When developing MPU and banner advertising in Flash, designers have to work within strict file size limits. Publishers usually limit the initial load to 30k or 40k (which doesn’t get you much) and sometimes allow a subsequent polite download of a further 50k or 60k (which doesn’t get you much more).
Below are some of the techniques and rules that designers should follow in order to reduce and minimise the file size of their Flash animations.
Avoid bitmap images
Try and use as few bitmap images and graphics as possible. Instead use vector graphics imported from Illustrator or drawn natively in Flash. Vectors have a much smaller footprint than bitmaps and are easier to manipulate and animate too.
Use vector fonts
As above, fonts written natively within Flash are treated as vector shapes so have a small footprint compared to imported bitmap fonts. Using vector fonts adds the flexibility to be able to animate and change the shape and size without losing clarity.
Animate using tweens
Use stop-motion tweens to animate single shapes rather than using different objects with each key frame. One animated object will have a much smaller footprint than several different objects being used throughout the scene.
Use movie clips
If you use the same object or element several times in the animation, use movie clips to animate that object and then reuse that movie clip where necessary. Also, if you do need to display bitmap images do so on the fly using movie clips to keep your file sizes down.
Optimise publish settings
Ensure ‘Compress movie’ is ticked as this dramatically affects the published file size. However, make sure you check your animation to ensure this doesn’t adversely affect it. Also you may want to untick ‘Export hidden layers’ to ensure no unnecessary layers add to the overall file size. Finally optimise the ‘JPEG quality’ setting to find the happy balance between quality and compression.
How do you optimise your Flash animations
Sometimes that MPU animation really needs to be hammered about to get it under the 30k threshold and it can require some creative thinking to achieve that. If you have any creative techniques you use for reducing file size, especially any that useActionScript, then I’d love to hear about them?
