Google has this positively obnoxious habit of making really cool features, but keeping them accessible only for developers and not easily discoverable for regular users. For example, it took Google about three years to make screenshots on Android not completely tedious. Now we're a similarly awkward stage with screen recording on Android 4.4. There are plenty of reasons you might want to create a video of what's happening on your phone's display (there's this nice little site called YouTube you may have heard of), but Google isn't making it particularly easy. At least you can do it now, right? Let's get you ready to record.
The official method
All phones and tablets on Android 4.4 have the ability to create and save screen recordings as .mp4 videos, but you first need to get going with the ADB developer tools. We've got a full guide on how to get ADB working, so I won't go into detail there. Just plug in your device with a USB cable and get your ADB console up. If you see the device appear when you enter adb devices in the command prompt (or terminal), you're ready to start recording.
The basic command for screen recording is: adb shell screenrecord. You'll add onto that a file path and name like /sdcard/movie.mp4. This begins screen recording immediately when you press enter. The limit for these videos is just 180 seconds (3 minutes), but you can stop the recording at any time by pressing ctrl+c in the ADB console. The video will be at the device's native resolution and 4Mbps. One major drawback: you don't get audio with the video.
These unmodified videos look okay, but you can do better with a few ADB command modifiers. Using --bit-rate lets you specify a higher or lower quality in kilobits, so entering adb shell screenrecord /sdcard/movie.mp4 --bit-rate 8000000 gets you a very crisp 8Mbps video. You can also use --size <width x height> to change the resolution of the video. You can probably see why this is a developer tool.
The root way
Paradoxically, if you've gone through the sometimes complicated process of rooting your device, taking a screen recording actually gets easier. There are a handful of apps that can trigger the native screen recording functionality without messing around in a command line. You get more control over settings, and the device doesn't have to be tethered to a computer.
Rec is one of the best root-required screen recorders because it has a slick, easy-to-use interface and it's very reliable. You can set the bitrate, stop recordings by shaking the device, and automatically toggle "Show touchpoints" for each video. This app can mix in audio captured from the microphone, but not internal audio.
A more advanced option, but one that tends to be a bit less user-friendly, is SCR. This app gives you control over bitrate, resolution, and all the other stuff, but it can also record the audio at the system level. Both SCR and Rec are far better than past root screen recorders because they are plugging into a native Android tool, even if they need root to make it happen.
Even if you don't have root, you can make great looking videos in a few minutes, once you get the kinks worked out.
Now, if only Google would make screen recording a simple user-accessible feature of the next Android release...