Dejero Product Review
5th April 2011
By Andrew Mooney, Managing Director, Digistor
We had the team from Dejero Canada in the office for most of last week conducting client demonstrations and some internal training on the Dejero Live Platform. For those of you not aware of Dejero’s Live Platform, it’s a solution that allows you to broadcast live pictures from any location in the world that has mobile 3G/4G coverage. Let’s take a closer look…
The Technology
The transmitter is a relatively light weight device (about 10Kg without batteries) that’s built inside a rugged Pelican case. Various inputs are available including HD-SDI, HDMI, FW and composite. It’s multi format and will accept both HD and SD signals. For our testing and demonstrations we used the HD-SDI input and fed it directly from the output of a JVC Camera.
This is where it gets cool…inside the transmitter are 4 independent 3G modems and the required antennas, as well as all the intelligence for signal processing and compression. For our test we used two Telstra SIMM cards, one Vodafone and one ‘3’ SIMM card. Although you can use normal post paid data SIMMS, more reliable performance is achieved with dedicated M2M (Machine to Machine) SIMMS. Our two Telstra SIMMS were M2M and the other two were post paid.
The incoming Video signal (HD-SDI in our case) is dynamically compressed based on available 3G bandwidth (signal strength) and intelligently split between the 3G modems, based on their respective bandwidth and transmitted over the local 3G Networks back to the receiver.
There is a cloud based management GUI allowing you to ‘patch’ your allocated transmitters to your allocated receivers. You may, for example, have 10 transmitters and only 2 receivers and with a simple ‘virtual patch’ you can select which transmitter is directed to which receiver. It’s also a great feature if you hire an additional transmitter and need to receive the signal. The virtual patch is instant and is therefore ideal for live, time critical applications.
The Receiver is a 2RU server and it’s a dual channel device thereby allowing you to receive signals from two of the transmitters simultaneously. On the back you’ll find 2 x HD-SDI outputs and genlock connections. The Receiver receives the data packets from the assigned transmitters via the internet and reconstructs the transmitted image. The Receiver does not have a GUI and as long as it has an internet connection and an IP address that’s accessible to the outside world, it’s happy.
The Tests
Speed: First up we looked at time to air from a cold power on… From when we plugged the batteries into the Transmitter until we had a stable picture out of the receiver was around 1min 40sec. That’s very impressive and means that within 2min of arriving at a location you can have a live picture back at the control room.
Picture Quality: Next we looked at picture quality… We viewed the output of the Receiver on a broadcast quality JVC HD-SDI display. This was more of a subjective test as we did not have any other products or signals to compare.
There are a number of settings in the transmitter that are operator configurable and are relevant to quality. The main setting relates to a trade-off between picture quality and latency. The ‘normal’ setting gives a great quality picture with a 3sec latency and a data rate of approximately 2-3Mb/sec. Selecting the ‘low’ setting drops the latency to approx 1sec and the data rate correspondingly drops to about 700Mb/sec. Picture quality was noticeably worse on this setting and most clients remarked that it would be better to trade off a couple of extra seconds of latency, with the ‘normal’ setting, rather than sacrifice the picture quality. The other setting was ‘high’ and increased the latency and made a subjective increase in picture quality. This setting would be ideal if there was no two-way communication required.
One point worth making here is the higher latency effectively increases the buffering in the data transmission and hence allows for greater error correction, which could be useful if your signal strength is fluctuating.
Summary
Most clients went away very impressed with the Dejero Live Platform and I can certainly say I was too. The picture quality was very impressive and with the appropriate M2M SIMMS you can maintain good signal strength and keep your costs under control. Coming up at NAB this year (2011) Dejero are introducing a few new features including store and forward, file transfer, and customer cloud portal access; all heavily requested.
Watch the Demo Video