Craft and Psychology
When it comes to outputting our finely crafted images to DVD, today's shooter faces enormous opportunity and risk. Increasingly sophisticated tools like Apple DVD Studio Pro 3 and Compressor provide substantial capabilities in authoring and encoding, but only if we exploit these tools appropriately.
Owing to the DVD format's relative high compression, we must be concerned with not only basic parameters like bit rate and encoding mode, but also how our images are ultimately decompressed and appreciated (or not) by our audiences. This means that the enterprising DV and HDV shooter must understand the idiosyncrasies and psychology of the DVD format. Here are some considerations to bear in mind when using Apple's Compressor.
Minding Our Image: Maintaining the integrity of our images means managing the DVD juggernaut on several fronts beyond the obvious considerations of bit rate and encode mode. Some level of noise reduction is also usually necessary because single-pixel artifacts seriously degrade the quality of any encoded file. Pro shooters know that an effective strategy of noise reduction is usually required in order to identify such extraneous data in the incoming video stream, and then eliminate it prior to compression.
Shooter Beware: Compared to other low-cost transcoders, Compressor's output may appear soft to some shooters, as a gentle blur is applied to the frame to ease an image's hard transitions. The strategy eliminates most egregious artifacts but at a price — a concomitant loss of contrast and sharpness.
The preferred solution for shooters is appropriate camera diffusion in the first place to help forestall (as much as possible) such undesired softness in the transcoder. For most DV and HDV cameras, a 1/2 Tiffen SoftFX or Black Diffusion FX filter will tastefully do the trick. This level of image control at the point of original capture is key in an era when DVD is the primary output vehicle. Indeed, Apple Compressor's performance noticeably improves when adequate diffusion on-camera is used because the transcoder's need for dramatic error correction is alleviated and critical frame blending is enhanced.
Noise Reduction: When utilizing noise reduction inside Compressor, be particularly mindful of high-detail scenes. In a recent case, when compressing a night scene, Compressor all but eliminated the blanket of stars from the clear night sky! Obviously, shooters must use common sense because encoding is a craft like any other. There are no rules that can be applied unthinkingly to every situation.
Whether the degree of softening and loss of detail is acceptable, only you the shooter can decide. For A-list directors and feature filmmakers, a more sophisticated MPEG-2 encoding tool will almost certainly be demanded. For almost everyone else in the corporate and non-theatrical worlds, a general-purpose encoding tool like Compressor may suffice, especially at moderate to high bit rates.
The Workflow Factor: In this time of digital gone mad, an efficient workflow is critical for shooters to meet both tight deadlines and high visual standards. If you are a Mac/Apple user, Compressor's tight integration with Final Cut Pro HD and DVD Studio Pro 3 makes it a convenient choice and also underscores the need to understand and fully exploit the tool's considerable capabilities.
Going 24p: For shooters, a major virtue of Apple's Production Suite as a whole is the all-24p workflow. We can shoot 24p, capture into FCP and edit at 24p, then output via Compressor at 24p — all without ever encountering the horrors of NTSC aliasing artifacts. Because every DVD player by design is 24p native, you are in effect exploiting one of the format's great strengths.
Avoiding Flicker in your Encoded File: When utilizing Compressor (whether as a free-standing application or in the background of DVD Studio Pro), shooters must be careful to avoid a field-dominance flip-flop that could produce an objectionable flicker onscreen. Original camera footage is invariably lower-field dominant, so this setting should be diligently maintained at every stage in the workflow, from capture in the NLE through export to the MPEG-2 transcoding tool.
One trend I don't particularly like is the annoying “automatic” settings popping up like weeds in “professional” software. Inasmuch as automatic field detection algorithms have been known to occasionally fail, the true professional should be sure to manually set Field Dominance in the Compressor Encoder settings.
Consider an Open GOP: Compressor offers shooters the ability to encode to DVD-compliant MPEG-2 streams with an Open or Closed GOP. In an Open GOP, one “group of pictures” looks ahead to the next group of pictures resulting in potentially better looking encodes, especially at low bit rates. In a Closed GOP, because each group of pictures is self-contained, navigation into and out of the encoded stream is facilitated and is therefore the safest and best choice to ensure smooth playback on most players. Nevertheless, shooters compelled to encode at around 3Mbps to 4Mbps may want to use an Open GOP if chapter entry point access is not anticipated, as in the case of most shooters' demo reels.
Shoot 16:9: The advent of DVD and DVD-recordable media has radically transformed how audiences see and appreciate our work. Even without the increased resolution of HD-DVD, shooters can still take ample advantage of today's standard by taking simple steps to improve perception of their DVD images.
Recent studies conducted for a digital cinema advocacy group suggest, for example, that shooting 16:9 alone may substantially improve viewers' perception of image quality. Call it widescreen, the Phi Factor, or the Golden Rectangle, but audiences are wild about the horizontal form. Shooting 16:9 makes sense — a more modern look, easier upconversion to future HD, and as illogical as it may seem, better-perceived images. The Compressor/DVD Studio Pro 3 workflow smoothly supports 16:9, and you should take advantage of it now.
Consider DTS: As shooters, it may seem paradoxical that audio quality impacts the perceived professionalism of our images on DVD. But it certainly does, based on multiple studies. In fact, improving audio quality presentation is the single best thing you can do to improve the look of your DVD. One way to accomplish this is to use vastly superior DTS audio. Thankfully, DTS (Digital Theatre Sound) is supported now in the latest version of DVD Studio Pro 3.
Industry-standard Dolby AC-3 has been around for decades, and while its efficiency is still impressive, the codec's performance is now considered mediocre, especially when compared to the audio quality commonly found in cinemas and music CDs.
DTS, usually configured in six-channel surround, is the clear alternative to Dolby AC-3. But at a rate of 1.6Mbps (as opposed to .448 Mbps for Dolby 5.1), DTS must be carefully considered in light of a DVD's overall bit budget. For the shooter, it is essential that the increased bandwidth required for DTS does not deleteriously impact the video encoding. Obviously this is a balancing act.
In general, for demo reels and other short-program DVDs, the slight tradeoff for improved audio is worth it. DTS audio is simply that much better.
With the ongoing evolution of DVD Studio Pro, the authoring tool's capabilities continue to expand. In version 3.0.2, support for double-layer burners enables for the first time accurate proofing from disc of DVD-9 projects. The graphical view (see figure 8) greatly facilitates layout and creation of a smooth and efficient navigational flow. Indeed, the overall workflow of DVD Studio Pro, which was already quite intuitive, is now even more so.
As professional shooters, our expertise as image creators no longer stops with the camera. As more of us have discovered, we need to be concerned now with the entire postproduction workflow, from image capture through preparation of the DVD. Truth is, the integrity of our images can be compromised at many points in the process, and so it is in our interest to assert our sensibilities and expertise at every stage.
For shooters, DVD offers enormous promise along with considerable peril. A master's control of DVD Studio Pro 3 with its many advanced features can help keep those perils in check.
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