Unfortunately reaching 480 Mbps on USB2 is never possible, because everything relies on a multiple bottlenecks of the standard, like half duplex, wasted space due to a need to fill up packets with stuffing bits, overheads of protocol and payload sizes.
At the end of the day realistic seems to be 280 Mbps of netto transfer (real data without protocol overheads), but... when dealing with Transport Streams another bottleneck comes out - TS packet size is fixed to 188 bytes. So additional overhead comes out from a need of splicing them and keep in sync. I wouldn't be surprised if that ~120 Mbps limit is not anything related to a faulty implementation, but a result of unavoidable tradeoffs when processing this kind of data... Although I would be happy to hear some specialist comment on this field
Transfer limitation can be seen e.g. on USB3 SSD disks - connecting it to USB2 only controller also won't give 480 Mbps, despite that on USB3 the same device easily exceeds that transfer speed.
Anyhow I also recall discussion (I think) with steven, who pointed out that there's no ready USB3 bridge solution for DVB TS processing (no USB3 DVB card exists, even Dektec having USB3 device is not pushing DVB-TS through it, it's a SDR device type), so this would bring a lot of work to prepare a device basically from the scratch (and later need to probably fix some issues that will originate only from the fact that this would be a completely new implementation, e.g. surely we would like to have i2c access like today to run blindscan etc.). Usage of Cypress EZ-USB FX2 guarantees good TTM.
But I do believe that sooner or later migration to some new USB3 controller will be needed.
E.g. DVB-S2X/64APSK with SR 107140 (like SR used on 15°W) would kill even 480 Mbps
So we had:
TBS5925 - profi
TBS5927 - profi
It's about a time for TBS5929!
(with USB3, DVB-S2X up to 256APSK, short frames support, blindscan etc.)
I'm buying first one made
