The inner workings of Koherence, LLC
MOUNTAIN VIEW, California (AB) Koherence Labs, the R&D arm of consumer electronics consulting firm Koherence, LLC, is rumored to have made a breakthrough in content recording. Dubbed “InfiniDVR,” the new technology allows an effectively unlimited recording capacity and permits viewing of all shows that have ever been or will be broadcast.
Continue reading “Breakthrough in DVR Storage and Time Shifting Rumored”
A bit more than a year ago I headed over to a former client’s headquarters to discuss a potential ATSC 3.0 project. The moment I stepped into the office I was swarmed by a group of engineers and managers with one primary question : are 3.0 broadcasts really going to be encrypted, and if so what DRM is going to be employed?
There’s been a lot of chatter about encryption of ATSC 3.0 broadcasts and what it means for free over-the-air TV. A lot of that discussion conflates encryption, content protection, and content rights management. This post will hopefully help in untangling things a bit while providing some context, and also some discussion around the unintended consequences that encryption may have on innovation in the consumer electronics space. Continue reading “ATSC 3.0: DRM and Encryption”
Previous posts at in-koherence have been rather skeptical of using SSDs as recording storage in DVRs. SSDs have a lifespan that is largely dictated by the amount of data written to them. This may not be much of a problem if you record one or two shows a day. However many users set up recordings for series which they might watch (but for some reason never find the time to…or maybe they decided it wasn’t such a great series after all, but who has time to cancel the subscription to the series?) This is amplified if multiple members of the household set up recordings on the DVR. The next thing you know it your four-tuner DVR is recording 20 hours of shows a day. For all its faults, the good old mechanical hard drive is superior in having a write limit that’s so high that it’s generally not considered.
But with rapidly falling prices, larger capacities (with correspondingly higher endurance ratings), and the increasing difficulty of finding non-SMR 2.5″ hard drives, the time has come to give SSDs a harder look. So we took a mid-grade SSD and ran the first SSD-based Project Entangle through its paces.
I was recently reminded that summer’s come and gone with nary a peep out of in-koherence. So just what’s been going on? Well in addition to various feature enhancements to Project Entangle, the in-koherent project SFBayATSC was rolled out in May.
SFBayATSC is actually a follow-on to a similar OTA ATSC monitoring site which was run by AVSForum member toast0. Earlier in the year toast0 gave notice that he’d be moving and that his monitoring system would be shutting down in May. The signal reception data he collected was quite useful to both viewers and broadcasters in the Bay Area, so that got us thinking…just maybe Project Entangle could fill the gap. So the signal analysis, already a part of Entangle, was beefed up, a cloud infrastructure was built, and SFBayATSC was born.
One of the goals of Project Entangle is to receive The Perfect Broadcast – a transport stream with no bits missing or in error. As anyone using OTA ATSC (and since you’re reading this you’re probably one of them) knows, this can be a challenging endeavor. Signals can be too weak, and ironically too strong. Multipath can turn an otherwise strong signal error-prone. Dynamic multipath is even harder to deal with as the demodulator needs to adapt to the changing properties of the signal.
But hard doesn’t mean impossible. One of the methods for obtaining The Perfect Broadcast that Project Entangle has been investigating is diversity. Essentially, diversity involves receiving two or more versions of a broadcast in different ways. The various versions are then combined to yield a signal that’s better than any of the individually received ones.
Continue reading “Enhancing OTA ATSC Reception Through Diversity”