Silverback: Usability testing for apes

Posted: 14 August 2008, 20:56

Like many in my field, I was intrigued by the nifty “Coming Soon” page for Silverback when word started pinging around the design-o-sphere. A page with a cool parallax effect (all the rage for a few months there), an illustration of a rather nerdy-looking gorilla (by the ever-talented Jon Hicks), and a notification sign up. No one really seemed to know what the hell this Silverback was, but the page was great and it was coming from Clearleft, so that was all many of us needed. Some surmised that the app was some sort of stats package, ala Mint, due to the graphs on the ape’s clipboard, and since these were, after all, web developers. No one even mentioned that is might be a desktop app.

Silverback App Illustration by Jon Hicks

Fast forward to about a month ago. Clearleft publicly released Silverback, their screen-recording, click tracking, iSight-capturing tool for “guerilla” user testing. My interest turned into desire—this was exactly what we needed at Trusera. We’d been finagling with makeshift setups for our usability sessions, including watching the screen in another room via an iChat screen share, and filming the subject with a camcorder. It seemed to work okay… so long as you were in the review room, watching each session live, for hours at a time. If not, we had a recording of the session via the handy-cam, but it lacked clarity in showing what the subject was looking at, and of course the recording didn’t even show what they were doing on the screen!

I downloaded the preview of the app immediately after I heard what it was, eager to at very least see if it ran at all. I was blown away. Not only was it “pretty” in a way one should expect from all good Mac apps, it made sense. And it worked… astonishingly well. When I started showing it to people at work, they seemed impressed, and most importantly, I never once had to explain how it worked. It was clearly the work of usability specialists and good UI designers (and of course, swell programmers, no doubt).

Yesterday, we gave our demo copy of Silverback a real crash course, using it in two 45-60 minute sessions. The process was seamless, and never once got in the way of the testing. In fact, perhaps the only stumbling block in the whole recording process was telling the app to stop recording (you can remember a tricky keyboard shortcut or click on the gorilla in your menubar, and choose stop from the drop-down menu). It seemed to be a trade off of staying out of the way versus being able to stop the session quickly.

The interface for storing the sessions is simple and easy to use, with areas for notes, a thumbnail of your recording and even a place for a picture of your subject (auto-filled from the iSight video feed, of course). The only part missing from organisational side of things is the ability to do a quick playback of the session from inside the app, without exporting the video.

Ah, export. One of the biggest stumbling blocks in this initial release. To watch the sessions, you need to export them to standalone MOV files. During the export, the user’s recorded clicks are merged with the screen capture video file, the iSight capture video, and the audio track. During the export process came the biggest headaches. Video processing takes a while on most any computer, and had that been the source of my frustration, I wouldn’t have lost sleep over it. However, one of our session exports continually caused app crashes, and several times it was a fairly far into the export.

Of course, that’s a bug and is to be expected in a brand new app. A related annoyance (this one being feature-ask, rather than a bug) is the relative lack of control over the video export. When you click the export button on a session, you are given the options of Quality (Best, High, Medium and Low) and Size (unfortunately in percentage of original resolution: 100%, 75%, 50% and 25%). My natural instinct was to go for Best at 100%, because I hate losing detail. However, exporting an hour at 1280×800 resolution resulted in a file weighing in at nearly 4GB! Obviously high resolution video at long lengths yields large file sizes, but given some compression codec options (h.264, or any other codecs installed on the system), the required exports could take up far less space without losing quality. I ended up exporting at Best with 50% resolution, which shrunk the file to about 1.2GB, at which point I fired up ffmpegx and got the file size down to 193MB without noticeable quality loss. Control over export codecs and audio quality would be a very welcome addition to the app.

I have a few other pie-in-the-sky suggestions, though they’d probably be for versions 2+ of the application. I would love the ability to do some trimming of dead video space in the sessions before I export (ala EyeTV’s feature to clip out commercials in recordings, and Screenflow’s video editing abilities). That is, of course, easier said than done.

Also handy would be the ability to constrain the area that is recorded, following the mouse if taken outside the box, ala SnapzProX’s video recording feature. Perhaps a little more control over the overlaid iSight video capture might be nice (opacity control with more control than on, off and semi-transparent), with a way to export the screen and iSight video side by side (though that may get messy).

But at the end of the day, Silverback has given our user testing sessions amazing portability, ease of capture, and great results. Will we be buying it at the end of our 30 day trial? Well, you’ll have to ask Jude (my boss), but I’d say there’s great potential for that. And really, I’m just looking forward to saving the gorillas.