Very short videos are having their moment. Twitter's Vine smartphone app, which shoots and posts clips of up to 6 seconds, has been a hit. And Instagram, the wildly popular photo-sharing app owned by Facebook, recently added shared video clips, which can last 15 seconds.

These clips are infinitely less work than traditional digital videos, which often take hours to edit in programs like iMovie and run 15 or 20 minutes or more. But instant, no-work short clips also conveylimited content. Instead of a whole holiday gathering, they tend to capture quick moments during a day, like a baby or pet doing something cute, friends acting goofy, or just a glimpse of a more meaningful event. They're like animated snapshots.

What if you could easily produce videos long enough to show viewers a decent chunk of a memorable occasion, yet short enough to avoid being boring and hard to share?

Well, there are services that let you simply gather relevant photos and video clips, and upload them for automated video editing. There, they get boiled down, enhanced with effects and turned into professional-looking videos typically lasting from one minute to a few minutes, accompanied by music, and easily shared. These programs let you choose styles, or visual themes, and videos are produced in accordance with the themes and the music.

This week, I tested two such services, Magisto and Animoto. Both work on iPhones and Android phones, but also via Web browsers on PCs and Macs. Both offer free versions, as well as paid versions with richer features.

I found both worked well, but Magisto was easier to use. It, however, offered fewer options and less control. It's focused on automated video editing based on algorithms it claims allow it to deduce the gist, or emotion, of the video, in accordance with the theme. Animoto offers more customization, with a greater variety of styles and more manual controls. It keys its production mainly from the music you choose.

Each has some drawbacks, but I generally preferred Magisto. It took less time and its free version offers longer videos. I'd use Animoto if I wanted greater control.

With each service, I was able to make short videos of family events like Thanksgiving dinner and a wedding, which took almost no effort and time. The videos looked professional and pleasing to people with whom I shared them.

Both services store your videos on their servers. Both allow you to share your videos by sending links to select groups of friends and family. They also allow you to share videos more widely on Facebook, Twitter and other social networks. But neither is a social network itself. Both offer either music they've licensed or allow you to upload your own.

Magisto, which launched in 2012, makes videos of up to one minute and 15 seconds long free of charge. A paid version costs $5 a month or $18 a year for videos of up to 21/2 minutes.

Animoto, which has been around since 2007 (it started out as a way to make slide shows from photos), gives you just 30-second videos free and charges $5 a month, or $30 a year, for videos of up to 10 minutes long, though the company says average projects are two to three minutes. Animoto also has costlier plans with longer durations for professionals like wedding photographers.

I used short video clips of events and tried each service in a Web browser and via iPhone apps. I emailed links to friends and family and did test posts to Facebook.

Magisto has a beautiful, clean interface, with clearly labeled steps and buttons that say 'Next,' and, when you're done, 'It's a Wrap!' and 'You're Done.' Like Animoto, the automated process takes a few minutes to produce the movie on its servers and notify you by email when your movie is ready.

My finished Magisto movies looked good and weren't cheesy. The service adds panning and zooming to photos, changes from color to monochrome, and creatively shows your video clips-for instance, quickly repeating key sections, or stopping the videos to make it look like a photo is being snapped, complete with a shutter sound. I especially liked one weddingproject I did accompanied by the song 'Chapel of Love.'

But Magisto's main drawback is that it only offers 11 themes and I found these either too specific or general to match my projects. The company says it's adding more themes. Also, the iPhone version is marred by a giant pop-up ad for a sponsorrunning a contest.

Animoto took longer to use, partly because I found its interface harder to decode, and partly because it let me choose which parts of my video clips it would use. Animoto only uses 10 seconds of each of your clips in its finished movie, interspersing these segments with photos and text you create. By default, it takes the first 10 seconds you create.

But Animoto doesn't work in a clear step-by-step fashion. In particular, when you're done, instead of saying the movie is completed and being processed on the server, it merely has a buttonsaying you can preview the video.

But Animoto has features Magisto lacks, like the ability to add text frames and 44 styles. These included many general ones, like 'Air' and 'Fire,' that would work with more projects.

I found my Animoto movies were pleasant, but a bit more basic than the Magisto examples. The same wedding looked less interesting and more like a slide show with some effects in Animoto.