New Tools for the Digital Video Handyman

Creating high-quality multimedia video still takes more than just pushing a button, but a series of new tools, and some updates to old favorites, is making life for the digital video producer much easier.

Compressing video for playback from CD-ROM has always been a bit of a black art. You have to juggle the competing issues of the limited rate at which data can be read from a CD-ROM and the consumer's demand for larger images, higher frame rates, and better sound. Very good results can be obtained using the current generation of software codecs--and codecs keep getting better--but the poor quality of the tools has meant that there was a very long learning curve to reach the point where one could consistently create high-quality CD-ROM video.

As an example of the problem, one of the most commonly used tools for QuickTime movie compression on the Mac has been MovieShop, a good program in its day, but one that has an intimidating user interface and no support or updates in several years. Despite the fact that it crashes a lot on current systems, folks stick with it because it does the job. Well, MovieShop is finally getting some competition!

Terran Interactive (408 278-9065, http://www.terran-int.com/) has released MovieCleaner Pro, a great tool for doing final compression of QuickTime movies. It is not an editing application like Adobe Premiere, but is instead used to take the output from Premiere, AfterEffects, or similar programs and create a final, CD-ready movie file.

MovieCleaner Pro does the mandatory tasks of creating movies with a limited data rate, but also handles re-sizing of movies, resampling of audio, and a unique feature called the "talking head filter." This filter allows you to give special handling to images that are shot with a locked-down camera, where the image throughout the movie is of a static background with a central talking head. By telling MC Pro what areas are the background, and hence do not change, it keeps those areas constant throughout the movie, greatly reducing both the bandwidth needed to play the movie and the "sparkle" effect often scene in static areas when the Cinepak codec is used.

If you are tired of feeding your current compression program one file at a time, and long to do your lengthy Cinepak compressions overnight, you'll be glad to know that MC Pro also has a batch mode allowing for long, unattended compression sessions. Best of all, it allows you to interrupt and resume batch compression!

MC Pro also has "noise reduction" filters that apply blurring to each frame before compression. By reducing video noise, this can reduce the needed data rate and reduce the "sparkles."

To ease the task of compression, MC Pro offers two levels of user interface. In the "simple" mode, you are presented with a series of questions (1x or 2x CD-ROM, codec, etc.) that walk you through the process of optimizing the compression settings. In "expert" mode, you have complete control over the settings, but even then the "Movie Expert" in the program will offer helpful advice if it doesn't think you are making a wise choice. Of course the final decision is yours.

Version 1.1 of MC Pro is currently shipping. By the time you read this, version 1.2 should be available which adds better cropping tools, more noise reduction filters, better video scaling and audio resampling, gamma correction, and IMA 4:1 audio compression support. You can sample the features of Pro version in a special MovieCleaner Lite available from Terran Interactive's web site, CompuServe's MacMedia Forum, and other on-line sources.

Version 4.2 of Adobe Premiere has also added new compression controls aimed at producing CD-ROM compatible movies. It offers batch compression and much more control over compression parameters than the standard "Make Movie" command in Premiere. Upgrading to 4.2 is free for current Premiere customers, so it is well worth checking out.

In addition to video compression, producing good CD-ROM movies requires care on the audio side. While we would all like 44.1 KHz, 16-bit CD-quality sound, it simply uses too much of the available bandwidth to be practical except in special cases. There are two ways to deal with this problem: reducing the sample rate and sample size, or using data compression as we do with the video.

The problem with reducing the sample rate and size is that the sound quality is very quickly degraded, particularly if a naive method is used to do the reduction. To go from 16-bit samples to 8-bit, or from 44.1 KHz to 22.05 KHz sample rate is far more complicated than simply lopping off the lower 8 bits, or taking every other sample. The good news is that affordable tools are now available to do the job right.

Macromedia (415 252-2000, http://www.macromedia.com/) has recently upgraded SoundEdit 16 to version 2.0. This new version has much improved sample reduction capabilities. Whereas earlier versions were pretty crude in their methods, version 2.0 produces audibly better results. In addition, SoundEdit 16 now supports IMA 4:1 audio compression.

IMA 4:1 audio compression was added to QuickTime back in version 2.0, but has not been well supported in audio tools until recently. Using the same algorithm as, but otherwise incompatible with, the ADPCM compression in WAV files, IMA compression allows you to fit 16-bit, 22 KHz audio in the same space, and at the same data rate, as 8-bit 11 KHz sound. As with all audio compression, there can be some audible artifacts, but for most audio, the results are quite good.

There are two things to be careful of, though. First, IMA compression requires 16-bit audio samples, so if your source material is 8-bit, it will convert it to 16-bit, but with no gain in compression. Secondly, the decompression process requires additional CPU cycles when the audio is played back, so if playing your movies is marginal on slower systems, adding the audio decompression burden may cause you to drop some frames.

For resampling audio it is hard to beat the tools produced by Waves (615 588-9307, http://www.waves.com/). Their tools were originally available only to owners of Digitools and other high-end audio systems, but they have recently been making them available as plug-ins for Premiere and other programs. My favorite tool, however, is WaveConvert, a stand-alone program which does audio resampling. Period. And a very nice job it does.

By keeping full arithmetic precision throughout the resampling process, and paying careful attention to dithering and noise shaping, WaveConvert can produce stunning results with only 8 bits and at low sample rates. It will also normalize your audio levels for you, and can boost overall gain and high-frequencies, useful tricks for keeping your audio above the noise inherent in 8-bit samples.

My only complaint is that it does not accept QuickTime audio directly, but requires you to export the audio to AIFF or SDII format first. And support for IMA 4:1 compression directly from WaveConvert would be nice. Maybe next version?

In a somewhat unusual move, when you purchase WaveConvert you get both the Mac and Windows versions in the same package.

For those who have struggled to create quality digital video for multimedia applications, using some incredible primitive tools, it is great to see software developers recognizing that there is a viable, hungry market for dedicated production tools.

MovieCleaner Pro offers a two-level user interface. The "expert" mode allows complete control over the settings and offers helpful advice.

Bob Currier is President of Synthetic Aperture, a multimedia production company specializing in digital video and QuickTime VR. He also serves as Sysop of the Macintosh Multimedia Forum on CompuServe.

He can be reached at rcurrier@synthetic-ap.com. Be sure to visit the Synthetic Aperture web site at <http://www.synthetic-ap.com/> for more tutorial information, sample content, and information on new media services.

This article orignally appeared in a slightly different form in Computer Video Production magazine.