The straight forward answer to this question is that you cannot do that, you cannot just do that if you have an electronic splitter of video or audio that receives a single signal and then splits it into two to make two identical signal and then sends it through on two different monitors, so in that case if you are going to connect your laptop or computer with AV output you are going to get two identical signals, so this results in two displays but duplication in that case.
But if you have HDMI splitter that does this job if you mean to extend desktop, so if it is for watching a video purpose, what you can do is your DVI to HDMI laptop cable will go to your monitor, and those both devices should be connected to your Single DVI port using the HDMI splitter, both devices may have different resolutions, and they both can use different frequencies to run.
HDMI to 2 Dual Monitors
Another important to note down here is that how many display monitors you can transfer your frequency to depends upon your display card too, for example if your video card can support to 2K resolution which means that you can transfer signal to two different monitors with 1080p resolutions, and if your video card can support about 4k resolution then you can run 2k on two separate display monitors or 4 different display monitors containing 1080p resolution, so you should keep that in mind that video card does play an important role after HDMI splitter.
There are some video processors that can do the job for you, and some latest models of laptops can provide you with different display monitors support that would be up to 3 to 4 with single HDMI port.