Appendix A: Tips for Reducing Your File Size | Camtasia Studio 4: The Definitive Guide (Wordware Applications Library)

Despite your best efforts to produce high-quality video with a small footprint, there are a number of factors that can bloat the size of your video files. This can be particularly frustrating if your final output destination is the web, where low bandwidth requirements are the key to success. In this book, I have outlined a number of tips for keeping your file sizes manageable. For your convenience, here they all are in one location.

Keep Your Dimensions Small

It’s just common sense. Making a full-screen recording will consume a lot more file space than would recording a small window. In addition, smaller files are easier for the user to play back because you don’t have to worry about a user’s screen resolution being smaller than the dimensions of your video. Everyone has their own favorite recording dimensions. Mine are 688 x 520, because even users with a maximum screen resolution of 800 x 600 can view your video with space left over for their task bar and the video controls. If the application you’re recording absolutely requires a full-screen recording, try reducing your own screen resolution to 800 x 600.

Globally changing your screen resolution can be accomplished thusly:

Choose Start > Control Panel. (In Windows 2000, it’s Start, then Settings, then Control Panel.)
Double-click the Display icon. The Display Properties dialog opens.
Click the Settings tab.
Drag the Screen Resolution slider to the left, until it reads 800 x 600.
To save your settings, click OK, then Yes (or OK in Windows 2000).

Monitor Your Content

Most problems with file size stem from recording content that is inappropriate for the codec selected. Either choose a more appropriate codec for your content, or edit out the content that your chosen codec doesn’t like.

For example, when using the TechSmith Screen Capture Codec (TSCC), you should take care to avoid the following:

Real-world video
Animated sequences
Color gradients
Lots of fade effects
Lots of screen transitions (some carry a higher file size penalty than others, so feel free to experiment)
Superfluous zooming and panning

Several of these tips apply to other codecs as well, particularly in regard to movement. Most codecs have ways of efficiently compressing content that doesn’t move around a lot, so keep in mind that dragging large windows around, having lots of scene changes (cuts), and zooming and panning all over the place are likely to show up in your file size no matter what codec you’re using. Remember that Camtasia Studio gives you convenient check boxes at production time that let you automatically disable callout fade effects and use instant zooming and panning, so if you have these elements in your production and are unhappy with the file size, reproducing your video with these boxes checked can be an effective quick fix.

Check Your Audio

Have you added voice narration to your video? Many people don’t realize this, but your audio track can comprise as much as 90% of your overall file size, depending on your compression settings. While I try to keep my audio very high quality for video on CD-ROM, there are some compromises to be made when bringing your stuff to the web. Try to compress that audio using codecs like MP3 LAME and µ-Law as well as experimenting with different attributes to see what works for you. One thing I can’t stress enough: Encode your audio in monaural format! You only have one mouth, right? Choosing stereo is a classic rookie mistake, and doubles the file size of your audio with zero increase in quality. So keep it mono.

One final tip regarding audio: If you’re adding audio narration, do try to keep your track as succinct as possible, editing out all the internal pauses. Unlike video, where long pauses don’t really add much to the file size (provided nothing is changing on the screen), silence in your audio track produces just as much data as the spoken word. Sometimes I look back on some of my earlier work and cringe, thinking, “I could drive a truck through some of the pauses I left in there!” Don’t let this happen to you.

Reduce Color Depth

Depending on the codec, you can also save some file space by reducing the number of colors displayed on your screen. I generally like Medium (16-bit); the visual difference between this and 32-bit color depth is nearly imperceptible. Not so with 8-bit color depth (256 colors), so I’d be careful if reducing the color depth this much.

To change your color depth, do the following:

Choose Start > Control Panel. (In Windows 2000, choose Start, then Settings, then Control Panel.)
Double-click the Display icon. The Display Properties dialog opens.
Click the Settings tab.
Choose a color depth from the Color Quality (or Colors) drop-down list.
To save your settings, click OK, then Yes (or OK in Windows 2000).

Break up Your Video into Smaller Chunks

Fortunately, the pop song adage “breaking up is hard to do” doesn’t really apply to Camtasia Studio. Bring your overly large video into Camtasia Studio, add a few markers at the topic transition points, and you can quickly produce a series of videos rather than just one. Yes, technically, the bandwidth savings are an illusion. The users still have to download the same amount; they’re just doing it in smaller chunks. True enough. But users will be able to start viewing content much more quickly, as the load time is now split across several videos, thus keeping the frustration level in check.

Try a Different File Format

When producing your videos, if you’re not getting the kind of results you expect, it might just be that you’re producing into a file format that isn’t appropriate for your video’s intended purpose. Remember, AVI files work best for CD-ROM, and SWF files work better for the web. WMV files are ideal for real-world video and game captures, while animated GIFs are good for small screen videos that are only a few seconds in length. All file formats have their individual strengths and weaknesses, which are all discussed in detail in Chapter 12, “The Production Process.” Matching the content and distribution method with the appropriate file output can have a profound effect on file size, so do your homework before picking an output format.

Try a Different Compression Scheme

And on a related note, even if you’re married to a particular file format, there’s still a lot you can do to get that file size down by simply playing with the compression settings. Producing to SWF? Try using JPEG compression. Going to AVI? Perhaps the content demands a codec that’s more tolerant of high-motion video, such as DivX. If you’re doing a lot of transitions and PIP sequences, you’ll need to become very acquainted with the various “high-motion” compression options: Flash videos should be FLV, QuickTime should be compressed with H.264, etc. Lossy compression algorithms work much better in these circumstances.

Reduce the Duration of Your Preload Movie

When producing to the web, you have the option of setting how much of the main video you want to preload before it begins. If you have a longer video (hence with more time to load the rest of the video while playing), you can set this to 10% or even less. While this does not actually lower the file size, it will feel like it to your audience, who will be spending less time watching the loading screen and more time enjoying your excellent video. However, do keep in mind that this technique does not work with shorter, graphically intense content, because there’s a lot to load and not a lot of time to do it. In this case, you’ll want to set the preload percentage high, say 50%. Otherwise, the video might pause midway through to finish loading, which as you can imagine is quite aggravating to the user.