Regarding Pioneer 520 and 560 usb ports and offloading

[jwillis84]

kodec, the DVR-555 units were not sold in North America so I've never used one. They were limited distribution "Multi System" aka "Middle Eastern Businessman" variants of the DVR-550: looking at my service manuals, it appears the primary difference was the 555 incorporated all three analog tuner bands (NTSC, PAL, SECAM) while the much more common 550 was sold to specific markets with just the one tuner required for that market (i.e. a DVR-550 sold in UK would have only a PAL tuner and the USA/Canada DVR-550 would have NTSC only).

One vague footnote in the service manuals indicates despite having HDMI output, the 555 apparently used the video encoding circuits from the earlier 540 chassis (10-bit vs the 12-bit 550/560 encoder). This is not entirely unusual: the Sony RDR-HX780 clone of the 550 also used the older 10-bit encoder. Presumably all of these models would have roughly the same performance as pass-thru signal conditioners, per my previous answer re the 540 vs 550.

An interesting topic

I just checked the manual for a DVR-530, the first to get USB type A and USB type B ports in the US and Canada.

It states the USB type 'A' is for keyboards, cameras and flash drives and is located on the front next to the firewire port.

It states the USB type 'B' is for pictbridge compatible printers and is located on the rear next to the fan.

Pictbridge as I recall was a printer that could 'browse' and select JPG or other pictures on a camera or other USB device in order to "print" them.

This makes sense in the way that USB type 'A' is used when 'hosting' or 'using' a device and USB type 'B' is used when 'servicing' or being 'used' by a device.

It doesn't rule out being used as an 'Editing' port.. but its a simpler explanation for the same effect as far as what they were used for and why they exist.