HamMultiPlayer is an interesting media player with some unusual features, in particular an ability to preview and watch multiple videos simultaneously. Other features include audio file support, and the ability to manage media by moving, copying or deleting it.
The program interface is initially confusing with rows of tiny buttons and boxes, and the most important features aren't clearly highlighted. A "getting started" page explains the next steps, though, and they're not difficult: choose your video folder, click Scan > Go and wait for a few seconds (or longer) as the previews are prepared.
Our test copy quickly displayed eight video thumbnails. Each of these has a player bar and works independently, so we could click Play to preview video #1 within its thumbnail, then start #3, #5 and #6 playing at the same time, and freely move around in any of the clips. (If that's too chaotic, double-clicking any thumbnail displays it in a single larger window.)
A separate bar supports operations which apply to every thumbnailed video. You can move the playback position, for instance. Clicking at different points updates the thumbnail for every clip, maybe helping you find one with particular content. There's a Play button to play all videos at once, and you can also tweak playback speed or volume.
You don't have to live with the default thumbnails + preview window + file folder view. Pressing tab steps through other options, maybe playing two videos side-by-side or a single video full-screen (control options are then accessible with a right-click). Other buttons enable a video wall-type display (four videos playing at once) or multi-monitor support.
If you decide you don't need one of the thumbnailed videos, it's easily replaced: just select it, and choose something else in the folder tree.
HamMultiPlayer isn't just about comparing multiple videos. You can also display different parts of the same video in a separate thumbnail, so #1 represents 0-5 minutes, #2 is 5-10, #3 is 10-15 and so on. That also might make it easier to find key scenes and compare them.
The more you explore the program, the more you find. Right-clicking a thumbnail, for example, might give you enough playback options to justify the download all on its own: brightness, contrast, saturation, gamma, hue, blur/ sharpness, denoising, audio sounds, an equaliser, individually customise playback speeds, and more.