Matrox Electronic Systems M.Key/100 - Manual (Page 18)

10
Using Matrox M.Key/100 with VFW programs
Configuring the Matrox MPEG-2 I-frame codecs
When you click your program’s
Configure button to configure a Matrox
MPEG-2 I-frame codec (SD or HD resolution, with or without alpha), a dialog
box similar to the following appears:
1 Drag the Data Rate slider until your desired data rate is displayed. The
higher the data rate you select, the better the video quality will be.
Depending on the capabilities of your system, however, you may not be able
to smoothly play back video at a high quality using your Video for Windows
program.
2 Beside Frame Rate , select a frame rate from the list. Make sure the frame
rate you select is appropriate for the format to which you are rendering.
¦ Note The Frame Rate setting is not available if you’re rendering to
MPEG-2 I-frame SD format without alpha.
3 To apply advanced settings to your MPEG-2 I-frame file, click the
Advanced button.
¦ Note The Advanced button is not available if you’re rendering to MPEG-2
I-frame SD format without alpha. The default advanced settings should
provide good results for most applications. We recommend that you change
these settings only when needed for special purposes.
4 Beside DC Precision , select the bit-depth precision of the DC intra block.
The higher the DC precision value that’s used to render your video, the more
likely that the DC content will be increased at the expense of the AC content
in the encoded stream. This may result in lowering the overall quality of the
compressed stream at a specified data rate.
5 Under Zig Zag Order , select one of the following:
$
Regular Sets the regular (default) zig zag scanning pattern of the AC
coefficient of the DCT block as defined in the ISO/IEC 13818-2
(figure 7-2) specification documentation.