Sony HD problem dark video in viewer

i use the sony ACHD1080i format with my sony hd camcorder.

i have noticed a nagging problem, however.

the PMB (picture motion browser) thumbnail stills show the original fidelity (brightness) of the video, but when i open the video using the PMB viewer, the video is at least half as bright (it's very dark) than the original.

I also use sony vegas pro 8.0c (build 260), and that viewer displays the video with original brightness as well.

my guess is that the PMB viewer is using some strange codec. however, i don't know how to correct the problem.

Does anyone know what is happening, or experienced same and have a fix??

from the attached files you can see that:

PMB_thumbs.jpg shows the brightness of the original videos (small thumbnails)

PMB_enlarged_thumbs.jpg shows shows the brightness of the original video (large thumbnail)

PMB_viewer.jpg shows the video is much darker in viewer mode.