[DJI-log-discuss] Tiny 0x39 records with unknown contents

[Ross Finlayson]

> On Jan 19, 2021, at 8:16 PM, Dennis Derichs <harms.dennis at gmail.com> wrote:
> 
> Using my Mavic Air 2 and the DJI Fly app on Android (file version 12) I recently took a timelapse video. Parsing the logs, I noticed a myriad of type 0x39 records that did not contain JPG data.
[…]
> Your current code ignores the record length for type 0x39, skips the first two bytes of the payload and then checks for the SOI marker. If not found, it skips past the next 0xff. I propose a change to this code. If the payload begins with 00 00, an SOI marker and image data should be expected. Otherwise the record length should be observed and the payload unscrambled like that of any other record.

Dennis,

Thanks for the note.  Your suggestion sounds good.  However, could you please post an example of a “.txt” file that contains records like this, so I can use it to test the new code?  (If the file is large, then please upload it to a (publicly-accessible) web server, and send the URL instead.)


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/