This is a quick guide to get you started with experimenting and using the advanced export mode of
iMovie, for both iMovie 08 and previous versions. This allows you to better customize the result
for your particular needs.
Why would you want to use this option? Well, here are a few reasons:
You are only allowed a 100MB file to YouTube. Customizing your settings, you will be able
to reduce the size of the file to under that 100MB limit.
Email applications often limit how large an email you can send. You maybe able to reduce the video
to an acceptable size that will allow you to send that video to a friend.
Well placing video on your website, you realize the bandwidth requirements of a full size DV
video is unacceptable from a download time bases for your viewers and the cost of payment
to support it. You could keep the image size the same, but reduce other factors to considerably
reduce the size of the file while still making a very presentable video.
You may want to set the video to a different codec (file) type, say for export for another
editor.
Our target will be a special window that allows us to choose many options, such as image codec,
size, data bit rate, quality, and audio options too. By altering these options, we can adjust
the tradeoffs for the end quality of your movie. I'm only mentioning the more commonly used options as this
is only an introduction guide. It is up to you to dig deeper and experiment.
iMovie 08 is a little different from previous versions. First the export options only appear
under the "Share" menu. Only the first two export options are of interest for this guide.
The first, "Export Movie...", allows for limited fixed options, as seen the large window below.
The option we are interested in is the "Export using QuickTime..." item, so select that one.
iMovie HD has two export options we are interested in that are under different menus and have different names.
As it turns out, that does not matter as all of the export options lead to the same window to which
we choose our next option.
This is the window that will lead us to our customization destination. Note the popup option labeled
"Compress movie for:". You need to select "Expert Settings" and then click the "Share" button.
I've displayed the window here twice to give you a better idea of what I am talking about.
This is the start of your intended destination where you are allowed to set the result to your desire.
This window also appears from some other applications.
For the "Export:" popup selection, choose "Movie to QuickTime Movie" and then click
on the "Options" button. The following window appears.
The options of most interest in this window are the video "Settings..." and "Size..." buttons.
The sound settings have similar options for customization.
The settings allow you to set the frame rate and data rate which most affects the size of your
output file. I often leave the frame rate at the current setting of the movie I am editing.
Usually 29.97 because to my eye that seems to be the smoothest image. The data rate affects
the quality of the image along with the compressor quality options and the encoding option.
As you can imagine, reducing the number of frames will reduce the file size.
The cost of that choice is that you may not find the result acceptable because the look
of the video may not be smooth enough given your content.
Keyframes are a little tricky to explain. The basics of it is that between each keyframe
of a video, only partial information exists for each image frame. Each key frame is an
entire content of what the editor contains. By increasing the frequency of the keyframes,
you allow the encoder to have better information to construct the frames in between.
The cost is a larger file.
You might think that choosing "All" for "Key Frames" would be a great idea.
That has worked out for the better once, but another time I found the video quality to be
very pixelated. I think this setting is yet another balance you have to determine by experimentation.
Data rate allows you to use more bits for each image there by allowing for a cleaner
looking result. The higher you make the number, the large the file will be, but the better
the quality. I'm not sure what effect the "Optimized For:" setting has, although in one
very small 18 second file it added just under 36,000 bytes (35K) to the file size.
The "Compressor" settings seem self explanatory to me. The thing to note is that multi-pass
causes the encoder to take much longer to create your file. The result may not always look
like it is worth it, but I use it for my final pass to extract every bit of quality I can
from my video.
The "Preview" insert window is helpful to see how your settings may affect the image quality.
The thing is I only noticed changes to the preview when choosing different options from the
"Compression Type:" popup at that top of the window. So it seems it is not useful when you
have predetermined that setting, such as H.264.
Also dark images like the sample probably won't be of much help.
The size setting also allows you to reduce the file size by reducing the image size. My favorite
size over the past few years has been 480x360 because it is large enough for my audience but
not too small, and the file size is reduced significantly from the 640x480 common size. Note that
the popup "Dimensions:" option has many presets, but not the one I prefer.
If you are exporting for use on sites such as YouTube, you should follow that sites recommendations.
If you are exporting a video not intended to be displayed on television,
then I suggest selecting "Deinterlace Source Video" if you are editing an
interlaced source such as DV from a video camera.
Finally I hit the "OK" button several times until I return the export destination window where I click
the "Save" button.
While rendering the video to your output file, the status of how long the process will take
and approximately how far along it is will be displayed.
Your movie is now available for your use. You may want to play with the options to create
several versions of your movie. By doing that, you can make a judgement call on which version
best suites your needs.
NOTES:
Javascript must be turned on to use this guide.
This may not be viewable using non-standards compliant browsers (eg. Microsoft IE).
