Apple Compressor (4.0) User Manual
Page 87
Chapter 5
Custom settings and output formats
87
7
If you want to use the timecode from your source video, leave the “Choose start timecode”
checkbox unselected.
Otherwise, select this checkbox and enter a new timecode value.
8
If you selected the “Choose start timecode” checkbox, and your video format is NTSC, select the
“Drop frame” checkbox if you want to use drop frame (rather than non-drop frame) timecode.
Stage 2: Open the Quality tab and choose quality settings
In the Quality tab, you set the MPEG-2 encoding attributes that have the greatest influence on
the resulting quality of your MPEG-2 video output file: encoding mode, average and maximum
bit rate, and type of motion estimation.
1
To open the Quality tab, click the Quality button in the MPEG-2 Encoder pane of the Inspector.
Choose bit rates that
fit your file size and
quality requirements.
Choose a mode that
fits your time and
quality requirements.
Choose a Motion
Estimation setting.
2
Make a selection from the Mode pop-up menu.
For best image quality, choose “One pass VBR Best” or “Two pass VBR Best.” For faster encoding
with excellent image quality, choose “One pass VBR” or “Two pass VBR.” For HD sources, choose
either “One pass VBR Best” or “Two pass VBR Best.”
With two-pass modes, the source media file is examined on the first pass and transcoded
on the second pass, with bit rates tailored to the video content. In contrast, one-pass modes
transcode the material more quickly, but allocate bits less optimally than do the corresponding
two-pass modes.
3
Choose an average bit rate using the Average Bit Rate slider or field, or click the Automatic button.
Note: Your choice of bit rate may be influenced by several factors, including the complexity of
your source video, the format and number of your audio streams, and the total duration of all
video clips to fit on your DVD.
Choose an appropriate bit rate based on the content and length of your source video and the
intended size (in bytes) of your output file. In DVD authoring, the entire video must fit on the
DVD disc—the lower the bit rate, the more data you can store. However, the higher the bit rate,
the better the image quality is.
As you change the Average Bit Rate value (with the slider or the field), the bit rate calculator
at the bottom of the Quality tab dynamically shows the maximum number of minutes of
video on a DVD-5 disc. The calculator assumes 1.5 Mbps for audio (two-channel AIFF). For more
information, see
on page 97.