About the MPEG-1 Video Tab
You use the Video tab to make settings related to the video format.
The Automatic button
• Enabled checkbox: Make sure this checkbox is selected if you want the MPEG-1 output
format to include the Video tab settings.
• Frame Rate pop-up menu: Choose the frame rate of the video you are encoding.
• With Purpose set to Web: The choices are 23.976, 25 (PAL frame rate), 29.97 (NTSC
frame rate), and Automatic.
• With Purpose set to DVD: The choices are 25 (PAL frame rate), 29.97 (NTSC frame rate),
and Automatic.
• Automatic button: Clicking the Automatic button forces the encoder to determine the
proper frame rate by choosing the rate that most closely matches the source frame
rate.
Note: Using the Automatic setting with nonstandard source frame rates may result in
output frame rates that do not match the intended video frame rate. For example, a
source frame rate of 15 fps with the Purpose set to DVD results in an automatic selection
of 25 (PAL). If you are intending to use the output on an NTSC DVD, you must choose
29.97 as the frame rate.
• Purpose buttons: Choose the intended purpose for the output files.
• Web: Forces the resolution to 320 x 240 regardless of the Frame Rate selection.
• DVD: Allows the Frame Rate selection to set the resolution. With the 29.97 frame
rate, the resolution is 352 x 240. With the 25 frame rate, the resolution is 352 x 288.
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Chapter 17
Creating MPEG-1 Output Files
• Bit Rate: Use this slider to choose the bit rate to use for the output video, or enter a
number directly in the text field. While the available range is from 0.5 Mbps to 2.0 Mbps,
the actual setting you should use depends on how the output is to be used. Higher bit
rates produce better picture quality, but they also produce larger output files.
• For web projects: Choose a bit rate that best balances the picture quality with file size
and download expectations.
• For VCD projects: The recommended video bit rate is 1.15 Mbps, with a system stream
(multiplexed video and audio in the same file) bit rate of under 1.3944 Mbps.
• For DVD projects: The typical video bit rate is 1.15 Mbps, with 1.856 Mbps being the
maximum allowed.