If you don't change the default 16-235 brightness levels from DV format video into 0-255 levels for MPEG2, the final result will look washed-out on your PC or DVD player. This could be done automatically, but manual adjustment gives you the opportunity to find the exact setting which makes your own video look the best. Of course you can also "break the rules" to achieve some special effect, if you like.

First, launch TMPGEnc and select some video to encode. Now, note there is a button in the lower right-hand corner labelled "Setting". Click that, which brings up the MPEG Setting window with six tabs along the top: Video, Advanced, GOP structure, Quantize matrix, Audio, and System. Click on "Advanced" which gives you the choice of many filters you can apply.

Click on the checkbox next to "Custom color correction" to enable it. Then double-click on the phrase "Custom color correction" itself, to bring up the settings dialog for that filter. There, click on the "Add" button at lower left which gives you the "RGB Brightness" type. You can use that but I prefer another one: in the "Type" pull-down menu click on the down arrow and select "Basic setting". Now you'll have five sliders for Brightness, Contrast, Gamma, and Red and Blue shifts. On the right, click on "Enable Filter" and "Show Histogram". A separate window will apear showing the pixel histograms for this video frame. There are two "Color" selections: chose the YCbCr button rather than RGB. Now, as you move the cue slider in the main correction window to scan through your video, the histogram window will show you the levels for each frame. Most important is the top graph (Y, or video intensity level). Standard DV levels (16-235 instead of 0-255) will not occupy the full width of the window.

For optimal MPEG2 encoding you want to adjust the filter's brightness and contrast sliders so the intensity histogram just fills the whole width (but not too much, which would clip whites or crush blacks). However you want to scan through your whole video and find the "extreme" dark and light scenes. If you adjust contrast based only on a low-contrast scene, you'll have bad looking video where the original was more dark, or bright. There is some judgement involved and this is one reason they pay the big bucks to "color shaders" in professional production.