User Guide

42 Chapter 4, Preparing Assets
Preparing Video Assets
After the number and format of audio tracks is known, it is possible to determine how much
bandwidth is left for video (see “The Bit Budget” on page 53). Depending on the length of
the video material and the capacity of the disc (for example, 4.7 GB for a single-side single-
layer disc), the video bit rate is generally set as high as possible without exceeding the
remaining available bandwidth.
The DVD-Video format uses a subset of the MPEG standards, requiring specific image
resolutions, frame rates, aspect ratios, and other parameters. Scenarist only lets you import
DVD-compliant MPEG files, so when you encode video, you must make sure that you set the
parameters correctly. Table 2 lists the encoding requirements for the supported video
formats.
The DVD Specification requires that video content within a single volume be set to the same
parameters for the following options:
• Format (MPEG-1 or MPEG-2)
• TV system (NTSC or PAL)
• Aspect ratio (4:3 Standard or 16:9 Widescreen)
• Frame size (352 x 240 or 720 x 480 for NTSC; 352 x 288 or 720 x 576 for PAL)
Table 2: Scenarist video stream requirements
Format Frame
Rate
Frame
Size
Aspect
Ratio
Encoding Bit Rate GOP Size
MPEG-1 NTSC
(525/6)
29.97 fps 352 x 240 4:3 1.856 Mbps max. 18 frames max.
PAL
(625/50)
25 fps 352 x 288 4:3 1.856 Mbps max. 15 frames max.
MPEG-2 NTSC
(525/60)
29.97 fps 720 x 480 4:3,16:9 9.80 Mbps max. 36 fields/
18 frames max.
PAL
(625/50)
25 fps 720 x 576 4:3,16:9 9.80 Mbps max. 30 fields/
15 frames max.