I've been following developments for multi-track-recordings for a while (as we need this all the time).
So far there are many unsatisfying options. I hope Blackmagic hears this and finally comes out with a multitrack recorder (Hyperdeck Quad anyone?)
This is what we have found so far:
Software: Several expensive options or hacky ones.
ScopeBox (Mac) being the budget friendly one. It works, we have used it with a BM Decklink Quad in a Thunderbolt enclosure with ok results.
Keep in mind that you need a really fast mac to record 4 streams. We have used a maxed out 2015 macbook pro (4x 2.8Ghz i7, 16gig RAM). We were able to record 4x 1080i50 in ProResLT. (ProRes422 or HQ resulted in occasional dropouts). Recording 4 streams in h.264 was definitely not an option.
Softron is about $1000 per stream. That'd be $4K for just the software (and you'd still need a beast of a PC/MAC and the capture card. Comes out north of $5K, even if you have the PC already - more expensive than hardware solutions. So that was a no go for us.
Hardware:
Convergent-Design Apollo: (We have one of those). Costs about $ 3k. Can record 4x3GSDI (or 2x4K) in all ProRes or DNXHD iterations.
Pros: Works nicely, had a few issues with sync at times, but nothing that could not be fixed in post). Allows use of cheap samsung EVO SSDs.
Cons: Needs own ingest tool to copy footage off the SSDs. Not a good rack-mountable/flightcase solution.
Aja Ki Pro Ultra Plus. Costs about $ 4K. Can record 4x3GSDI or 1x4K (considered it, but decided against it for SSD costs)
Pros: Great rack-mountable solution.
Cons: Only allows use of AJAs own SSDs (AJA PAKs), which are insanely expensive ($1500 for 1TB)
4x Blackmagic Hyperdeck Shuttle (about $1500) (we have two of those)
Pros: Cheapest hardware solution. Should be able to record Timecode RT188 but I would not know how to get the same timecode on 4 different camera signals (other than using the AUX outputs of the bigger ATEMS)
Cons: Can only record ProResHQ (large files). Can loop through, but needs BNC to microBNC adapters. No way I'd know of to trigger all of them simultaneously.
4x Hyperdeck Mini (total $ 2800) (we have one of those)
Pros: relatively budget friendly, rest see Hyperdeck Studio
Cons: only records on SD-cards
4x Hyperdeck Studio (total $ 4000) (we have two of those)
Pros: Would probably work best. Uses Cheap SSDs. No need for ingest, files can be used immediately. Timecode should be no problem. Could be triggered by a Skaarhoj device or a simple custom program using the SDK.
Cons: 4 of them make the system bulky and heavy (not really mobile-unit-friendly)
Our hacky solution we use as second backup sometimes:
Running 4 camera streams through a Blackmagic Multiview 4. Turn off all overlays and record the Multiview in 4K 25p in a Hyperdeck 12G (or a Videoassist 4K or any other 4K recorder if budget is really tight). Get's you a synced recording of 4 streams in a 2x2 matrix. In post, on a 1080 timeline, you can simply position the 4K recording according to the stream you need (works fine in FCPX, even as Multicam). Catch: Only 4K p25 possible (so you don't get 1080i50 streams, but 1080p25). Pros: Can loop through.
For the time being, our most used solution is the convergent design Apollo. It can't loop through, so you'd need a hub for that (or, if you use the TVS, with it's 4 HDMI inputs, you could use Micro SDI-HDMI converters, which can loop through the SDI signal).
Once again: BMD: I'm really hoping for Hyperdeck Quad. The 12G Hyperdeck obviously has more than enough processing power already to process the amount of data (4K in 50p = 8x1080 in 50i or 25p). All we need is 4 SDI inputs and the option to record it as 4x1080i50. How come Convergent Design can do this at a $3K price point and Blackmagic can't?
Cheers,
Daniel