Apple DVD Studio Pro 4 - Manual (Page 70)

• Start: Sets the starting timecode of the encoded MPEG stream. This is most often set
to match the timecode of the original video, ensuring that any timecode-based lists
you have, such as a chapter list, marker positioning file, or subtitle file, match the
encoded video.
• Drop Frame: Select this checkbox to use drop frame timecode for assets using the NTSC
frame rate.
• Field Order: Choose the field order (Top or Bottom) that matches the video being
encoded. This is also known as the field dominance setting in other products. Each
interlaced NTSC and PAL video frame is comprised of two fields, each containing every
other video line. The top field is also known as field two, the upper field, or the odd field.
The bottom field is also known as field one, the lower field, or the even field.
If the field order is set incorrectly, any motion in the video will appear very jagged when
played back. Most professional and DV sources are field one dominant, and should use
the Bottom setting. If you are unsure of the field order of your source video, choose
Auto to let the encoder attempt to determine the field order.
Note: The Field Order setting does not apply to progressive scan video.
• Mode: You can choose from three encoding modes, each with its own advantages and
disadvantages.
See MPEG Encoding Methods for more information on the encoding methods.
• One Pass: With this option chosen, the encoder uses a one-pass encoding method
with a constant bit rate (CBR). Note that the integrated MPEG encoder One Pass
mode actually varies the bit rate a small amount.
• One Pass VBR: With this option chosen, the encoder uses the one-pass variable bit
rate (VBR) encoding method.
• Two Pass VBR: With this option chosen, the encoder uses the two-pass VBR encoding
method (one pass to create a motion profile of the video and a second pass to perform
the encode).
• Bit Rate: Set the bit rate for the One Pass encoding method and the basic bit rate for
the One Pass VBR and Two Pass VBR encoding methods. When using one of the VBR
encoding methods, you cannot set Bit Rate any higher than 85% of the Max Bit Rate
setting. See
Choosing a Bit Rate for SD Projects for more information.
• Max Bit Rate: Set the maximum bit rate that can be used during a One Pass VBR or Two
Pass VBR encode. You cannot set the Max Bit Rate setting lower than the Bit Rate setting
or 5 Mbps (whichever is higher). Because the VBR methods are most effective when
the maximum bit rate is about double the basic bit rate, or at least 1 to 3 Mbps higher
than the basic bit rate, the Max Bit Rate setting is forced to be higher than the Bit Rate
setting.
Note: The Max Bit Rate setting does not affect the size of the encoded file—it only sets
the upper limit that can be used during the encode.
70 Chapter 4 Preparing Video Assets