The point of using byte array packets

Neoflash · Dec 30, 2018

I noticed that some of the unofficial APIs listed in the wiki are sending byte arrays instead of the command strIngs described in the official SDK docs. Is it worth the added complexity. What are the advantages to doing that?

briest · Dec 31, 2018

Initial SDK was much more limited than current (see SDK 1.0); but even today there are more known unofficial commands than the SDK offers (wifi configuration, video stream parameters, photo, ...). Just compare.

Neoflash · Dec 31, 2018

briest said:
Initial SDK was much more limited than current (see SDK 1.0); but even today there are more known unofficial commands than the SDK offers (wifi configuration, video stream parameters, photo, ...). Just compare.

Thanks. As far as I can see, in terms of controlling the drone's movements, the current SDK seems to have everything I need. If all I'm trying to do is write a simple SDK wrapper to be able to fly the drone with a controller from my PC, am I correct in my understanding that it can be achieved with the SDK, usinge the "rc a b c d" set command?

Thanks again.

hellowill89 · Dec 31, 2018

Hi @briest , where can I find information about the unofficial commands such as video stream parameters? I'm having a hard time determining the sps and pps for the video stream.

briest · Jan 1, 2019

I'm afraid I won't be of much help: the sources I know about (and you surely know them too) are forum's wiki and usage examples in available code (TelloLib, pytello, TelloPy).

I have not analyzed video stream from Tello (I'm by no means a programmer); for what I understand about h.264 stream is that PPS and SPS formats are quite well defined, but their presence in stream is optional; they can be provided out of band or even be left out completely, when sender and receiver have some pre-agreement about parameters used.

For what I read in pytello and TelloPy, SPS/PPS are sent in reply to command 0x0025 (wiki lists it as "start video", but apparently there is no problem in sending it repeatedly), so maybe they're sent on demand only and absent otherwise? But this is only my speculation -- you have at least three developers here that have managed to receive and decode video, so better ask them

aTello app is even opensource, but unfortunately it has some glitches in video decoding; author of TelloFPV claims best video results (and these claims are not unfounded, video is really smooth), but no sources to read I know of.