Hi Rick
Thanks so much for your reply!
This article was indeed helpful, as it contains a lot of
general tips, and is well written. So it was of good use to me,
however I am still looking for more specific answers. Excuse the
long post, but I hope it provokes some thought into providing more
detailed information for all levels of users, and ensures they get
off to a good start when they make their projects.
Please let me start by giving the example of the sound files.
Are there accurate figures or formulas available to really pinpoint
the areas we should consider to minimize our files? I did a couple
of short tests on a single slide movie, and imported MP3's into it,
Specifically to see what effect the Audio Settings had on the size
of the resultant movie. Here's what I found:
TEST 1
Testing Criteria: File Length
Original MP3: File size: 673.8 kB
File Length: 43.0 seconds
Bit Rate: 128kbps
Sample Rate: 44.100kHz
Highest: 877Kb 20.395Kbps 100%
High: 718Kb 16.698Kbps 82%
Medium: 553Kb 12.860Kbps 63%
vs.
Original MP3: File size: 12.82Mb
File Length: 820.2 seconds
Bit Rate: 128kbps
Sample Rate: 44.100kHz
Highest: 12.4Mb 15.48Kbps 100%
High: 9.3Mb 11.611Kbps 75%
Medium: 6.25Mb 7.803Kbps 50%
Conclusion: The longer the file, the better the reduction?
TEST 2
Testing Criteria: Bit Rate
Original MP3: File size: 7.3Mb
File Length: 235.5 seconds
Bit Rate: 256kbps
Sample Rate: 44.100kHz
Highest: 3.72Mb 16.18Kbps 100%
High: 2.82Mb 12.26Kbps 76%
Medium: 1.95Mb 8.48Kbps 52%
vs.
Original MP3: File size: 7.3Mb
File Length: 479.5 seconds
Bit Rate: 128kbps
Sample Rate: 44.100kHz
Highest: 7.39Mb 15.78Kbps 100%
High: 5.55Mb 11.85Kbps 75%
Medium: 3.77Mb 8.05Kbps 51%
Conclusion: Bit Rate has no effect on reduction?
These conclusion are by no means correct, but you see my
point, there must be a more mathematically correct method of
evaluating file size.
Please take these other points as mentioned in David's
article:
1. Minimize file size by reducing the recording area in
Captivate:
Sure, but what is the relationship between recording area and
file size? I know there's a relationship between total number of
pixels x bytes per pixel, but there must be more to it than that.
2. Reduce the amount of background noise;
3. Reduce the color gradients in your recording area:
How much does this really affect the final size? Is it closer
to .05% reduction or 50% reduction? I can see how this may be
appropriate for simple slideshows, but what if the animations are
graphically intensive, do the color gradients really matter then?
Is this point outdated with the increasing complexity of
animations?
4. When recording in "Full Motion" format, Captivate converts
the recording from AVI format to static screen shots. This
increases the overall file size more than a traditional recording:
Again, in producing a thoroughly enthralling animation, with
3D graphics and voiceovers, etc, full motion is a necessity. If the
Full Motion Recording options (which is only briefly mentioned in
the demonstration) are altered, is there a proven relationship
between all the settings (Smoother Movie/Video Quality/Video Color
Mode) and the final size of that recording?
5. Remove any extra slides that do not add any value to the
presentation:
Sounds like a sensible idea. Is there anywhere where we can
see the size of an actual slide?
6. If you insert large images, expect your Captivate file
size to grow more than if you insert small images:
Like point 1, what's the magic formula? Even a ballpark
figure would help. David mentions SWF files and the file size
should increase only by about the same amount as the inserted SWF
file. That's good stuff - a tangible amount.
7. On the Start and End tab:
Okay, but I'm definitely going to need those. Again is there
anywhere where we can find out how big they are?
8. Advanced movie compression: Select this option to compress
slide data shared between slides, thereby reducing overall file
size:
Sweet, consider it done. How much did it just save me?
9. Compress compiled SWF file: Do not deselect this option.
I won't. In fact I am not sure why it's even an option!
10. Include Breeze metadata: This option, which is selected
by default, increases the size of the project. If you are not going
to use the project with Macromedia Breeze, deselect the option to
decrease the size of the finished project file (SWF). However, if
there is the possibility that the output file (SWF) may be used in
Breeze, it is best to select this option.
Bit of a crap shoot at this stage. If I knew just how much I
was saving in the file size, I would be better informed to know
whether to include it or not.
11. 508 compliance: Publishing 508-compliant output increases
your file size. If audience analysis concludes that are no learners
with disabilities that need to access your content—or if you
are not otherwise required to comply with Section 508 government
regulations—you can safely turn off 508 support.
C'mon sevens! Again if only I knew the real impact on my
filesize, I would know whether to just leave it checked, just in
case it will one day be needed.
12. Frames per second: The default setting is 30 Flash frames
per second (fps) and this is appropriate in most cases. Note:
Decreasing the number of frames per second does not significantly
decrease the size of your Captivate project and therefore is not
recommended. For example, decreasing the fps rate by half does not
halve the file size. Also, reducing the fame rate of Captivate is
not the same as reducing the frame rate of an AVI. Lowering the
frame rate of an AVI removes static images from the file, which
reduces its size. Removing a single frame from a Captivate project
where no change takes place does not reduce the file size.
Mine defaults to 10 fps, is that bad? Now I'm confused! So
what is the best frame rate, and just how much does it reduce the
file size when changed?
13. Movie background color: Depending upon the type of slide
and how you took screen shots, the background color might not
appear on all slides. Double-click the color box to open the color
picker, and select a new color. Remember that using a bright
background color will increase the file size.
Does this ~really~ matter if I have 3D Virtual models and
constant audio? Or is it like worrying about if the temperature in
Antarctica is -70 below or -71?
14. JPEG image quality: Adjust this setting depending upon
the images used in your movie. Lowering your image quality to as
low as 50% (from the default 75%) is often not noticeable to the
naked eye. Higher percentage values allow for very high quality
images. Of course, this also increases file size.
Okay, but numbers would be good again.
15. Play tap audio for recorded typing when movie is
generated: This option plays tapping sounds in the final movie
whenever keys are pressed during recording. Including this option
adds a small audio file to your project and does increase the file
size, but only by a small amount.
No sure how much they'll hear the taps with me talking over
them the whole way through it, but I can turn them off. I think a
lot of people finding them slightly annoying anyway, but how much
did I just gain with that happy move?
16. Including a playback control bar increases the file size
by a small amount. If your users do not need a playback
control—as is often the case with simulations and
quizzes—select None from the menu.
Well they are going to need to play these things back
somehow, but I may have that created separately. What's the average
size of a playback control bar anyway? And how does You Tube get
away with all this stuff?
I am not trying to be cynical, I'm really not, but I am
surprised that this has been raised and addressed by
Macromedia/Adobe already. I would assume that as users develop more
engaging and interactive content, these will become more important.
Is there any hope or support for someone like myself, who wants to
know every shortcut there is in order to deliver the best possible
animations? Is this something that should be brought up with David
directly.
As always, any help from any of the experts here, would be
gratefully received!
Thanks and I look forward to your replies.
Cheers,
spritc.
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