Record tablet's screen AND audio

I've been wondering, after trying this command on my Nexus 7:

adb shell screenrecord /sdcard/demo.mp4

Is there a way to record the screen AND audio of the tablet using the factory screenrecord command? Checking the Android documentation, it says nothing about recording the audio too, but we all know the Android documentation is not that complete

I could do it this way :

• connect the Android device to computer with a jack cable (headphone output to microphone input);
• record video with adb shell;
• record audio with Audacity (or anything else)
• then merge video and audio with a video editor (pitivi, openshot, avconv...)