Why compress my beautiful video?
Even if your complete, master quality clip can fit within your Xprove account’s storage allotment, in most cases it’s not a good idea to upload it in that format. A one-minute, fully rendered DV clip will take up more than 160 MB of disk space. The same clip rendered in 8-bit, uncompressed 601 would consume more than 900 megabytes. Aside from taking a long time to upload (and download), your client’s Mac or PC might not be able to play the clip in real-time.
Compression is a compromise. How much data can you throw out and still have an acceptable image? Only you and your clients know the answer to that, but we can offer some guidelines.
Xprove recommends QuickTime®
Though it’s possible to upload Window Media files (.wmv) to the Clips area of an Xprove project, QuickTime movies perform the most reliably. There are numerous Mac and PC applications that will compress QuickTime files for Xprove, but we’ve found that you can get good results with Apple’s QuickTime Pro. At $29.95, the price is right too. (If you have Final Cut Pro installed on your machine, you already have QuickTime Pro.)
Bandwidth settings
Megabytes, megabits, kilobytes, and kilobits–it can get pretty confusing. In general you want your clip’s bandwidth requirements to fit within your client’s bandwidth capabilities. A typical office accesses the internet via T1, which is 1.5 megabits per second, but few office workers get full T1 performance. Home users with DSL or a cable modem typically have connections ranging from 768 kilobits per second all the way up to 5 megabits per second.
We’ve found for most people 800 kilobits per second yields an acceptable result. The image is of high enough quality for an online approval. In some instances you may want to use more bandwidth (higher quality), in others you’ll opt to use less bandwidth (faster performance).
Compressing with QuickTime Pro®
Step 1
Open your source QuickTime movie in QuickTime Pro.
From theFilemenu, select Export. If you don’t see the Export option, you don’t have QuickTime Pro installed. It can be purchased and downloaded from Apple.
A Save dialog box will open. From the Export pull-down menu, select Movie to QuickTime Movie. (pictured)
Next, click the Options button next to the Export pull down menu.
Step 2
In the Options dialog (pictured), click the Settings button. At the top you will find the Compression Type pull-down menu. This is where you select a codec. We recommend selecting either the H.264 codec or MPEG-4. The H.264 codec yields better results, but takes longer to render. Also, if your client has not yet upgraded to QuickTime 7, you must choose MPEG-4.
For Frame Rate, select Current from the pull-down menu.
Set Key Frames to Automatic.
Restrict the data rate. We suggest selecting a limit from 296 kbits/sec to 512 kbits/sec. The lower data rate creates smaller files, while the higher number produces better picture quality. Most broadband connections can comfortably handle 512 kbits/sec (plus audio), so as long as you have the space in your Xprove account, go for the higher number.
Your next choice is whether to use single-pass or multi-pass encoding. Multi-pass yields better results, but takes considerably longer to encode.
You can ignore the Filters button.
Step 3
Click the Size button. For 4:3 display choose Custom and set width and height to either 320x240 or 480x360. For 16:9 display choose either 320x180 or 480x270.
Step 4
In Audio settings choose AAC with a target bit range of either 96 or 128.
A note on file names
It’s good practice to avoid non-alphanumeric characters other than hyphens and underscores in file names. Different operating systems have different rules about file names. For example Mac OS X forbids colons in file names and Windows forbids slashes. Though not expressly forbidden, it's good form to avoid spaces as well when sending files over the internet.
QuickTime, QuickTime Pro and Final Cut Pro are registered trademarks of Apple Computer, Inc. Xprove is neither affliated with nor sponsored by Apple Computer, Inc. Avid is a registered trademark of Avid Technology, Inc. Xprove is neither affiliated with nor sponsored by Avid Technology, Inc.