Listen to Video audio while iPhone is locked

I figured this must be posible; I wanted to listen to the audio part of a video podcast (Wine Library TV) while my iPhone was locked in my pocket.

I came across this by accident; if you:

• Play the video
• Lock the iPhone (or iPod touch I’d imagine)
• Wake up the iPhone
• Double Press ‘Home’
• Use the controls to play the video

The video will play but because the device is locked, the video won’t display and the screen will turn off. Now you can listen to the audio part of a video podcast with the iPhone in your pocket and the video not playing.

Chris