash Lite 1.1 do not support the Speech compression option. For content targeting those player versions, use mp3,
ADPCM, or Raw compression.
Sample rate Controls sound fidelity and file size. A lower rate decreases file size but can also degrade sound quality. Select from the following
options:

5 kHz Acceptable for speech.

11 kHz Recommended for speech.

22 kHz Acceptable for most types of music on the web.

44 kHz The standard CD audio rate. However, because compression is applied, the sound is not CD quality in the SWF file.

Guidelines for exporting sound in Flash documents

Besides sampling rate and compression, there are several ways to use sound efficiently in a document and keep file size small:

Set the in and out points to prevent silent areas from being stored in the Flash Professional file and to reduce the size of the sound data in
the file.

Get more out of the same sounds by applying different effects for sounds (such as volume envelopes, looping, and in/out points) at different
keyframes. You can get a number of sound effects by using only one sound file.

Loop short sounds for background music.

Do not set streaming sound to loop.

When exporting audio in embedded video clips, remember that the audio is exported using the global streaming settings selected in the
Publish Settings dialog box.

Use stream synchronization to keep the animation synchronized to your sound track when you preview your animation in the editor. If your
computer is not fast enough to draw the animation frames so that they keep up with your sound track, Flash Professional skips frames.

When exporting QuickTime movies, use as many sounds and channels as you want without worrying about file size. The sounds are
combined into a single sound track when you export as a QuickTime file. The number of sounds you use has no effect on the final file size.