release notes des drivers nvidia...
Poor Quality S-Video Output on Some TVs
NVIDIA drivers differentiate an S-video TV from a composite TV by searching
for 75-Ohm loads on the chrominance and luminance lines. If the driver detects
only one such load, it assumes that it has a composite TV and drives both
chroma and luma onto that line. This approach allows both types of TV to
display in color.
Unfortunately, some S-video TVs do not apply the correct load to both lines,
causing the driver to detect an S-video TV as a composite. The driver, in turn,
sends the lower quality signal to the S-video TV. To work around this problem,
use the Control Panel to override the ?Auto-select? feature. This can be done
following these steps:
1 In the Settings tab of the Display Properties Control Panel, click Advanced.
2 In the nView tab, click Device Settings and click Select Output Device.
3 In the Device Selection tab, click the TV option.
4 Change the ?Video output format? to S-video.
c tet de là que ça vient...