Android's Headphone Jack is Versatile, Yet Underused

By Ryan Whitwam

Android support for line-in audio is a little lacking. But does video-out make up for it?

The Android ecosystem is made up of a widely diverged set of hardware specs. With that, you get huge choice in the type of phone you use, but you also have to look carefully to figure out what capabilities you're getting. The spec sheets rarely have room every little thing a phone can do, and some features are obscure enough that marketers don't feel the need to publicize them. Which brings us to the 3.5mm headphone jack. Really, the most information you're likely to see posted about that port is whether or not the phone has one. 

already discussed using an iPhone headphone jack as a line-in for audio recording, but what can Android do? 

A line-in, sometimes

Android does not, at this time, support the use of external mics when recording video. Believe us, we tried. This involved a series of tests with an external microphone, moving both it and the phone around to different positions whilst counting. We are willing to look like fools to test things for our readers. We found that we could not get the headphone jack to act as a line-in for the video. This is backed up by various postings online

Of course we know that audio is getting into the phone from the headphone jack, since we can use it to place calls. While you cannot record audio from this while shooting video, it does work for recording voice notes. For example, using the Evernote app you can record with the headset mic. You can also do voice searches from Android phones using an external mic.  

Will this ever be possible?

It is entirely possible that an Android phone will come along that does do this. The problem is all software, so a company could build this into their custom Android version. We are not currently aware of any versions of Android that can do this. But the ability to transmit audio into the phone and record it is there in the hardware. The best course of action would be for Google to make this possible in the Android trunk. We keep seeing all these 720p capable phones, but we'd really like to get audio of similarly high quality.

For the time being, though, you'll have to make due. We actually find the way the Nexus One handles the recording of audio rather good. The Nexus One has a dual mic system for noise cancellation. When you are recording video, it will use the secondary mic for the sound. This makes a great deal of sense because the secondary mic is on the back of the phone. This means it is usually pointing at the subject of the video. 

Video out from the 3.5mm jack

send video signals through the headphone jack. This is clearly not a standard piece of hardware, and is the sort of thing we would have never thought to look for. All you need to get the video out is a cable with AV ports on one side, and 3.5 mm jack on the other.  

Most phones that do video out use a miniHDMI port or sometimes a USB port, but this is a new one. The source demo video says it supports HD resolution, but we find that claim dubious. The produced looks acceptable and there is no appreciable lag. Phones like the Evo 4G can usually only play certain content over the HDMI, but the Galaxy S will output whatever is on the screen over the headphone jack. Even the home screen can be shown on a TV. As far as we're aware, this is entirely unique.  

We see in the demo that the racing game Asphalt 5 is played on a TV. An accelerometer based game is a perfect fit for this interface. You can have the video blown up in front of you and still use the phone's accelerometer controls to play the game. It's like having a portable game console ready to be hooked up to a TV. 

Most people will just use the headphone jack to listen to audio, but it's capable of much more. We would like to see Google build in support for external mics while recording video. But we'd also like to see the use of dual mic systems continue as well. We feel that in most situations, the audio from an internal mic that is at least pointed in the right direction can be fairly good.  

We cannot promise you that we'd ever use video out capability were it built into our 3.5mm jack, but it would be nice to have the option. The most intriguing thing is that it can be used to display the entire interface. We'll be sure to keep an eye on the American Galaxy S phones to see if they support this. In the meantime, is there anything you need your 3.5mm jack to do that is doesn't?     
Image credit: HD blog, Geardiary