iSkysoft iMedia Converter for Mac supports the customized watermark which will add much more fun! Please enjoy:

Click edit menu, you will get video Edit panel.

Choose watermark option by clicking "watermark" bottom:

choose watermark option

then check "Enable Watermak" to enable watermark function:

enable watermark

Add watermark

There are 2 kinds of watermark for you: Image watermark and Text watermark

Image watermark:

1. Check image watermark option to edit image watermark.

2. Click   to specify the image you want to use as watermark.

3. Adjust Transparency, Vertical Margin and Horizontal Margin by dragging the sliders.

4. Resize the height or width by inputting numbers in Image Size area or clicking .

Text watermark

1. Check text watermark option to edit text watermark.

2. Type in the text you attempt to use as watermark in text watermark area.

3. Click   to select the font you like for the text. Click to choose color for the text.

4. Adjust Transparency, Vertical Space and Level Space by dragging the sliders.

Tip: You can check "Apply to All" option to apply the current settings to all the imported files.