Using an iPad as a second PC monitor for subjective tests involving video


After scouring the internet for a way of turning my iPad into a second screen for my laptop I came across two applications which seemed like they could provide exactly what I needed:

  1. Air Display

  2. Twomon USB 

In order to make a choice between the two it was necessary to try them out.

1. Air Display


This app allows one to connect a computer wirelessly to an iPad/Android device. I found it very easy to use, once installing the app on the iPad and downloading the “Display Host” onto the laptop. This initial promise however was thwarted once I had the Pro Tools session up and running and had dragged the video window onto the iPad screen.

Unfortunately the wireless connection did not allow quick enough/large enough data transfer to allow for seamless video playback. The ‘lagginess’ experienced was enough to force me to decide against using Air Display for the subjective tests. Too many times the video would flit from being in and out of sync with the audio, completely ruining the effects I had painstakingly created.

2. TwomonUSB


As the name suggests, TwomonUSB works through connecting your mobile device to your computer via a trusty old USB cable. Like Air Display, in order to work, TwomonUSB requires you to download an iOS app as well as software to turn your computer into a server.

In comparison to Air Display, video playback on the iPad was smoother however it was not close enough to the HD playback achieved on the laptop. At times I also felt there was a slight lag also.

In conclusion both apps work well in converting your iPad into a secondary computer monitor, with TwomonUSB having the edge in terms of stability and data transfer speed. For video playback however Air Display is not really a viable option, whereas TwomonUSB provided an adequate performance to be able to enjoy a film, just about.  Neither provide smooth and reliable enough playback to be used for subjective testing as they both demonstrate instances where the video lags behind the audio, causing synchronisation problems.

In the next post I will outline the alternative method I have devised…

This entry was posted in Apps, MSc Audio Production, Review, Subjective testing, University of Salford and tagged , , , , , , . Bookmark the permalink.

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