9397 750 14325 © Koninklijke Philips Electronics N.V. 2004. All rights reserved.
Product data sheet Rev. 03 — 9 December 2004 9 of 55
Philips Semiconductors
SAA7128H; SAA7129H
Digital video encoder
7.1.1.4 Configuration 4
Only MP
B
input is in use; its signal is both composite (and S-video) and RGB encoded
(RGBIN = ENCIN = 0).
7.1.2 Parameters of the fader
Basically, there are three independent fade factors available, allowing for the equation:
Output = (FADEx × In1) + [(1 − FADEx) × In2]
Where x = 1, 2 or 3.
Factor FADE1 is effective, when a color in the data stream fed to the MPEG port fader
input is recognized as being between KEY1L and KEY1U. That means, the color is not
identified by a single numeric value, but an upper and lower threshold in a 24-bit YUV
color space can be defined. FADE1 = 00h results in 100 % signal at the MPEG port fader
input and 0 % signal at the fader video port input. Variation of 63 steps is possible up to
FADE1 = 3Fh, resulting in 0 % signal at the MPEG port fader input and 100 % signal at
the fader video port input.
Factor FADE2 is effective, when a color in the data stream fed to the MPEG port fader
input is recognized as being between KEY2L and KEY2U. FADE2 is to be seen in
conjunction with a color that is defined by a 24-bit internal Color Look-Up Table (CLUT).
FADE2 = 00h results in 100 % of the internally defined LUT color and 0 % signal at the
fader video port input. Variation of 63 steps is possible up to FADE2 = 3Fh, resulting in
0 % of the internally defined LUT color and 100 % signal at the fader video port input.
Finally, factor FADE3 is effective, when a color in the data stream fed to the MPEG port
fader input is recognized as neither being between KEY1L and KEY1U nor being between
KEY2L and KEY2H. FADE3 = 00h results in 100 % signal at the MPEG port fader input
and 0 % signal at the fader video port input. Variation of 63 steps is possible up to
FADE3 = 3Fh, resulting in 0 % signal at the MPEG port fader input and 100 % signal at
the fader video port input.
Optionally, all upper and lower thresholds can be ignored, enabling to fade signals only
against the LUT color.
If bit CFADM is set HIGH, all data at the MPEG port fader are faded against the LUT color,
if bit CFADV is set HIGH, all data at the video port fader are faded against the LUT color.
Fig 7. Configuration 4
mhb578
ENCODER
PATH
RGB PATH
MP
A
MP
B
e.g. video recorder
e.g. TV
