asmodyne,
Do not you think it is time to dwell into the CHDK code deeply enough, as you said.
And then came back and be so kind to tell us what you did.
10x
I would have though the strength of a community's workforce is the eclecticism of its members area of knowledge (work compartmentalization, anyone ?).
I've seen enough references about selfish uses of CHDK-DE in this forum to know that me, diving into the trunk implementation, won't bring anything more to the CHDK circle.
Beside, I already obtained what it needed from the PTP interface two day ago: quick instant snapshots in an easy-to-read format, the whole thing using LibUsbDotNet and C#.
Since reyalp is working on the live view implementation and is willing as I am to have it working in the trunk, I don't see why I wouldn't offer some time to implement a managed API to access it.
I said I
would have made the scripts status report through the interrupt ep.
Would.
The CHDK ptp 2.0 is working fair enough as it is, so we move on. For now, I'm following reyalp's workline, and implement a managed library around what's already existing
and will appear as a generic feature on the trunk.
One last bit of information, since some lads enjoy poking my pride : I've already worked on ARM7 and ARM9 cores in asm and C.
ARM7 was for the time I developped GameBoy Advance game.

Now, I'm using a mini2440 (ARM920T) in os'less mode as a PLC, since its 1.3MP camera interface was what made me decide to buy it. But experimentations brough me to the conclusion that 1.3MP are too small a resolution, and those nasty pinhole lenses made me wonder for pictures a bit more...sharp and exposed

. Hence my interest in CHDK. See the path I took here ?
So please, do know I'm
sorry if I take your advice about "
dwelling into the CHDK code" as mere attempt to boast.

Shame is, I didn't had/take the time to dwell into the CHDK code deeply enough to do it myself
This limits your ability to meaningfully participate in the discussion.
I know. But having read the whole PIMA-15740 2000 and its USB implementation in the
pass past
2 weeks make me a bit dizzy for now.

I'll dive in, promise

(where should I start reading if I want to understand you live-view code btw ? The A540 sub in the repository link you gave earlier, is that it ?)
So, the endpoints MaxPacketSize(s) are platform-dependant ? Nothing the CHDK can fiddle with ?
Nothing that CHDK currently fiddles with. We use the cameras PTP stack, we don't talk to the low level USB stuff. It might be doable, but there's no obvious need... if your camera is USB 1.1, changing the packet size isn't going to help your transfer rate that much.
Eyup. The bottleneck would be the bitrate itself.
I see. So it solely relies on the mechanism mweerden describes: registering extraneous/extern handlers to ptp commands, right ?
Thus the immuable device's USB config. Makes sense.