The Future Software Blog
Programming Department: Sychronisation - 09 November '09
We were asked recently how easy it would be to synchronise a couple of videos so that they started at the same time.
Our immediate response was no problem, after all you can start multiple copies of the DigiSHOW player within a second,
but then you start to ask a few questions and suddenly it's not quite so simple. How synchronised is synchronised?
What is acceptable for the required application? Do we need to synchronise audio or just video? These are just a few of
the questions that need to be addressed.
As many of our clients do not use or require the audio facilities built into DigiSHOW I will at a stroke save you a
little time reading this, by completely ignoring audio synchronisation. We can save that for another article.
If it had been just one video that the client wanted to show on multiple screens then we could have used one player
and several distribution amplifiers but the client did ask for a couple of videos.
We could have used two DigiSHOW ActiveSigns, one for each video, with them networked together. This would certainly
have allowed us to start the videos at the same time (at least to an observer) and additionally it would have allowed us
to mix in other forms of content such as still images, live web pages, flash and so forth.
However following those all important discussions with the client it transpired that they wanted not only field
accurate starting of the videos but they also required them to be synchronised to an external synchronising signal
(genlock)and play seamlessly back to back. This seemed like a job for the DigiSHOW SDIX. This would allow them to
synchronise up to five mpeg2 video files with an external genlock signal and enable them to leave the equipment running
24/7. At the time our own in-house system had been running unattended continuously for over three months.
They liked the system so much they bought two. Whilst this is not what many people may consider as strictly digital
signage, because of our roots and experience in the broadcast market we were able to deliver the right solution for the client.