User`s guide

54 Creating DTV Clips
Creating DTV Clips
Before Making Your Own Clips
Creating your own DTV clips is not a simple task. If you do not possess the
equipment, time, or experience to do so, we highly suggest you outsource this
work to a post-production facility. For a list of post-production companies that
have experience encoding material specifically for the DVMHD, please visit our
website or contact an Alcorn McBride representative.
What is DTV?
The Digital Television (DTV) standard was created to replace the current analog
television standards with a suite of high and standard definition formats based
on new digital transmission, imaging and display technologies. The DVMHD
has been designed as a next-generation, dedicated playback device for the DTV
standard and beyond.
Unlike current analog video standards (which transmit position information for
an electron gun to create an image on the screen), DTV utilizes the MPEG-2
standard to digitize and compress the original image into a digital bitstream that
can be stored, transmitted, decoded, and displayed. Despite this fundamental
technological shift, the primary communication tools of television (audio and
video) remain, with the added benefits of film-like pictures and digital surround
sound, essentially the same.
Video Formats
Rather than define a single image format, like the old analog TV specification,
the ATSC developed a suite of formats that encompass both “High Definition”
(HDTV), and “Standard Definition” (SDTV). These formats allow content
providers to choose the format that best fits the program material. For example,
a “movie of the week” might best be displayed in the 16x9 aspect ratio at 24fps,
progressively scanned – close to the original film format. Alternatively, a
situation comedy might be filmed and displayed in the 4x3 aspect ratio, yet at a
higher frame rate.
This freedom of choice among video formats extends its benefits to dedicated
playback venues, as well. Show producers can now choose the display format
that is most appropriate for their presentation, rather than compromising artistic
integrity to accommodate video display technology.
The formats supported in the DTV standard are grouped according to picture
size and aspect ratio. There are four standard picture sizes (1920x1080,
1280x720, 704x480, and 640x480). These sizes combine with over six different
frame rates and two scan methods (Interlaced and Progressive) to provide over
twenty different formats.